Interview with a Social Insect Scientist: Marina Choppin

Marina’s article (together with Lori Lach), where they explored that the novel host to Nosema ceranae, Apis mellifera is less likely to detect the parasite than its original host, the asian honeybee A. cerana, can be found here.

IS: Who are you, and what do you do?

MC: My name is Marina Choppin, I am 26 years old and was born in France. I did my bachelor’s degree in biology in Bordeaux and my master’s degree both in Tours and Cairns in Australia. I am currently based in Mainz and have just defende my PhD in May! During my PhD I investigated the mechanisms that underlie longevity and fecundity in ants and I have worked with bees and termites before. So my focus is on social insects and I am interested in questions related to evolution, using tools like behavioral observations, experimental manipulations, and bioinformatics.

IS: How did you develop an interest in your research?

MC: I grew up close to nature in Corsica where the biodiversity is mind-blowing and I always had a particular interest in insects. They are everywhere and paying attention to them is like diving into a whole new world! Later on, I started my master’s degree in Tours which had a strong focus on insect biology and I got to learn about social insects, which were so intriguing to me. So I studied termites at the IRBI (Research Institute for the Biology of Insect) in Tours with Dr. Christophe Lucas during a 2-month project and got hooked!

Collecting Apis mellifera honey bees for the experiment described in Chopin and Lach, Insectes Sociaux 2022. Wearing a bee suit in a tropical climate was not always fun…

IS: What is your favorite social insect, and why?

MC: I would say the soldier caste of turtle ants because they represent evolution at its finest. Their head is shaped in a way that allows them to block the entrance of their nest, which is amazing. And they are cute too!

IS: What is the best moment/discovery in your research so far? What made it so memorable?

MC: Probably the first time I published as a first author because this manuscript was not necessarily planned as a part of my PhD project. We collected the ants for my PhD in the US in Arizona and when we got back to the lab I measured all the queens from all the nests, over 2000 individuals, because the ant species I studied has two queen morphs that differ in size so I needed to assign my queens to one or the other morph. But after analyzing the data set out of curiosity, we found an interesting pattern: an influence of colony composition on queen body size depending on their morph. So we also measured workers, did behavioral experiments, chemical assays, and demographic analyses to further investigate the relationships between queen and worker traits, colony composition, and environment and we ended up writing a nice story that we published in Myrmecological News. It was great to build on an unexpected finding because it was different from the usual experiment planning which is way more thought-through of course.

IS: Do you teach or do outreach/science communication? How do you incorporate your research into these areas?

MC: Not actively, no. I have helped with practical courses during my PhD which was nice because I love statistics and I tried to make it more enjoyable for students as well. And I recently created a Twitter account to share my research but it isn’t very intuitive for me for some reason. But I do love talking about my research with friends or people I meet during my travels because they are always super intrigued and come up with non-expert questions that can catch you off guard and make you think deeper about your work!  

Apis mellifera honey bees at the entrance of their hive on the campus of James Cook University (JCU) in Cairns (Australia) where I conducted my master thesis under the supervision of Dr. Lori Lach.

IS: What do you think are some of the important current questions in social insect research, and what’s essential for future research?

MC: I am a bit biased of course but there are still many interesting questions to investigate when it comes to social insect aging. Trying to understand how social insect queens can achieve extraordinarily long lifespans while remaining highly fecund is still a mystery, although more and more studies add to our knowledge on the topic! I also think that with the cutting-edge molecular protocols and associated bioinformatic tools that are currently being developed and applied to social insect research we will be able to get deeper insights into this mystery in the coming years. The field of epigenetics is also essential to navigate and promising because phenotypic plasticity is a pillar of social insect societies.

IS: What research questions generate the biggest debate in social insect research at the moment?

MC: I feel like in general different scientists have different opinions on the same topics, regardless of what the topic is. Which makes science interesting and stimulating. But I know for example that the functional relevance of DNA methylation in social insect genome is still actively debated! And once again the newest chromatin profiling techniques might provide answers to this question.

Feeding my experimental ant colonies in one of the climate chambers in the laboratory in Mainz where I did my PhD. I actually took this picture for my family, to show them my working environment, hence the heart shape with my hands!

IS: What is the last book you read? Would you recommend it? Why or why not?

MC: I recently read “The Power of Now” by Eckhart Tolle. We know that living in the present is important but it is so difficult to do. Humans, and me the first, tend to seek reassurance in the past through memories that give us a sense of identity or to anticipate and overthink the future because it is a source of uncertainties. I would recommend this book to people that are interested in trying to make their human experience more enjoyable and less worrisome. Although the author sometimes places himself in a “know-it-all” position that I find annoying and unnecessary. We are all here to learn after all.

IS: Outside of science, what are your favorite activities, hobbies, or sports?

MC: Talking about books, I do like to read and I listen to podcasts pretty much on a daily basis. I like to learn about different topics outside of biology like health, nutrition or psychology. I also like to write and I have been doing it since I was a kid, I started writing a book that I put aside when writing my PhD thesis and I’m looking forward to getting back to it! I also travel as much as possible, by myself as well because it makes it a completely different experience. I also enjoy working out, doing yoga, and meditating. I love the outdoors and find nature very therapeutic so I try to walk around and hike in my free time and do horseback riding when I get the chance. And because life is all about balance, I also enjoy going out for drinks with my friends!

Setup of the Proboscis Extension Response (PER) assay that I used for the experiment described in Choppin and Lach, Insectes Sociaux 2022. Bees were placed in Eppendorf tubes so that they cannot move, while we can touch their antennae with a filter paper soaked in the desired solution and see whether they extend their proboscis as a sign of interest to consume the solution.

IS: How do you keep going when things get tough?

MC: I appreciate this question because mental health is such an important topic that is sometimes overlooked in academia. When things get tough I try to do extra self-care, be less strict with myself in terms of productivity and routine, and most importantly I try to remind myself that this is temporary. Nothing lasts forever, bad times included! 

IS: If you were to go live on an uninhabited island and could only bring three things, what would you bring? Why?

MC: I think answering this question requires thinking about two things: the survival aspect and the psychological aspect, in terms of loneliness. For my survival, very cliché answer but I would bring a knife. For my mental health, I would bring a notebook and a pen (hopefully it counts as one item, otherwise I would only take the pen!) and finally, I would bring this big scarf I have which I brought on all my travels, camping trips, and festival. I would use it as a blanket at night and to protect my head from the sun during the day!

Horseback riding on the island of Holbox in Mexico. I traveled there by myself in 2021 for a couple of days, to escape winter (and the pandemic admittedly). The biodiversity on the island was amazing.

IS: Who do you think has had the most considerable influence on your science career?

MC: Dr. Romain Libbrecht for sure. He is one of the group leaders in Mainz and he was my PhD mentor. I find him brilliant as a scientist and amazing as a human. He is particularly skilled when it comes to statistics and it was always extremely rewarding and enjoyable to brainstorm with him on the best way to analyze challenging data sets. I learned a lot from him and I am really grateful for his help. He also made me feel more confident in my vision of science, which is all about rigor, quality, and critical thinking, because I believe that we share these values.

IS: What advice would you give to someone hoping to be a social insect researcher in the future?

MC: Maybe to keep an open mind because these little creatures do not operate like most living organisms! And to avoid anthropomorphism. It is too easy to draw parallels between ant and human societies for example, but it won’t necessarily benefit your research. At least in my opinion!

Members of the SoLong Research Unit that I integrated when I started my PhD. In this research unit, researchers from different universities, mostly based in Germany, are investigating aging in ants, bees, termites, and Drosophila. Here we were attending the ESEB in Turku (Finland) in 2019. 

IS: What is your favorite place science has taken you?

MC: The Chiricahua mountains in Arizona where we collected the ants for my project. We stayed at the SWRS (South Western Research Station) and this was one of the most amazing places I have experienced. We ran into amazing wildlife all the time, like hummingbirds, bobcats, rattlesnakes, tarantulas, or coatis. The landscapes were stunning and it was simply amazing to share a beer in the evening, under the stars, with other students and researchers from all over the world that gathered in this remote area because of their common interest in nature basically.

Interview with Social Insect Scientists: The head team of ‘Ants of Brazil’: Fernando Schmidt, Carla Ribas and Rodrigo Feitosa

The first scientific work coming out from the ‘Ants of Brazil’ initiative was recently published in Insectes Sociaux (‘Ant diversity studies in Brazil: an overview of the myrmecological research in a megadiverse country’) here.

IS: Who are you, and what do you do?

Ants of Brazil – AB: We are a workgroup of 38 Brazilian ant researchers that aim to provide a base line for the improvement of Brazilian myrmecological studies for the international scientific community. The head team is made up by Fernando Schmidt, Carla Ribas and Rodrigo Feitosa, who have been good friends since 2005 and currently have professorship positions at Federal University of Acre (in Northern Brazil), Federal University of Lavras (in South-eastern Brazil) and Federal University of Paraná (in Southern Brazil), respectively. In 2012, inspired by several international initiatives in Myrmecology, we created the Ant of Brazil workgroup that has three basic action lines:  teaching, research, and science communication, by disseminating knowledge on ant diversity and related studies.

Regarding the teaching line, we have offered 8 day-courses every two years on ant systematics, taxonomy and ecology which always take place in one of the six Brazilian official biomes (Amazon Forest, Atlantic Forest, Caatinga, Cerrado, Pampa, and Pantanal). In the research line, we have a big data base on published ant diversity papers with the aim to provide scientometric and conceptual synthesis and meta-analyses on diversity patterns of ants in the Brazilian territory, of which our paper Schmidt et al. (2022) in Insectes Sociaux is the first one published. Finally, as an initiative in science communication, we support a group in Facebook (Formigas do Brasil) where ant people can disseminate their projects and papers, ask help for ant identification and material processing. Currently, the group has more than 1,500 members.

Part of the ant researchers that make up the Ants of Brazil workgroup at Simpósio de Mirmecologia: An international ant meeting in 2013 in Fortaleza, Northeastern Brazil.

IS: How did you develop an interest in your research?

AB: We have worked in  several comprehensive papers on Brazilian ants by a scientometric approach, such as the profile of ant diversity studies developed in Brazil (Schmidt et al. 2022), the diversity and occurrence of ant taxa in the Brazilian biomes (Feitosa et al. under revision), the use of taxonomic tools to validate ant identification in Brazil (Feitosa et al. under revision) and conceptual synthesis and meta-analyses on diversity patterns of ants in the Brazilian territory, testing the effect of seasonality (Queiroz et al. under revision), soil use, resource and conditions and interactions (manuscripts in preparation).  

IS: What is your favorite social insect, and why?

Fernando: My primary interest in ants is their use as a model in diversity patterns and bioindication research. However, my favourite genus is Odontomachus.

Carla: Oh! In the beginning I just used ants as a model to do ecology research, but since I discovered more and more about ants, I really love these amazing insects! Now I like them so much, that I marked them on my body for life! I have a tattoo (actually of seven ants!) on my right arm, it is my favourite genus, Cephalotes.

Rodrigo: Ants, of course! No social insect group exhibit such a diversity of ecological and behavioral strategies. Not to mention the fantastic morphological diversity. Among ants, my favorite is certainly the genus Daceton from the Amazonian lowlands of South America. Wonderful spiny, arboreal, trap-jaw ants.

IS: What is the best moment/discovery in your research so far? What made it so memorable?

Fernando: It was the publication of the main manuscript of my Doctorate project, which is about ant diversity patterns in tropical rainforest and savannas in Brazil and Indonesia, which besides the nice paper (Schmidt et al. 2017) also allowed me to travel to wonderful tropical places. Additionally, the first paper from our data base published in Insectes Sociaux is also a remarkable match in my career.

Carla: This is a difficult question because I really love my research with ants. Specifically, I like the field samplings a lot, when I can see ants working and it allows me to discover wonderful places in Brazil. During my doctorate I studied the latitudinal gradient of ants, travelling from the North to the South of Brazil. This is really great, to see the ants in all their biomes! I also think that it is amazing to listen to people talking about their popular knowledge about ants. This is, for now, one of the best moments in my career, when I started to exchange knowledge about ants with non-academic people!

Rodrigo: Probably the first record of worker transportation performed by queens in the little fire ant Wasmannia auropunctata. Fantastic behavior that I observed in the semidecidual forests of central Brazil, published in 2007 in Insectes Sociaux. I also love each record of rarely collected ants during my field trips in the Brazilian forests.

The head team of Ants of Brazil in a lovely scene: Carla Ribas, Fernando Schmidt and Rodrigo Feitosa.

IS: Do you teach or do outreach/science communication? How do you incorporate your research into these areas?

Fernando: I teach and have incorporated the results of my research and ant colleagues in my teaching class. (IS: also, check out Fernando’s instagram: @ecoformiga)

Carla: Yes! I do both! I disseminate my research about ants in the different subjects that I teach, as well as by social media of my lab (instagram: @lef_ufla) and in interviews about the articles, such as this for the Insectes Sociaux blog. More recently, as I already mentioned, I love to exchange knowledge about ants in ethnomyrmecology research and in schools in Lavras.

Rodrigo: We do science communication by the social media channel of my lab (instagram: @Feitosalab), where we share the results of our projects and publications in a non-academic language to reach people from all the social classes and backgrounds. We also promote activities involving primary schools in our town, Curitiba.

IS: What do you think are some of the important current questions in social insect research, and what’s essential for future research?

AB: We would like to encourage colleagues to collaborate and form workgroups such as Ants of Brazil in their countries or regions, which can allow a comprehensive view of studies on ant diversity at a global scale. Moreover, in at least one of our papers we also provide examples of inter-institutional workgroups and highlight their importance to improve the sampling cover and knowledge on ant diversity in tropical regions like Brazil. We also should invest additional effort in studies about ant natural history, as this area is the very basis of almost everything we do in myrmecology. Additionally, a rich field of research is ant socio-biodiversity, where we can share knowledge with non-academic partners, learning from them about ants and disseminating our research and knowledge of ants in general.

Last edition (2018) of the Ants of Brazil course in the Atlantic forest of Santa Tereza, Southeastern Brazil.

IS: What research questions generate the biggest debate in social insect research at the moment?

AB: Probably the different and sometimes divergent methods to infer evolutionary relationships and diversification rates in most groups of social insects, ants included. In ecology, we think that discovering ecosystem functions that ants perform, functional diversity patterns and how we affect it, becomes a central issue.

IS: What is the last book you read? Would you recommend it? Why or why not?

Fernando: ‘Letters to a young scientist’ by Edward O. Wilson. Wilson offers nice advice to not only young scientists, but for scientists of all ages.  Wilson brilliantly approaches several stages of the scientific method and scientific life using inspired personal examples. I super recommend this book to everyone who wishes to become a scientist or already is one. Books from Wilson do not need justification, just read them!

Carla: Sapiens – Uma Breve História da Humanidade by Yuval Harari. Besides telling the biological story of Homo sapiens, it also links it to the history of the world. It is fantastic!

Rodrigo: O Sábio e a Floresta by Moacir Werneck De Castro. A biography of the German naturalist Fritz Müller (1821-1897) who emigrated to southern Brazil and helped to promote Darwinism based on his observations on the natural history of the organisms that inhabited the Brazilian Atlantic Forest. A must read for every nature lover, biologist or not.

IS: Outside of science, what are your favorite activities, hobbies, or sports?

Fernando: I like to play with my children and to work in the garden.

Carla: Meeting with friends for a nice talk and drink beer is very good to free the mind from routine and also helps to have new ideas about ants, when your friends are also ant researchers, like Fernando and Rodrigo! In these (hopefully past) pandemic times, I watched movies and played with my child, besides staying in contact with nature and going on walks, since I used to live in a rural area.

Rodrigo: I’m a beer enthusiast! I enjoy both drinking and studying the history of beer and its different styles. I like to fish too!

Students of our course sampling litter ants with a Winkler shifter in 2016 in Rio Branco, Amazon forest, Northern Brazil.

IS: How do you keep going when things get tough?

AB: Our last paper published in Insectes Sociux is good example of dedication, persistence and a lot of patience to overcome the direct and indirect drawbacks related to a paper publication such as planning the study aims, sampling/carrying out experiments, data analyses and writing. Besides the difficulties in these common steps of a scientific paper, in our study we also had to deal with the coordination of a big group of people with different expectations and points of view. However, the Brazilian myrmecological community is very friendly and collaborative which was essential to carrying out the work smoothly and patiently along the 10 years spent on the study. Specifically, for us in the head team, parallel to the big job that this paper requested, we also experienced along these 10 years notable marks in our professional and personal lives such as professorship positions, the first student project to supervise, child births, administrative positions, and everything else that takes our time to work on the paper. Thus, besides huge dedication, high levels of persistence and patience were necessary to achieve the final results, which we wish to celebrate in an appropriated way when we meet again.

IS: If you were to go live on an uninhabited island and could only bring three things, what would you bring? Why?

Fernando: Essential things to survive: entomological stuff to sample ants, a computer for paper writing and data analyses, food and beer to have meals and fun.

Carla: Beer (relax and fun), books (knowledge and fun) and paper to write down new ideas.

Rodrigo: Beer, a fishing rod, and a good book collection.

IS: Who do you think has had the most considerable influence on your science career?

Fernando: My advisors and professors and for the papers, mainly the review ones from Alan Andersen, and the seminal paper of Andrés Baselga on beta diversity partitioning, which I have worked on since my doctorate.

Carla: My advisor, José H. Schoereder, who studies ant ecology and gave me inspiration not just as an excellent researcher, but as an incredible human being. My graduate friends for life that also studied ant ecology – Renata Campos and Tathiana Sobrinho, and these two lovely friends that have been sharing amazing experiences and life time with me – Fernando and Rodrigo. But I really think that the influence in my career comes from every partner that I shared knowledge about ants with, from these cited above, my advised students, and non-academic people. All these people together are my influence!

Rodrigo: My advisor, Beto Brandão, the incredible ant taxonomist Barry Bolton and, for sure, Edward O. Wilson.

Students working on ant sorting, mounting and identification in the laboratory of our course in 2018 in the Atlantic forest of Santa Tereza, Southeastern Brazil.

IS: What advice would you give to someone hoping to be a social insect researcher in the future?

AB: Regarding ant diversity and ecology, many patterns have been described and the responses of ant communities to natural or human-induced disturbances are becoming more predictable; however, the mechanisms behind these patterns are still very little investigated. To explore the drivers and processes related to ant assemblage structure, big data bases, such as the one provided by ‘Ants of Brazil‘ and several others, would be essential, with which a lot of elegant studies on the mechanisms behind ant diversity patterns could be done even without additional ant sampling. And do not forget that people are as important as ants in our research! Exchange knowledge with them!

IS: What is your favorite place science has taken you?

Fernando: During my doctorate, I had the opportunity to do an internship for one year in Germany in the Agroecology group of Prof. Teja Tscharntke – University of Göttingen. Beside the fruitful scientific time, my wife (who is a scientist too) and I had the opportunity to travel to several countries around the world.

Carla: During my doctorate I travelled from the South to the North of Brazil to sample ants. This was fantastic!

Rodrigo: The Brazilian savanna (Cerrado). What a magic ecosystem!

Vegans vs. omnivores: differences in foraging tool use in ants with different diet

By Gábor Lőrinczi

Based on the research article “Comparison of foraging tool use in two species of myrmicine ants (Hymenoptera: Formicidae)” by Gábor Módra, István Maák, Ádám Lőrincz and Gábor Lőrinczi in Insectes Sociaux, 69, pages 5–12 (2022).

Some ants are real tool users. For example, some myrmicine ants (i.e., ants that belong to the highly diverse subfamily Myrmicinae) place or drop bits of leaf, wood, soil etc. into liquid food (e.g., rotten fruit pulp, body fluids of dead arthropods, droplets of honeydew released by aphids, etc.), and then they carry the food-soaked objects to the nest, where nestmates can feed on them. This behavior is similar to that shown by many primates who use leaves, mosses, paper, rags, etc. as “sponges” to soak up water and other liquids.

In this video, you can see a laboratory colony of Aphaenogaster subterranea using various tools to carry honey-water.

A worker of Aphaenogaster subterranea placing
a piece of sponge into honey-water. Photo credits: Imola Bóni.

While this so-called foraging tool use is well documented and makes good intuitive sense in omnivorous ants like Aphaenogaster species, studies on granivorous ants (i.e., ants that primarily feed on seeds), which interestingly are also known to use tools when feeding on liquids, are still scarce.

So what about harvester ants? Do they have a different tool-using behavior as compared to omnivorous species? And why do they show this behavior in the first place? To answer these questions, we compared the foraging tool use in captive colonies of two closely related myrmicine ants with different diet, Aphaenogaster subterranea, an omnivorous species, and Messor structor, a mainly granivorous species.

A honey-water bait fully covered by various tools by the workers of
Aphaenogaster subterranea. Photo credits: Gábor Lőrinczi.

In our experiments, we provided colonies with honey-water baits and a mixture of six types of objects (sand grains, small soil grains, large soil grains, pine needles, leaves and sponges) they could use as tools. During the observations, we recorded the type and number of tools placed into honey-water baits, and the type and number of food-soaked tools retrieved and transported to the nest.

The experimental design used in the study.
Drawing credits: Gábor Lőrinczi.

As we have expected, the two species showed many differences in the nature of their tool-using behavior. Firstly, the foraging workers of A. subterranea both dropped more tools into honey-water baits and retrieved more of these tools than the workers of M. structor. Secondly, A. subterranea preferred smaller tools over larger ones, while M. structor showed no preference towards any specific tool type. Thirdly, tool dropping was much faster in A. subterranea, and both the dropping and retrieving of tools began much earlier than in M. structor.

Workers of Aphaenogaster subterranea (A) and Messor structor (B) placing tools
into honey-water baits. Photo credits: Tamás Maruzs (A), Gábor Lőrinczi (B).

We think that for Aphaenogaster species that regularly utilize and compete for liquid food sources, the ability to efficiently hide and transport edible liquids with the help of tools may be more important than it is for harvester ants like Messor species, which mainly feed on seeds. Using tools, however, may still be useful for harvester ants, for example, when local seed sources are not available but there are other opportunities to acquire food for the colony.

The team of researchers. From left to right, István Maák, Gábor Lőrinczi,
Gábor Módra and Ádám Lőrincz.

Ready to rebel to an almost royal queen: brain genes and social networks unveil the hidden side of a coevolutionary arms race in Polistes wasps

By Alessandro Cini

A blog post accompanying the Best Paper Announcement for 2020, just out online in Insectes Sociaux. And while you’re at it, why not (re)read Alessandro Cini, Rebecca Branconi, Solenn Patalano, Rita Cervo, and Seirian Sumner ‘Behavioural and neurogenomic responses of host workers to social parasite invasion in a social insect‘, Insectes Sociaux 67, pages 295–308 (2020)!

Social insect colonies represent meaty resources for parasites and predators, but even more so for obligate social parasites, i.e. those species which have evolved to exploit on what is probably the most precious resource within the colony of social insects: alloparental brood care. The exploitation of this energy-expensive social trait is so rewarding that indeed several species of ants, bees and wasps have even lost some of their defining traits as social insects, i.e. nest building and production of the worker caste, thus becoming completely dependent on the host species.

The huge selective pressure to defeat the host species equipped these obligate social parasites with a plentiful bouquet of adaptations, from enlarged and thickened body parts, to better engage in violent fights, to sophisticated sensory tricks, to break the host communication code and deceive its social system. These adaptations are so astonishing that we often forget that there is indeed another player in the game: the host! Hosts as well are under strong selection pressure to put in place effective defensive strategies and prevent, or at least reduce, the fitness costs imposed by the presence of the social parasite. Indeed, even after a successful colony takeover, even if the social parasite might look utterly integrated, its throne possession should not be taken for granted.

Two main types of “last-resort” host reactions have been so far identified. First, host workers openly react to the social parasite, as it happens in Temnothorax ants, by identifying the offspring of the parasite and killing it. Otherwise, the reaction can be more concealed. This is the case of the paper wasp Polistes dominula, the unique host species of the obligate inquiline social parasite Polistes sulcifer (figure 1). Here, rather than directly facing the parasite or its offspring, the workers adopt a subtle strategy which sees them working for the parasite while at the same time investing in their own reproduction. Indeed, as I found together with colleagues from University of Florence and University Pierre et Marie Curie some years ago, host workers perceive that something is going wrong in their colony and react by developing ovaries. This physiological reaction makes them “ready to go” for their own direct fitness, meaning that they are ready to lay eggs if the opportunity arises. Thus, the parasitic female queen is indeed, as we called it at that time, “Almost royal”.

Figure 1. The socially parasitic queen of Polistes sulcifer has usurped the colony since a few days, and she stands, apparently quiet, in the middle of the comb…Is she aware that the host workers are “plotting” against her royalty?!

This discovery represented an exciting moment of my PhD, as we were somehow dismantling the stereotype of the super-powerful and neatly integrated social parasite. But clearly, this evidence raised a wealth of questions on both the ultimate and proximal reasons of this interaction:  is it the lack of suppression of worker reproduction by the social parasite reflecting its inability to control host worker reproduction or is it rather a concession to workers (a sort of incentive to stay and help)? Also, which were the cues on which workers detected the change in the “throne” ownership?

Understanding the timing of the worker reaction is crucial to start answering these questions, as the costs and benefits for both parties depend on when the workers start rebelling.  However, while our first study demonstrated that a reaction was already in place in the long term (at least five-six weeks after the colony takeover), it did not clarify when it started.

We thus combined two tools, brain transcriptomics and analysis of social networks, to look for potential early markers of such an intriguing rebellion. As it usually happens, we took great advantage of some useful prior knowledge. First, we (especially thanks to the smart expertise of Solenn Patalano, at that time post-doc in London) looked at some candidate genes supposedly changing between reproductive and non-reproductive wasps. We predicted that if workers were reproductively rebelling to the social parasite, their genetic expression should have switched from a “non-reproductive”-like gene expression pattern to a more “reproductive”-like one. Indeed, we detected that soon after the usurpation (within the first two weeks from the colony takeover) one gene, the Imaginal disc growth factor (Idgf4) gene, considered to be responsive to changes in the social environment, was significantly down-regulated in workers from parasitized colonies. This might suggest that parasitized workers are anticipating a shift toward a less worker-like phenotype in preparation for their reproductive rebellion.

Then we (actually the passionate and meticulous Rebecca Branconi, at that time Master student in Florence) analysed several hours of video recordings to understand the fine-scale dominance behaviour of workers, knowing that in P. dominula societies the dominant and reproductive individuals are the most central ones in the colonial social network. Here again, we found a clear signature of a shift in individual centrality for parasitized workers already two weeks after the usurpation. As expected, where the parasite replaced the host queen, workers changed their social behaviour, performing and receiving more dominance acts, in a sort of potential fine-level social reorganization of the colony. Thus, both gene expression and social network analyses concurred in suggesting that workers were rapidly reacting to the parasite presence, well before any physiological change was evident.

In the coevolutionary arms race between the social parasite and the host, thus, host workers might be more ahead than we have been thinking. While this arms race has been running for a long time, we are just now uncovering some if its most fascinating sides.  

This Insectes Sociaux prize for the best paper is extremely welcome! First, as it comes from the reference journal of our community, a community in which I grew up scientifically thanks to many people and many shared scientific moments. Second, as it rewards a collective effort made with people whose expertise and knowledge enriched and thrilled me over these years, and in particular two amazing and inspirational mentors, Rita Cervo and Seirian Sumner, which I thus heartily thank!  

Some references to deepen the topic

Achenbach, A., & Foitzik, S. (2009). First evidence for slave rebellion: enslaved ant workers systematically kill the brood of their social parasite Protomognathus americanus. Evolution: International Journal of Organic Evolution63(4), 1068-1075.

Grüter, C., Jongepier, E., & Foitzik, S. (2018). Insect societies fight back: the evolution of defensive traits against social parasites. Philosophical Transactions of the Royal Society B: Biological Sciences373(1751), 20170200.

Cini, A., Sumner, S., & Cervo, R. (2019). Inquiline social parasites as tools to unlock the secrets of insect sociality. Philosophical Transactions of the Royal Society B374(1769), 20180193.

Cini, A., Nieri, R., Dapporto, L., Monnin, T., & Cervo, R. (2014). Almost royal: incomplete suppression of host worker ovarian development by a social parasite wasp. Behavioral ecology and sociobiology68(3), 467-475.

Drones may make an effort to extend flight range day by day

By Shinya Hayashi

Based on the research article ‘Age-related variation of homing range in honeybee males (Apis mellifera)‘ by Shinya Hayashi, T. Sasaki, S. Ibrahim Farkhary, K. Kaneko, Y. Hosaka and T. Satoh in Insectes Sociaux.

As you know, honeybee (Apis mellifera L.) workers go back and forth between the colony and the field for foraging activity. Interestingly, male bees also go back and forth between the colony and mating places until the accomplishment of successful mating. Males die in case of successful mating, but it means that they played an important role in passing themselves and the colony’s genes on, amid fierce competition for females (queens). Male bees are often referred to as “drones” because they do not participate with foraging, brood care, and defense of the colony. However, the drones’ behavior as mentioned above looks just like a hard working honeybee worker. Males sometimes fly a few kilometers from the natal colony, but the flight range can vary greatly. Understanding the factors and processes causing variation in the flight range is important because their mating distances from the natal colony can affect not only an increased probability of successful encounters with queens, but also a decreased probability of inbreeding by visiting more distant mating places from the colony. However, a measurement of factors affecting the flight range is difficult because it often needs to track individual movement in the field. An evaluation based on the capable distance of returning to the colony is an alternative method.

The photo shows honeybee males going in and out the entrance of the hive. Male bees are marked with various colors to know their age (days after emergence). Picture by S. Hayashi.

We observed honeybee males’ return success and time by releasing males of different age at locations 200-1100 m from the colony, and tested whether the retuning range varies temporally. We found that older males can return to the hive from a greater distance and faster than younger ones. Older males also had a higher returning performance than younger ones. The results are supporting the possibility that males change the flight range temporally. However, we could not identify what causes the difference in returning range because, while males age, other factors such as their physical development and their flight experiences change also. Then, we evaluated a males’ flight abilities (flight time, flight distances, and flight velocity) by fixing them to a roundabout to see if these factors cause the difference in returning performance with age. We found that flight abilities did not vary due to males’ age and flight experience. Honeybee males leave their nest on a daily basis to fly around its vicinity. Therefore, older males would have had more opportunities to explore and learn the surroundings of their colony. This is why we think that male honeybees undergo a behavioral learning process and this enables them to expand their return and flight range, which increases their likelihood to have successful encounters with honeybee queens.

Interview with a Social Insect Scientist: Jim Hunt

Jim’s recent review article on the origin of the worker phenotype in paper wasps can be found here.

IS: Who are you, and what do you do?

JH: My name is Jim Hunt. I was James in public school, but on the way out the door of my last day of high school I became Jim. James was simply too stuffy. At age 77 I’m retired and no longer active in research, but I spent my professorial career in pursuit of the origin of eusociality in paper wasps. There were a few studies of solitary mud daubers and tropical swarm-founding wasps along the way, but I never lost focus on my long-term goal. My research ranged from behavior to molecular biology. The review out in Insectes Sociaux pulls it all together and places it in context as the solution to a quest I began in 1974.

IS: How did you develop an interest in your research?

JH: Edward O. Wilson’s book The Insect Societies appeared in 1971, during the time I was a graduate student at the University of California at Berkeley. I read it cover to cover. Twice. My Ph.D. research was on the comparative ecology of ants in Mediterranean climate habitats of southern California and central Chile. My postdoctoral research at Harvard was to be a similarly-structured study of ants in the Sonoran Desert of southern Arizona and a corresponding hot desert in Catamarca Provence, northwestern Argentina. Between those projects, in the summer of 1973, I attended the First International Congress of Systematic and Evolutionary Biology at the University of Colorado. I listened as Herbert Baker, professor of Botany at Berkeley, presented research that he and his wife, Irene, had pursued on the presence and abundance of free amino acids in floral nectar of different guilds of flower types (hummingbird pollinated, bee pollinated, bat pollinated, etc.). While listening I recalled a photo in Wilson’s book by Ulrich Maschwitz showing an adult Vespula vulgaris, a yellowjacket wasp, drinking saliva from a larva in its nest. As I listened to Baker, I thought it might be interesting to someday use their analytical methods on the larval saliva. Then on a Friday evening in March of 1974, while talking with a non-biologist housemate, I had a bolt-from-the-blue AHA! That’s why they’re social !! – the saliva is nourishment for the adult! I knew in that instant I’d found my passion. At first, I was thinking like an ecologist – a wasp could improve its foraging energy efficiency by combining prey foraging for larvae and nourishment for itself into a single trip. That weekend I wrote a short manuscript describing the idea and on Monday morning discussed it with Wilson, my postdoctoral sponsor. Unbeknownst to me, he was writing Sociobiology: The New Synthesis, in which he placed all of his eggs into an inclusive fitness basket. He vigorously disagreed with my idea. “It isn’t right. It can’t be right. … Even if it’s right, and I’m not saying that it is, no one will believe you until you have years of data to back yourself up.” I left Wilson’s office with my career path laid out in front of me. In August I took a position at the University of Missouri-St. Louis. On my first weekend there, a faculty member took me to one of the University’s field stations. I spotted a large colony of Polistes fuscatus on an abandoned building and moved closer for a better look. One of the wasps greeted me with a sting beneath my right eye, and my love affair with Polistes was underway.

IS: What is your favorite social insect, and why?

JH: Polistes metricus was the most abundant paper wasp at the two field sites where I pursued field studies almost every season of the 33 years I was at the University of Missouri-St. Louis. I put wooden boxes with open bottoms on posts about 1.5 m high that I spaced about 10 m apart in rows in open fields of mixed grasses and forbs. Foundresses established nests beneath the box lids that could be lifted off for easy access. In early years the occupancy rate was 60% or more. Students and I could monitor colony growth, feed individual larvae, feed whole colonies, or remove individual larvae for physiological or gene expression analyses, depending on what that year’s experiment was. They were easy to bring into the lab and rear under controlled conditions. Importantly, P. metricus is a single-foundress species, therefore I avoided multiple foundress colonies and the confusions and misleading pathways that such colonies unavoidably have.

Polistes metricus being reared in the lab by Amy L. Toth, then at the University of Illinois. Note that colored paper has been supplied as the source for pulp with which this foundress has continued construction of her nest after having been brought in from the field.

IS: What is the best moment/discovery in your research so far? What made it so memorable?

JH: During a project in Costa Rica on the paper wasp Mischocyttarus immarginatus, I was collecting larval saliva and encountered a remarkable behavior. I could easily take saliva from larvae in pre-emergence nests with only a foundress present, but in post-emergence nests with multiple workers feeding larvae that would become gynes and males, larvae refused to give me a single drop. Instead, they rolled their heads forward into a pocket on their ventral surface and withdrew it into the nest cell. The resulting turgor pressure caused a rigid pointed lobe to come quickly forward beyond the head. It would have prevented an adult wasp from taking saliva. It also prevented me. It was an unmistakable sign that the saliva was valuable nourishment that the larva retained for its own development. A day or so after returning home I described the remarkable behavior to a senior member of my department and said that its discovery was pure serendipity. He replied, “Ah, but serendipity doesn’t come sit in your lap while you’re lounging behind your desk in your office”.

I subsequently learned that every Mischocyttarus has a similar larval lobe, although its morphology varies among species. In a corresponding behavior, gyne and male larvae of Polistes metricus (and all Polistes?) roll their heads forward and withdraw into the nest cell, causing the ventral surface to become turgid and foremost in the nest cell, blocking access to the mouthparts. It’s easy to feed them but impossible to take saliva from them.

IS: Do you teach or do outreach/science communication? How do you incorporate your research into these areas?

JH: While at UM-St. Louis I led several workshops for high school biology teachers to introduce them to taking their teaching outdoors. I co-authored a short publication on common wasps and bees for the Missouri Department of Natural Resources and did an inventory survey of insect collections in colleges and universities around the state. There were a few TV and newspaper interviews during yellowjacket outbreak years in St. Louis. Lamentably, there was little more than that.

IS: What do you think are some of the important current questions in social insect research, and what’s essential for future research?

JH: Having done my last research in 2015 has left me out of date in areas other than my own, which I follow through published literature and occasional correspondence with colleagues. Anything else I might say would be speculation.  

IS: What research questions generate the biggest debate in social insect research at the moment?

JH: In my research area, the biggest debate concerns the role of relatedness in “the evolution of eusociality.” In his 2011 book Principles of Social Evolution, Andrew F. G. Bourke lumps me together with E. O. Wilson and others as poor saps who just cannot understand and therefore acknowledge the central role played by inclusive fitness. It was good company to be in. I couldn’t have been prouder. With my paper now having appeared in Insectes Sociaux, it’s game, set and match.

IS: What is the last book you read? Would you recommend it? Why or why not?

JH: Wilmington’s Lie: The Murderous Coup of 1898 and The Rise of White Supremacy by David Zucchino. Winner of the 2021 Pulitzer Prize, it’s a horrific true story of events that took place in Wilmington, North Carolina, during the years following the U.S. Civil War. The centerpiece of the story is the coup d’état of a democratically elected mixed race city government. It was the only coup d’état in US history, but it’s also a story that disappeared almost immediately after it occurred. I grew up in North Carolina and live here now, but I’d never heard of it until about 2 years ago when it was described to me by a high school friend who is an historian.

Wilmington was the largest city in North Carolina at the time and had been the last open port of the Confederacy. During Reconstruction after the Civil War, black and white racial mixing was present in Wilmington’s municipal government and police force, the state legislature, and the state’s delegation to the US House of Representatives. Wilmington had a large working class Black population and also a thriving Black middle class. A Black owned and edited daily newspaper served the Black citizens. White merchants advertised in it. At the same time, however, nighttime acts of white terrorism were taking place in rural locations throughout the region.    

I attended Josephus Daniels Junior High School in Raleigh, my hometown. Daniels had been Secretary of the Navy during World War I and was later the ambassador to Mexico. I was proud of my school’s namesake. In Zucchino’s book I learned that, in his position as editor and publisher of the state’s largest newspaper, Daniels was also an unabashed racist. With fake news, race baiting, and outrageous editorial agitation, he led the state’s White population to become increasingly fearful of an imaginary Black supremacy. White supremacists in Wilmington gave speeches that enflamed emotions. White citizens of Wilmington purchased thousands of guns. 

The coup d’état occurred two days following a municipal election marked by precinct gerrymandering, extreme voter intimidation of Blacks, and ballot box stuffing by White supremacists. White supremacists’ plans were scarcely concealed, and newspaper reporters from Atlanta to New York were there to record it. On the day of the coup, the office of the Black newspaper was burned and more than 60 black men were murdered. Blacks fearful for their lives fled into the woods and swamps. Members of the mixed-race board of aldermen were forced to resign, marched to the train station, and told to never return.

Blacks who had fled the city were urged to return – as long as they stayed “in their place.” The coup d’état marked the beginning of the southern apartheid – Jim Crow. Although lengthy, the book tells the heretofore untold tale of one of the most significant milestones in US history. It should be required reading for anyone interested in US history – or, especially, anyone seeking insight into the political and social climate of the USA today. I highly recommend it.

IS: Outside of science, what are your favorite activities, hobbies, or sports?

JH: In the summer I was 8, my dad was enrolled in grad school at the University of Maryland. He bought me a beginner’s stamp collecting kit to keep me busy while we were there, and almost immediately I was hooked. I continued to fill spaces in albums until the end of high school, but then things went dormant. In the early ‘90s the collecting bug, soon an obsession, came roaring back. Filling album spaces gave way to preparing exhibits for competitions at stamp shows around the country. They’re like all-breeds dog shows – no two exhibits are on the same topic. I now show the world’s best collection of the revenue stamps of Boliva (yawn), revenue stamps of Chile used to pay postage (yawn), and the provisional stamps of Arequipa, Peru, from 1880 to 1886. That one has an historical context and is actually somewhat interesting for non-collectors. I’ll continue to target my collecting for new exhibits until I no longer am able.

IS: How do you keep going when things get tough?

JH: My partner (“wife”) and I (“husband”) will soon celebrate our seventh anniversary. We’ve traveled to faraway places for a month at a time, including three trips to Latvia, where she was born. With the pandemic here, we’re no longer able to travel internationally. Instead, we’ve begun exploring North Carolina via week-long stays at lovely B&Bs. Our house is on a steep hillside in the woods. When looking out the front picture windows, we’re living in a treehouse in the forest canopy. We try to make every day we’re home rich and enjoyable. My tough times are behind me. Life is good.

IS: If you were to go live on an uninhabited island and could only bring three things, what would you bring? Why?

JH: My trifocals, so that I can see; a hat to protect my baldpate from sunburn; and the retainer that I wear at night to keep my lower teeth from migrating into misalignment. If those are presumed to be givens, then my three things would be a room-size tent in which I can stand up – I’ve done more than enough crawling into camping tents in my life; a machete – a marvelous multi-function tool; and a solar powered 3D printer to make trinkets for barter with the hordes of tourists that will inevitably flock to visit a previously uninhabited island.

IS: Who do you think has had the most considerable influence on your science career?

JH: When one has reached my age there has been abundant time for many people to have influenced a career. Those whom I acknowledge here are not the only ones, but their influence has been significant at steps along my way.

Thomas L. Quay, the father of my best friend in elementary and junior high school, was a professor and ornithologist at North Carolina State University. He took me out locally on natural history trips and to the Duke University Marine Biology Lab. By the time I was in high school he made sure someone took me along on Audubon bird counts. When I entered State as a freshman, Dr. Quay gave me a job as his assistant, an office with a view out onto the campus, and a key to the building. Almost immediately I began hanging out with Zoology Department graduate students, dressing the way they did and going to the field to assist in their thesis and dissertation research on birds and mammals. With that jump-start, I was trained and ready for grad school.

My master’s thesis advisor at Louisiana State University, George H. Lowery, Jr., came next and was one of the two persons who had the greatest impact on my career. One night in the fall of 1967, Doc (as we all called him) came down to my desk in the grad student warren in the basement of the Museum of Zoology and asked me to come along on a trip to the post office uptown. He said we had to find a thesis project for me. Doc focused his career on building the bird collection at LSU. Each year he sent a team of grad students to the Amazonian rainforest of Peru to collect birds and mammals and return the study specimens to the museum. I told him that I wanted to go to the tropics but wanted to do a research project rather than go on a collecting expedition. He said, “find a project, and I’ll send you.” At about the same time he had bartered for a shoebill and a kagu, representing the last two bird families missing from the museum’s collection. With that accomplished, he decided it would be good if his students learned the families of birds of the world. One, Zeledoniidae, had a single species – the wrenthrush. It had short, rounded wings, almost no tail, and was highly restricted in habitat and geographic range to the high elevation cloud forests of Costa Rica. Monotypic families are anathema to taxonomists, and was it a wren or was it a thrush? About two weeks after our conversation in the car, I went to Doc’s office and proposed a field study of the wrenthrush. It was morphologically and ecologically unique, making it suited to my interest, and it fell into Doc’s area of interest as well. He thought it was a great idea. But I said that I’d need transportation to go to and from my study site. He pointed through his office wall to the parking area outside and said, “Take the carryall!” But I said I’d need to get it there and didn’t speak a word of Spanish. “Take Al!” Doc put me on a museum assistantship as a source of income for the trip. He shared a good-ole-boy evening over Wild Turkey Bourbon with Edward McIlhenny Simmons and returned with a check to cover the costs of the trip. A bottle of McIlhenny Tabasco Sauce has adorned my office ever since. Early in 1968, Al Gardner, a Spanish speaking fellow grad student, and I hit the road. Our trip took 8 days. Al showed me how to get from San Jose to where a study area could be found, and about a week later he flew home.

In the Costa Rican cloud forest, 1968, while doing my master’s degree research on the wrenthrush, Zeledonia coronata. The wire cages were part of a dissertation research project by Robert K. Colwell, then a grad student at the University of Michigan and later my major professor at the University of California at Berkeley.

Everything significant in my early career came from that trip. When I returned, Doc encouraged and supported me in moving to a doctoral program with a stronger focus on ecology. In the summer of 1969, Frank A. Pitelka, an ornithologist and Head of the Department of Zoology at the University of California at Berkeley signed my application, saying “Oh, what the hell. Let’s give him a chance.” In Costa Rica in ‘68 I’d met a member of the selection committee, and the following summer was admitted to “Advanced Tropical Ecology,” a two-month course in Costa Rica co-coordinated by Daniel Janzen with Harold Mooney as the first visiting instructor. A year later, after searching in vain for a field site in northern California to study ant ecology, I wrote Janzen, who called and said to call Mooney before he left for Spain. Mooney was leading a comparative ecosystems program in the chaparral/matorral environments of California and Chile. He said to write a grant proposal and have it ready to go as soon as he was back from Spain. Not long after that I was on my way to Chile.

Atop Cerro Robles, Chile, in 1972 while pursuing my dissertation research on the comparative community ecology of ants in Mediterranean scrub ecosystems of southern California and central Chile. In the photo, L to R, fellow grad students Bill Glanz and Eduardo Fuentes, our major professor Rob Colwell, and me.

The Chile project had a sister project in the deserts of Arizona and Argentina. The director was Otto Solbrig, who also had been a visiting instructor on the advanced tropical ecology course. Otto wanted someone to look at ant communities and offered me two years of support as a post doc at Harvard. My sponsor was Edward O. Wilson, whom I’d met two years earlier at Berkeley. After the first year, I was worried about job prospects and accepted a one-year teaching appointment at the University of Missouri-St. Louis. The faculty member there who recommended me to the dean was Theodore Fleming, someone else whom I’d met in 1968 in Costa Rica. Upon arrival in St. Louis, I began my inquiry into the origin of eusociality in paper wasps. I remained in St. Louis for 33 years.

My first nest boxes. I spent the summers of 1975 and 1976 at boxes like these, beginning from scratch to learn the behaviors and basic biology of Polistes paper wasps.

The person with the second-most impact on my career is Raghavendra Gadagkar. In 2001 and at the invitation of Klaus Hartfelder, I gave a presentation to a meeting in Berlin of the North-west European Section of the IUSSI. Afterward, Raghavendra came up and said that he’d forgotten how much fun it is to listen to me think – the highest academic compliment I’ve ever received. At dinner the following evening he asked about the background of a paper I’d published in Evolution in 1999. I said that it was the only decent chapter of an unsuccessful mid-1990s attempt to write a book on the evolution of social wasps. He asked if I thought I might be ready to try again. I said yes. He said he knew of a place where I could do it – the Wissenschaftskolleg zu Berlin. The where?? He described an academic institution in which 35 or so fellows of diverse disciplines come for a year, each to write a book. And then, with a bit of a twinkle in his eye, he said, “I’m on the committee that selects new fellows.” I knew in an instant that I’d just been invited to spend a year in Berlin.

Academic year 2003-04 at the Wissenschaftskolleg was one of the best years of my life, both personally and professionally. I wrote my book, The Evolution of Social Wasps, and restored my faith in my academic abilities. Along the way I had the second-most important Aha! insight of my career – that gyne paper wasps are in reproductive diapause. I promptly walked to the office of the Academic Director and said I’d like Wiko to fund bringing Gro Amdam for a week, that we’d write a paper together, publish it in Science, and change forever the way the origin of paper wasp eusociality is understood. He didn’t hesitate. Gro came and we worked on our separate parts before putting it together and submitting it to Science. It’s one of my favorite papers – an idea, a model, and no data.

In 2006, Eugene Robinson invited me to spend a semester in his lab at the University of Illinois. His only paper wasp student, Amy Toth, and I became academic friends and colleagues. She and Robinson’s lab tech, Tom Newman, taught me how to do bench work in a molecular biology lab, and we produced a nice paper together. During that same semester I enticed another grad student, Heather Hines, to take a look at the molecular phylogenetics of Vespidae. Her results showed unequivocally that sociality arose twice independently – subfamilies Stenogastrinae and Polistinae do not have a most-recent common ancestor. A vituperative rejoinder was published in defense of a single-origin of eusociality hypothesis, but in the end enough independent studies replicated Heather’s findings that there is no longer room for disagreement. In 2007, the Head of the Biology Department at N.C. State University, Damian Shea, provided me a 50% salary for three years to finish my career here. I took early retirement from UM-St.Louis, and the 3-year period carried me until I was old enough for full Social Security benefits. Although I now work from a home office and am no longer pursuing research, I’ll have an online virtual existence as a visiting Professor of Biological Sciences at State until I die.

2007 was my first year as a Visiting Professor at North Carolina State University. Here I’m on a day trip to the Anza Borrego desert during the Wednesday off-day of the 2007 annual meeting of the Entomological Society of America. With me are Ed Vargo, Anne-Geneviève Bagnères and Freddie-Jeanne Richard. Freddie-Jeanne and I co-authored two review articles published in Insectes Sociaux in 2013.

[When I arrived at NC State in 2007, the Head of the Department of Entomology offered me my choice of two offices. The one I selected had been my office in the summer of 1963 – and it hadn’t changed! I broke out laughing and asked if he could at least paint the walls and put down carpet. I turned it into the best-looking office in the building.]

IS: What advice would you give to someone hoping to be a social insect researcher in the future?

JH: Know thy organism. Go outdoors. Learn where it lives, how it lives, how it behaves. Read natural history literature. If the organism occurs on the other side of the world, read the local natural history literature if you can handle the language. In particular, read older natural history literature. Researchers in both the past and now who document natural history have made valuable contributions. By reading their work you can glean tidbits of information or significant insights that may, either now or in the future, become cogs in the wheels of your thinking. Or if not yours, that of someone else.

If you see it report it. If something is unusual or unexpected, write a short note and publish it. This will mean placing papers in so-called “minor journals.” If you’re under pressure to earn tenure, put your observation in a file and publish it after you’ve passed that milestone. Do a thorough literature search before you publish. During your reading you may discover that your observation was reported decades ago but has been long overlooked. Give priority to that researcher.

Read Darwin.

IS: What is your favorite place science has taken you?

JH: My favorite place, by far, is the high elevation cloud forest of Costa Rica. I went for my master’s thesis research – a natural history study of an enigmatic little songbird, the wrenthrush, Zeledonia coronata. It’s a rare bird and hard to find. I’m the only person to have studied it in the field. I was the first to record its songs and calls, found the first nests to be reported in a publication (there were second-hand anecdotal mentions from the 1930s), and found the first eggs and nestlings. Albumin of the first-laid egg went to Charles Sibley at Yale, who was doing protein electrophoresis as a pioneering venture into molecular systematics. His finding that it was not a thrush was perhaps the only unequivocal new determination in his studies. But neither is it a wren – recent molecular phylogenetics has it out on a branch of its own, indicating mountain-top isolation a long, long time ago in a restrictive environment with a limited geographic range. I spent 101 nights at a roadside restaurant, La Georgina, at an elevation of 3,100 meters, a few kilometers from the 3,341 meter highest point of the Pan-American Highway near the 3,491 meter peak of Cerro de la Muerte – the mountain of death. Every night during the dry season the sky was clear and star-filled, and the temperature dropped to freezing. I slept in an Eddie Bauer 4 lb down sleeping bag (I still have it) on the bed in my room, which was about the size of a solitary confinement jail cell. When the rainy season came, nighttime temperatures were not quite down to freezing, but every day was chilly with fog, and cold rain was frequent. Sometimes the door to the restaurant would be left open, and fog just rolled into the dining room. I began to learn Spanish by going down the menu board on the wall and ordering every item except the white lightning rum (guaro) that truck drivers drank one shot after another to warm themselves before heading back out on the rocky unpaved highway. A website, “Driving the wild Cerro de la Muerte road,” describes the current highway as paved but filled with potholes, riddled with blind corners, hair-raising cliffs, and careless drivers. I never drove the highway at night.

La Georgina as it is today. Only the central building was there in 1968. The first window on the end wall was the full width of my room. My bed was parallel to the window with only a few centimeters between the ends of the bed and the walls on either side.

It was high adventure. It was 1968. I was 23 and on my own for my first trip to the tropics. I wore long johns, and the guard dogs that spent every night inside the restaurant gave me fleas. The cloud forest floor was always wet, so I wore wool socks and high-top lace-up rubber boots. In the rainy season I wore rain pants and a rain jacket. In rainy season afternoons when my birds were no longer calling (the only way I could locate them in the dense, moss-covered vegetation), I headed out with a double-barrel 12-guage shotgun with supplementary cylinders I could drop inside to accommodate smaller 410 shotgun shells and even 32-caliber dust shot. I’d collect a bird or two, sit by the upstairs front windows for light (the generator ran only for breakfast and dinner), and prepare study specimens that I took back to the Museum at LSU.

IS: Is there anything you wish we would’ve asked you that we should ask other social insect scientists in the future?

JH: Although I’ve retired (and disappeared), I’d ask younger scientists to envision where their research program will be 5 years from now. 10? 20?

At the Wissenschaftskolleg zu Berlin, 2013.

It’s been a good career.

Interested in Jim’s treasure trove of research? Check out his website, which can be found here.

Interview with a Social Insect Scientist: Olivia Bernauer

You can read Olivia’s research article about life cycle, nesting biology, and social organisation of the bee Exoneura angophorae at the upper extreme of its altitudinal distribution here.

IS: Who are you, and what do you do?

OB: My name is Olivia Bernauer, and I have been working with pollinators and social hymenopterans for the last eight years. Recently, my research interests have focused on foraging behaviour and the implications for pollination, examinations of pollination efficiency, which is a measure of how much pollen is deposited on a flower by different insects after a single visit, and social insect biology. In my recent publication, we investigated the nesting biology and social organization of the facultatively social allodapine bee, Exoneura angophorae, at the upper limit of its altitudinal range.

Photo of Olivia hiking near Coorongooba campground in Wollemi National Park, NSW (Australia).

IS: How did you develop an interest in your research?

OB: I think two things led me to develop an interest in social insects and pollinators. First, I have been obsessed with flowers since I first learned to walk and talk, and second, I took an entomology course at UW Madison during my undergraduate education and fell in love with insects, in general. Once my eyes were opened up to the magical world of entomology, I viewed flowers with a new sense of wonder, savouring every flower visitor. Toward the end of my undergraduate education, I joined an entomology research lab and began an independent research project studying how a fungicide affects bumble bees and have been hooked ever since.

Olivia standing next to her experimental bumble bee colonies during her undergraduate education.

IS: What is your favorite social insect, and why?

OB: My favorite social insect is Bombus fervidus. I love all bumble bees, I mean, how can you not love such fluffy bees?! But B. fervidus is a really striking species, it’s got a rather long abdomen which is adorned in beautiful yellow hairs, and seeing them always brings a smile to my face. I also love how much the workers can vary in size, with some workers being quite large and, at first glance, could even be mistaken for a queen while others are so small.

IS: What is the best moment/discovery in your research so far? What made it so memorable?

OB: One of the most exciting moments of my research so far was when I first encountered the social parasite of Exoneura angophorae in my nest dissections from my recent publication. My supervisor had mentioned that I may come across these parasites, and to keep an eye out for them. I came across a nest of bees that looked quite similar to E. angophorae, but something was a bit off about them. I popped them under the microscope and sure enough, they were different bees – their faces were concave, mandibles tiny, and scopal hairs quite reduced. We encountered only a few other nests containing Inquilina species, only 8 out of 609, so each time we found them, it was very exciting. The next exciting work is to determine which Inquilina species we have found and whether it may be a new species.

IS: Do you teach or do outreach/science communication? How do you incorporate your research into these areas?

OB: Yes! I really enjoy engaging with the public to talk about insects, the importance of pollination, and what can be done to support insect pollinators. My lab group regularly engages with schools and community events to help educate school children and members of the public about the local insects which contribute to pollination. One of my favorite outreach tools is our “suitcase” stingless bee hives. They’re hives installed into wooden boxes with a sheet of plexiglass over the top of the hive. The flat and shallow design encourages the bees to spread out and when the suitcase is opened, we can show off the inner workings of the bee hives! My PhD work focused on apple pollination, and I also have had the opportunity to engage with our growers to share findings and discuss useful future research avenues. By collaborating with the growers, we can tailor our research to better understand pollination and assist the growers in solving any problems they may have.

Members of Olivia’s pollination lab group attending an outreach event, Kurrajong-a-buzz, in November 2019.

IS: What do you think are some of the important current questions in social insect research, and what’s essential for future research?

OB: I think that further investigations into the biology of social parasites are an important future direction for social insect research. I know that some research has been done on bumble bee social parasites (Bombus (Psithyrus) sp.), but understanding other social parasites, for example, Inquilina sp., would be interesting and important.

IS: What research questions generate the biggest debate in social insect research at the moment?

OB: One area of social insect research that generates the most debate and discussion is the evolution of eusociality. It feels like this has been a subject of debate for a long time and that despite lots of good research, we still don’t have a complete picture of how eusociality evolved.

IS: What is the last book you read? Would you recommend it? Why or why not?

OB: The last book I read was The Less People Know About Us by Axton Betz-Hamilton. I would definitely recommend this book to anyone who likes a good mystery story. This book is a memoir about the author’s experience with identity theft and I first heard about her story on an episode of the Criminal podcast years before the book came out. I remember listening to the podcast with my jaw dropped in surprise about the twists and turns Axton’s story takes. When I found out she had also written a book about her story, I was eager to check it out and was not disappointed.

IS: Outside of science, what are your favorite activities, hobbies, or sports?

OB: I spend most of my free time outside. I love going for bushwalks and am obsessed with native flora. I get really excited when I find wild orchids and encounter new-to-me plants. I also enjoy fishing with my partner (I always catch the best fish), camping, and exploring new places. In summer I enjoy snorkelling and will spend hours observing creatures in tidepools when given the chance (see the adorable bubble snails below). When I can’t be outside, I like to spend my time reading true crime books and trying new recipes in the kitchen.

Two bubble snail species I found while walking among tidepools. The rose petal bubble snail on the left (Hydatina physis) and the red lined bubble snail on the right (Bullina lineata).

IS: How do you keep going when things get tough?

OB: For me, when things get tough, I typically take a break from the work and spend some time recharging with friends or in nature. Once I’ve had a bit of a rest, I’m able to get back to work and am able to work more effectively. It also helps me to take a step back and think about the big picture, what are my long-term goals and how will this work help me get there.

IS: If you were to go live on an uninhabited island and could only bring three things, what would you bring? Why?

OB: If I had to live on an uninhabited island and could only bring three things with me, I think I would take a good magnifying glass, a sharp axe, and a hammock. I would bring the magnifying glass with me so that I could take a closer look at the plants and insects around me and, hopefully, I’d be resourceful enough to find a way to document and study them while on the island. I could also use the magnifying glass to start a fire to keep warm, cook food, and as a source of light. The sharp axe would have many uses, it would allow me to build a structure to live in and harvest food. The hammock would provide me a comfy place to sleep from the get-go and could also be used to provide protection from the sun until I was able to build a proper structure to live in.

IS: Who do you think has had the most considerable influence on your science career?

OB: When I think about my scientific journey, two people immediately come to mind. First, Dr. Robert Bohanan, my first scientific mentor, who facilitated my first independent research project. He taught me, leading by example, the importance of a high-quality mentor and helped to open my eyes to different avenues of science and teaching. I was fortunate to find another high-quality mentor in Dr. Hannah Gaines-Day. She mentored me through my first research project on bumble bees and helped encouraged me to pursue graduate school. I credit these two scientists for helping shape my first scientific experiences and for setting me on my current career path.

The inside of a Tetragonula carbonaria stingless bee hive, showcasing the spiral brood pattern and the queen, the bee with a lighter-coloured, enlarged abdomen near the centre of the photo.

IS: What advice would you give to someone hoping to be a social insect researcher in the future?

OB: My advice to someone wanting to get involved in social insect research would be to seek out a high-quality mentor. Having someone to support you, challenge you, and share their expertise and experience is so beneficial when getting involved in research.

IS: What is your favorite place science has taken you?

OB: My favorite place science has taken me, so far, is to Australia. I found a PhD position advertised on twitter to study apple pollination in Australia and applied thinking there’s no way they’d pick the girl from Wisconsin, but 3.5 years later, here we are. It’s been such a delight to get acquainted with the Australian insect fauna, I have particularly enjoyed getting to know the stingless bee, Tetragonula carbonaria, which has the most beautiful, intricate, spiral comb and loves to forage on apple pollen! Plus, Australia has given me a chance to meet and appreciate some really neat ants including giant bull ants and the green weaver ants, which are quite tasty!

On the left are two Australian giant bull ants (Myrmecia gulosa) that were fighting and on the right, a green weaver ant (Oecophylla smaragdina).

IS: Is there anything you wish we would’ve asked you that we should ask other social insect scientists in the future?

OB: If your study species could speak, what would you ask them?

The smell of the German wasp Vespula germanica

By Cintia Akemi Oi

Based on the short communication “Cuticular hydrocarbons as cues of caste and sex in the German wasp Vespula germanica” by R.C. da Silva, R.L Brown, F.S. do Nascimento, T. Wenseelers and C.A. Oi in Insectes Sociaux.

One of the most used mechanisms of communication in social insects (ants, bees, wasps and termites) is the chemical one, which occurs through pheromones. Those pheromones are chemical molecules that are produced by glands or specialized cells. We focused our research on characterizing the chemical compounds that cover the insect body. The question we wanted to answer was if within the same species of wasp Vespula germanica, the different castes and sex would have unique chemical signatures, like a badge or ID. This is super interesting because the workers need to know if there is a queen in the colony, males need to recognize virgin queens to mate and vice-versa, for the colony to function cohesively.

Example of pupae (phase that precede the adult phase): (1) male, (2) worker, and (3) virgin queen of Vespula germanica. Black bar represents 5 mm. Photo credits: Rafael C. da Silva.

The class of chemical compounds that was under this investigation are the cuticular hydrocarbons (CHCs). These chemical compounds cover the insect body to prevent water loss and to offer protection. Usually there is a mix of CHCs formed by high molecular weight compounds, composed by long-chain hydrocarbons (molecules of carbon and hydrogen). In social insects, CHCs were co-opted to have a communicative role. CHCs are helpful to differentiate castes, sex, nest membership, task, health condition and even to prevent parasites or water loss. Thus, by touching each other with their antennae, social insects have access to the information reflected by a certain individual.

Cuticular hydrocarbons are found over the surface body of insects in general. In social insects they contribute to chemical communication. Drawing credits: Wesley B. Moser.

To do our research, colonies of V. germanica were collected in Belgium and brought to the lab at KU Leuven University. Then, individuals belonging to the groups males, queens, virgin queens, and workers were separated and stored in the freezer. Those groups are easily recognized because of their body morphology. For the characterization of the smell, each individual was placed in a glass vial that was filled with a solvent (we used hexane to extract the CHC layer). Then, the samples were analysed in a Gas Chromatography-Mass Spectrometer to separate the compounds and to allow us to identify the chemical composition, which we called ‘chemical profile’.

Chemical communication using cuticular hydrocarbons (CHCs) in Vespula germanica. Chemical cues are correlated with caste, sex and nest membership. Drawing credits: Wesley B. Moser.

Among the findings, we show that the chemical profile of males, queens, virgin queens, and workers is similar in number of compounds, but differs in abundance. We can discriminate each of the groups based on their chemical signature. These results indicate that there is a specific chemical badge carried by the adults of V. germanica. In addition to that, CHCs also differ according to their colony origin. Our results are interesting because they can serve as basis to the investigation of the identity of specific queen pheromones (as the commercialized QMP in honeybees) or sexual pheromones (to develop traps where this species is invasive). To confirm whether CHCs have indeed the functions mentioned above, it is important to test them in controlled bioassays using synthetic versions of the candidates. 

(a) Queen of Vespula germanica walking over a comb full of pupae (white closed caps – individuals developing). (b) Ovaries of a mature queen, each white piece represents one oocyte that is developing, which at the end becomes an egg. Photo credits: Cintia A. Oi and Rafael C. da Silva.

Our work has been published as short communication in Insects Sociaux and has been conducted in cooperation between researchers from Brazil (Universidade de São Paulo (USP-Ribeirão Preto)), New Zealand (Manaaki Whenua – Landcare Research) and Belgium (University of Leuven (KU Leuven)).

Also, this work was partially funded from an ongoing bilateral project between Belgium and Brazil (funded by FWO and FAPESP), in which we aim to understand the division of labour in wasps and how hormones affect traits like reproduction, behavioural and chemical communication.

Follow me if you want to stay tuned with our latest research (Twitter @Cin_Oi).

Interview with a Social Insect Scientist: Rafael Carvalho da Silva

You can read Rafael’s recent research article about the chemical composition on the cuticle of the German wasp Vespula germanica here.

IS: Who are you, and what do you do?

My name is Rafael Carvalho da Silva, but my close friends call me Rafa. I am currently a Ph.D. student at Universidade de São Paulo (USP), Ribeirão Preto – SP / Brazil. I developed my research project at Laboratório e Comportamento e Insetos Sociais (Lab CEIS), which is led by Professor Dr. Fabio Santos Nascimento. I got my Master’s degree in Science (Entomology – 2018) at the same university, and since 2016 have been studying how cuticular hydrocarbons (CHCs) are used by social wasps to mediate different types of interactions. During my Master’s, I focused on studying one species of social wasps to evaluate whether CHCs would reflect information concerning the dominance hierarchy system. Now, in my Ph.D. project, which I started in 2018, I am interested to study the role of brood (mostly eggs) as communicative sources in the societies of wasps and the effect of juvenile hormone in physiological modulation (e.g. chemical signaling and reproduction).

Team of the Laboratório de Comportamento e Ecologia de Insetos Sociais (Lab CEIS)

IS: How did you develop an interest in your research?

I have always been passionate about animals during elementary and high school. The disciplines such as Science and Biology were always the ones that I was mostly interested in. I remembered spending hours observing foraging trails of leaf-cutting ants, when I spent my holidays at my grandmother’s house. During the first two years of my Bachelor Biology course, I was interested in studying frogs to check how temperature affects tadpole development, and also if foam nests protect eggs from the temperature variation during the day. In my third year, because I attended an Entomology course, I switched to insects. Also, I received a didactic grant to teach about insects in a public high school. So, after these two nice experiences, I was sure that after finishing my bachelor course, I would enroll in an Entomology postgraduation program. Ribeirão Preto city was always my first option, because not only has it one of the best universities in the region, but also an Entomology degree is highly prestigious nationally and internationally. My current advisor offered me a volunteer internship to survey wasp nests distributed on the campus of Ribeirão Preto, and so my journey with the wasps started.

Fieldwork conducted at the beginning of 2020 at Universidade de São Paulo, Ribeirão Preto – SP/Brazil

IS: What is your favorite social insect, and why?

Even though I had already worked with different social insects during the past years, my favorite species is Mischocyttarus cerberus. I, of course, would choose a wasp species, because besides their importance for the environment providing ecological services (e.g. predation of several crop pests and pollination), they also perform many interesting behaviours. The species Mischocyttarus cerberus is a primitively eusocial wasp species that is commonly found in shed locations on campus where I work. They build small nests without an envelope, which allows us to stand in front of their nests and easily observe adult females interacting with each other and the brood – it is almost impossible to not feel excited about the way they interact with each other. The most interesting fact about them is that they organize themselves in a dominance hierarchy system, in which aggressive acts (e.g., biting) are used to induce other females to leave the nest and forage, for instance. Further down below, you can find a picture of a nest of M. cerberus containing females with a yellow face and males with a white face.

Nest transference of the swarming-found wasp Polybia sp. during my volunteer internship at Universidade de São Paulo, Ribeirão Preto – SP / Brazil

IS: What is the best moment/discovery in your research so far? What made it so memorable?

Conducting a project with my favorite wasp during my Master’s and later having the chance to publish the results of my discoveries “Dominance hierarchy, ovarian activity and cuticular hydrocarbons in the primitively eusocial wasp Mischocyttarus cerberus (Vespidae, Polistinae, Mischocyttarini) (da Silva et al. 2020 Journal of Chemical Ecology)”, was definitely the best moment in my research so far, until now. Even though Mischocyttarus wasps are common in Brazil, the number of studies investigating the role of CHCs in their societies is still low compared to social wasps from other genera Polistes, Ropalidia and Vespula.

Nest of Mischocyttarus cerberus containing females (yellow face) and males (white face).

IS: Do you teach or do outreach/science communication? How do you incorporate your research into these areas?

Yes, since my Bachelor I undertake activities for science communication. During the third and fourth year of my Bachelor studies, I received a didactic grant to teach about insects in a public high school. In my fourth year, I volunteered to teach Agronomy students for an Entomology course. Additionally, I had always participated in citizen science events, where I presented the professional career of a Biologist, to convince people why insects are good and not bad. During my Master’s and now as a Ph.D. student, whenever I am invited, I give lectures about wasps or chemical ecology.  In 2019, I returned to my old elementary school to give a talk to show my trajectory as young scientist to children and teenagers. When I have the chance, I enjoy doing something like this a lot, because through these moments we may cause a positive impact for science and specifically insects, and even may inspire someone else’s life. On campus, because I videotape wasp nests outdoors, it is common that people get curious and come to ask me what I am doing. Then I explain that I am studying the behaviour of wasps, and they often ask me with a weird face “Why wasps?”. In these moments I think that it is fundamental to teach people about these animals, and maybe try to change their perception about insects in general as well. Considering the difficulties of science in Brazil, even when I am not formally doing science communication, I am still trying to reach different people personally or online and teach them how science is important for all of our lives.

Sometimes the nests of Mischocyttarus cerberus are hanging in higher places that requires to use a big ladder to reach them.

IS: What do you think are some of the important current questions in social insect research, and what’s essential for future research?

Well, I would not say the most important, because at the end I believe that all different questions and topics (from describing species to understanding specific processes of insect physiology) have their level of importance and relevance, but maybe the most current questions are covering subjects like the genetic and genomic basis behind social behaviour. In addition to that, considering that we have been facing difficult times because of the pandemic situation, the questions covering subjects like social immunity, such as “How do individuals in a colony of social insects deal with infectious diseases?” are also appealing. Through them we may learn some things that could be applied to our society. I believe the work related to this social immunity topic will be essential in the near future.

Lecture given about “Chemical Ecology” for undergrad students during the XVIII Summer Course in Entomology – Universidade de São Paulo (USP), Ribeirão Preto – SP / Brazil.

IS: What research questions generate the biggest debate in social insect research at the moment?

In my opinion some questions that still generate a lot of discussion among researchers studying social insects are “How do queen pheromones work in colonies of social insects? Are they manipulative signals or are they honest signals?”, “Which traits does juvenile hormone modulate in queens and workers belonging to different levels of sociality? Does it regulate different traits depending on caste (queens = reproductive traits; workers = behavioural traits)? Or alternatively, does it modulate several traits regardless of castes?”. These are questions I have particular interest in and are related to my research topic. As I said, although these are questions that researchers started to ask decades ago, they still generate debate among scientists working on behaviour of social insects.

A Mischocyttarus cerberus female touching the nest with its antennae.

IS: What is the last book you read? Would you recommend it? Why or why not?

The last book I read is called “The third pillow by Nelson Luiz de Carvalho”, which is a fictitious Brazilian novel based on real facts. If you are someone who reads a novel book expecting a happy ending, I would not recommend this one. But for someone who does not mind about the ending, then I would highly recommend it. This is the type of book that you take on Sunday afternoon, have a seat, grab a cup of coffee, and read at once. It is easy reading and has a lot of drama.

A Polistes versicolor foundress looking at the camera.

IS: Outside of science, what are your favorite activities, hobbies, or sports?

Outside of science, I enjoy taking pictures, going for a walk with friends, spend time just relaxing at home, and watch a good thriller movie, which I am a big fan of. Before the pandemic, I used to gather with my friends whenever possible to hang out, have some beers or eat ice-cream.

Guards of Tetragonisca angustula around the nest tube entrance.

IS: How do you keep going when things get tough?

When things get tough, I usually do things that I know that are relaxing for me, such as talk to one of my closest friends, go for a walk alone while listening to my favorite songs or just watch a good movie or TV series.

IS: If you were to go live on an uninhabited island and could only bring three things, what would you bring? Why?

Considering that even if I were alone on the island, I would try to do something meaningful to spend my time, I would take with me a notebook, a package with pens and pencils and a camera with infinite memory and solar charger. Having these things would allow me to register and describe the animals (especially insects) on the island.

Workers of Trigona sp. collecting honeydew of treehoppers.

IS: Who do you think has had the most considerable influence on your science career?

Honestly, it is impossible to name a single person, rather I would say that a couple of people were or still are a positive influence on me. While I was still a Bachelor student, three professors were fundamental to me, for different reasons, but mainly because they either got me in contact with insects or because they would give me good advice (Professor Dr. Marcelo dos Santos Fernandes, Professor Dr. Hertz Figueiredo dos Santos and Professor Dr. Kenji Claudio Augusto Senô). I also would like to highlight that my current advisor Professor Dr. Fabio Santos do Nascimento also had a considerable positive influence on my career, because he was the one that introduced me to the world of social wasps and is still advising me on my Ph.D up to this moment. I also give a lot of credit to my co-supervisor Dr. Cintia Akemi Oi, she has, for sure, a great positive impact on my scientific career, starting in 2018, when I had the chance to start collaborating with her while I was still a Master student. She has been always supportive, and we often have moments in which we brainstorm and plan our future projects.

Late instar larvae of Vespa crabro used in one of the projects developed while I was in Leuven in 2019, Belgium.

IS: What advice would you give to someone hoping to be a social insect researcher in the future?

As advice, I would give the following: try to be involved with activities of the lab that you are interested in as soon as possible. Don’t wait and start early! Starting early will even allow you to switch to a different place if the work developed in your first lab does not please you. In addition to that, find a balance between “staying in a place because of the work” and “staying in a place where you feel good”, it will be important to work in a place where you have the chance to learn a lot and develop several skills, but it is equally important to look for a place where you will feel welcome. Lastly, it is important to stay up to date about the work that is being done in your area of study.

Team of Laboratory of Socioecology and Social Evolution (KU Leuven).

IS: What is your favorite place science has taken you?

I would have to say Leuven in Belgium. In 2019, I had the chance of spending three months in the Laboratory of Socioecology and Social Evolution, headed by Professor Dr. Tom Wenseelers (KU Leuven) due to the bilateral project we currently have (USP and KU Leuven). While I was there, I could visit some cities there and got the chance of meeting new people and making good friends. I got involved in different projects and worked with different European wasp species. I do not remember if I ever ate so much chocolate and fries, and drank so many different beers as I did there.

Just when you thought it was safe to go back near the water… army ant predation on river turtle nests

By Sean O’Donnell, Ph.D.

All photographs by Jana Reintjes

Based on the short communication “Predation on nests of three species of Amazon River turtles (Podocnemis) by underground-foraging army ants (Labidus coecus)” by Da Costa Reis M., Reintjes J., Chen D. and O’Donnell S. in Insectes Sociaux.

East of the northern Ucayali River in Peru is a geologically subsiding basin crossed by winding rivers and extensive wetlands. Much of this topographically flat region is flooded for several months annually by seasonal heavy rains. In this basin is the privately owned and managed Tapiche Reserve, a protected area of about 6000 ha that spans the Tapiche River. The reserve “land” is mostly under water at least two meters deep during the flood season. When the waters retreat, sandy beaches on the Tapiche River edges are visited by females of three species of Amazon river turtles (genus Podocnemis). Like sea turtles, Amazon river turtles lay their eggs in nests dug into beach soils.

(Top) A female Amazon River Turtle (Podocnemis species) nesting on a Tapiche River beach. (Bottom) A researcher removing eggs from a Giant Amazon River Turtle (P. expansa) nest.

Turtle eggs are subject to heavy human poaching on the Tapiche River, so the Tapiche Reserve staff (co-authors Murilo Reis, Jana Reintjes and Deborah Chen) have run a river turtle rescue and head-start program annually since 2012. They collect eggs from the reserve’s beaches and rear them in a guarded hatchery built on a beach at the reserve lodge. Eggs are placed in artificial nests in the hatchery, dug to dimensions that match the natural turtle nests. 

(Top) Preparing artificial nests for Amazon River Turtles in a hatchery at the Tapiche Reserve Lodge. (Bottom) Completed turtle hatchery.

Turtle egg rescue efforts were especially successful in 2020. Over 9000 eggs were collected from 240 nests of three species of Amazon River Turtles, including the first nests of the critically endangered Giant Amazon River Turtle recorded in the area. Unfortunately, in fall 2020, the hatchery was attacked by subterranean army ants (Labidus coecus). The ants entered the nests by tunneling from below. The ant raid, never visible from the surface, was impressive in its extent and its persistence. Many thousands of polymorphic L. coecus workers were observed when the turtle nests were checked over the course of nine days in October; we believe the raid was continuously active throughout this period. The army ant raid grew in intensity over time and turtle mortality in one section of the hatchery, which contained the youngest turtles, approached 90%.

(Left) A partially excavated turtle nest being raided by Labidus coecus army ants. (Center) A turtle hatchling with most of the tissue removed from its body cavity; note the L. coecus worker clinging to the carapace. (Right) Damaged turtle eggs and a dead hatchling from a raided nest.

Paleotropical driver ants (genus Dorylus) regularly attack and consume vertebrates (Gotwald 1995), but it is often assumed that the blunt, non-crossing mandibles of Neotropical army ant workers preclude piercing of vertebrate skin and predation on vertebrates. Our paper adds to a growing literature suggesting vertebrates are on Latin American army ant menus more often than has been recognized (O’Donnell et al. 2005; Sazima 2017; López-Martínez et al. 2020). Relatively immobile vertebrates (including eggs and nestlings) may be especially vulnerable to Neotropical army ant predation. Larger-bodied L. coecus workers have impressive muscle-filled head capsules and large mandibles. Our observations suggested the ants entered turtle eggs and were also able to access hatchlings’ body cavities via soft tissues such as the eyes and yolk sacks. Army ant venom may also be relevant. Hatchlings that were stung by L. coecus workers appeared to be temporarily paralyzed, and some turtles died after being stung.

            The L. coecus raid on riverside turtle nests raises interesting questions about access to the Tapiche beaches by mobile subterranean ant colonies. A small area around the lodge remains marginally above water (all of the soil is saturated) at the height of the flood season, but there are few other patches of land within several kilometers in all directions. There are two possibilities to explain a Labidus raid reaching the lodge beach: either these usually subterranean ants have some way of persisting in the area through the flood, perhaps by moving into trees or rotten logs above the water level, or the ants traveled several kilometers underground from the nearest dry land to reach the banks of the Tapiche River.   

Amazon River Turtles that survived the L. coecus raid being prepared for release in a nearby oxbow lake.

Army ant behavior present challenges for preventing predation on natural turtle nests and hatcheries. Army ant raids are massive and mobile, but some species such as L. coecus can raid continually for several days against rich food resources. Turtle nests in clusters on a beach or in a hatchery can suffer extensive damage from an army ant raid. Constructing hatcheries to prevent ant worker access from the soil beneath may discourage army ant predation, as long as abiotic conditions appropriate for turtle development can be maintained.

References

Gotwald Jr, W.H. 1995. Army ants: the biology of social predation. Cornell University Press.

López-Martínez GA,  Rondón-Zabala JI, Martínez-Parales E, Moya-Arévalo RH, Rodríguez OA (2020) Depredacion por insectos de nidos y neonates protegidos de Podocnemis vogli (sabanas inundables del Casanare). Acta Biol Colom 25:354-358.

O’Donnell, S., M. Kaspari, J. Lattke. 2005. Extraordinary predation by the Neotropical army ant Cheliomyrmex andicola: Implications for the evolution of the army ant syndrome. Biotropica 37: 706-709.

Sazima I (2017) New World Army Ants Eciton burchellii kill and consume leaf-litter inhabiting lizards in the Atlantic Forest, Southeast Brazil. Trop Nat Hist 17:119-122.