Who will be the next termite queen?

By Zhuang-Dong Bai

Zhuang-Dong’s study, exploring the evolution of a harmonious behavioral strategy to reduce conflict over reproduction in the lower termite Reticulitermes labralis can be found here. Like it -> check him out on ResearchGate.

Eusocial insects such as ants and termites represent an important biomass on Earth and ecologically dominate many ecosystems (Tuma et al. 2020; Wilson 1990). One key to this success is the reproductive division of labor among colony individuals, meaning that a minority of specialist individuals monopolize reproduction, whereas workers and soldiers raise the offspring of these breeders as helpers (Wilson 1971). In some species, when the primary queens are too old or lost, other colony individuals have the capability to develop into replacement queens soon after to undertake reproduction. In these species, the differentiation of reproductive individuals in the colony is particularly important for its prosperity.
However, my supervisor put forward a simple but profound question: “If most or all colony individuals have the same reproductive potential to differentiate into queens, conflicts are difficult to avoid because there will be a similar reproductive interest among colony members, are there any behavioral cues performed by individuals to indicate that they have priority to become replacement reproductives?”
By reviewing the literature, we found that research of this question has mainly focused on the primitive eusocial wasp Ropalidia marginata, in which, when the wasp queen is lost or removed, one and only one of the workers becomes hyper-aggressive and is then considered as the next queen of the colony. Surprisingly, this species has not just one designated heir, but a long reproductive queue and these workers successively take over the role of egg laying (Bang and Gadagkar 2012; Bhadra and Gadagkar 2008). In the termite Cryptotermes secundus, it has been first reported that butting and proctodeal trophallaxis (anal feeding) are the ‘dominance’ behaviors that indicate which workers inherit the breeding position when reproductives are absent (Hoffmann and Korb 2011). Both examples suggest that some differences of an individuals’ behavioral profile may prevent overt conflict in colonies during the replacement of reproductives. However, these behavioral traits are all shown by workers in the absence of the queen. Do workers also show some behavioral traits in the presence of the queen and do these predict differential outcomes when they have a chance to differentiate in the future?
Here, to study this aspect, we used the lower termite species Reticulitermes labralis as experimental subject, whose workers may develop into replacement queens when queens are artificially removed or dead (Su et al., 2017). First, we collected five colonies of Reticulitermes labralis from northern Qinling Mountains, Xi’an, Shaanxi Province, China (108° 46´ E, 34° 00´ N). Then, we put 100 termites (96 workers and 4 soldiers) into a Petri dish with moist filter paper at the bottom. In total, we set up 15 groups from five colonies, and all these 15 groups were reared in a controlled climate chamber to produce replacement reproductives. After one month, one or more replacement reproductives were differentiated in each group. We randomly picked out
50 individuals (48 workers, one soldier, and one replacement queen) from each of the 15 groups and kept them in another Petri dish for 2 days without disturbance to allow the termites to adapt to their new environment. Then, workers were marked with an individual color code consisting of one or two dots of paint on the abdomen and/or on the thorax.

Termites marked with color codes. The yellow arrow points out the queen, the blue arrow the soldier.

After two days, we recorded termite behaviors of these 15 groups with a camera for one hour for subsequent analysis. See an example of 10-seconds recording for two groups here:

Color marked termites in two Petri dishes.

Then, we removed the replacement queens from the Petri dishes and continued to observe the individuals until a new replacement queen appeared in each group. In the video, we tracked what the behavior of the replacement queen (when it was still at worker status) was towards other individuals in the presence of the queen. Moreover, we selected three female workers that did not differentiate into queens in each group as control. We kept observing for 3 days after the appearance of the first replacement queen to be sure that this worker who differentiated into a replacement queen was the only first one to differentiate. The behaviors measured were (i) the number of butting (one worker moves repeatedly backwards and forwards to contact another worker), (ii) the number of antennation with other workers (contacting other workers with antennae), (iii) the number of antennation with the queen (contacting the queen with antennae), (iv) the number of allogrooming by other workers, (v) the number of mouth-to-mouth feeding occurrences (as a receiver), (vi) the number of anus-to-mouth feeding occurrences (as a donor), and (vii) the locomotion time.
Our results showed that when the queen was present, the workers who successfully replaced queens in the future had three different behavioral profiles compared to workers which did not develop into queens. That is, in a group with a queen present,
the workers who differentiated into replacement queens moved less, performed more anal feeding, and were groomed more than others.
Our study revealed that the significant differences in the behaviors exhibited by workers in a group with a queen present may give priority to these workers to differentiate into replacement queens when the queen is removed. And this could be considered as an important behavioral mechanism to reduce intra-colony reproduction conflicts. Anal feeding, allogrooming, and weak mobility of workers might function as the notable behaviors indicating their commitment in the differentiation pathway. These specific workers may be regarded as the “cryptic heir” designated to be the next queen (Bhadra & Gadagkar, 2008). Moreover, these could reduce the reproductive competition among workers, like the reproductive queue without overt conflict in the primitively eusocial wasp Ropalidia marginata (Bang & Gadagkar, 2012). Instead, these workers ensure that the colony will be quickly headed by a new queen in case of the sudden death of the original one.

Bang A, Gadagkar R, 2012. Reproductive queue without overt conflict in the primitively eusocial wasp ropalidia marginata. P Natl Acad Sci USA 109:14494-14499.
Bhadra A, Gadagkar R, 2008. We know that the wasps ‘know’: Cryptic successors to the queen in ropalidia marginata. Biol Lett 4:634-637.
Hoffmann K, Korb J, 2011. Is there conflict over direct reproduction in lower termite colonies? Anim Behav 81:265-274.
Su X, Yang X, Li J, Xing L, Liu H, et al., 2017. The transition path from female workers to neotenic reproductives in the termite reticulitermes labralis. Evol Dev 19:218-226.
Tuma J, Eggleton P, Fayle TM, 2020. Ant-termite interactions: An important but under-explored ecological linkage. Biol Rev 95:555-572.
Wilson EO, 1971. The insect societies. Cambridge, Massachusetts: Harvard University Press.

Interview with a Social Insect Scientist: Madison Sankovitz

We will start off this years blog with an old friend. Madison has been Insectes Sociaux’s Social Media Editor until 2021. Her Insectes Sociaux article how the effects of ants on soil vary with elevation by comparing moisture, carbon, and nitrogen levels in soil samples can be found here.

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

MS: I am a PostDoc, and I study ecology and genomics of social insects. My dissertation centers on understanding how ants build soil nests in different temperature environments and how climate plays a role in their ability to be ecosystem engineers. I am also a queer woman, and I think diversity in humans leads to a better world, just as diversity in insects does!

Madison in the lab. The research for the Insectes Sociaux Paper was done during her PhD. She is now a Postdoc at the University of Boulder, Colorado.

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

MS: I have been obsessed with insects ever since I was a little kid. When I was five years old, if you had asked me what I wanted to be when I grew up, I would have said “entomologist”! But I didn’t know that studying insects was an actual career path. I happened to take an animal behavior course on a whim during college, and it changed so much for me. The professor, Dr. Mike Breed, was teaching the class about his honey bee research, and I remembered my early love of these animals. Mike ended up being a tremendous mentor to me, helping me through my first ant research and encouraging me to apply to graduate school. He also took me to my first IUSSI meeting, where I remember thinking, I’ve found my people!

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

MS: It’s hard to pick just one! As of now, my favorite is ants. Not only do they dominate soil ecosystems globally through their division of labor and outstanding architectural skills, but they offer a bottomless well of questions related to the evolution of sociality. But this answer may change as I learn more about other amazing insects throughout my career!

Clearly, our interviewee has changed her favourite insect over time. Although we must admit, butterflies are cool, so we’ll let it slide 🙂

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

MS: For some of my dissertation research, I built large ant farms and custom temperature chambers to observe ants building nests under the influence of various temperatures at the soil surface. Designing and building the boxes took a long time and lots of hard work and collaboration. It was the most incredible moment when I started to see the ants finally making a home in my boxes and knew I would be able to collect valuable data from my creation.

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

MS: I view science communication as an integral part of my research. My work as a scientist feels incomplete if I’m not always working on a communication project alongside my research. Over time this has taken various forms, but currently, I am focusing my efforts on improving my infographic and data visualization skills so that anyone can understand my research.

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

MS: Understanding how we can harness the power of beneficial insects, both above and below ground, to make our agricultural practices more sustainable. Assessing the complex global factors leading to pollinator decline and developing methods to mitigate the harm.

For her PhD, Madison studied the fascinating topic of ant nest building in soil.

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

MS: Shantaram by Gregory David Roberts. I would highly recommend it. It’s loosely based on Robert’s life, a robber and heroin addict from Australia who escaped prison and went to live in Bombay, India. The book explores various sides of love, happiness, friendship, pain, and regret. What it teaches most is the power of forgiveness and compassion, both towards yourself and others, in living a free life. Learning to let go to keep moving forward.

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

MS: I spend a lot of time making art, including drawing, painting, collaging, and printmaking. I adore my bicycles and ride them to both familiar and unexplored places. Roller skating is another highlight of my days – I love being on wheels!

A bee collecting pollen for her colony.

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

I am lucky to have a support system through family and friends. This idea of the solitary Ph.D. student is nonsense. I can indeed attribute my success to my hard work and ambition, but also to the support of my people, who are always there for me.

I love reading interviews where creative people speak openly about failure. There’s a fantastic book I’ve read over and over called In the Company of Women, where makers, artists, and entrepreneurs give very candid advice. For the most part, everyone fails before they succeed. And only delusional people get through life without feeling like a huge loser and/or imposter at some point.

I try my best to get into a state of flow with my work. When I completely immerse myself in my work and lose a sense of time and all other to-dos, I forget how tough it can be, and I remember what I truly love about entomology.

Finally, I remind myself how lucky I am to wake up every day and do what I do. I put myself in the shoes of young Madison and think about how ecstatic she would be to know where her future self is at in life.

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

There is no formula for success –just begin and then continue. Do the work over and over again. Everything worthwhile takes time.

You don’t need to give up parts of yourself to be a scientist. In fact, the more facets of life you explore, and the more dimensions of yourself you bring to the table, the better scientist you will be.

Don’t be afraid to express your genuine excitement about social insects! The world doesn’t need more closed-off researchers working away in the lab 24/7. Share your excitement and love for what you do.

Finally, keep doing what you enjoy, and don’t be afraid to go after what you want! Trust yourself and your ideas. You know best what you’re capable of.

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

MS: During college, I spent a semester in Australia studying rainforest, reef, and cultural ecology. Those ecosystems are vastly different than the Rocky Mountains of Colorado, where I had done all my scientific studies thus far, and I was constantly blown away by their rich species diversity and beauty. It was also the first time I really observed the effects of anthropogenic climate change; I saw coral bleaching and deforestation first-hand. It significantly changed my understanding of the state of the world and my motivations for being a scientist.

More than meets the eye – hidden variation affects how ants plant seeds of forest wildflowers

By Kirsten M. Prior and Carmela M. Buono

Kirsten’s and Carmela’s study, where they and their colleagues ask if functional variation partitions discretely between Aphaenogaster species or along a continuum in this species complex, can be found here.

Ants are high on the list of good seed-dispersing animals. Many seeds of plants capitalize on dispersal by these small yet effective dispersers by producing seeds with lipid-rich appendages called elaiosomes that are attractive to ants and nutritious for growing colonies. Approximately 11,000 plants possess elaiosomes (“myrmecochores”), with several described hotspots of myrmecochory across the globe. North American (NA) eastern deciduous forests are one of these hotspots, where 30-40% of understory plants have adaptations for dispersal by ants. Ant-dispersed plants are many of the beloved showy spring ephemerals in the forest understory, including Trilliums, bloodroot, wild ginger, and violets.

We used seeds of four common ant-dispersed plant in NA eastern forests in our study: Anemone acutiloba (Sharp-lobed hepatica); Sanguinaria canadensis (Bloodroot); Asaurm canadense (Wild ginger); Trillium grandiflorum (White trillium). Seeds with eliaosomes are shown. Photo credits: K. Prior and C. Buono

Some ants are better at dispersing myrmecochorous seeds than others. Good seed-dispersing ants are attracted to the lipid-rich appendages on seeds. They grab the appendages, carry seeds to their nest, remove the nutritious appendage and feed it to the growing brood. They then deposit the intact seed in a waste midden – often a location conducive to germination. Some ants are poor-seed dispersers in that they interact with but don’t move seeds, rob elaiosomes (remove them but not disperse the seeds), or even eat whole seeds or damage them. In hotspots of myrmecochory, there are usually only one to a handful of good seed-dispersing ants, often called “keystone dispersers.” The common woodland ant, Aphaenogaster sp., is the keystone disperser of understory myrmecochores in NA eastern deciduous forests, as they are responsible for most dispersal.

However, there is not just only one species of the keystone disperser, Aphaenogaster, in NA forests – and as it turns out, it’s a bit complicated! There are multiple described species of Aphaenogaster in the eastern US that interact with seeds – including A. fulva, A. rudis, and A. picea – that we refer to as the Aphaenogaster seed disperser complex (ASDC). A. fulva is distinguishable from the other ASDC taxa based on both consistent differences in diagnostic traits and forming a discrete genetic clade. On the other hand, the relationship between A. rudis and A. picea is more nuanced and uncertain. Overlapping and inconsistent patterns from sequence data suggest that they may not be fully resolved species at all due to incomplete divergence of ongoing hybridization. Unsurprisingly, even with a trained eye, these two named species are challenging to delineate and have overlapping characteristics, especially where they co-occur.

We collected six populations of ants in the ASDC for our study. Here they are pictured in order of populations that are more A. picea like to more A. rudis like based on variation in thorax shape, including the length and direction of the propodeal spine.

Our research team is interested in how the identity of mutualist partners (i.e., seed dispersers) affects the outcomes of ant dispersed–plant communities. How do seemingly minor differences in the behavior of ants, such as how many seeds they move and which seeds they prefer, scale up to affect plant communities? For the ADDC in NA eastern deciduous forests, we predicted that there might not only be differences among named species but also intraspecific variation along a gradient within the ASDC that coincides with population-level differentiation.

In our new paper, “Uncovering how behavioral variation underlying mutualist partner quality is partitioned within a species complex of keystone seed-dispersing ants,” Our team from Binghamton University asked if behaviors relating to seed dispersal differed discretely or continuously along a gradient between named species A. rudis and A. picea. Graduate and undergraduate students from Kirsten Prior’s ecology lab (priorecologylab.com) and Tom Powell’s (powellevolab.com) evolutionary-ecology lab teamed up for this study. First, Carmela Buono (Ph.D. candidate) and undergraduate mentee Will Smisko (Undergraduate Summer Scholar Fellow) collected multiple colonies of six populations of putative A. rudis and A. picea. In arenas with myrmecochore seeds, they ran a behavior experiment to measure foraging rates, seed removal rates, and seed preferences. Next, Carmela and undergraduate mentee Allie Radin came up with the idea to test aggression within populations, among populations (within species), and among species – as our previous work shows that aggression can affect seed dispersal behavior. 

Gabriella Quartuccia (Ph.D. candidate) and undergraduate mentee Andrew Lupinksi (Undergraduate Summer Scholar Fellow) developed an approach to quantify complex variation in the ASDC. Key diagnostic characteristics that delineate putative species are found in the thorax (for example, the length and direction of the propodeal spine). Gabby and Andrew created landmarks on the thorax to create 2D shapes and compared 2D shapes among colonies to uncover how they differed. This morphometric analysis delineated putative species, picking up known differences – such as A. rudis having shorter spines that point more upward. However, they also revealed significant colony-level (and population-level) variation, with some populations of what was initially described as A. rudis being more A. picea-like and vice versa. This approach quantified what was primarily descriptive before – that there are intermediate ants in this species complex!

Carmela Buono (Ph.D. student; first picture) led the behavior experiments with Will Smisko (Undergraduate student; third picture), and Allie Radin (Undergraduate; not pictured). Gabby Quartuccia (Ph.D. student; second picture) led the morphometric analysis with Andrew Lupinsky (Undergraduate student; not pictured). We collected colonies in ant boxes (shown in pictures). Photo credits: C. Buono, G. Quartuccia

What was exciting was when we compared colony morphometrics to colony behavior. We found differences in behavior between named species. However, we also found a relationship between colony morphometrics and behavior, such that colonies with intermediate morphotypes had intermediate behaviors!

This is an exciting finding with implications for uncovering variation in this critical ecosystem function. Our work shows that behavioral differences in ant partners are likely to affect plant communities – but not only between species but also among populations along a gradient in the ASDC. Uncovering how partner variation affects mutualisms is a critical question, yet few studies have considered intraspecific variation – despite its likely importance. Here we show that intraspecific variation is as significant (if not more) than interspecific variation, which should not be surprising in this system given that partners are in incomplete stages of speciation.

This study is an exciting starting point for understanding functional variation in this critical mutualism for our research teams. Gabby and Tom are performing population genomics in the ASDC, and the Prior lab, including Carmela and Ph.D. student Rosey Ines, are measuring variation in traits and setting up experiments to understand how functional differences in the ASDC scale up to affect plant communities. 

Collecting ants in ant boxes. Video Credit: C. Buono

Interview with a Social Insect Scientist: Eric Darrouzet

Eric’s article, where he and his co-authors analyzed whether beehives face predation threats from more than one hornet colony (Vespa velutina nigrithorax), using both hydrocarbons and microsatellites, can be found here.

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

ED: I am an associate professor at the University of Tours, where I serve as director of the Agrosciences Department (one of the university’s teaching departments). I am also a researcher at the Research Institute for Insect Biology (IRBI; UMR CNRS 7261). I mainly study chemical communication in eusocial insects, such as hornets, termites, bees, and ants.

Dr Eric Darrouzet is associate professor in the University of Tours (France). He manages a team in the Research Institute for Insect Biology (UMR CNRS) to work on the Asian hornet Vespa velutina nigrithorax.

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

ED: Early on, I studied reproductive mechanisms in parasitoid wasps and quickly moved into analysing the chemical cues that females use to maximise reproduction. Within a few years, I became interested in eusocial insects, given that chemical communication is probably the most important structuring force in their societies. My initial work was with termites (Reticulitermes species). In 2007, I got interested in an invasive eusocial insect that had arrived in France just 3 years prior: the Asian hornet (Vespa velutina nigrithorax).

I was convinced that studying chemical communication (e.g., chemical signatures composed of cuticular hydrocarbons, alarm pheromones, sex pheromones) could help develop targeted and efficient systems for controlling this invasive species. Moreover, as very little was known about this hornet, it was possible to answer numerous biological and ecological questions about it and other hornet species.

A hornet nest

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

ED: Hornet species, of course! In all seriousness, every social insect taxon is exciting to research. There are so many topics to study in insect societies, like nest architecture, communication systems, social structure, and how females become queens, just to name a few examples. At present, I am very interested in hornet species. This group was relatively little studied in the past, and so many scientific questions remain to be explored.

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

ED: That is a difficult question. However, when I discovered a parasite (Conops vesicularis) that could kill Vespa velutina foundresses (Darrouzet et al, 2015), that was a great moment. It happened like this: I was dissecting queens to show a colleague what their reproductive tracts look like. I was quite puzzled to observe a white mass in one of their abdomens because it was the first time I had observed such a structure. It turns out that it was a parasite! We demonstrated that this local species, a parasitoid fly, can parasitise and kill Asian hornet foundresses as colonies are getting started.

A hornet worker of the invasive species in Europe, Vespa velutina nigrithorax.

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

ED: I regularly do outreach to share information about social insects, their nests, and the invasive hornet V. velutina (its biology and ecology; its impacts on biodiversity, our economy, and our health; and potential control strategies). My most common audiences are students, beekeepers, everyday citizens, and journalists. Sometimes I will draw on my own work to develop points made during these outreach efforts.

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

ED: In science, all questions are important and interesting. Because it is my field of specialty, I think it is essential to analyse communication systems in social insects. Communication is the link among all the individuals making up a group, such as a colony. Sociality can only exist because those individuals are communicating.

Moreover, by analysing communication systems, we can come up with better ways for controlling insect pests, including invasive species. For example, we can develop specific baits to improve trapping systems, synthetic pheromones to disrupt reproduction, or repulsive compounds to drive away specific species, like agricultural pests. Gathering knowledge about insect chemical communication is crucial to this work.

A member of the Hornet Team is collecting hornet workers in predation in front of a hive.

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

ED: What a difficult question! Whatever the scientific domain, you wll find debates around specific questions. Inf I focus on my area of expertise – chemical communication in insects – I question the function of every chemical compound in a pheromone blend. Is it that each compound possesses a specific function or that a mixture containing a particular relative quantity of these compounds givesrise to a function? One challenge is also linked to our technical capacity to identify all the compounds present. Maybe compounds present at low levels could have an active role in the pheromone blend. However, when we are cmparing blends among individuals, it is difficult (or impossible) to analyse all the compounds present. So, in general, we focus on the main compounds so that we can obtain several fundamental pieces of information. That said, we are left wondering what insects are actually perceiving. Is it the main compounds in the pheromone blend, or all of the compounds in the blend, including those present at very low levels? It is a difficult but interesting question! I think that if there are so many compounds present, each compound must have a function. But what function is that? The question remains open.

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

ED: The last book I read was written by a colleague at my university: Le bateau de Palmyre, quand les mondes anciens se rencontraient (The Palmyre boat, when ancient civilizations met”) (Éditions Tallandier). The author, Maurice Sartre, presents what we know about travel and exploration by ancient civilizations. He shows that global trade existed thousands of years before modern times…and that humans probably faced the same problems as we do today with regards to invasive species.

A hornet nest was collected in a tree.

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

ED: I am fascinated by ancient civilizations. I have read books about Mesopotamian and Egyptian civilizations, for example. It is amazing to see what these peoples built, how they lived, and what their cultures were like.

Since I study V. velutina, I am in contact with several beekeepers, and some have become friends. Consequently, I was inspired by them to try beekeeping myself! I have my own apiary, which I got started one year ago. It is extremely interesting. I spend a lot of time observing the workers’ activities and managing my colonies. Producing my “own” honey is also fantastic! What’s more, I now have my own experimental site, right there in my garden, where I can test traps targeting V. velutina, which preys on bees.

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

ED: Doing scientific research is always difficult. We have to keep at it, trying things again and again. I remember my PhD advisor telling me that research is 90% failure and 10% success. So, challenges are a normal part of the job.

A bee hive is attacked by some hornet workers. The honey bees are stressed and stay at the hive entrance to defend their colony.

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

ED: First, I would like to bring my family. My wife and children are what is most important in my life. The second would be books. I have so many books at home, and knowledge is extremely important to me. Therefore, I would bring scientific books, technical books (we would need to figure out how to survive on that island!), and literature.

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

ED: A scientific career is influenced by so many people and colleagues. Choosing a single person is really hard. My high school biology teacher had the earliest influence on me, and she is the reason that I studied biology in college. Next, I would probably say my PhD advisor, who taught me how to be a scientist, how to think, how to implement scientific protocols, and how to rigorously approach scientific results, among other things.   

A honey bee colony could be attacked by a lot of hornets. In this example, 20 to 30 hornets were in predation. The colony was greatly impacted by the predation pressure and was killed in few months.

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

ED: It is hard to become a scientific researcher these days. If speaking to a motivated student, I would say: choose and work with a good scientific lab and team during your PhD. This team should be publishing regularly. You need to learn different techniques and publish several articles to have a chance at obtaining a position. However, the best advice I could give to young people is to listen to themselves: think hard about how you feel about your potential dissertation topic, research lab and team, and, most of all, PhD advisor. You are committing to 3 years of work!   

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

ED: Thanks to my job, I have had the opportunity to travel to different countries. For example, I was lucky enough to go to China twice for a scientific collaboration. My collaborators and I conducted research on the viruses exchanged between honey bees and hornets. It was a fantastic project. Thanks to my Chinese colleague, Dr Chunsheng Hou, I learned about apiaries in China, different hornet species, how some companies rear hornets, and practical applications involving hornets (e.g., food, traditional medicine, pest control). Scientifically, it was very thrilling. Moreover, I was able to make one of my dreams come true: I took a walk along the Great Wall!

A hornet worker killed a honey bee. The hornet collects only the thorax to feed the larvae in its colony.

Introduced species and the olfactory landscape of foraging

By Ros Gloag

A blog post about the work of the Insectes Sociaux’s 2021 Best Paper Award “Australian stingless bees detect odours left at food sources by nestmates, conspecifics and honey bees”, by Rosalyn Gloag, Jordan P Smith, Ruby E Stephens, Tim A Heard and Madeleine Beekman, Insect Soc 68:151–159. https://doi.org/10.1007/s00040-021-00823-7.

My colleagues and I received a lovely email this month to tell us that our paper had been selected for the Insectes Sociaux Best Paper Award 2021 by the Editorial Board. We couldn’t be happier to know that Australia’s amazing stingless bees are getting a bit of a spotlight!

This project arose from the combination of two lines of questioning. The first was a desire to better understand how Australian stingless bees (Tetragonula spp and Austroplebia spp) recruit their nestmates to profitable food sources. When people think of nestmate recruitment in social bees, they are likely to think of the famous waggle dance of honey bees (Apis sp.). Honey bee foragers encode information on the location of food sources in a dance, which they perform inside the darkened nest to their sisters. Stingless bees, meanwhile, have no special dance and yet are nevertheless very efficient recruiters. How do they do it? Studies of stingless bee species in South and Central America have shown that they regularly use pheromones or other odours at, or near, food sources to help guide nestmates to food. There is a relative dearth of information, however, about the recruitment mechanisms used by stingless bees in other parts of their global tropical distribution.

Honey bees and Tetragonula clypearis feeding at an artificial feeder (not as part of the study discussed here, but this photo still illustrates nicely their willingness to co-feed and the relative size of each species! (photo. R. Gloag)

Our second line of questioning involved the possible impacts of introduced bees on native bees in the ecosystems they invade. In Australia, honey bees are not native. They were brought to the continent in 1822 for beekeeping, and later naturalized throughout Australian bushland. In recent years, I have spent a lot of time studying feral Apis populations in Australia and a common question from the public is whether honey bees here impact native bees in any way. I always explain to them that scientists are very interested in this too, but that it is not an easy question to answer because any impacts are likely to be indirect (e.g. competition for resources or nest sites). Honey bees today are hugely abundant in Australian ecosystems and it is common to see them foraging on the same flowers as stingless bees and other native bees. We know that bees can detect the odours of sympatric species at flowers when foraging, but does this apply also to cases where one species is a recent invader? Do Australia’s native bees either avoid or prefer flowers that carry the “whiff” of a honey bee? If so, this could be one avenue by which introduced Apis indirectly affect the foraging ecology of native bees.

We decided to test this idea with very simple binary choice trials (see Figure 1 from the paper). In these trials, foraging stingless bees must choose between identical feeders: one of which has been previously used by other bees (that is, walked all over and potentially odour-marked) and one of which is unused (that is, clean of any bee odours). The first trials were completed in Tetragonula carbonaria by Jordan Smith as part of his undergraduate Honours project (just one of the great things he did – the other was to estimate the species foraging range here). These first trials were very interesting, clearly we needed to continue.

The beautiful spiral brood comb of Tetragonula carbonaria, one of Australia’s endemic stingless bees. (photo. R. Gloag)

Over the next few field seasons, I continued with additional trials. Ruby Stephens lent a hand once she had wrapped up her own Honours project (a great study of nestmate recognition in T. carbonaria – find it here). Progress was not fast; there were interruptions for maternity leaves, new jobs, COVID. Eventually though we had an analyzed dataset for three species of Australian stingless bee (Tetragonula carbonaria, Tetragonula clypearis and Austroplebia australis – representing the three major clades of stingless bees in Australia) each tested in foraging choice trials against the odours of nestmates, non-nestmate conspecifics and honey bees. All three species preferred feeders previously used by other bees, even honey bees, consistent with being able to detect food-marking odours and use these in their foraging decisions. We also tested two of the species (T. carbonaria and A. australis) in choice trials offering feeders marked with vanilla vs no-odour and found no forager preference, indicating it is not simply that stingless bees prefer the smelliest feeder, or that they are attracted to all novel odours.

So stingless bees in Australia use odours at food sources as part of their recruitment strategy, just like their Neotropical relatives. Those odours might be either pheromones, chemical “footprints” or a mix of the two. They also can detect and respond to honey bee odours (almost certain to be footprints in that case). What does it mean that stingless bee foragers were attracted to food sources marked with honey bee odours? My view is that it shows that stingless bees are highly adaptable foragers that can readily learn that any particular odour signals food. I suspect responses to honey bee odours might differ in different contexts, though this remains to be tested. Certainly we are left now with a whole range of new questions: How does the ability to detect the odours of introduced species impact native bee foraging in natural contexts? Do honey bees also respond to the odours of stingless bees? More broadly, how do social insects respond to the pheromones of introduced species that share their ecological space and trophic level?

We thank again the Insectes Sociaux Editorial Board for bestowing on this study the Best Paper 2021 Award, and look forward to learning more about stingless bee foraging ecology in the future.

Interview with a Social Insect Scientist: Clea Santos Ferreira Mariano

Clea’s article, where she and her co-authors Érica Araújo, Jacques Delabie reviewed current definitions of somatic developmental anomalies in ants and propose a simplified classification system, can be found here.

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

I am Brazilian and live in the state of Bahia, in the Brazilian northeast. My background is in entomology, focusing on the diversity and development of ants through the prism of cytogenetics. Recently, I have also studied the diversity of commensals that live in and around ant colonies. I teach zoology at one of the state universities of Bahia, UESC, at Ilhéus.

Photo of the authors, from left to right: Érica Araújo, Jacques Delabie and Cléa Mariano, at the State University of Santa Cruz, Ilhéus-BA

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

During my undergraduate course, I had a professor with excellent training in entomology, the late Max de Menezes. He opened my eyes to the interest in working with insects, but it was through the opportunity to go to the field to help a good friend (Riviane Bellenand) to collect ant nests (Ectatomma tuberculatum) that I discovered what I really wanted to do. It was also around that time that I started to become interested in the morphology of ants as I observed rare malformed individuals with genetic or developmental abnormalities in the laboratory. I found this fascinating and ever since then, I have been accumulating information and material on these aspects.

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

I am fascinated by ants in general, mainly because of their diversity of life habits. What I find most exciting about these organisms is that, despite being recognized as being so organized with long-awaited life patterns, there is always a species that breaks the rules, that doesn’t follow the pre-defined models. However, the ants I am more in love with are the Ponerinae of the genus Neoponera. They preferentially live in forests or agroforests, where they are rather diverse because some species can live on the ground and others on the trees, and they offer a great variation in size, behavior and use of resources. These ants are fantastic animals!

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

When I began to study the chromosomes of Ponerinae ants, karyotypes allowed me to establish well-defined groups of species not only from their chromosome characters, but also from other reasons, such as morphology and strata explored in their environment. For me, it was more evidence that cytogenetics had a great potential for studying biological diversity. Currently, we see everywhere that studies on cryptic species or integrative taxonomy and cytogenetics are a tool which allows exploring that.

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

In the undergraduate course where I am teaching, I include scientifically dissemination content of the topics studied (invertebrate zoology and social insect biology), to show to students how to bring scientific content closer to the non-academic community. In the postgraduate program in zoology, to which I am linked, we have two disciplines related to scientific dissemination with the aim not only to publicize the research work carried out, but also to prepare students in the production of this kind of material (with the theme of their own projects) in order to reach the non-academic public.

Field Travel to Belmonte with the lab team, 04/2015

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

I think it is essential that social insect scholars know the processes of evolution and maintenance of sociality, since these aspects modulate important characters of social groups. Access to this knowledge does not always imply the use of methods that include technological innovation. Natural history studies allow not only the interpretation of the mechanisms that maintain sociality, but also open doors to investigations not yet carried out. I make this observation especially in the scenario in which I am inserted: in a country and region with an exceptional biodiversity, but with a limited access to financial resources destined for so-called “basic” research. I have the privilege of being allowed to carry out experiments and observations within the grounds of my own institution (UESC) but also in the experimental areas of a close partner (Laboratory of Myrmecology at Centro de Pesquisas do Cacau CEPEC/CEPLAC), both within the Brazilian Atlantic Forest domain. This region has still an incredible potential to be explored for further studies on social insects, which sometimes compensates for the lack of resources in research investment.

I believe that integrative studies are fundamental for the future of research on social insects, i.e. putting together two or more of these disciplines: taxonomy, morphology and anatomy, genetics, behavior, biogeography, community ecology (mutualism, commensalism, competition, etc.). Also all the topics traditionally considered “natural history” are important and cannot be forgotten.

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

I am especially interested in the nature of interactions between social insects and the organisms associated with them, whether in their nests or inside their own body: how these relationships are established, what are the recognition mechanisms that “allow” the entry and fixing of these organisms to the social organisms (for ants, see the paper of von Beeren et al., 2021, Frontiers in Zoology https://doi.org/10.1186/s12983-021-00427-8).

Comite of Organization, Myrmecology Meeting at Ilheus, 2015

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

As a scientific book, the last book that I read was the biography of Alexandre Yersin (Peste et Choléra, Patrick Deville, Femina Literary Prize in France in 2012). I strongly recommend it not only for the exceptional life of this scientist but mainly because this text is an ode to perseverance, which may be one of the first qualities of a researcher.  

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

Cooking and reading. I also love going to the beach. The entire coastline of Bahia is wonderful.

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

I remember hard times I have gone through, I think of other people who had fewer opportunities or who went through bigger problems than mine, I breathe and try to move on (sometimes this can take a few days).

Exploring ant nest in the cocoa pod.

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

A pad of paper, a box of pencils – to write, talk to myself and plan for the future. And a blanket, to feel myself welcomed.

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

I would be unfair if I didn’t name the three people who have influenced me the most in my career:

Jacques Delabie is an example of the generosity of a person who, in a conversation, can lead you to think of a thousand projects, who strives that each one he works with grows, offers opportunities for everyone to succeed. He always encouraged me, during our conversations and our coexistence.

My graduate advisor, Dr. Silvia Pompolo, who is an exigent (in the good sense) professional and is for me the personification of the necessary care for research work, the exact application of laboratory protocols; always fair and interested in everything new in social Hymenoptera cytogenetics.

Finally, I cannot forget Professor Lucio Campos, who managed (before he retired) to stimulate any student’s interest in social insects, simply by talking during a walk from the university to the city center.

All of them I consider influential for me not only because they supported and guided me in the beginning of my research, but also because of the example of human resources trainers that they are.

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

Do not make a prejudgment, open your eyes, don’t get stuck in a bubble, however good your research proposal may seem.

“Innovation” research currently represents progress, but there is still much that can be studied in social insects.

Be curious, read a lot and observe even more; for each question you have already answered continue with “what if…?”

Listen to the more experienced, but also ask your own questions and hypothesize.

Work as a team; follow the example of social insects.

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

Tropical forests are my favorite places, especially the Amazon. The strength and, at the same time, the fragility of this type of environment are impressive. Just thinking that the answers to so many questions about the diversity of life are in front of us and we can help to understand and that we can lose so much richness in a few generations leaves me astonished…

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.