Biting down on colony membership in the Eastern subterranean termite

A blog post highlighting the article by V. Simkovic, G. J. Thompson, J. N. McNeil in Insectes Sociaux

By Vicki Simkovic

If you want to discover the secrets of life as a subterranean termite, you (literally) have to dig beneath the surface. Hidden from view, termite colony members (namely workers) are busy excavating and connecting networks of foraging tunnels to various food and nest sites. Each termite worker is small, delicate and soft-bodied, yet is formidable and impressive as part of its larger colony. A colony containing thousands to millions of termites – made up of workers, soldiers and reproductives – can build hundreds of intersecting tunnels within an hour and in urban centers a single colony can stretch across several city blocks. How they determine who belongs to which colony, however, is not as clear as you might expect.


Eastern subterranean termite (Reticulitermes flavipes) workers.   Photo: V. Simkovic

One integral aspect of social living is maintaining well-defined colony boundaries through the defense of nest territory, keeping colony members safe in the colony and defending the colony from intruders. Among termites, both workers and soldiers participate in defensive behaviors, which can be both active (i.e. biting, lunging, stinging) and passive (social avoidance or blocking tunnel entrances) (Šobotník et al., 2010; Prestwich 1984). However, in some cases, colonies may take on a more diffuse form with no obvious inter-colony aggression or nestmate recognition. Why some colonies are well defined (‘closed’) while others are diffuse (‘open’) is not well understood.

To find out more, we studied Canadian populations of the Eastern subterranean termite (Reticulitermes flavipes), as they provide an interesting case study in nestmate recognition and territorial defense. Colonies of R. flavipes are found in isolated pockets in Ontario, having been introduced to the province on at least three separate occasions (Scaduto et al. 2012). Populations show a mixture of open versus closed societies, they may vary in their propensity for inter-colony aggression or resource defensiveness, and their differing backgrounds provide a potential source of genetically variable recognition cues (Scaduto et al. 2012). In the City of Toronto, termite colonies show low levels of genetic diversity, low inter-colony aggression (Grace 1996), and are more typical of invasive ‘open societies’. In contrast, termites in the Pelee region form discrete colonies that are genetically well differentiated from each other (Raffoul et al. 2011). The Pelee termites live independently of any human habitation, are potentially native to the area (Kirby 1965) and are effectively ‘closed’ societies.

Finding out about the cryptic world beneath our feet is not always easy. As termite behaviour occurs underground, we need to collect a sub-sample of live individuals and study their interactions in artificial lab-designed arenas or assays to evaluate their behaviour. However, designing an assay that truly reflects field conditions can be challenging. One method common method in termite and ant aggression studies is using a Petri dish lined with moist filter paper. Although convenient and easy to replicate, this artificial situation may not reflect ecological context, particularly for termite species, which are soft-bodied and desiccate quickly in open air. In previous studies using Petri dishes, R. flavipes showed no evidence of aggression towards non-nestmates (either intra or interspecific) and possibly a lack of nestmate recognition (Polizzi and Forschler 1998; 1999; Bulmer and Traniello 2002a, b; Fisher and Gold 2003; Perdereau et al. 2011).


Petri dish trials.   Photo: V. Simkovic


Resource Foraging Design: experimental set-up used to examine the distribution and survivorship of workers as they tunnel and forage through a shared resource. Side containers consisted of moistened inert sand, joined by eight small glass tubes to the central chamber that contained moist sand, 60g of water-soaked maple and oak shavings, two corrugated cardboard rolls and small wooden blocks. Two longer glass tubes also directly joined the compartments. Photo: V. Simkovic

We paired Ontario populations (Toronto and Pelee colonies) of R. flavipes of varying geographic distance in both short-term (5-minute) Petri dish and longer-term (2- and 7- day) shared-resource assays, in order to test for evidence of aggression or nestmate recognition. The resource-design assay was meant to be more reflective of field conditions and introduce the soil interface, simulating two colonies meeting and foraging at a central food resource. In Petri dish trials, we found no evidence of aggression or nestmate recognition. However, in shared-resource assays we observed very little inter-colony mixing and high mortality in non-nestmate pairings, indicating that R. flavipes can sort and potentially compete on the basis of nest origin, and that this recognition is influenced by ecological context. In our study, the soil interface was essential as aggressive encounters occurred while the termites were foraging for new resources. This behavior would not be evident from Petri-dish style assays, which lack the soil interface and may explain why prior studies of nestmate recognition have had mixed results. These results therefore highlight the importance of designing an assay that accurately reflects the ecological context of a species.



Šobotník J, Jirošová A, Hanus R (2010) Chemical warfare in termites. J Insect Physiol 56:1012–1021

Preswitch GD (1984) Defense mechanisms of termites. Ann Rev Entomol 29:201–232

Scaduto DA, Garner SR, Leach EL, Thompson GJ (2012) Genetic evidence for multiple invasions of the Eastern subterranean termite into Canada. Environ Entomol 41:1680–1686

Grace JK (1996) Absence of overt agonistic behavior in a northern population of Reticulitermes flavipes (Isoptera, Rhinotermitidae). Sociobiology 28:103–110

Raffoul M, Hecnar SJ, Prezioso S, Hecnar DR, Thompson GJ (2011) Trap response and genetic structure of Eastern subterranean termites (Isoptera, Rhinotermitidae) in Point Pelee National Park, Ontario, Canada. Can Entomol 143:263–271

Kirby CS (1965) The distribution of termites in Ontario after 25 years. Can Entomol 97:310–314

Bulmer MS, Traniello JFA (2002a) Foraging range expansion and colony genetic organization in the subterranean termite Reticulitermes flavipes (Isoptera: Rhinotermitidae). Environ Entomol 31:293–298

Bulmer MS, Traniello JFA (2002b) Lack of aggression and spatial association of colony members in Reticulitermes flavipes. J Ins Behav 15:121–126

Fisher ML, Gold RE (2003) Intercolony aggression in Reticulitermes flavipes (Isoptera: Rhinotermitidae). Sociobiology 42:651–661

Perdereau E, Dedeine F, Christides JP, Dupont S, Bagnères AG (2011) Competition between invasive and indigenous species: an insular case study of subterranean termites. Biol Invasions 13:1457–1470

Untangling the opposing effects of ants on plants: lessons from the field

ants harvesting

Ants harvesting.   Photo: A. Fargi-Brener and M. Tadey

A blog post highlighing the Insectes Sociaux Best Paper Award Winner for 2017

Alejandro Farji-Brener and Mariana Tadey received the prize for their paper “Consequences of leaf-cutting ants on plant fitness: integrating negative effects of herbivory and positive effects from soil improvement”. This paper appeared in the February 2017 issue of the journal and can be found here.

Written by Alejandro Farji-Brener and Mariana Tadey

At the same time that I [Alejandro] was working on the ecology of the leaf-cutting ant, Acromyrmex lobicornis, in the north-western part of the Patagonian steppe (Argentina), Mariana was investigating the indirect effects of livestock on pollination in the Patagonian Monte Desert, 400km away from my study site. Mariana told me about the great abundance of leaf-cutting ants in her study area and soon we started our first ecological investigations there. It was interesting because in the Patagonian steppe, leaf-cutting ants were restricted to roadsides and in the Monte Desert, they were everywhere!

Looking at the ants, it was very impressive to see them harvesting a lot of plant species and dumping huge amounts of organic waste on the soil surface. We knew about the literature describing the potential negative effects of leaf-cutting ants as plant-damaging herbivores and the literature describing their positive effect on vegetation as soil improvers via dumping their nutrient-rich organic waste. Given these opposing effects of ants in an ecosystem, we wondered what their net effect was on the nearby plants.

Acromyrmex nest mound (above) and its waste piles (below)

Acromyrmex nest mound (above, pictured with measuring tape) and its waste piles (below). Photo: Farji-Brener and Tadey

Up to this point, several studies demonstrated the trade-off between herbivory and nutrient intake under greenhouse conditions. However, there were few studies investigating what happens in nature were plants are subjected to both situations, the loss of green tissue by ant defoliation and the enhanced plant growth caused by the ant-generated organic waste piles. Given that in this water poor habitat, both the loss of photosynthetic tissue and nutrient availability are key factors for the health and survival of plants, we thought that the net consequence on plant fitness should depend on the relative importance of these opposite ecological effects. Hence, we started our research about the fitness of native plants growing on, or near, ant organic waste piles (our nutrient hot spots) and on bare soil.

In our study site, plant species were differentially subject to defoliation by leafcutter ants, but there was no clear pattern of growth compensation for defoliation due to plant growth on organic waste. We proposed that this lack of compensation was caused by the water limitations imposed by the aridity of this environment, which restricted nutrient uptake for the plants. Overall, our work suggests that the interpretation of nice outcomes from controlled experiments may be unsupported by work under field conditions, highlighting the importance of the ecological context in scientific studies. Studies like ours allow us to include the particularities of ecosystems into theoretical frameworks so we can improve our understanding of how ecosystems work. Our study also shows how collaboration among scientists can lead to a big change our understanding of how organisms interact in nature.

ants carrying leaves

Ants carrying leaves. Photo: Farji-Brener and Tadey.

Teleporting ants: how foragers cope with unusual navigational tasks


Melophorus bagoti.   Photo: Patrick Schultheiss

A blog post highlighting the article by C. A. Freas & K. Cheng in Insectes Sociaux

By Cody A Freas and Ken Cheng

Imagine that you travel from your house to your favourite restaurant by walking 10 blocks due west and then need to return home. Under normal circumstances you would simply walk back 10 blocks due east. Ant foragers travelling from home to find food, can easily return to the nest in this situation through a process called path integration. During path integration, ants count their steps to estimate distance and use the sky to keep track of their current direction, combining these two measurements to travel back home. Now let’s imagine a less conventional trip. After travelling 10 blocks to the west, you leave the restaurant and are suddenly transported 10 blocks south of home. The first time this occurs you may have some difficulty, yet if this happens every time you make this trip, you would most likely become rather talented at managing this new homeward route. Humans and other animals can deal with unusual navigational problems such as teleportation by using familiar visual cues like landmarks in their environment (Warren et al. 2017).

Ants can also learn to adjust their homeward trip when the outgoing and incoming journeys do not match, by shifting the direction of their path integration system. Ant foragers will keep track of their direction and distance on both the outbound and inbound portions of their foraging trips. On succeeding trips, an ant can learn to shift its homeward direction based on experience during previous trips, which is called calibration. Earlier work involving these shifts in ants has focused on Cataglyphis fortis, a north African species living in environments with no landmarks where these foragers are able to partially shift their homeward heading after being displaced every time they collect food from a feeder (Collett et al. 1999; Wehner et al. 2002). Yet these foragers are unable to fully shift their homeward direction to the correct nest direction even after many trips, instead taking a compromise direction. In the current study, we explored this navigational process in the Australian desert ant Melophorus bagoti, a species living in areas with many landmarks (buildings, trees and bushes) which could help guide these ants after being moved off their normal route. Each time a forager reached a feeder and picked up some food, we moved them to another location 45º, 90º, 135º, or 180º away from the nest-feeder path and then allowed them to return home. Before releasing each forager, we tested their homeward heading in a uniform arena designed to block the surrounding landmarks and only allow ants to rely on path integration to navigate. The purpose of this test was to see how quickly and the degree to which their path integration system changed or calibrated in response to having different outgoing and incoming trip directions.

We found that foragers learn to acclimate to teleportation quickly. After being teleported on three consecutive trips, these foragers began to choose a compromise direction between their original position and their teleported position. Furthermore, we found that these foragers continued to improve over the first ten trips ultimately reaching a plateau. The directional difference (45º, 90º, 135º, or 180º) of the outbound and inbound trips appears to affect the degree to which ants can shift to the inbound path. When the difference is small (at 45º), ants are able to shift completely to the homeward direction and many return directly home. Yet as the difference between routes increases, ants shift less, choosing compromise directions at 90º and 135º locations. When we transported the foragers 180º from the feeder route, the ants did not shift their homeward path at all. These ants will travel in the wrong direction every time they are moved 180º off outbound route even after 25 trips.

The underlying cause of the differences we find in M. bagoti when compared to C. fortis remain unknown, but it is possible that the presence of landmark cues plays a large role. M. bagoti inhabits a cluttered habitat with many landmark cues to guide them when they are moved off the outbound route, while C. fortis lives in a barren desert and must search to find the nest after being moved. The presence of landmarks during training in our study may help M. bagoti foragers find the correct homeward direction easily, resulting in larger shifts just as recognisable landmarks would help a teleported human return home from a similar trip. To further explore this question, we hope to replicate this experiment on a third desert ant species endemic to southern Spain (Cataglyphis velox) which is closely related to C. fortis yet lives in cluttered environments similar to M. bagoti.


Collett M, Collett TS, Wehner R (1999) Calibration of vector navigation in desert ants. Curr Biol 9:1031–1034

Warren WH, Rothman DB, Schnapp BH, Ericson JD (2017) Wormholes in virtual space: From cognitive maps to cognitive graphs. Cognition, 166:152-163.

Wehner R, Gallizzi K, Frei C, Vesely M (2002) Calibration processes in desert ant navigation: vector courses and systematic search. J Comp Physiol A 188:683–693.

What’s in a face?

Highlighting the article written by R. Branconi,  D. Baracchi , S. Turillazzi and R. Cervo (2018) in Insectes Sociaux

Written by Insectes Sociaux Editor-in-Chief, Michael Breed (


Polistes dominula Photo: Jean-Raphaël Guillaumin/flickr


Social recognition in animals often relies on multiple cues representing disparate sensory modalities.  Humans can individually identify others using several types of cue, including voice, appearance, gait, odor, and mannerism. This redundancy makes social recognition particularly robust to changes in surrounding conditions. Even in full darkness human individual recognition is accomplished by voice and odor. The use of overlapping information sets in recognition suggests that identification of others is a key adaptive trait in human social biology.

In eusocial insects, social recognition is equally important and often relies on chemical cues carried on the external surfaces of colony members.  A very large body of literature supports the use of chemical cues in social recognition in a wide variety of bees, ants, wasps and termites (Breed 2014).  Odors work well in the dark environments of nest interiors and can be blended among workers to yield colony-level identity badges.

The finding, slightly over a decade ago, that a species of paper wasp, Polistes dominula (=dominulus), uses visual signals for social recognition was surprising and, indeed, revolutionary (Tibbets 2006). Other wasps, such as Liostenogaster, are now known to also use variation in facial markings as social signals. The social use of visual signals is probably facilitated by the openness of Polistes nests, allowing vision to function as a cue when wasps are on the nest surface. The variability in cuticular marking patterns is an important component of this system, and significantly, the degree of variability differs among populations of P. dominula.

In this issue Branconi et al (2018) test the function of facial pattern variation in an Italian population of P. dominula. Branconi and colleagues found no evidence for social discrimination based on facial markings. Their extensive experiments were performed in two behavioral contexts, competition during foraging and nest defense.  They carefully controlled for odor and movement cues, but did not manipulate potential visual signals by modifying markings on the animals’ faces.  In this respect, the experiments differ from those of Tibbets (2006 and a series of more recent studies), leaving a gap that should be filled in future work. The findings of Branconi et al (2018) follow on a similar set of tests in a Spanish population by Green and Fields (2011) which also yielded negative results.

The Italian and Spanish populations have far less phenotypic variation in facial markings than the North American population, an interesting factor in the evolutionary dynamic. A very salient question is whether in the North American population release, from the evolutionary pressures of parasites or predators that are present in the wasp’s native habitat, has relaxed canalization of facial patterns. High levels of signal stereotypy are perfect for species recognition, which is valuable in exclusion of intruders to a nest. On the other hand, highly variable signals are foundational for individual recognition (Breed and Bekoff 1981).

As a general feature, social wasps may have evolved to use visual signals in species identification. Stereotypical, at the species level, cuticular color patterns are prominent in many wasps. Perhaps aposematic signals were co-opted in evolution for recognition purposes.  Perhaps it went the other way, with initial selection pressure for interspecific variation in coloration for identification purposes, and then enhancement of these signals through selection for increased aposematic value.  Explorations of the evolutionary pathways leading first to cuticular coloration patterns and then to intraspecific variation in pattern will yield fascinating results.

This study should stimulate reflection on the value of negative results, and of the importance of expressing negative results as contributing to a larger view of a problem, rather than invalidating a specific set of previous studies. There is no basis in Branconi et al’s (2018) results and interpretation to question the veracity of the findings from the North American population, and Branconi et al (2018) have in a quite laudable way steered clear of questioning the earlier findings. This study should open the door to truly matched studies between North American and European populations of P. dominula, as well as to deeper considerations of the evolutionary dynamics that have caused wasp populations to differ so dramatically in phenotypic variation of visual signals.


Branconi R, Baracchi D, Turillazzi S, Cervo R (2018) Testing the signal value of clypeal black patterning in an Italian population of the paper wasp Polistes dominula. Insectes Sociaux

Breed MD (2014)  Kin and nestmate recognition: the influence of W.D. Hamilton on 50 years of research.  Anim Behav 92:271–279

Breed MD, Bekoff M (1981) Individual recognition and social relationships. J Theoret Biol 88:589-593

Green JP, Field J (2011) Interpopulation variation in status signalling in the paper wasp Polistes dominulus. Anim Behav 81(1):205–209.

Tibbetts EA (2006) Badges of status in workers and gyne Polistes dominulus wasps. Ann Zool Fenn 43:575–582


Michael Breed, Department of Ecology and Evolutionary Biology, The University of Colorado, Boulder, Boulder CO 80309-0334 USA



Happy New Year! And we’re seeking a new Social Media Editor

Happy New Year social insect enthusiasts!

It’s been a big year. The Insectes Sociaux blog has had over six thousand readers from all over the globe. I would like to take this opportunity to express my heartfelt thanks to all of the blog contributors and interviewees for providing some brilliant content for the blog. I will be leaving my position as Social Media Editor with great memories, as you have made my job very enjoyable and rewarding. We will be seeking my replacement in the next few months.

I’ve had a brilliant two and a half years with Insectes Sociaux but it’s time for me to move on. This has not been an easy decision for me to make, but life (as it tends to do) has taken me on a different path and I think it’s time to let someone else experience this wonderful opportunity.

Part of what makes working for Insectes Sociaux special is that it is a truly international journal and the success of the journal depends on global science conducted by individuals at all career stages, all over the world. Since I became Social Media Editor, I have sought contributors to the blog that have been as diverse as the contributors to the journal. This has not only increased representation of all groups in the diverse social insect community, but has also increased the impact of the blog, as more social media users share the blog with the members of their increasingly global networks. I am proud to have been a part of this and hope to see this diversity continue in the future.

For those of you who may be interested in the becoming the next Insectes Sociaux Social Media Editor, I offer a brief description of how the role worked for me. For about two hours a week, I spend my time contacting potential blog contributors and social insect scientist interviewees, managing Twitter and Facebook, finding images and videos to complement the blog posts and laying out the blogs for publication on the WordPress site. But most of all, I spend time editing the blog posts, working with the authors to present their research and their experience doing it in the clearest and most engaging way for a non-expert audience. My aims have been to make the science accessible and to help the blog contributors find their voice.

If this sounds like something that you might want to take on, please get in touch with me at or Prof. Michael Breed, Insectes Sociaux Editor-in-Chief to express your interest.

Thanks again everyone,


Interview with a social insect scientist: Michael Breed

IS: Who are you and what do you do?

MB: My name is Michael Breed, and I am a professor at the University of Colorado, Boulder, where I have taught since 1977. My chief passions are my research on social insect behaviour and ecology, and teaching animal behaviour. I also direct a Residential Academic Program with about 400 first year college students in one of my University’s dormitories, Baker Hall.

IS: How did you end up researching social insects?

MB: By good fortune I landed in graduate school at the University of Kansas. As an undergraduate I’d developed an interest in insects and I applied to graduate programs in entomology, but I didn’t have much of an idea about how to go about applying for graduate schools so I just applied to entomology programs that were ranked in the top ten by the National Research Council. I was pretty clueless about differences among programs and the importance of choosing an advisor. I also had money limitations and couldn’t make more than a couple of visits to check out programs. By very happy coincidence KU was close to my parents’ home in Kansas City and I went over to Lawrence and met Professors Michener (Mich), Taylor and Bell. I must have made a positive impression on Mich because later they offered me admission and Mich offered me an assistantship working on sweat bees. At that point I didn’t even know what a sweat bee was, but I was glad to have the job and to get started. It only took a week or two of doing experiments on Lasioglossum zephyrum for me to hooked, both on bees and on the study of social behaviour.

My story is pretty much the opposite of how I would advise one of my undergraduates when they’re applying to graduate school. It also shows how being a little random in making life choices can work out well.

Before leaving this topic, I want to mention that as an undergraduate I majored in both English Literature and Biology and I was equally interested in the two areas. I made my decision to apply to graduate school before I chose between literature and biology, based on my desire to teach at the college level. My self-perception was that I wanted to do the actual creative process, rather than study the results of the creative process. In literature, to me this would have meant a career in creative writing and I didn’t feel confident in my ability to succeed as a novelist. In science, the creative process of identifying a big question, proposing specific hypotheses, designing experiments, and interpreting the results seemed much more accessible. I’ve been very glad that I made this choice but I have also maintained my lifelong interest in literature.

IS: What is your favourite social insect and why?


Paraponera clavata. Photo: bathyporeia/Flickr

MB: Paraponera clavata, also known as the bullet ant or the giant tropical ant. I was at La Selva Biological Station in Costa Rica in the early 1980s working on a cockroach project that wasn’t going well. I walked out to La Selva’s arboretum and sat on a log to think things through, and a Paraponera worker walked up close to where I was sitting. I had read about ponerines in Wilson’s Insect Societies and knew they were both fascinating and understudied and this Paraponera worker looked so studiable! And I would have to say cute in a puppy-like way! That one encounter started a super satisfying research thread that carried me back to La Selva nearly every year for two decades.

Ironically, Paraponera are no longer thought to be in the Ponerinae, but they hold their own little taxonomic niche and knowing about them still helps to inform understanding the evolution of social mechanisms in ants.

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

MB: I really like it when someone replicates a result I had or when I hit on the same result as a group working in parallel with me. This tells me that I’ve chosen a topic that other scientists think is interesting, and independent replication is rare in behaviour and ecology. The first instance I can think of this was when I was working on queen recognition in honeybees and it turned out that Rolf Boch and Roger Morse had been working along the same lines—I saw the two studies as mutually confirming and as together being more convincing than either would have been separately. Since then I’ve had this happen several other times, and each time I’ve thought it was very exciting to know that what I had thought/interpreted was more likely to be actually true.

IS: If teaching is part of your work, what courses do you teach? Has your work on social insects helped to shape your teaching?

MB: I teach animal behaviour to about 110 students each fall semester. Most of them are more interested in birds and mammals and I’ve had to adapt to addressing their interests but that doesn’t keep me from scattering in social insect examples along the way. Teaching remains exciting and challenging, in a good way, for me. The excitement comes from helping the students to understand concepts that have motivated me through my career. The challenge comes from the continuous change in the students. This year’s students are different in their needs and capabilities than last year’s, and over longer periods of time there is definitely major change—the gen-xers were so much different than the millennials and the post-millennials are yet different again. Nothing against the previous generations but I probably like the post-millennials the best—my current students are really delightful to work with. I hope that knowing about social behaviour on the level of insects helps me to be somewhat cognitive about the group personality of my students.

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

MB: I just finished Woman in White by Wilkie Collins. This is a classic, one of the progenitors of the genre of detective fiction, and I decided to re-read it as an escape from all the science stuff. I tend to have more than one book going at a time, so I’m also reading John Le Carre’s new George Smiley book, Call for the Dead, as well as Draft No. 4, On the Writing Process by John McPhee, and The Abundance, a collection of essays by Annie Dillard.

Of the four, I’d recommend reading Dillard to all biologists—there’s an essay in this book about viewing a solar eclipse that was originally published in Teaching a Stone to Talk that really resonated with me based on my experience seeing the eclipse this last August. McPhee’s take on the writing process is very unique, but I also think this book is a great read if you’re interested in the craft of writing. You have to have patience with Victorian prose and with a writer who apparently was paid by the word to read Collins, but there are real rewards in being immersed in such a well-crafted story.

IS: Did any one book have a major influence in shaping your career? What was the book and how did it affect you?

MB: When I was a new graduate student, my major advisor, Charles Michener, gave me a copy of the proof of his book, The Social Behavior of the Bees, to read. The fascinating stuff in this book about bee behaviour shaped my graduate work and ultimately my career. It was published in 1974 and I think it’s still a great place for any bee biologist to start.

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

MB: Hiking, photography, attending theatre productions, and playing poker.

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

MB: I tend to use work to distract myself from distressing things, so if I have something difficult going on I’ll bury myself in work. Unfortunately, though, a career in science is a lot about rejection—journal submissions and grant proposals that are turned down—and it is key to be able to persist despite defeats. Like most people sometimes I have to fight self-doubt in the form of imposter syndrome. The sheer joys of discovery and of working with students serve as great counterbalances to occasional feelings of inadequacy. Having supportive family, good friends and positive social relationships really helps.

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

MB: My wife, Cheryl, a dog (we’d have to get a new one as ours passed away last spring), and writing materials. If a person and a dog don’t count as “things” then I’d say writing materials, a computer chess game, and hiking shoes.

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

MB: Without a doubt, my major professor, Charles Michener. He was a kind and generous mentor. I wrote an essay for this same blog about him that talks about what a great mentor he was:

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

MB: Use your time effectively. I have an old New Yorker cartoon on my desk that shows deadlines arriving like waves rolling into a beach that I look at when I’m tempted to procrastinate. Keeping on top of what needs to be done next is so very important. Do the most important thing first, not the easiest thing. Don’t mistake answering emails for actually getting work done. But also keep in mind that to be effective in your work you need to eat well, sleep, exercise and have a social life.


Army imposters: the art of blending in

A blog post highlighting the article by S. Pérez-Espona, W.P. Goodall Copestake, S. M. Berghoff, K. J. Edwards, N.R. Franks in Insectes Sociaux

By Sílvia Pérez-Espona

Neotropical army ants of the genus Eciton represent one of the many fascinating examples of interaction between species, with hundreds of (vertebrate and invertebrate) species reported associated with Eciton burchellii, and many more yet to be described (Rettenmeyer et al., 2011). Among the plethora of species found with this army ant, are the staphylinid beetles belonging to the genera Ecitophya and Ecitomorpha. These beetles have evolved to mimic the appearance and colouration of the most abundant worker cast (medias) of different Eciton species. These army ‘imposters’ are considered hunting guests, as they are found in the conspicuous raiding (and emigrating) columns of Eciton colonies ants where they feed on dropped prey or at booty caches. The mimicry of these two genera of myrmecophiles can be explained as a combined strategy to avoid predators (Bayesian mimicry) and to integrate into colony life (Wasmannian mimicry).


Ecitophya simulans next to an Eciton burchellii foreli media worker. Photo: Taku Shimada.

This intriguing example of mimicry and adaptation of Ecitophya and Ecitomorpha with their Eciton host was first described by Erich Wassmann in the late 19th century. Since then, studies of these two myrmecophile genera have mainly focused on resolving their challenging taxonomy as well studies of their behaviour in the field (e.g Akre and Rettenmeyer, 1966; Kistner and Jacobson, 1990; Reichensperger, 1935, 1933). We took a genetic approach to assess the evolutionary relationships between Ecitophya and Ecitomorpha with their Eciton hosts, with a special emphasis on the association of these myrmecophiles with E. burchellii, the only Eciton species known to harbour both beetle genera. To this end, we sequenced the same mitochondrial marker, cytochrome oxidase subunit I (COI, cox1), for ants and beetles collected from colonies located in west (Bosque Protector de Palo Seco, Reserva Forestal Fortuna) and central Panama (Área Protegida de San Lorenzo National Park and its buffer zone). COI is a maternally-inherited genetic marker widely used for studies assessing phylogenetic relationships between closely related taxa, as well as phylogeographic and population-level studies such as the ones we conducted in our study. Phylogenetic, molecular clock and population genetics analyses were conducted in order to determine the degree of specialization of species of Ecitophya and Ecitomorpha to their Eciton host. If there was a high specialization of the myrmecophiles with one particular host, molecular signatures would support earlier taxonomical classifications of Ecitophya and Ecitomorpha by Reichensperger (1933, 1935), based on the assumption that each myrmecophile species evolved to adapt to colony life of a particular Eciton species.


Raiding column of Eciton burchellii foreli. Photo: Silvia Perez-Espona

Indeed, our analyses revealed that Ecitophya and Ecitomorpha are truly host-specific and thus support the earlier taxonomic classifications by Reichensperger. Therefore, current taxonomic classifications that considered a lack of consistent morphological characters to support Reichensperger’s views need to be revised. Phylogenetic relationships between species of Ecitophya (found with different species of Eciton, in contrast to Ecitomorpha which is only found with E. burchellii), however, did not mirror those of their host; indicating that at this more specific level, the evolutionary path of this myrmecophile differed from that of its Eciton hosts. These analyses also provided further insights into the taxonomy of Eciton burchellii, indicating that the genetic divergence between the subspecies E. b. foreli and E. b. parvispinum was higher than between other recognised Eciton species, and that therefore E. burchellii ‘s taxonomy also warrants further taxonomical revision. Our molecular clock analyses indicated that the diversification of Eciton is likely to pre-date the diversification of the myrmecophiles and that Ecitophya’s species diversification (and therefore potential association with Eciton) might be older than that of Ecitomorpha. This possible earlier association of Ecitophya with Eciton, and therefore longer time-frame to adapt with the host, could explain why beetles from this genus are found with a larger number of Eciton species.

Population-level analyses of the Ecitophya and Ecitomorpha associates of Eciton burchellii showed strong patterns of population structure between colonies at broad geographical scales (west versus central Panama). In contrast, higher gene flow was observed at small geographical scales, with Ecitophya and Ecitomorpha lineages not being Eciton lineage- or colony-specific. Gene flow within each species of myrmecophile was also detected across the Chagres River, a landscape feature that acts as dispersal barrier for E. burchellii females (Pérez-Espona et al., 2012). This, therefore, confirms a higher dispersal ability of female Ecitophya and Ecitomorpha than their Eciton hosts. Morphological studies have described fully developed wings in both myrmecophiles (Kistner and Jacobson, 1990); however, flight ability in these beetles has only been reported anecdotally as observations of hovering during disturbance of colonies (Mann, 1921; Pérez-Espona pers.obs.). Considering the strong specialization to their host, and the likely dependence of these myrmecophiles to colony life, it is possible that the main dispersal events between colonies might take place by the beetles riding on alate Eciton males when they leave their natal colonies in search of a mate.

Ecological and evolutionary studies of Ecitophya and Ecitomorpha with Eciton army ant colonies are still in their infancy. This study demonstrates the usefulness of genetic approaches to provide insights into the biology and evolutionary history of these myrmecophiles with their Eciton hosts, as well as to help resolve the taxonomic challenges they present. We hope that our study will serve as a platform for the many further investigations that are still needed to fully understand this captivating manifestation of Darwin’s ‘entangled bank’.


Akre, R.D., Rettenmeyer, C.W., 1966. Behavior of Staphylinidae associated with army ants (Formicidae: Ecitonini). J. Kansas Entomol. Soc. 39(4), 745–782.

Kistner, D.H., Jacobson, H.R., 1990. Cladistic analysis and taxonomic revision of the ecitophilous tribe Ecitocharini with studies of their behavior and evolution (Coleoptera, Staphylinidae, Aleocharinae). Sociobiology 17, 333–480.

Mann, W.M., 1921. Three new myrmecophilous beetles. Proc. United States Natl. Museum 59, 547–552.

Pérez-Espona, S., McLeod, J.E., Franks, N.R., 2012. Landscape genetics of a top neotropical predator. Mol. Ecol. 21, 5969–5985. doi:10.1111/mec.12088

Reichensperger, A., 1935. Beitrag zur Kenntnis der Myrmecophilenfauna Brasiliens und Costa Ricas III. (Col. Staphyl. Hist.). Arb. iiber Morphol. Taxon. Entomol. aus Berlin-Dahlem 2, 188–218.

Reichensperger, A., 1933. Ecitophilen aus Costa Rica (II), Brasilien und Peru (Staph. Hist. Clavig.). Rev. Entomol. 3, 179–194.

Rettenmeyer, C.W., Rettenmeyer, M.E., Joseph, J., Berghoff, S.M., 2011. The largest animal association centered on one species: The army ant Eciton burchellii and its more than 300 associates. Insectes Soc. 58, 281–292. doi:10.1007/s00040-010-0128-8


Dr Sílvia Pérez-Espona during collection of specimens in a forest fragmented area in the Área protegida de San Lorenzo’s buffer zone.

The curious case of antennating ants telling each other where to go


A blog post highlighting the article by S. Popp, P. Buckham-Bonnett, S.E.F. Evison, E.J.H. Robinson and T.J. Czaczkes in Insectes Sociaux

Written by Tomer Czaczkes and Sophie Evison

Anyone who has spent a few minutes watching ants running along a trail will have noticed that when two ants meet, they often interact for a second or two. It seems obvious to anyone watching that some sort of information transfer is occurring. But what could they be communicating? One of the most tempting hypotheses is that the returning ant is telling the outgoing ant where to go: “take the next left to a great patch of aphids!” in the way that the honey bee waggle dance conveys information about the location of food patches to other workers. However, as inviting as this hypothesis is, multiple investigations over the centuries have found no evidence to support an antennal language in ants. The widely accepted view is summed up by Hölldobler and Wilson in their bible of myrmecology (1990): “‘ants antennate nestmates in order to smell them, not to inform them’’.

However, from the mid 1990s, a Russian scientist named Zhanna Reznikova has been researching the communication skills and numerical competency of wood ants (family: Formicidae). Reznikova and colleagues report finding astounding physical communication abilities: not only could ants communicate a complex series of turns to nestmates by physical contact, they could also encode numbers (i.e. take the 27th turn to the food”) (Reznikova and Ryabko 1994). Sophie Evison first heard about this during her doctoral studies from Reznikova herself, at a Central European Workshop on Myrmecology. Of course, she had to try this herself, so using the ants Evison had available at the time – Lasius niger – she carried out a (fairly rudimentary) replication of Reznikova’s experiment. Evison’s experiment simply tested whether returning L. niger foragers could tell outgoing foragers the correct direction to go at an upcoming T-maze. Amazingly, initial experiments appeared to show that these ants were communicating a form of directional information about a T shaped maze simply via antennation, with no other cues. However, to be candid, these results had similar impact to those of Reznikova’s, and the findings only ever appeared in Evison’s doctoral thesis.

Reznikova’s discoveries are incredible. Why were they not picked up? Simply put, no one believed them. However, incredulity is not a basis for scientific discourse. Many incredible scientific findings – in both the current and original meaning of the word – have gone on to be proven right, and changed the face of science forever. It seems incredible that we live on a spherical ball of rock, but it is true. Although before it was widely accepted, this fact had to be independently verified by repeated observations. The appropriate response from a modern but incredulous scientific community should be replication, not dismissal.

Why then did no one try to replicate these results? Why didn’t we, in our recent Insectes Sociaux study, try to replicate it exactly? The answer is simple: No incentives. Replication – the backbone of the scientific method – has no career rewards – especially for low traction ideas. We all remember the STAP cell fiasco, but do you remember who tried to replicate it and failed? Indeed, when we take into account the time lost performing such replications, they can reasonably be considered harmful to a career. This is especially true in the specific Reznikova case, as their method requires weeks of patient observation to define stable working ‘teams’ before tests can even begin.

Our recent study in Insectes Sociaux has convinced us that, at least in two Lasius species, on-trail physical interactions do not communicate direction, but these are only two species. This increases the burden of proof for such physical communication, but does not rule it out. Of course, even though we set out to find evidence for such communication, we also find the results of Reznikova incredible. And while incredulity alone is not a basis for scientific discourse, it is far from meaningless. The collective intuition of our research community should not be ignored. Perhaps we should be taking a Bayesian approach, adjusting our demands for evidence by our level of incredulity. There an important part of this story that helped to keep our collective investigation going all these years: during a Royal Society event, the artificial intelligence expert Donald Michie mentioned to Elva Robinson that he had spent some time with Reznikova, and was very interested by her results. He had planned to investigate the claims further, but tragically lost his life in a car accident. Donald’s perspective on the work of Reznikova was important; it provided an externally driven impetus to resolve our contrasting findings.

So what would it take to convince us of the Reznikova findings? We propose replication by an unaffiliated research team, with meticulous video documentation. But let’s face it – for the reasons stated above, we don’t think this is going to happen. We hope to be proven wrong.



Staying close to home

Highlighting the article written by A. Friedel, R. J. Paxton, A. Soro (2017) in Insectes Sociaux

Written by Insectes Sociaux Editor-in-Chief, Michael Breed (

In this issue of Insectes Sociaux, Friedel et al. (2017) report on their investigations of population structure of a eusocial sweat bee, Lasioglossum malachurum. Their fascinating study exemplifies the complex choices that dispersing animals face. An animal that moves far from its birth location encounters unknown arrays of predators, uncertainty in finding a suitable destination habitat, and the possibility that all of the good habitat space in their path is already occupied. On the other hand, staying close to home raises the likelihood of competing with close relatives as well as inheriting any diseases or parasites that beset the previous generation.

For animals living in aggregations some challenges may be amplified. In addition to high potential for competition with close relatives, disease and parasite problems are compounded, as many possible hosts live in close proximity to one another. Aggregations may form via philopatry, in which animals establish nests close to their natal nest, which creates potential questions about social evolution. If more than one individual lives in a nest, as is the case in the closely related Lasioglossum zephyrum, Then the mechanisms of social recognition that maintain high levels of familial relationship within each nest may break down. High genetic similarity among nearby colonies, as in Lasioglossum malachurum, may blur kin distinctions, setting up possible difficulties for kin-selection explanations of the evolution of a worker caste. Given these intriguing contradictions between advantages in settling near the natal location and dispersing further, this investigation (Friedel et al. 2017) of genetic structure is particularly interesting and timely.

Friedel et al. (2017) specifically test the hypothesis that when gynes (potential queens) search for a new nesting site they are likely to choose a location near their natal nest. By using microsatellite markers to investigate genetic similarity they were able to determine that bees in neighboring nests have higher degrees of genetic similarity than bees from more distant nests within the same aggregation. They found in three of four aggregations studied that bees from very close nests were more genetically similar than expected if random dispersal had taken place. In other words, very short range dispersal seems to have resulted in the formation of aggregations of individuals or nests in small pockets within larger expanses of seemingly suitable habitat. Colonies located further apart within each aggregation showed random degrees of genetic similarity. The aggregation in which no population substructure was observed is very large and perhaps older, leading the authors to suggest that founder effects account for small scale genetic similarity within aggregations and that over time immigration of unrelated bees in the aggregation dilutes these effects. This study sets the stage for assessing how population genetic substructure affects social evolution and disease-host relationships.

The halictid bee studied by Friedel et al. (2017) is typical of many eusocial insects, which establish their nests in aggregations of tens, hundreds or even thousands of individual colonies. Aggregated nests are common in many species of halictid sweat bee, in some species of Apidae, such as Apis dorsata, and in some species of the social wasps Polistes, Mischocyttarus, and Ropalidia. We can also look beyond insects to find many interesting behavioral and evolutionary analogies that can be seen in the aggregated nesting of birds, such as oropendolas, Psarocolius spp., and various swallows Hirundo spp., and in mammals such as prairie dogs, Cynomys spp.

The repeated appearance of aggregated nesting across this wide range of taxa raises many interesting evolutionary and behavioral questions. On the surface, if aggregated nests result from limited dispersal from natal sites, this could have major effects on population genetic structure, leading to high levels of genetic similarity among individuals within small sampling areas in the aggregation. As Friedel et al. (2017) point out, this may represent a transitory phase in the development of aggregations across generational time, as long-term movement of unrelated animals into the aggregation may counterbalance the short-term effects of an aggregation having been initiated by a single female and her immediate offspring.


A. Friedel, R. J. Paxton, A. Soro (2017) Spatial patterns of relatedness within nesting aggregations of the primitively eusocial sweat bee Lasioglossum malachurum. Insectes Sociaux DOI: 10.1007/s00040-017-0559-6




Do fungus-farming leaf cutter ants smell like fungus?

Figure 1

Superficial view of an Atta bisphaerica leaf-cutting ant nest, in the Brazilian savannah. Photo: Lohan Valadares

A blog post highlighting the article by L. Valaderes and F.S. do Nascimento in Insectes Sociaux

By Lohan Valadares  (@valadareslohan, @lo.han.792)

About 30 million years ago, in the South American savannahs, ants that cultivate fungus have over evolutionary time become the leaf-cutting ants (genera Atta and Acromyrmex). These ants reside in large subterranean nests of the Neotropical region, with galleries and fungus chambers that shelter thousands to millions of individuals, where they farm the fungus Leucoagaricus gongylophorus. The fungus has never been found free-living without the ants, and it is generally accepted that both organisms have co-evolved into an obligate mutualism, which means that one organism cannot live without the other. For the ants, the fungus is priceless as it serves as a rearing site and unique nutritional substrate for brood development. In exchange, the ants protect the fungus against parasites and forage for fresh vegetation, which is used as substrate for fungal growth. Recently, chemical analyses of the fungus gardens of Acromyrmex species have revealed the presence of hydrocarbons, a class of chemical compound found commonly on the cuticle of insects (Viana et al., 2001, Richard et al., 2007). These two species are so intertwined, however, that whether it is the ants or the fungus which are the ultimate producers of these hydrocarbons is not yet clear.

Cuticular hydrocarbons (CHCs) are of particular importance for social insects, and decades of studies have demonstrated that they are important as nestmate recognition cues. Consequently, variations in these substances have been associated with caste, age, dominance hierarchy, worker subcastes, and developmental stages. Furthermore, the leaves used as the fungus substrate seem to be an important source of CHCs for leaf-cutting ants (Richard et al., 2004, Valadares et al., 2015). This leads us to hypothesise that the intermediate organism in this process – the symbiotic fungus – is actually the one promoting the transference of these substances, or may actually be involved in the synthesis of hydrocarbons itself.

To explore the resemblance between the chemical compounds of both organisms involved in this symbiotic association, we studied the resemblance between the CHC profile of fungal cultivars with those of the ants, focusing on the changes in the CHC composition during the ants’ larval-to-adult moulting in the leaf-cutting ant Atta sexdens and its associated fungus. Our main question was: how do the changes in the CHC profile associated with the moulting cycle correlate with the hydrocarbon profile of the fungus cultivated by the ant Atta sexdens? To assess it, we collected pieces of fungal mycelium, and ant larvae, pupae and adult workers from laboratory populations, and soaked them in a solvent to extract their hydrocarbons, which later on were injected into a gas chromatography–mass spectrometry (GC–MS) for separation and identification of hydrocarbons.

Figure 2

An excavated fungus chamber of an Acromyrmex subterraneus leaf-cutting ant nest, in the Brazilian savannah. Photo: Lohan Valadares

Our analyses demonstrated that ant and fungus shared 58% of hydrocarbons, and the rest were all ant-specific hydrocarbons that were absent from the symbiotic fungus. Our comparative analyses revealed a great similarity between the hydrocarbon profiles of larva and fungus, due to the fact that both groups shared mainly highly concentrated linear hydrocarbons. As individuals progressed through developmental stages, the chemical profiles between ant and fungus became increasingly different. As the moulting cycle progressed, the hydrocarbon profile was characterised by a great shift from the ‘less pronounced’ state of the brood’s chemical profile towards a more diverse chemical profile of adult workers comprised of highly concentrated branched hydrocarbons.

Our findings coincide with the observations made for Acromyrmex leaf-cutting ants (Vianna et al. 2001, Richard et al. 2007), strengthening the evidence for the intimate relationship between brood and fungus as a variable shaping the hydrocarbon profile of both species. However, because we don’t know in detail how the hydrocarbons are biologically synthesised and transferred between these organisms, it is difficult to interpret whether the ants or the fungus (or even both organisms) are the ones actually synthesising hydrocarbons. However, we believe that our descriptive and comparative analyses indicating such strong resemblances has suggested new exciting opportunities of research tha­t will help us to understand how this co-evolutionary relationship has shaped the chemical profile of both organisms. If we consider the optimistic scenario where the fungus is actually the one to be transferring these compounds to the ants, how does this transference impact colony odour? Do these substances play a role in nestmate recognition? Several questions remain to be answered and hopefully our work has contributed to the journey towards the understanding of the chemo-ecology between leaf-cutting ants and their fungal cultivars.



Branstetter, M.G., Jesovnik, Aa, Sosa-Calvo, J., Lloyd, M.W., Faircloth, B.G., Brady, S.G., Schultz, T.R. (2017). Dry habitats were crucibles of domestication in the evolution of agriculture. Proceedings Royal Society B. 284: 20170095.

Richard, F.J., Heftz, A., Christides, J.P., Errard, C. (2004) Food influence on colonial recognition and chemical signature between nestmates in the fungus-growing ant Acromyrmex subterraneus subterraneus. J Chem Ecol 14: 9–16

Richard, F.J., Poulsen, M., Hefetz, E.C., Nash, D.R., Boomsma, J.J. (2007). The origin of the chemical profiles of fungal symbionts and their significance for nestmate recognition in Acromyrmex leaf-cutting ants. Behav Ecol Sociobiol 61(11):1637-1649

Valadares, L., Nascimento, D., Nascimento, F.S. (2015) Foliar substrate affects cuticular hydrocarbon profiles and intraspecific aggression in the leafcutter ant Atta sexdens. Insects 6: 141-151

Viana, A.M., Frézard, A., Malosse, C., Della Lucia, T.M., Errard, C., Lenoir, A. (2001) Colonial recognition of fungus in the fungus-growing ant Acromyrmex subterraneus subterraneus (Hymenoptera: Formicidae). Chemoecol 11(1): 29-36