insects

The surprising vulnerability of a termite’s secret roomate

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By Igor Eloi

Igor is a PhD student based at the UFRN campus on the brazilian coast. He is fascinated by how social insects, like termites, behave and interact with other species. In this blog, he shares key insights from a research paper exploring how fragment edges affect termite guests. His lastest research in Insectes Sociaux can be read here.

A termite nest is more than a mound of earth and wood; it’s a bustling city, a climate-controlled fortress engineered and built by tiny insects. These complex structures are not just homes for termites, a rather exquisite diversity of organisms have evolved to life within their walls.

There residents are known as”termitophiles”—organisms that live their entire lives, or at least critical parts of them, in an obligatory relationship with termite society. They are not merely guests but are deeply integrated into the colony’s day-to-day routine. These creatures have evolved alongside their hosts for millennia, developing bizarre forms and behaviors to survive and thrive inside the fortress. Which raises a rather pertinent question: If a creature is perfectly adapted to live inside a protective, self-regulating termite nest, does that make it immune to changes in the outside world? In other words, what happens to these hidden, highly specialized residents when human activity, like a simple dirt road, encroaches on their world? Our study set out to find the answer, revealing just how far the ripples of habitat disturbance can travel.

We focused on studying two Aleocharinae beetles, that live in an asymmetric “obligatory relationship” with a their host. This means that while termites live fine without the beetles, the beetles themselves cannot survive without the colony. We examined two distinct types found in the arboreal nests of the termite Constrictotermes cyphergaster (Nasutitermitinae).

Lateral (left) and dorsal (right) views of the termite Constrictotermes cyphergaster (Nasutitermitinae), host species of the studied Aleocharinae beetles.

On the image below, the first, Termitocola silvestrii, is a miniature tank. This species is equipped with a “limuloid” or drop-shaped body, featuring a large, shield-like pronotum thought to be a defensive adaptation against termite attacks. Anecdotal observations suggest it may act as part of the colony’s cleanup crew, feeding on dead termites. While these beetles possess wings, researchers speculate they may lose the ability to fly after successfully settling within a host colony. This secret society has its rules, and both species rely on momentarily leaving the nest—either for reproduction or dispersal—exposing their hidden world to the conditions of the wider forest.

Lateral and dorsal views of the rove beetle Termitocola silvestrii, a limuloid (drop-shaped) Aleocharinae species associated with the termite Constrictotermes cyphergaster. The large, shield-like pronotum is thought to provide protection against termite attacks.

The second, Corotoca fontesi, has a bizarre “physogastric” body, with a swollen, soft abdomen that gives it a strange, almost larval appearance and reduces its mobility. Its life cycle is a drama of dependence and risk. To reproduce, the female must venture outside the nest during the termites’ open-air foraging expeditions (Moreira et al. 2019). She then deposits a single, motile larva into the ground litter. The larva develops alone in the soil, and how it later finds and integrates into a new host nest remains one of the fascinating mysteries of its life cycle.

Lateral and dorsal views of the rove beetle Corotoca fontesi, a physogastric Aleocharinae species associated with the termite Constrictotermes cyphergaster. The swollen, soft abdomen gives the beetle a larval-like appearance.

The central finding of our study is that despite living inside the protective, climate-controlled environment of a termite nest, the abundance of these specialized beetles is negatively impacted by proximity to a forest edge. This finding demonstrates that the so-called “edge effect”—the ecological changes that occur where two habitats meet—penetrates the defenses of the termite fortress.

One might assume that the nest would act as a perfect buffer against external environmental stressors. However, the study’s results suggest otherwise, highlighting that even for organisms living deep within a host structure, the human-made landscape changes of the outside world matters immensely.

Finally, it is our thought that the mechanisms behind the impact of edge effect over the abundance of termitophiles might lie in one (or the combination) of these:

  1. Direct Impact: The harsher environmental conditions at the forest edge—such as different temperatures or humidity—could directly harm the beetles during the parts of their life cycle spent outside the nest. For example, the larvae of Corotoca developing in the soil could be exposed to increased predation or unsuitable microclimates (Zilberman et al. 2019).
  2. Host-Mediated Impact: The termite colonies themselves might be stressed by the edge conditions. This could make them “lower-quality hosts,” perhaps with fewer resources or a smaller workforce, rendering them unable to support large populations of their beetle symbionts.
  3. Dispersal Limitation: The altered landscape near the road could act as a barrier. This might make it more difficult for adult beetles to travel between nests, limiting their ability to find and colonize nests located near the forest edge.

References:

Moreira IE, Pires-Silva CM, Ribeiro KG, et al (2019) Run to the nest: A parody on the Iron Maiden song by Corotoca spp.(Coleoptera, Staphylinidae). Papéis Avulsos De Zoologia 59:e20195918–e20195918.

Siqueira-Rocha, L., Eloi, I., A Luna-Filho, V. et al. Aleocharinae termitophiles are affected by habitat fragmentation in deciduous dry forests. Insect. Soc. (2026). https://doi.org/10.1007/s00040-025-01076-4

Zilberman B, Pires-Silva CM, Moreira IE, et al (2019) State of knowledge of viviparity in Staphylinidae and the evolutionary significance of this phenomenon in Corotoca Schiødte, 1853. Papéis Avulsos De Zoologia 59:e20195919–e20195919. https://doi.org/10/gng3q8

Hovering battles at the ant nest: the remarkable behavior of a rare ant parasitoid wasp

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By Satsuki Kajiwara

Satsuki is a PhD student in the Entomology Laboratory at Kyushu University, Japan, where she studies ant-associated parasitoid wasps. In this blog post, she shares her discovery of aerial fights between female Ogkosoma cremieri competing for access to ant larvae. Her lastest research in Insectes Sociaux can be read here.

Ant colonies, with their abundant resources and secure environments, are frequently exploited by various organisms that have evolved strategies to infiltrate and persist within them. These organisms, known as myrmecophiles, depend on ants for at least part of their life cycle.

The subfamily Hybrizontinae, which I am currently studying, represents a highly specialized group of parasitoid wasps that attack only ant larvae (Lachaud and Pérez- Lachaud 2012). Their known host ants belong to the genera Lasius (including the subgenera Lasius and Dendrolasius) and Myrmica. Notably, two species in the subgenus Dendrolasius exhibit unusual behavior: they transport their larvae between tree trunks and underground nests depending on the season (Kajiwara and Yamauchi 2023). Because Hybrizontinae wasps parasitize larvae during these transport events, the timing of larval movement is critical for their reproductive success (Komatsu and Konishi 2010).

Females of this subfamily oviposit by inserting their ovipositor into larvae being carried by worker ants—an opportunity that occurs only during the brief moments when larvae are exposed outside the nest.

Two basic host-searching strategies are known: (1) hovering near ant nest entrance and (2) ambushing along ant trails by clinging to vegetation.

Two host-searching strategies observed in the subfamily Hybrizontinae.

While surveying ant parasitoid wasps on my university campus in Japan, I was fortunate to discover a hovering female of Ogkosoma cremieri (Romand) near a nest of Lasius capitatus (Kuznetsov-Ugamsky). This unexpected encounter became the starting point for a more detailed behavioral study.

An adult female of Ogkosoma cremieri hovering in front of the nest of Lasius capitatus

Although earlier researchers reported hovering behavior in this species, they did not identify the specific time of day when it occurs. My observations revealed that females hover between 06:30 and 17:00, indicating sustained activity throughout the daytime.

One day I witnessed something remarkable. A female O. cremieri hovered at the nest entrance and approached larvae being carried by workers. When several females were present, they sometimes engaged in aerial jostling: the wasp positioned in front of the nest (red arrow in the image below) drove off an approaching female (yellow arrow) by pushing her while hovering. The displaced wasp was then attacked by ants and dragged into the nest, showing how dangerous it can be for wasps to approach ant brood. Aggressive competition between parasitoid females has been observed before in other ichneumonids, but usually on the ground or on plants — witnessing physical pushing while hovering appears to be a novel behaviour.

Aerial struggle between two female O. cremieri hovering at a Lasius capitatus nest entrance, where competition for host larvae can escalate into ant attacks. A, two females(yellow and red arrows) hovering in front of a Lasius capitatus nest; B, the female positioned in front of the nest (red arrow) attacked the approaching female (yellow arrow); C, the approaching female (yellow arrow) was pushed away by the female in front of the nest (red arrow), and the pushed-aside female (yellow arrow) was attacked by ants.

Interestingly, L. capitatus workers transport large numbers of larvae from tree trunks into underground nests at night. However, no oviposition behavior by O. cremieri toward these larvae was observed. This pattern suggests that nocturnal larval transport may serve as an adaptive strategy by ants to avoid parasitoid attacks. Consistent with this interpretation, my observations also suggest that O. cremieri is not a nocturnal species. Females became active at night only when the area was illuminated with a flashlight or headlamp—likely a response to artificial light rather than natural nocturnal activity.

Future comparative studies across genera may reveal how morphological traits and behavioral strategies have diversified within this intriguing group of parasitoids.


References:

Kajiwara S, Yamauchi T (2023) Larval transport by adults of Lasius morisitai (Hymenoptera: Formicidae): The season and the time of day. Nat Environ Sci Res 36:15–17 [in Japanese]. https://doi.org/10.32280/nesr.36.0_15

Kajiwara, S., Yamauchi, T. Parasitoidic strategy of Ogkosoma cremieri (Hymenoptera: Ichneumonidae: Hybrizontinae) against Lasius capitatus (Hymenoptera: Formicidae). Insectes Sociaux (2025). https://doi.org/10.1007/s00040-025-01072-8

Komatsu T, Konishi K (2010) Parasitic behaviors of two ant parasitoid wasps (Ichneumonidae: Hybrizontinae). Sociobiology 56(3):575–584

Lachaud J-P, Pérez-Lachaud G (2012) Diversity of species and behavior of hymenopteran parasitoids of ants: A review. Psyche2012:134746. https://doi.org/10.1155/2012/134746

Interview with a social insect scientist: Stefano Cavallo

/ Damien Gergonne / Leave a comment

Stefano is a biologist specializing in animal behavior and currently works as a research fellow in behavioral ecology at the University of Florence. In this interview, he recalls moment he realized that even ants show individual personalities. His lastest research in Insectes Sociaux can be read here.

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

I’m Stefano Cavallo, a passionate biologist specialized in animal behaviour. I’m living in Pisa and currently work at the University of Florence as a research fellow in behavioural ecology. My interests range from communication and cognitive aspects of animal behaviour in invertebrates and beyond. At the moment, my project focuses on exploring phenotypic plasticity—particularly behavioural plasticity—in marine decapods.

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

Since I was a child, I’ve always been passionate about animals. Although I grew up in a city, I had the chance to keep and observe a variety of species—fish, amphibians, reptiles, birds, mammals, and of course, insects. Among them, social insects, and especially ants, have always fascinated me. Their remarkable social organization combined with apparent simplicity sparked both curiosity and deep biological admiration in me. As my studies in biology progressed, I developed a strong interest in behavioral biology. What I find most stimulating is the possibility of identifying similar behavioral patterns in evolutionarily distant species, both human and non-human.

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

It’s hard to choose just one. I’m fascinated by social insects for very different reasons: for instance, the interspecific relationships of Atta ants, the communicative flight and cognitive abilities of Apis mellifera, and the complex social structure of Polistes dominula all capture my interest. What I find most stimulating is not a single species, but rather those organisms capable of challenging the “dogmas” of biology. For example, the recent discovery by Juvé et al. (2025) on Messor ibericus which destroy species definitions.

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

One of the best moments in my research was when I first realized that even ants—creatures we often think of as identical and mechanical—show individual personalities. That realization was unforgettable: it felt like discovering a hidden layer of complexity within a familiar world. From that moment on, I stopped seeing colonies as uniform units and started seeing them as societies of individuals.

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

No, at the moment I don’t deal with these aspects but in the future I hope it can become part of my job as a scientist. I think it is important to disseminate scientific advances to a wide audience and shorten the distances between laboratories, research and the general public.

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

As we know, the environment today is subject to strong anthropogenic pressures and global warming is shaping habitats very quickly. The effects on social insects are still poorly understood. I believe it is essential to focus on these aspects and understand how changing conditions act on the biology and behavior of social insects.

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

I love being in nature, trekking in the mountains, climbing, swimming and snorkelling

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

The last book I read was Entangled Life: How Fungi Make Our Worlds, Change Our Minds and Shape Our Futures by Merlin Sheldrake. I would definitely recommend it—it’s a fascinating and beautifully written synthesis of what we know about fungi. These organisms are extraordinary in the way they challenge traditional paradigms of biology and reveal how deeply interconnected life really is.

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

I practice tai-chi and mindfulness techniques to stay in the present moment and focus on beautiful things.

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

I would bring a knife, a tinderbox and a book on edible plants. These three things would help me get food, be able to cook and warm up and not die of intoxication haha!

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

I believe that the most important role was played by two high school teachers. My chemistry professor and biology professor taught me scientific rigor and wonder at the living world

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

If I had to advise someone to hop to be a social insect researcher, I would tell them to follow the thirst for knowledge and not stop at appearances. I would ask him to always look with a critical eye at those who claim to have absolute certainties in biology.

IS: Has learning from a mistake ever led you to success?

I couldn’t point to a specific mistake, but I believe that in private life and at work we often learn by falling and making mistakes. Trying by trial and error: this is generally just how we manage to grow.

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

My favourite place where science took me is Paris, in the experimental and comparative ethology laboratory of the Sorbonne University in northern Paris. I was lucky enough to work in the group led by Professor Patrizia d’Ettore who with dedicated passion dedicates herself to research in the myrmecological field.

Digging on fast-forward: How heat shapes ant architecture

/ Damien Gergonne / Leave a comment

In this blog post, the authors of the Insectes Sociaux article title “High environmental temperatures put nest excavation by ants on fast forward: they dig the same nests, faster” (Rathery et al. 2025) talk about their research on the effects of environmental temperature on ant digging activity.

Imagine watching a video of someone doing normal everyday activities. First, at normal speed, then, at double speed: suddenly everyone moves like olympic sprinters, but still appear calm and relaxed. Now slow down the video: every step and gesture becomes painfully sluggish.

Imagine if that could also happen in real life: one day, it’s only noon and you have already wrapped up all the work for the day; the next day, you have barely had breakfast and the day is already getting to an end!

These situations look unrealistic to us, but ants experience them all the time!

Ants are ectotherms – animals that don’t maintain a constant body temperature. As a result, their physiology and behaviour depends heavily on the temperature of the environment. In warmer weather, ants move faster, they likely forage more quickly, and probably they also age faster. In our study, for instance, the walking speed of Lasius flavus ants doubled when the temperature rose by about 12 °C.

Of course, the sped-up video analogy only goes so far. For example, gravity does not change with temperature, so winged ants need to flap their wings at least at a minimum speed in order to fly, and this might become completely impossible in cold weather. At high-temperature, when ants are moving too fast, they might struggle to take in enough oxygen to keep up with their energy consumption. So, while some behaviours might simply speed up with increasing temperature, other behaviours are likely to hit a physical or physiological limit, and could change in unexpected ways. In all cases, the changes of behaviour induced by temperature are likely to be important for colony survival, and may play a role in future adaptations of ants to the changing climate.

IS: How did you choose this research topic, and to explore it with Lasius flavus?

“It was a combination of love for the topic, but also of practical circumstances”, says Alann Rathery, lead author of the study. Originally planning to study termite nests in Australia, his plans were upended by the Covid-19 pandemic. “I had to pivot quickly, soon abandoned the idea of travelling to Australia I began collecting ants from my backyard in London. At some point, I even ran some preliminary experiments in my room!“

The image is just a frame grab from the video linked: laboratory in Alann Rathery’s room where preliminary experiment leading to the present study were conducted during the Covid19 pandemic.

“Luckily, the yellow meadow ants (Lasius flavus), which are one of the most abundant ant species in the meadows of South-West London, are very interesting ants. They are important ecological engineers, that shape the local landscape with their mounds, creating ecological niches for many other plant and animal species.”

Image of a meadow disseminated with yellow meadow ant mounds. ©Wikipedia.

IS: Can you tell us a bit about the experiments that you did?

“We have long been curious about how environmental factors – like temperature and humidity – affect the behaviour of social insects” – says Andrea Perna, senior author of the study. – “These environmental cues may help ants and termites figure out things that they cannot measure directly, like how deep inside the nest they are. One of the key functions of nests is to provide the colony with a suitable environment in terms of temperature and humidity: it makes sense that insects respond to these cues. In a related study (Facchini et al. 2024), for instance we found that termites may use water evaporating from damp soil as a signal to coordinate how and where to build their nests.

When it comes to ants, previous studies had indicated that they likely respond to temperature gradients – differences in temperature across space – during nest building. But it wasn’t clear whether temperature alone, without a gradient, could influence how ants dig or build. So we set out to test two things: first, how ant digging speed changes depending on temperature, and second, whether the shape of the nests that they excavated was different at different temperatures.

We followed a somewhat classical approach for the experiments, letting ants excavate in-between two glass plates, so that we could image the growth of the pattern over time while the experimental colonies were housed inside temperature-controlled incubators”.

“The experiments were technically a bit challenging – adds Alann Rathery – we had to image ant colonies continuously over multiple days, and the space inside the incubators was a bit tight, so I had to build a custom imaging system with Raspberry Pi computers and cameras – one inside each incubator. I connected them all to a router outside, and through that I could control the cameras remotely to automatically record photos and videos.” Analyzing the footage wasn’t simple either. “The ant tunnels grow into very complex shapes, and it takes a solid analysis pipeline to automatically extract and quantify the structures. But some of the patterns they create are really beautiful!”

Do you want to see these structures grow? Here is a time-lapse video of the growing galleries.

Screen shots from the time-lapse video of the growing galleries.

IS: What’s next for this type of research?

“There’s still a lot we don’t know about what happens at the individual level when ants dig these intricate underground networks. In our study, we didn’t focus on the detailed behavior of individual ants as they carve out tunnels in the soil. But what they do, how they decide where to dig, how new branches start, are all incredibly interesting questions. Some of this behavior can be seen in action in a real-time video clip from our experiments. Analysing in detail this type of footage is fascinating, but could easily become an heavy research task.

Another promising direction for this research would be looking at the internal structure of natural nests in the wild: how do galleries inside the mound differ, depending if the mound was built in a sunlit area compared to a shady one?Are there shape differences between the northern exposed and the southern side of the mound?

The nests built by social insects are more than just shelters: they are the physical records of the life and activity of a colony. If we learn to better read the information written in these structures, we might uncover new insights into the hidden lives of these wonderful insects”.

References:

Rathery, A., Facchini, G., Halsey, L.G., Perna, A. High environmental temperatures put nest excavation by ants on fast forward: they dig the same nests, faster. Insect. Soc. (2025). https://doi.org/10.1007/s00040-025-01049-7

Facchini, G., Rathery, A., Douady, S., Sillam-Dussès, D., Perna, A. (2024). Substrate evaporation drives collective construction in termites. Elife, 12, RP86843. https://doi.org/10.7554/eLife.86843.4

Insect architects: How termites, ants, and bees build without blueprints

/ Damien Gergonne / Leave a comment

by Paige Caine

Paige Caine is a PhD student in Dr. Michael Goodisman’s lab at Georgia Tech. She study fire ants and yellowjackets wasps. In this blog, she explains how social insects, such as termites, ants, or bees, collectively manage to build complex nests. Her latest research on social insects can be read here.

A builder stands at the foot of her construction, a massive skyscraper towering thousands of times her height. The imposing architectural feat stretches stories underground as well, and is home to thousands of individuals. She can’t see the results of all her hard work though; she’s blind. In fact, the entire team of builders responsible for the structural triumph is blind, and they didn’t have a chief architect or any blueprints to guide them. How did they do it?

To answer this question, let’s meet the construction crew: Cathedral Termites. Native to Australia, this species of termites has blind workers measuring only about 3-4.5 millimeters long, yet they build massive nests to house their queens, kings, and young. 

A Cathedral Termite (Nasutitermes triodiae) mound.

But this feat isn’t unique to Cathedral Termites—most social insects construct some form of nest. These structural marvels range in size and shape, from Cathedral Termite mounds to charismatic honeybee hives to tiny ant homes contained within acorns.  In the absence of realtors, social insects often use collective decision-making to choose a nest location that optimizes temperature, sunlight, precipitation level, predation risk, and proximity to resources (Jeanne and Morgan 1992; London and Jeanne 2000; Suzuki et al. 2007). These strategies typically involve sending a few scouts to locate potential nesting sites. The scouts then recruit colony-mates to “vote” on sites by physically going to that site and contributing to the recruitment effort. Eventually, a quorum is reached, and the losing party packs up from their rejected sites and heads to the winning location (Pratt 2005).

Once the site has been chosen, a range of different construction methods are used to build the nest. Termites and ants tend to excavate their homes, while social bees and wasps tend to build their homes from manipulated biological material—chewed up wood pulp in the case of social wasps or wax in the case of some bees.

A social wasp nest from the yellowjacket Vespula squamosa. While these structures are built underground, this nest has been excavated (left), and then separated into the individual layers of comb (right).

A common problem during collective construction—and one most human commuters are accustomed to—is crowding. To excavate a massive structure composed of tunnels and chambers, ants and termites must navigate narrow spaces containing hundreds or even thousands of individuals. One way termites solve this problem is through something referred to as a “bucket brigade;” like humans passing water towards a fire via a series of buckets, some termite species form a queue and pass excavated material along from individual to individual until it reaches the deposition site (Bardunias and Su 2010). Some ants, on the other hand, utilize “laziness” to avoid crowding, by having certain individuals sit still while a minority actually contributes significantly to construction (Aguilar et al. 2018).

But, if there’s no blueprint and no architect in charge of doling out specific tasks, how are all these individual construction behaviors coordinated?

One common means of coordination is stigmergy, which means communicating across time via the environment. Each time an individual interacts with the incipient construction, they leave behind traces of their behavior, either by shaping the material or leaving behind chemicals. These cues tell individuals who later approach the construction what has been done, and what’s left to do.

A diagram displaying stigmergy at work in honeybee nest construction, based on (Nazzi 2016). Different colored bees indicate distinct individuals A) Bee #1 interacts with cells constructed by her nestmates. B) Cells act as cues for bee #1 to extend the floor of the nest. C) Floor acts as a cue for bee #2 to begin constructing stubs of a wall. D) Third bee detects these wall stubs and responds by adding to the stubs to encircle a cell. E) Fourth bee notices cells constructed by her nestmates and responds by extending the floor further. F) After additional building activity by several bees, the comb of cells hits the edge of the cavity.

Now that we know how social insects build their remarkable nests, another natural question is why?

Social insect nests offer many advantages to residents. For one, they offer protection from weather, much like a human home. They also protect against infection, with many species actively incorporating antimicrobial bacteria or other antibiotic agents into the walls (Tranter et al. 2013; Madden et al. 2013; Chouvenc et al. 2013). Nests also enable protection against larger threats, functioning as defendable fortresses. In fact, many species employ guards at nest entrances, and often close their doors at night (Bennett and Baudier 2021).  Finally, nests help large insect societies organize their behaviors by physically contributing to division of labor, as well as by influencing the efficiency of collective tasks like foraging.

Termites nesting in paper (left), which they eat as they construct. Ants nesting in soil (right), showcasing some of the many interior tunnels and chambers.

Overall, social insect nest construction is an impressive feat, and the results are both structurally remarkable and highly functional. One day, we may be able to imitate such techniques using swarm robotics. Today, many engineers are already working on bio-inspired robot collectives capable of construction. Robotic models are even being designed to test hypotheses about collective behaviors in social insect groups, an approach recently termed “robophysics.” In the future, robophysical models may unlock some of the principles underlying social insect nest construction, strengthening our understanding of collective behavior in both engineering and biology.

Robots engaged in construction. Left photo credit: Eliza Grinnell/Harvard SEAS. Right photo credit: Daniel Soto, Joonha Hwang

References:

Aguilar J, Monaenkova D, Linevich V, et al (2018) Collective clog control: Optimizing traffic flow in confined biological and robophysical excavation. Science 361:672–677. https://doi.org/10.1126/science.aan3891

Bardunias PM, Su NY (2010) Queue Size Determines the Width of Tunnels in the Formosan Subterranean Termite (Isoptera: Rhinotermitidae). J Insect Behav 23:189–204. https://doi.org/10.1007/s10905-010-9206-z

Bennett MM, Baudier KM (2021) The Night Shift: Nest Closure and Guarding Behaviors in the Stingless Bee, Tetragonisca angustula. J Insect Behav 34:162–172. https://doi.org/10.1007/s10905-021-09779-9

Caine, P.B., Robertson, A.T., Treers, L.K. et al. Architecture of the insect society: comparative analysis of collective construction and social function of nests. Insect. Soc. (2025). https://doi.org/10.1007/s00040-025-01057-7

Chouvenc T, Efstathion CA, Elliott ML, Su N-Y (2013) Extended disease resistance emerging from the faecal nest of a subterranean termite. Proceedings of the Royal Society B: Biological Sciences 280:20131885. https://doi.org/10.1098/rspb.2013.1885

Jeanne RL, Morgan RC (1992) The influence of temperature on nest site choice and reproductive strategy in a temperate zone Polistes wasp. Ecological Entomology 17:135–141. https://doi.org/10.1111/j.1365-2311.1992.tb01170.x

London KB, Jeanne RL (2000) The interaction between mode of colony founding, nest architecture and ant defense in polistine wasps. Ethology Ecology & Evolution https://doi.org/10.1080/03949370.2000.9728440

Madden AA, Grassetti A, Soriano J-AN, Starks PT (2013) Actinomycetes with Antimicrobial Activity Isolated from Paper Wasp (Hymenoptera: Vespidae: Polistinae) Nests. Environ Entomol 42:703–710. https://doi.org/10.1603/EN12159

Nazzi F (2016) The hexagonal shape of the honeycomb cells depends on the construction behavior of bees. Sci Rep 6:28341. https://doi.org/10.1038/srep28341

Pratt SC (2005) Quorum sensing by encounter rates in the ant Temnothorax albipennis. Behav Ecol 16:488–496. https://doi.org/10.1093/beheco/ari020

Suzuki Y, Kawaguchi LG, Toquenaga Y (2007) Estimating nest locations of bumblebee Bombus ardens from flower quality and distribution. Ecol Res 22:220–227. https://doi.org/10.1007/s11284-006-0010-3

Tranter C, Graystock P, Shaw C, et al (2013) Sanitizing the fortress: protection of ant brood and nest material by worker antibiotics | Behavioral Ecology and Sociobiology. Behavioral Ecology and Sociobiology 68:499–507. https://doi.org/10.1007/s00265-013-1664-9

At what point does a male social wasp leave his natal nest to reproduce?

/ Damien Gergonne / Leave a comment

By Daniela Torres Garcia

In this blog, Daniela Torres Garcia, from the University of São Paulo, describe how she discovered that the number of females in a Mischocyttarus cerberus wasp nest influences the departure of males for mating. This latest research on social insects can be read here.

In social hymenopterans, male reproductive success depends entirely on the timing of reproduction, as males play no role in maintaining the colony—at least in the widely studied species. Males of many species, including social wasps, undergo post-pupal sexual maturation within the natal nest before dispersing to mate, during which time they rely on their nestmates for protection and food.

This leads us to a key question: do all males leave the nest at the same time, or is there something that makes some of them stay longer or shorter in their natal nest?

To answer this, we observed a population in southeastern Brazil of the Neotropical species Mischocyttarus cerberus. We conducted a rigorous monitoring of the nests of this species over several weeks to track male dispersal, and we found that the time a male spends in the nest before leaving varies. Some males leave the day after emerging, while others remain for almost a week.

Nest of M. cerberus with females and males. Photo by Andres Rodrigues De Souza.

Given this variability, we asked what factors might be influencing male dispersal timing. Does the social context affect this variability? That is, does the number of adult females in the nest influence how long the males stay? Do males stay longer when more adult females are present?

We addressed these questions using two approaches: on the one hand, observationally, by monitoring 36 natural nests; on the other hand, experimentally, by manipulating the number of females in 22 nests to see whether this caused a change in male dispersal behavior. And what did we find? Males in nests with more females stayed longer, thereby delaying their dispersal.

On average, males left after 3 days, but some took up to 8 days. We found that in nests with three females, males stayed for about 2.8 days, whereas in nests with only one female, they left after just 1.7 days. This suggests that females modulate male dispersal, which can last up to 8 days—similar to another social wasp, Polistes lanio (up to 7 days) (Southon et al., 2020). Why? Probably because staying in the nest is safer and more comfortable. More females mean better defense against predators and more food available. It is worth remembering that the sting—the primary defense mechanism of this group—is associated with the female reproductive system and thus is absent in males.

Male M. cerberus resting on the underside of a leaf within the study area. Photo by Andres Rodrigues De Souza.

Therefore, it is not surprising that males from nests with more females delay their dispersal to complete their sexual maturation in a safer and more comfortable environment, thereby increasing their survival and future reproductive competitiveness (i.e., by accumulating energy reserves). The accumulation of these reserves could help them avoid having to expose themselves on flowers to obtain food once dispersed.

Taken together, these results highlight the role of social context in shaping male reproductive strategies and suggest that pre-dispersal social life may be an underestimated factor in the physical fitness of males in social insects.

The reproductive biology of male social insects has often been studied at mating sites, such as leks and swarms (Beani et al., 1992; Beani et al., 2014). However, less attention has been given to male behavior prior to reaching these sites (e.g., Southon et al., 2020), despite its potential to influence male competitive ability. Therefore, pre-dispersal social life may be an overlooked aspect of male paper wasps’ reproductive strategies.

Left: Researcher tagging M. cerberus males for tracking, under an air conditioning unit. Right: M. cerberus nest under study, with several workers visible on the cells

References

Beani L, Dessì-Fulgheri F, Cappa F, Toth A (2014) The trap of sex in social insects: from the female to the male perspective. Neurosci Biobehav Rev 46:519–533. https://doi.org/10.1016/j.neubiorev.2014.09.014

Beani L, Cervo R, Lorenzi CM, Turillazzi S (1992) Landmark-based mating systems in four Polistes species (Hymenoptera: Vespidae). J Kansas Entomol Soc 8:211–217 https://www.jstor.org/stable/25085358

Garcia, D. T., Santos, E. F., Santos, S. A., do Nascimento, F. S., Krams, I., Rantala, M. J., & de Souza, A. R. (2025). Social context predicts male dispersal in nests of a paper wasp. Insectes Sociaux, 1-4. https://doi.org/10.1007/s00040-025-01050-0

Southon, R. J., Radford, A. N., & Sumner, S. (2020). Hormone-mediated dispersal and sexual maturation in males of the social paper wasp Polistes lanio. Journal of Experimental Biology, 223(23), jeb226472.

What makes a queen successful?

/ Damien Gergonne / Leave a comment

By Luisa M. Jaimes-Nino

Luisa is a researcher at Johannes Gutenberg University Mainz. She specializes in studying the life-history traits of ants, their senescence, and the genetic and non-genetic mechanisms influencing queen fitness. Read her latest article in Insectes Sociaux here.

Queens, and kings in termites, are highly fertile and long lived insects. But certainly there is variation to which extent they are fertile. We were intrigued to understand what causes variation in fitness traits?

A Cardiocondyla obscurior queen (right), and brood and workers (left). ©Laure-Anne Poissonier.

We wondered if very fertile queens were also more successful by producing very fertile daughters. Is this caused by a genetic factor or perhaps the maternal status, such as maternal age? Old mothers might produce less fit queens and workers, and this can have a detrimental effect for the future of the whole colony. The negative effect of parental age, known as Lansing effect, has been documented across a wide range of taxa but not yet investigated in social insects.

We used Cardiocondyla obscurior ants as model given their high variability in fertility and  longevity. We investigated how fertility varies by selecting mothers that produced a low and high number of eggs after 15 weeks. We profited from a study in which we monitored a batch of queens in controlled conditions for their entire life (Jaimes-Nino et al., 2022), and monitored their daugthers too, to test if they presented a similar fertility and longevity.

In this experimental study, each daughter queen was mated to her wingless brother, kept in a single-queen colony on a plaster nest, and monitored monthly for productivity (i.e., number of eggs and pupae produced). ©LM Jaimes-Nino.

Our model species is polygynous, meaning that a large number of queens cohabit within a single colony. However, it is known that those queens that live longer, produce also more eggs (Kramer et al., 2015) and more queen daugthers (Jaimes-Nino et al., 2022). Previous studies have shown that queens remain heathly for a long portion of their lives because their mortality rate and gene expression pattern remain stable until old age (Harrison et al., 2021; Jaimes-Nino et al., 2022). Therefore, it is important to test whether old queens produce daugthers that are equally fit compared to those of younger queens, given that they produce the majority of them within the colony!

A) Wingless male and queen, B) three chambered plexiglas insert covered by plastic foil served as nest, and C) queen (right) and (worker) with brood inside the artificial nest chamber. ©Photo LM Jaimes-Nino.

Our results showed that mothers and daugthers do not “look” alike —  they do not have a similar fertility or longevity. This could indicate that their genetic background does not account for the observed variation. This can be expected from C. obscurior, as it exhibits extreme inbreeding.

Furthermore, contrary to the Lansing effect reported in other taxa, we found that daugthers produced by old mothers were just as fit as those produced by young mothers. This aligns with the hypothesis that, since the majority of sexuals are produced later in life, there must be mechanisms in place to maintain the health of these queens as they age! We believe that selection against aging remains strong in older queens. The specific mechanisms by which C. obscurior queens are able to produce equally fit daugthers at such advanced ages awaits further investigation.

Wingless (ergatoid) males with long mandibles mate in the nest with closely related gynes. ©Laure-Anne Poissonier.

Strikingly, the maternal lines differed in productivity suggesting background variation influenced by the maternal environment or male quality. In this species, ergatoid males (worker-like males) figth against rivals to monopolize queen access. Our study offers new avenues of research, to disentangle the effect of mother, father and developmental environment, on the final reproductive success of queens.

References

Harrison, M.C., Jaimes Niño, L.M., Rodrigues, M.A., Ryll, J., Flatt, T., Oettler, J., et al. 2021. Gene Coexpression Network reveals highly conserved, well-regulated anti-ageing mechanisms in old ant queens. Genome Biology and Evolution 13: 1–13. https://doi.org/10.1093/gbe/evab093

Jaimes-Nino, L.M., Heinze, J. & Oettler, J. 2022. Late-life fitness gains and reproductive death in Cardiocondyla obscurior ants. eLife 11: 1–17. https://doi.org/10.7554/eLife.74695

Kramer, B.H., Schrempf, A., Scheuerlein, A. & Heinze, J. 2015. Ant colonies do not trade-off reproduction against maintenance. PLoS ONE 10: 1–13. https://doi.org/10.1371/journal.pone.0137969

How does a caterpillar use its tentacles to get the attention of ants?

/ Damien Gergonne / Leave a comment

By Amalia Ceballos-González

In this blog, Amalia from the University of São Paulo tells the story of how she and her colleagues studied a strange functional behaviour in a myrmecophilous riodinid caterpillar. Read her latest article in Insectes Sociaux here.

Caterpillars that establish close interactions with ants have developed various adaptations to maintain the ants’ attention. These adaptations involves specialized organs that produce nutritional rewards or chemical signals to attract ants. The butterfly families Lycaenidae and Riodinidae provide many examples of myrmecophilous caterpillars, including species with these organs. In our recent study, published in Insectes Sociaux, we explored the impact of these specialized organs on ants by focusing on a species from the less-studied family Riodinidae, Synargis calyce, which interacts with various ant species. In our study area, the most frequent interaction involved the ant species Camponotus crassus.

Caterpillars of Synargis calyce interacting with different ant species. (a) With Camponotus crassus, (b) with Camponotus renggeri, (c) with Wasmannia auropunctata, and (d) with Paratrechina longicornis. ©Amalia V. Ceballos-González.

Caterpillars of this species possess two pairs of tentacular organs. The first pair, known as ATOs (Anterior Tentacle Organs), likely release volatiles that influence ant behavior, although there is insufficient evidence to confirm this. The second pair, known as TNOs (Tentacle Nectary Organs), secrete a nutritive substance (primarily composed by sugars and amino acids) that ants consume. Whether these organs work synergically or if one is more relevant than the other was still unclear for our study species and it is also the case for many other species of the family Riodinidae.

Illustration showing the position of the tentacular organs (TNOs and ATOs)  in a caterpillar of the Riodinidae family. Below, a photograph of Synargis calyce indicates the two pairs of tentacular organs with arrows (Yellow = ATOs, Blue = TNOs). Drawing adapted from DeVries (1991). ©Amalia V. Ceballos-González.

To uncover those aspects, we aimed to explore this pair of tentacular organs by checking ants’ reaction. Our research was conducted at the University of São Paulo, Ribeirão Preto campus. Our first objective was to create an ethogram documenting the behavioral interactions between caterpillars and ants. During these observations, we identified a striking behavior. The ethogram revealed that after the eversion of ATOs, ants exhibited stereotyped “jumping” behavior. This behavior involved ants rapidly lifting their legs and jumping towards the caterpillar’s head.

 Synargis calyce caterpillar interacting with a Camponotus ant.

Next, we conducted experiments in which we experimentally manipulated – by allowing or preventing them to evert – the two types of caterpillar organs (TNOs and ATOs), to determine their role in maintaining ant attendance. Our findings demonstrated that TNOs are more effective in maintaining the attention of attendant ants, likely due to the rewards these organs provide. However, we also found that caterpillars with only functional ATOs received more attention compared to those with neither organ functioning. This indicates that TNOs play a central role in sustaining ant-caterpillar interactions, while ATOs serve a complementary function.

Three caterpillars (possibly third instar) interacting with Camponotus ants.

In conclusion, the interactions between S. calyce caterpillars and attendant ants are primarily driven by the rewards produced by TNOs, with ATOs playing a smaller, supportive role. These findings are consistent with observations in Lycaenidae species, which exhibit similar mutually beneficial relationships with ants. The evolution of these organs may represent a case of convergent adaptation to environmental pressures experienced by caterpillars in both families.

Viruses of eusocial insects: high and underestimated diversity

/ Damien Gergonne / Leave a comment

By Anna Zueva

In this blog, Anna Zueva, researcher at the A.N. Severtsov Institute of Ecology and Evolution (Moscow), reveals the hidden world of viruses in eusocial insects. Read her latest article in Insectes Sociaux here.

Eusocial insects are a kind of human society in miniature. Each part of the community has its own functions and features. The system of social insects’ family works as a coherent and well-coordinated mechanism, and the life of each individual strongly depends on the life of the whole complex.

The functioning of even a fine-tuned system can be disrupted. For example, in the history of mankind there are known episodes when whole civilizations suffered from local epidemics and even pandemics caused by microscopic entities – viruses. But is that the case for social insects?

Our work started from our interest in viruses of invertebrates. Tropics are especially promising for us, as this region is known for its great biodiversity and has lots of still unknown biological species, including of course microorganisms and viruses.

We started our investigation with the research on viruses of termites of Cát Tiên National Park – a part of the Đồng Nai Biosphere Reserve (Fig. 1). We are grateful to the South branch of the Joint Russian-Vietnamese Tropical Research and Technological Center for invaluable help in our studies.

Figure 1. A gap in the tropical monsoon forest of Cát Tiên National Park (Vietnam). ©Anna Zueva

We took samples of termites of three different species feeding on different substrates – lichens and fungi – as we expected that food resource can affect the composition of viruses associated with insects (Fig. 2, 3).

Figure 2. One of the studied species of termites, Hospitalitermes bicolor (Haviland) feeding on lichens. ©Alexei Tiunov
Figure 3. A small termitarium. ©Andrey Zuev

Thought we did not observed any visible symptoms of infection, we detected four new viruses related to viruses previously discovered in termites. We also found the evidence of presence of virus probably belonging to termites’ food substrate (Litov et al. 2022), which partly support our suggestion about the effect of feeding type on the insect virome.

Potentially, eusocial insects can be a model for studying the spread of viruses via social interactions. In the recently published review (Zueva et al 2024), we aimed to actualize the information on the diversity of viruses associated with termites and ants, which are among the most functionally important soil invertebrates. In our review we analyzed 93 articles dedicated to viral findings in both groups of insects. To date, viruses were detected in 54 ant species and in 28 species of termites. We have pointed out 270 viruses and viral genetic variants detected in soil-dwelling social insects, and less than one third of them were associated with termites (Fig. 4). It is obvious that the virome of termites is still mostly undescribed. In addition, both for ants and termites, the information on symptoms or on replication of viruses in their insect hosts remains strongly limited. More studies of the virome of soil-dwelling eusocial organisms with more attention to viral replication and infection symptoms are needed (Zueva et al. 2024).

The most amazing is, that despite the presence of numerous potentially harmful viruses and intense interactions between individuals within a colony, evidences of massive viral epidemics in termites are virtually unknown. We found the information only about one possible virus-caused termite family extinction (Chouvenc et al. 2013). This is especially surprising since termites are important pests of human structures and agriculture, and the search for viruses that infect them has been ongoing for a long time.

Figure 4. Visualization of the presence of viruses in ants and termites (based on Zueva et al. 2024).

There are numerous other unsolved questions on the virome of social insects. How many more viruses of eusocial insects we still don’t know about? Are they able to cause acute dangerous infections or are they just present in the insect tissues and do not manifest themselves until the immune system of host is critically compromised?

We are planning to continue our work in tropics, both on social insects and beyond them. We are sure that this region is a great source of new virological investigations, both on social and solitary invertebrates. By the way, a recent research of our team revealed at least eight new viruses in millipedes collected in the Cat Tien National Park (Litov et al. 2024).

References:

Chouvenc T, Mullins AJ, Efstathion CA, Su NY (2013) Virus-like symptoms in a termite (Isoptera: Kalotermitidae) field colony. Florida Entomologist 96(4):1612–1614. https://doi.org/10.1653/024.096.0450

Litov A.G., Semenyuk I.I., Belova O.A., Polienko A.E., Thinh N.V., Karganova G.G., Tiunov A.V. (2024) Extensive diversity of viruses in millipedes collected in the Dong Nai Biosphere Reserve (Vietnam). Viruses, 16: 1486. https://doi.org/10.3390/v16091486.

Litov AG, Zueva AI, Tiunov AV, Van Thinh N, Belyaeva NV, Karganova GG (2022) Virome of Three Termite Species from Southern Vietnam. Viruses 14(5):860. https://doi.org/10.3390/v14050860

Zueva AI, Zuev AG, Litov AG, Karganova GG, Tiunov AV (2024). Viruses of ants and termites: a review. Insectes Sociaux, 1-12. https://doi.org/10.1007/s00040-024-01008-8

Interview with a social insect scientist: Tom Ratz

/ Damien Gergonne / Leave a comment

Tom Ratz is a researcher at the University of Zurich, studying social interactions in arthropods like Drosophila and beetles. One of his most surprising discoveries came during his PhD while observing burying beetle mothers. Check out his latest work in Insectes Sociaux here!

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

I am an SNSF Ambizione Fellow based at the Department of Evolutionary biology and Environmental Studies, University of Zurich, Switzerland. My research broadly explores social interactions in arthropods and their role in evolution. My current focus is on agonistic interactions in the highly aggressive species of fruit fly Drosophila prolongata. My group uses a combination of behavioural experiments, quantitative genetic tools, and experimental evolution to test how the competitive environment shapes the evolution of social and non-social traits. 

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

My fascination with the insect world began early, around the age of eight, when I started collecting beetles in the backyard of my house. I was captivated by the hidden, bustling world of insects happening all around us, often unnoticed. I wanted to pursue a career in entomology and enrolled in a biology degree. During my studies, I found myself particularly drawn to ethology and behavioural ecology. Applying these fields to insects felt like an exciting way to maintain a connection to entomology while exploring broader scientific questions about behaviour and ecology.

Aggressive encounter between two male Drosophila prolongata. In the first image (left), one male chases the other, leading to an escalation into a fight involving leg fencing (right).

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

Burying beetles are my favourite social insects. I studied them during my PhD and still find their social behaviour incredibly enigmatic–most of which takes place on or inside the decaying carcass of a vertebrate! In a sense, what is a crypt to some is a cradle for burying beetles. Aside from their important ecological role as efficient buriers of small rodent and bird corpses, the complexity of their social interactions within family is, to me, unparalleled in the arthropod world. These behaviours include larvae begging for food and parents regurgitating a “soup” of pre-digested carcass flesh to feed them. Conveniently, burying beetles are mostly undisturbed by experimental conditions, making their behaviour relatively easy to observe and study in the lab.

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

A memorable discovery was analysing the data of my first PhD experiment and finding that they absolutely defied our initial predictions. Contrary to expectations, burying beetle mothers didn’t reduce care when experimentally handicapped by a led weight attached to them –instead, they provided more care. At first, this result was puzzling to me, but it became a revelation about the importance of understanding a species’ natural history. It makes sense for a parent to increase investment towards the current brood when prospects for future reproduction are low, which is the case with handicapping, even if the cost of care is higher. This insight highlighted a crucial lesson: while theoretical predictions are valuable, they must be contextualised within the specific biology of the study system.

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

In both teaching and science communication I try to incorporate my own research as case studies to illustrate key concepts and bring scientific research to life. I find that people are more engaged when they can interact directly with the researchers behind the studies.

Lab stock and experimental populations of the fruit fly Drosophila prolongata

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

In my opinion, some critical questions in the field include clarifying the role of social behaviour in shaping population dynamics and evolutionary responses. It is increasingly clear that social interactions within a group can drastically influence the population growth, survival, and how animals respond and adapt to environmental changes. However, what remains less understood is when and to what extend behavioural dynamics taking place among interacting individuals can impact group fitness and drive long-term phenotypic evolution.

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

One of my top hobbies is spending time outdoors. I’ve been fortunate to live near beautiful natural landscapes and mountains, which has allowed me to enjoy hiking throughout the year. It’s a great way to clear the mind and recharge. I’m also a regular at the bouldering gym. And of course, entomology remains an important hobby of mine.

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

The book “In search of us: adventures in anthropology” by Lucy Moore, and I highly recommend it. It’s a fascinating account of the origins of anthropology, told through the stories of people who helped found the discipline. It’s rich in field work and historical anecdotes. The author does a nice job of highlighting the complexities of the influential figures in the field–acknowledging both their biases as Westerners and their progressive ideas ahead of their time.

Burying beetles parents feeding their larvae.

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

Talking things through with colleagues, friend, or family often helps. While it may not directly solve the problem, verbalising it can normalise the issue and make it feel less dramatic (which it often is). Sometimes, simply going for a walk works wonders–a change of scenery can help put things into perspective.

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

If it can count as one item, I’d bring my partner with me. She’s incredibly resourceful and crafty, and would surely be a great survival companion (as she is in life!). I’d make sure she brings her Swiss army knife, so that’s item number two covered. And obviously a tube to collect beetles as my third item.

Tom, collecting beetles in Greece

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

My PhD supervisor, Per Smiseth, has been a major influence on my scientific career. He’s a mentor with exceptional work ethics. Another key figure was Sylvain Pincebourde, who took me as an intern in his lab when I just a first-year undergraduate. That was my very first  real research experience, and was incredibly formative. I also owe a great deal to many other mentors and colleagues who have had an important role in shaping my interest and career in Science, including Joël Meunier, Pierre-Olivier Montiglio, Niels Dingemanse, Cristina Tuni, Stefan Lüpold, and Wolf Blanckenhorn.

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

A general piece of advice, not just for someone interested in social insects, is to focus on work you’re passionate about and truly enjoy. With genuine interest and motivation, nearly everything seems to become achievable.

IS: Has learning from a mistake ever led you to success?

Yes! And, sadly, the most painful mistakes are often the ones that teach us the most.

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

The tropical forests of Panama are a favourite of mine. I also have a soft spot for Mediterranean ecosystems. Despite their dryness, I’m always surprised by their abundance and diversity of plants and animals.