socialinsects

Interview with a social insect scientist: Tomer Czaczkes

/ Damien Gergonne / Leave a comment

Tommy is a researcher at the University of Regensburg, where he leads the ACElab since 2016. He study value perception and decision-making in invertebrates (mostly ants). His latest work in Insectes Sociaux can be found here.

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

My name is Tomer (Tommy, please) Czaczkes, and I study the behaviour of mostly ants, sometimes bees, and very occasionally other arthropods. My current focus is on comparative psychology – understanding how animals think, learn, and make decisions. I’m trying to apply our hard-earned knowledge of behavioural ecology to controlling invasive ants. I also dabble in collective behaviour.

Tommy Czaczkes thinking about Lasius fuliginosus.

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

Ah, well. During my undergraduate the average grades for different modules were available, and I noted that while cell biology and microbiology had pretty low average grades, behaviour and ecology had quite high ones. I know which side of the bread is buttered, and, honestly, I never expected to stay in research. Then, during my undergraduate project, I realized that while the miserable vertebrate ecology people would have to trek for hours through the forest to sight their animal, I, as an experimental behavioural ecologist working on ants, could collect 50 datapoints in half a day, while drinking rum.

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

Oooh, a tough question! I’m torn between two ant species: Lasius niger and Pheidole oxyops. L. niger is perhaps the most common ant in Europe, and as my PhD supervisor Francis Ratnieks always says “it’s the common animals that are most interesting. They’re clearly doing something right.”. L. niger are extremely smart, polite, helpful, and make excellent colleagues. P. oxyops, however, do wonderful cooperative transport – the collective carrying of loads. They have an amazing, explosive recruitment behaviour, and love cheese. They’re also extremely common, but alas, in Brazil and not in Germany, where I’m based.

Pheidole oxyops carrying a 10x10mm square of choose by the corners (published in Insectes Sociaux).

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

Seeing ants being visibly disappointed when they received food which was poorer than what they were expecting – poor things! It was clear from the moment I did the first pilot on that project that we would have a clear and strong effect. It was memorable because it was simply so easy to relate to: the disappointed ants would check the food, break away, try again to make sure, and circle around looking for the good stuff they were sure was there before. It was simply so cute and relatable.

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

I enjoy going into schools and kindergartens, to talk to kids about ants and insects in general. It’s always fun to bring an ant colony or two, and show the “mama ant” and her babies. For the bigger kids, it’s fun to do a pheromone following assay – makes me feel like an ant whisperer, who can use my super science powers to talk to insects.

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

This is showing my own biases here, but I think the question of insect sentience and intelligence is a huge question, and social insects are central to the experimental examination of these topics. We’ve had a slew of high impact work reporting all sorts of impressive cognitive abilities, with a big swing from behaviourism to cognition. I expect that very soon the swing will move the other way again, with people starting to push for simpler explanations, or attempting replication studies. Animal behaviour as a subject is overdue a big replication study, the likes of which shook up the worlds of experimental psychology and cancer research (amongst others) recently. I have attempted to replicate some of my own work, with some things replicating wonderfully, and others simply not there next time I looked. And yes, I publish the failed replications too.

Lasius niger worker who is very satisfied with her drop of sucrose solution.

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

I really enjoy hiking in the mountains, when I can get out. When not, I’m a big fan of sci-fi books and computer games. My mind is still somewhat blown by my VR set.

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

I’m almost through “Delusions of Gender” by Cordelia Fine. The book speaks against the supposed ‘evidence’ for a simplistic biological basis for gender roles. Would I recommend it? It’s convincing and helpful, but sometimes feels like being bludgeoned with an endless series of (reasonable) criticisms of studies. It’s well researched and useful, but perhaps not the page turner it could have been.

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

Give up! No, really. On days where I can’t focus, I simply stop working. If an experiment runs into wall after wall, I’ll drop it. But for things like rejections, failures, etc – I take the long view, and remind myself that this is normal, and this too shall pass. Oh, and moaning. Moaning helps.

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

Assuming my basic survival needs were met? My ebook stuffed with books (for entertainment), a solar charger to charge it, and a Swiss army knife to bootstrap other tools from. I think I’ve played too much Minecraft.

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

Certainly my Doctoral supervisor, Prof. Francis Ratnieks. He has an absolutely excellent eye for interesting biology. Moreover, I admire (and have tried to emulate) his quick, cheap, and cheerful approach to research projects – avoiding the huge, long term, ultra-high tech projects, and preferring short, fun, and simple projects which require only some ants, a few strips of paper, and some drops of sucrose. And a good idea, of course.

In this experiment, Tommy’s team was testing whether ants prefer food they have worked harder for (they do). A good example of their experimental designs. Note the Lego, paper runways, and complete lack of high tech gubbins.

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

Read “The Ants” by Hölldobler and Wilson. Yes, it’s almost 35 years old, but it’s a wonderful primer to most of the major topics in social insect biology. I read it cover to cover to prepare for my PhD, and that knowledge has stood me in good stead since then.

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

Not nearly as much as I would have hoped. I seem doomed to making the same mistakes over and over again. However, at least by now I recognise them with absolute clarity in hindsight.

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

The La Selva biological field station in Costa Rica, where I did my Bachelors project (on leaf cutter ants). Being surrounded by researchers for the first time, in a beautiful jungle, with amazing animals, was life changing. I also met my future wife there, so that was a nice bonus.

Networks and ants: how do ants maintain connections?

/ Damien Gergonne / Leave a comment

By Balint Kovács

In this blog, Balint Kovács, who is an assistant Research Fellow at the HUN-REN-PE Evolutionary Ecology Research Group, explains how social networks in ant colonies are structured and influenced by different castes. His latest work in Social Insects can be read here.

How do the animals maintain connections? What do these connections look like? What shapes them? These are the basic questions posed by a generalist network scientist. When we talk about social animals, sooner or later, we arrive at the ant colonies. Ants are famously and extremely social, and many tales and stories highlight their industriousness and diligence. But what are the real facts? How can we describe these communities scientifically? My passion for social animals led me to investigate this question during my research work and PhD studies. I researched multiple animal species in the context of social networks, and of course, ants had to be one of them. Let’s see what we found in our observations.

In human societies, different jobs and workplaces create different microcultures and behavior patterns. But what about ants? Do different work tasks (castes) create different roles for individuals? If we look closely at these castes, what will we find?

Our research used a previously published paper (Mersch et al., 2013) about carpenter ants (Camponotus fellah). In this research, three main castes were defined:

Nurses: individuals who spend most of their time near the core of the nest. These workers guard and take care of the eggs.

Foragers: these individuals are responsible for gathering food. Most of the time, they search for resources for the colony.

Cleaners: their responsibility is to clean the nest and maintain tunnels. So, we have castes and queens. Now, we need to examine their connections. Mersch et al. tagged and tracked all individuals for approximately a month in six colonies of these ants to detect interactions among individuals. More specifically, they observed when two individuals touched each other with their antennas. We used these interactions to create networks. In these networks, or graphs, the nodes were the individuals, and the edges represented the interactions. So, we have nodes (ant individuals) and edges (interactions between them). With this information for each day, we can model networks for each day as well. A whole network for six colonies in one day looks like this:

Too many edges, too many nodes. Quite chaotic. Our idea was to model networks only for castes.

Nurses:

Foragers:

Cleaners:

Okay. Now we had networks for each colony, each day, and each caste. Almost done. But we had another idea as well: What about the queens? What if the individuals’ networks looked different when they interacted directly with the queen? To investigate this question, we modeled another two types of networks: Queen-related and No Queen-related networks. To distinguish these additional “castes” of individuals, we called the subnetworks.

Queen-related:

No Queen-related:

Now we had all that we wanted: interactions, castes, and subnetworks. The last step was to compare these networks to each other to see the basic differences between networks and, therefore, the differences in behavior among these worker groups.

But how is this possible? Visually, we can see some differences, but we need to prove it. In network studies, we use network indices to describe network properties. Every index tells something about the group we modeled. Multiple indices are available in the literature; here we used three basic indices: Network Centralization Index (NCI), Clustering Coefficient (CC), Average Path Length (APL), and Small-World Index (SW). NCI gives the hierarchical properties of a group, CC is an indicator of the rates of cliques within the group, APL calculates the average “step” (network edges) between all individuals, and SW represents how many “neighbors” are required to reach everyone within the group. In other words, NCI represents the hierarchy rate, CC shows how easily information can flow through the group, APL calculates the “speed” of this information flow within the group, and SW shows how “closed” the group is.

We used a statistical method (Linear Mixed Models, LMM) to compare these indices between castes and subnetworks. The results showed that Cleaners are less hierarchical (low NCI), with fewer cliques (low CC) than Foragers and Nurses, with slower information flow (high APL).

The presence of the queen surprisingly influenced only the information flow. Those individuals who were connected with the queen established “faster” networks than individuals with no queen connections.

In summary, our results revealed new information about castes and individuals through their networks. It seems like the tasks of nursing and foraging require a more centralized, denser, and faster information flow than the cleaning task. Moreover, the presence of the queen makes information flow faster within the group. So, the role of the queen seems essential not only for producing offspring but also for “controlling” the castes as well.

Cited article:

Mersch, Danielle P., Alessandro Crespi, and Laurent Keller. “Tracking individuals shows spatial fidelity is a key regulator of ant social organization.” Science 340.6136 (2013): 1090-1093.

Interview with a Social Insect Scientist: Riley Shultz

/ Damien Gergonne / Leave a comment

Riley works in the Department of Entomology at Purdue University and is interested in honey bee health. Her recent research published in Insectes Sociaux can be viewed here.

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

I am a PhD student researcher in the Department of Entomology at Purdue University. I work in the Harpur Lab investigating honey bee health with a focus on honey bee drones. The Harpur lab strives to bridge the gaps in our knowledge about genomics, the evolution of eusocial species, and their adaptive traits. My specific research interests include mutation and molecular mechanisms of repair.

A frame of drone bees with nurse bees tending to the newly emerging adults.

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

I have always had a fascination with honey bees and medicine. When I was in high school my dad brought home a nuc of bees and invited me to join in the hobby with him. Spending summers doing mite washes, observing colony behaviors, and of course harvesting honey sparked my fascination with social insects. I ended up joining a bee lab during my undergraduate at Washington State University and developed further research interests in honey bee health. Now during my MS and PhD at Purdue University I am able to foster my interests in mutation using the unique haplodiploid honey bee.

Riley’s dad checking hobby beehives in 2018.

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

Honey bees from day one have captured my full attention. There are so many unique behaviors in these eusocial insects that make them a fascinating study subject. While my research interests lie more on the pathways within the insect itself, the colony structure of honey bees make them highly complex.

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

This past summer I worked with a mutant honey bee colony, where drones in the colony had either white or dark eyes. We ran a series of experiments to learn more about the sight deterioration in the white-eyed males. While we presumed that the white eye drones would go blind at some point, it was really exciting to perform some simple tests on this. I spent hours outside a colony observing drones leaving and returning to the colony. This was memorable partly due to the sheer amount of time I spent observing the mutants’ behaviors, but it was also fun to observe bee behaviors more generally.

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

The Harpur lab works to spend a lot of time doing various outreach activities. I really enjoy connecting with the local community to talk about honey bees and pollinators more generally. I’ve done outreach with the local library as well as with scout troops in the area. My favorite moment is always when young children overcome their fear of an insect. It is a fun puzzle to teach children about honey bee genetics, and we all look forward to helping children ‘build-a-bee’ as a simple way to learn about the inner workings of a colony.

Honey bees swarming to find a new location to establish a colony. Honey bees were collected from the fruit tree and put in a new hive.

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

Insects play an integral role in human lives. They provide a powerful model for medical research, pollination to our agricultural systems, vital roles in our ecosystems, and so much more. I think we still lack fundamental knowledge on many social insect systems and discoveries within these systems will be key to innovative studies. Conducting comprehensive studies on the genotypes and associated phenotypes is crucial as it lays the essential groundwork for future practical research endeavors.

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

I am an avid reader of fiction. When I’m not pouring over journal articles, you’ll find my nose in a book. Reading is a really nice way to escape and embrace your creative side. I enjoy hiking and kayaking. Spending summers on Idaho’s whitewater was the perfect way to cool off after beekeeping.

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

The book I am currently reading for my insect genomics course is “A Primer of Population Genetics and Genomics” by Daniel L Hartl. This book has helped further my understanding of population genetics for someone whose background is more molecular biology. For my personal enjoyment, I recently read “Six of Crows” by Leigh Bardugo. I am a huge fan of books that describe things outside of our reality. While this book is more realistic than some, I really enjoyed how well-developed the character’s backstories were. There is a real art to developing a story where the reader can get inside the character’s head and understand the forces that drive them.

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

I am fortunate to have a supportive family and partner, as well as friends and colleagues. The going may get tough in the winter time for someone researching bees, but holding out till the next summer is well worth the wait.

Riley’s co-workers and her harvesting honey and collecting drones in 2023.

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 really large book, some sunscreen, and some semipermeable membranes to filter seawater. I am well known as the coworker who advises sunscreen even when wearing a bee suit as well as the one who carries around a comically large water bottle.

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

This is a hard question to answer. My first research experience as an undergraduate was not very rewarding. I switched my path to work in an entomology lab and was met with immense support from my co-advisors Dr. Nicholas Naeger and Dr. Jennifer Han. I found a renewed passion for research and was able to grow my interest in honey bees with an independent project under their advisory. I attribute my current career trajectory to the experiences created by these mentors. I would also name my current advisor Dr. Brock Harpur for his enthusiasm in studying social insects as well as his continued support for all of the students in his lab. He has helped me to refine my skills in designing robust experiments as well as writing grants.

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

My advice would be to pursue your passion and not stress over the small things. Working with social insects can be labor intensive as well as unreliable. I cannot count the number of rainy days in the summer that have added new challenges to working with honey bees. I think learning to adapt to these new challenges and to frame your mindset as each stress being a little ‘puzzle’ will help in the long term.

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

Absolutely. I have made many mistakes in my short career, but those are the moments that allow me to remember and adapt. When something works the very first time I do it, it’s often forgettable. If something went wrong, I was bound to learn from that experience as well as gain new skills along the way.

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

I haven’t had too much need for travel in my career at this point, but my favorite place thus far is probably traveling to the Plant and Animal Genome conference in San Diego. There I was not only able to attend a wonderful conference and do a bit of sightseeing, but I was also able to connect with my advisor’s colleagues. I always look forward to making connections with people who share the same interests in insects!