IS: Who are you and what do you do?

JR: My name is Juliana Rangel, Assistant Professor of Apiculture at Texas A&M University in College Station, TX, USA. I run a research and teaching program focusing on the health and biology of managed and feral Apis mellifera colonies.

IS: How did you end up researching social insects?

JR: When I was an undergraduate student at the University of California, San Diego, I emailed Dr. James Nieh, who had just started his position as Assistant Professor in the unit of Ecology, Behavior and Evolution, which was also my major. Coming from Colombia, I wanted to get experience with research, especially in projects that were being conducted in the tropics. Coincidentally Dr Nieh had a research project in Brazil studying communication mechanisms in stingless Melipona bees. I worked for a semester analysing sound pulses produced by Melipona mandaçaia foragers upon being trained to feeders… I really liked what I was doing! Then Dr. Nieh invited me to be his research assistant in Brazil working with actual colonies… the rest is history. I worked with stingless honey bees for the rest of my undergraduate years, and in 2004 I started a doctoral degree in the department of Neurobiology and Behavior at Cornell University still working with stingless bees. My project wasn’t going fast enough so a couple of years into it my Ph. D. advisor, Dr. Tom Seeley, suggested that I switched to working with Apis mellifera. I have worked on several research projects exploring various aspects of reproductive biology of queens and drones ever since, and I love it.

IS: What is your favourite social insect and why?

JR: Of course Apis mellifera. Despite being widely studied, there are still so many fascinating discoveries about its biology that never stop to amaze me… the way that colony organization is decentralized and yet so meticulously timed and executed is a feat difficult to top by any other organism… and the rules applied in decision-making processes are just as captivating. I am particularly amazed at how sperm storage is maintained for so long in honey bee queens after mating… overall there are just too many factoids about honey bee biology that make it the ideal organism to study and love.

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

JR: I have had many great moments of discovery, but my favorite one happened in 2009. I was on Appledore Island, Maine, studying with Tom Seeley the signals (and signallers) that initiate a swarm’s departure from the parental nest. We set up glass walled observation colonies and artificial boxes that nest-site scouts soon discovered and started recruiting nest mates to. Upon arrival to the boxes our assistant Sean Griffin (who still also studies pollinators) would label scouts with paint on their thorax so that we could identify their arrival back at the observation colony. We soon discovered that indeed, nest-site scouts start the house hunting process days before a swarm leaves the parental nest, a great discovery of its own. Even though Sean had labelled a few hundred bees from one colony that was preparing to issue a swarm in a couple of days, we did not find that many labelled bees back in the colony. Something was off… when the swarm left a couple of days later, we suspected something weird and opened the nest box, only to find hundreds of labelled bees “guarding” it by staying inside until the swarm movedinto the box. This exciting discovery led us to conduct a follow up study the next summer in which we set up pairs of swarms on stands (we could distinguish the two form the color of their cuticle) and video taped what happened inside nest boxes. Indeed swarms compete for high quality nest sites by keeping guard inside the coveted boxes, and engage in overt aggression ranging from behavioural escalation of intent, to direct stinging and lethal combat. Really cool stuff…

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

JR: I teach three courses. Two undergraduate courses are focused on honey bees: Honey Bee Biology which is a course for juniors and is solely lecture-based. And my favorite, Introduction to Beekeeping, which is a field, hands-on ‘laboratory’ course that teaches students how to start their own colonies and how to manage them throughout the year. I also teach a graduate-level course on “Professional Contract and Grant Writing” which helps students understand the “art” of grant writing and award management.

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

JR: I am currently reading “Bee Genetics and Breeding” by Tom Rinderer. It’s a very thorough book on all aspects of honey bee breeding. I would highly recommend it to people studying honey bee reproductive biology. Although it was written in the late 80s, it still has a lot of pertinent information about queen and drone biology, some of which has not been advanced much since the book was written.

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

JR: Yes, “The Wisdom of the Hive” by my Ph.D. advisor Tom Seeley. I had to read it for my oral exams, and it gave me a lot of insights into what we knew and didn’t know (then) about colony organization. Oh, and of course “Honey Bee Biology” by Mark Winston, because even though it has not been updated since 1987, it shows how much we still don’t know about honey bee biology. The are “must reads” by anyone studying Apis mellifera.

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

JR: I love to travel and to go camping. Now that I am a new mother of a six-month old baby, I love spending time with my husband and kid just walking and traveling with them… and with our red heeler dog, Max. I also love to cook and to entertain friends and family at our home… and I play the guitar and sing Latin American folk songs, especially during gatherings.

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

JR: I rely on my family for support, and try to communicate with colleagues and mentors who have always supported me. I have always found that talking about what is going on, regardless of how difficult the situation might be, is very positive for resolution. As my wise mother always says, “no two days are alike” and “each day comes with its own rush,” both of which are true. Taking life one day at a time but with a good plan for the future has worked well for me.

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

JR: This one is very tough. Would I be alone or with my family? If I was alone I would bring my baby, my husband, and my mother… but what about the rest of my family? And Max? Oh this question is tough. If it had to be things, not people… tools to seek and cook food and/or to make a shelter. That’s all. Maybe a pen and paper.

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

JR: Of course it has to be my PhD advisor, Tom Seeley. I am just so lucky to have been accepted in his lab and to have worked so closely with him during my years at Cornell. I could not have asked for a better advisor. I still keep in touch with Tom and ask for advise on life-changing opportunities… his words are always wise and accurate. He also finds joy in seeing me progress in my academic and personal life, which is always a plus.

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

JR: I would say go for it. You know that if you’re in an academic life, you will never be rich. We don’t do this for the money. As the late Dr Tom Eisner said, we do it “for love of insects.” I would encourage students to explore questions that have a basic biology aspect to their research… too much of the current research focuses on next-generation “-omics” work that often overlooks past the importance of knowing basic biology: behaviour, ecology… which are the studies that I find most fascinating still to date. Learn a wide set of experimental tools to be competitive in the current job market, be flexible with your job expectations, and do good, ethical work, always. Oh, and have fun while doing it!

 

A blog post highlighting the article by H.F. McCreery in Insectes Sociaux

By Helen McCreery (@HelenMcCreery)

Ants are famous for their ability to carry heavy things. But some food items are too large and heavy for an ant to carry alone. In some species, ants that come across these large food items will return to the nest to recruit help to carry it home.

Ant species differ dramatically in how effective groups are at cooperatively transporting these items. A small number of species – such as weaver ants and crazy ants – can rapidly carry extremely heavy objects many thousands of times the mass of each individual. On the other hand, most ant species are relatively uncoordinated, and may not succeed at all.

What makes some ant species excel at cooperative transport? One major challenge of cooperative transport is that the group must agree on a travel direction. I hypothesized a behavioral trait possessed by individual ants – persistence – affects groups’ ability to coordinate their efforts in a particular travel direction, and thus, to succeed.

Persistence is a measure of how likely an individual is to change the direction she’s trying to move an object – or even to give up – if she’s unsuccessful. Highly persistent ants will keep pulling in the same direction for a long time, even if it’s not working. If a group is full of highly persistent individuals, they may fail because they pull in opposing directions for a long time. On the other hand, if a group is full of low-persistence individuals, they may change direction too frequently or simply not try for long enough to get going. Some previous work (McCreery et al. 2016) showed that in most cases high persistence improves coordination, at least in a theoretical context. I tested this hypothesis experimentally, by comparing cooperative transport ability in species that differ in persistence, and by manipulating persistence in groups of one species.

For the first part of this project, I worked with four ant species that ranged from impressively successful at cooperative transport (crazy ants: Paratrechina longicornis) to poor cooperative transporters (Formica pallidefulva), with Formica podzolica and Formica obscuripes making up the middle ground – groups in these two species seem to be moderately effective at carrying objects together (see video below). I measured persistence for dozens of individuals in each of these species by watching them complete an impossible task – trying to move a dead cricket I pinned to the ground. Separately, I measured the degree of coordination of groups in each of these species by recording groups engaged in cooperative transport. I measured two aspects of their coordination: success fraction (in what proportion of attempts did groups move at least 10 cm?) and path directness (did they move in a straight line or did they change direction frequently?). If species with highly persistent individuals were also more successful, it would support my hypothesis.

 

Video: H. McCreery

In the four species that I compared, I found just that pattern. Importantly, I found that there was substantial variation among species in both persistence and in coordination. P. longicornis individuals were the most persistent by far, and formed groups that were the most coordinated, succeeding in over 97% of attempts. On the other hand, F. pallidefulva individuals had dramatically lower persistence and were the least coordinated – F. pallidefulva groups only succeeded in about a quarter of attempts. The two other species, F. podzolica and F. obscuripes, both had individuals that were moderately persistent, and formed groups that were moderately coordinated – these groups succeeded most of the time, but with relatively indirect paths, they tended to travel about twice the distance they needed to because they frequently changed direction. High individual persistence is correlated with high group coordination in these four species.

In the second part of this project, I wanted to test whether coordination could be improved by increasing persistence so I manipulated persistence in groups of F. podzolica. I did this by measuring the path-directness of groups, and then adding one or two infinitely persistent “fake ants,” and measuring path-directness again. I added fake ants by mimicking the pulling force that such ants would apply on an object. I gave groups of ants heavy baits attached to string. Using a pulley system, I could add a pulling force on the baits by adding weight on the end of the string (see above figure). Check out the video below to see how I measured the pulling force of these ants.

 

I measured the pulling force of F. podzolica workers by recording them pulling on coiled chains. They enthusiastically pulled on these chains without bait!
Video: H. McCreery

The fake ants that I added to these transport groups were infinitely persistent, because the string would never stop pulling and never change direction. While the force of one ant made no difference, adding the pulling force of two ants going the same direction seemed to moderately improve coordination. These groups tended to move with more direct paths after I added the fake ants. I was surprised to see even a moderate effect, given that I only mimicked a single possible cue (the pulling force); my fake ants did not mimic anything else about real ants. Together with the results from the first part of this project (species comparison), these results suggest an important role of individual persistence in coordination during cooperative transport.

I found that species with more persistent individuals formed more coordinated transport groups, and that artificially increasing persistence moderately improved coordination. It can be difficult to draw strong conclusions when comparing across species, and indeed, the four species I evaluated differ in many more traits than just persistence. It is possible that another difference among these species, instead of persistence, has a more important effect on coordination. Despite this difficulty, comparing cooperative transport across species that dramatically differ is an important step in understanding the mechanisms of coordination. I would be interested to see if other species, beyond these four, fit a similar pattern with respect to persistence and coordination. The results of this study further suggest additional, targeted experiments that could get at the specifics a causal relationship between persistence and coordination.

Reference

McCreery HF, Correll N, Breed MD, Flaxman S (2016) Consensus or Deadlock? Consequences of Simple Behavioral Rules for Coordination in Group Decisions. PLOS ONE 11:e0162768. DOI: 10.1371/journal.pone.0162768