Humans (and Other Social Insects)  by Andrew Kerr March 2007 Most of us would rather avoid them altogether, but Dr. Michael Goodisman is spending quality time with the real organism that was the inspiration for our heavily anthropomorphized Georgia Tech mascot: the yellow jacket. In this conversation, we discuss yellow jackets, where human and insect behavior overlap, and the pleasures of pulling wings off of flies. Q - Were you always interested in insects in particular, or did your general biology work lead you down this path? A - I've been interested in insects for a long time. When I was at Cornell I became more interested in genetics. When I came to the University of Georgia to interview I met my future advisor, and he combined both: he's a geneticist, and he worked on fire ants. I saw these ants, these crazy ants in a tray, and I was like, "This is so cool. I gotta work with this guy and work with these animals." Q - I used to collect wasps as a kid. I was drawn to them by the fact that they are very beautiful. But the danger was also very alluring. A - That's also part of it. I think more people in the world are killed by wasps than any other venomous animal. I collect colonies from around the city, and I get phone calls from people who run over a nest with their lawn mower, get mass attacks--and they're nasty. A lot of these social insects, because they live in these societies, they are very protective of their nests, of their young. You mess with the nest and you're in trouble. Q - We had a colony back behind my apartment, but it seemed to disappear the following year. A - They only live one year. They're like annual plants. Each nest is founded by a single queen in the spring like a single seed that gives rise to a plant. The queen initially builds a little nest and produces workers, which is sort of like vegetative growth initially, and then towards the end of the year the colony produces sexuals, much like a plant producing seeds right before it dies. Over winter the colony typically dies off and the old nest is not reused. Q - What sort of research do you do? A - I'm very broadly interested in social biology and particularly in social evolution. I use social insects as models for studying these topics. We study behavior of social animals and development of social systems. We're very interested in social evolution and using comparative approaches--looking at wasps and bees and ants and other highly social animals--and seeing how they're similar. We use a lot of genetic techniques. Q - When I interviewed Dr. Todd Streelman, he told me about homologous genes, genes shared across different species that control similar aspects of morphology (morphology = the shapes of organisms). Are social behaviors perhaps tied to shared genes as well? A - That's one of the things that we're interested in. Social wasps represent an independent evolutionary origin from social bees. What makes highly social systems highly social is they have different castes--queens versus workers, for example. We're interested in knowing if the same genes are involved in producing castes in wasps and bees. We're not quite able to say the same genes are involved, yet, but we're finding that genes with the same functions may be involved. For example, we've done some recent work that shows that queens tend to turn on a lot of genes related to metabolism; other work by other groups has found that it's the same with bees. Q - The popular consensus seems to be that the queen "runs the show." But of course the males are also passing down a genetic legacy of their own, by mating with the queen. Very little gets said about the males, however; it seems the focus remains on the queen. I guess my question is, is the queen really running the show? A - People often say that the queen is running the show, and I think a lot of that comes from what we, as humans, put onto the biological system. But we don't often say that the queen is running the show anymore. Workers, although they are not reproducing, are also running the show in their own way. Some people say that the workers are "farming" the queen--that she's reproducing for them. They control who gets fed in the colony and how they get fed [what the larvae are fed determines which grow up to be workers and which grow up to be queens]. There's evidence that suggests that there's conflict between the queen and the workers. Instead of always looking at the hive as a cooperative group, we also look at it as a group in conflict. Males are interesting. In ants, bees, and wasps almost all the individuals you see are female. The queens are female and so are the workers. Males don't do a lot of work in the colony; they basically show up for a very brief time to mate, and then they die. [With mating,] the way it works in ants, bees, and wasps, which are in the group hymenoptera, is that females are diploid and males are haploid. Q - What does that mean? A - Most organisms have two copies of each gene. You get one copy from Mom and one copy from Dad. But in this group, females have two copies of each gene, but males only have one. The males basically represent the unfertilized eggs of queens. Queens lay these eggs that are unfertilized by any sperm, and these eggs grow up into males. What that means is that the queen can control if she wants to lay a female or male egg, depending upon whether she fertilizes the egg or not. That allows her to potentially control the sex ratio in the colony. If she wants to produce a lot of males she can produce a lot of male eggs and the workers may have no choice but to rear those male eggs. If she wants to produce a lot of females for whatever reason, she can do that. Kind of a cool thing. There is some theory that suggests that depending on the genetic make-up of the colony, there are some queens in a population that would prefer to produce exclusively female offspring and there are some queens that would want to produce exclusively male offspring. But there are cases it's been shown experimentally and otherwise that there are queens or colonies that can sense the genetic relationships within their nests and therefore rear predominantly or exclusively queens or males. For example, fire ants--which we all know and love, right?--their colonies will very often produce exclusively one sex. If you kick over a fire ant mound at the right time of year you'll see that there are either all new queens being produced or all males. Q - If the queen is creating the males, where does genetic diversity come in? A - In most cases the queen will not mate with her sons. She mates with males from outside the nest. Yellow jackets go on mating flights, so you get outbreeding. Same with fire ants; you get vast mating flights. Q - On your Georgia Tech page you refer to "high fitness" colonies. What is it that determines a colony's "fitness"? A - We've found something in yellow jackets, which is that certain colonies seem to produce a lot more reproductive offspring than others. That's probably what I was referring to in terms of "high fitness." Q - Which is to say, some colonies produce more queens, and the more queens you produce the "fitter" you are? A - More queens, exactly. So this is a little show and tell [look at the picture on the right--ed.] . This is yellow jacket comb. They rear workers and males in a comb of this size--this is called worker comb. But when they want to rear new reproductive queens they build this, which you can see is much larger-celled. Some colonies seem to produce a lot more queen comb than others, and there seems to be a relationship between how many times the queen has mated and the amount of queen comb that is produced. So it turns out that queens that mate a lot had colonies that produced a lot of queen comb, and so our hypothesis is that multiple mating by queens somehow enhances colony fitness. Q - What is it that makes a larva develop into a queen, versus a worker? A - Queens and workers are genetically identical, but depending on what they're fed as larvae you will get development into either a queen or a worker. In honey bees the queen and worker-destined larvae are fed different things: so-called "royal jelly" versus "worker jelly." If a larva is fed royal jelly she develops into a queen, worker jelly she develops into a worker. In yellow jackets it seems the amount they're fed is important. What happens is a particular larva gets fed something by the workers, royal jelly or what have you, and that triggers a bunch of genes to turn on that are only going to be expressed in the queen but not in the workers. Q - That's actually pretty mindblowing. The idea that simply by eating different foods you can transform into a very different type of organism! Does this phenomenon ever occur in higher order species? A - Like vertebrates? Q - Sure! A - The phenomenon of producing different forms from the same genes is known as "phenotypic plasticity." Many, many animals can do it to different extents. You can think of trivial examples. In humans depending on how much you eat you're going to look different. If you eat a lot when you're young you grow taller and if you don't you're shorter. There are other arthropods or insects that show these kinds of things. There are beetles that develop long horns, or don't, depending on their growth, and there are water fleas that may or may not develop little helmets. In terms of, like, you say, vertebrate examples, such extreme examples as this? I can't think of anything quite this extreme amongst vertebrates. Q - Going back to homologous genes, does your research have applications to our understanding of how people, which are also highly social animals, conduct themselves? A - When you look at how insect societies are organized, the importance of helping your brother, or your sister, the same things happen in human society potentially. We as humans tend to behave in certain ways towards our siblings and our offspring, and we do that because ultimately that enhances our fitness. Why are you nice to your brother, or why are we nice to our children? It seems obvious. But on some level it's because you're hardwired to do that because it will increase your "fitness" [i.e., your genes are being passed down]. One of the interesting ideas that was brought up in the 70's was that the same types of selection and the same types of behaviors that apply to these sort of highly social animals that we look at as these primitive little things may in fact be happening in human societies. It was actually talked about [with regards to] why are people racist; we favor "our own" because we're hardwired to pass on our genes at the expense of others. Making these kinds of connections is basically known as sociobiology, the application of evolutionary logical principles that we think apply in social insects and other social animals and applying them in humans. It's possible that those things do apply and they probably do apply. There is evidence for example (this is obviously a little bit unpleasant to talk about) that when you have a guy who marries a woman who has a child already, that there's a higher incidence of abuse towards a child that is not your own. And that potentially makes sense evolutionarily, because this is not an individual that you're related to. So why would you treat them particularly well? Let's say there's a mutation that enters a population that will, it's a bit of a stretch, but that will allow you to help a relative and increase the number of offspring produced by that relative. If that increase in offspring is high enough, then you are gaining "fitness" by having your brother's offspring produced. So there was a famous geneticist [J.B.S. Haldane] who studied social evolution who said he would gladly give his life for two brothers, or four nephews, or what have you because the number of genes is the same essentially. [There is a good essay on this, which also makes mention of bees, called "So Cleverly Kind an Animal," which appears in Stephen Jay Gould's classic collection of essays Ever Since Darwin--ed.]. So there are potential applications, or at least things you can think about. Q - This idea of workers "farming" the queens, a hive in conflict, the interrelatedness within the colony. It's just completely mind-blowing from an evolutionary perspective, the fact that, essentially, each hive takes a step along the evolutionary journey as a team. A - It's not intuitive. In fact, that analogy's been made--you may have heard of it defined as a "super-organism." That's a term that fell out of favor, but it's coming back. It's worth making the analogy between the idea of a colony as a super organism and an organism itself. Think about a body made up like us. We have lots of different cells and the cells have different functions, much like individuals in the colony do. The major difference is that the DNA in all our cells is exactly the same. In a social insect colony that's not the case, because the individuals are not genetically identical--and that's a very important distinction. But otherwise there are similarities. You have some individuals doing some functions while others do other functions. A worker cannot exist on her own, and a queen cannot exist without workers, in some cases. The parts cannot survive without each other. Q - Collecting the nests must be a very "interesting" experience. Can you describe that? A - I initiate my students into it as well. It's kind of exciting because we need to get the nests "alive." We don't gas them and kill them. What we do is we dress up in full bee suits, and then we sort of approach the nest, which is usually underground, and we pour ether into there, and that knocks them out. Then you have to dig up the nest quickly before they "come to," throw the nest in a box, and bring it back to the lab. In that time there are workers that are coming back from foraging, or ones that you didn't knock out, that are up for the fight. It's always a bit of a rush when you do it. Q - How long do they live in the lab? A - Not for long. We are trying to get colonies to survive for a long time. For a lot of our developmental biology work we need to collect different developmental stages. We'll have combs that have larvae and eggs and that kind of thing, and we'll pull those out and analyze them. I have a student who's doing mating behavior, and so we'll bring back colonies that are basically ripe at the end of the year that contain unmated queens and males, and she'll set up mating trials in the lab to look at how they mate and with whom. They'll usually survive only a couple of weeks at most before we're done with them. Q - I recall seeing an ad at Georgia Tech for yellow jacket nests. I presume that came from your lab. A - We rely on folks for phone calls, we collect their nests when people give us a call. Q - Call your lab--don't call the exterminator! A - Don't exterminate, we'll come up and get it for free, and we'll put on a good show! We enjoy doing it! [Call (404) 385-6311 or email michael.goodisman@biology.gatech.edu--ed.] Q - Let's cover a few personal details. You went to Cornell University? A - I was there from 88 to 92. Q - Winter gets pretty cold up there. A - The weather stinks, but I'm from Syracuse, which is worse! It's about an hour and a half north of Cornell. Syracuse has tough weather, I'll put it that way, to be polite. My folks are still up there and so I do miss them terribly. After I graduated from Cornell I moved south and I've been in warm places since then and I wouldn't want to go back. For example we had 70 degrees yesterday and I talked to my folks and the high was like 15. I email them every time it happens and say, "Well, it's nice and warm here! Wearing shorts!" Q - Coming from Washington, D.C., I grew used to having some wintery weather. I miss it, so every year I try to take a trip where I'll be able to see snow. A - I don't miss it at all. In fact I lived in Tucson Arizona for a while. It's crazy hot but I'll take that any day over cold! Q - You studied in Queensland, Australia. Sounds like that would have been paradise! A - It was amazing. In terms of the biology, for someone who studies insects, there's crazy, crazy social insects down there. I mean huge ants that will really put the hurt on you, undescribed bees, frogs in your toilet, and all kinds of things! So it was a really good time, a really good experience. I would love to go back, try to arrange things to go back at least to visit. Q - What did you do down there? A - I did a few things. My interest in yellow jackets actually predates being at Georgia Tech [Georgia Tech's mascot is a yellow jacket--ed]. I actually studied invasive yellow jackets down in Australia. There's a species there that is now invasive in the U.S. that I did a little bit of work on. Q - "Invasive"--that means an introduced species? A - Exactly right, it's an introduced species. Down there it was called the European wasp. Both New Zealand and Australia have been invaded by a couple of species of yellow jacket wasp, and I did a little bit of work on how they moved across the country and where they might have originated. I also did some work on termites. They have crazy termites there, huge termite mounds, and I did a little bit of work again on the reproductive biology and the mating behavior of a particularly nasty pest termite. It eats houses and other kinds of things up in Queensland. So that was a lot of fun. Q - Were you always interested in insects in particular or were you interested in biology in general and were led down the path to insects? A - I've always been interested in insects and this is sort of a creepy story which you may chose to edit out but maybe not. So it turns out there was a study done, and it was found that a very large proportion of PhD's in entomology tortured insects when they were young. And I fell into that category, I have to admit. Q - What? The magnifying glass on the anthill sort of thing? A - Well, yeah, at least. Q - Pulling the wings off of flies? A - Yeah, well, whatever... Q - You were just demonstrating an aptitude for experimentation! A - That's a polite way to put it. That's very kind of you.