Science Interviews


Sun, 18th Jun 2006

In Search of Social Beetles

Dr William Foster, Department of Zoology, University of Cambridge

Part of the show Social Insects and Locust-Inspired Car Safety

Chris - One of your interests is in social animals and you're going to be going out to the back of beyond to Thailand soon. Why is that and what is it you're going to find there?

William - We're hoping to look for social behaviour in beetles. Social behaviour in insects is very important because the most successful animals in the world, of all animals, are ants and termites. They're successful because they're social. They're able to have huge colonies and be very well organised. This has evolved rather infrequently; it only appears in ants, bees wasps and termites. We'd like to be able to see whether the largest group of animals in the world, the beetles, whether any of them are social. There's a particular group of beetles there called passalid beetles, and the Americans call them bess beetles. They have quite advanced parental care, that is that the parents look after the young and do things like help the larvae make the pupal case around them. They can't do this themselves and the parents have to push from one side while the larvae push from the other. It's a very elaborate social care. This has been known for a while but no-one has ever studied them very thoroughly. We know there are large colonies of various species in this part of South East Asia and we want to go and find them.

Chris - So when you're mounting an expedition like that, how do you set it all up? What are the steps involved and how much is this going to cost?

William - It doesn't cost all that much. We're doing it with the Natural History Museum in London and they are mainly going to collect beetles and lepidoptera, butterflies and moths, in the area generally. They've done most of the organisation. What is really required I a permit to bring the material out of Thailand. All countries quite correctly don't like people going in and pillaging all their animals. We haven't yet got the permit and the Natural History Museum are still negotiating with the Thai authorities, but we will have that. Otherwise, you just need somewhere to live, nets, tubes and alcohol. That's 80% alcohol in which to put the insects when we've caught them.

Chris - So not for the scientists to drink then?

William - No!

Chris - So going back to these beetles, do we think that the origin of this social behaviour in ants and wasps, evolved from a common ancestor or have they independently evolved to have this interdependence on each other?

William - It's happened independently several times, but not that often. The termites probably had two origins of social behaviour for example, the ants probably only one. Another group that is social are the aphids. You would expect them to be social because they're colonial. They're clonal and all the same genetically. The Portuguese Man of War is also a social animal. It's clonal it's identical and only some of the animals in a Portuguese Man of War that reproduce.

Chris - So is that the same in aphids? Rather than just cloning themselves they will actually have sex?

William - Well only some of them reproduce. Some of them are totally sterile.

Chris - This is green fly, not Portuguese Man of War.

William - Yes, this is green fly. Some of them are just warriors, like there are warrior polyps.

Chris - Is that to distract predators? If you've got fifty million green flies and a couple of them don't actually do anything except sit there eating and being all fat and juicy, if something comes along to eat the green fly it's more likely to pick on one of the sterile ones. That leaves behind the ones that will reproduce and can foster offspring.

William - Well it's more the case that there are soldiers that are heavily armed baby ones that rush around over the colony kicking off parasitic wasps or anything that's trying to eat them.

Chris - There was an interesting story recently where scientists were looking at how plants have their own alert system where they use chemical signals. When a caterpillar or a green fly eats the plant, the plant releases various chemicals that actually attracts predators that eat the animals that are eating the plant.

William - They don't attract predators but parasitoid wasps. They come flying in and lay their eggs on the caterpillars that are eating the plant. It's a relatively recent discovery but it's definitely true and there's lots of good evidence for this now.

Chris - Going back to your Thailand situation, why is it that no-one's ever discovered that there are these social beetles knocking around given the wealth of information you've already told us? These things have this interdependent relationship with each other. They can't reproduce without another's help.

William - People have studied them a little bit. Some work has been done in America. An American school teacher in the 1930s kept them by his bed and watched them doing various things. I suppose there's not much money in them and they're not that important ecologically. They are quite important. They live in wood and break down wood. No-one's really been that interested in the theory; the evolution of social behaviour.

Chris - Isn't there a claim that in the same way Claire is trying to look at locusts to see if we can borrow from biology to make cars safer, people are interested in how ants communicate and signals are passed through colonies to make computers work faster?

William - Yes, indeed. I thin there are lots of analogies one can make with social insect colonies and how to make things like brains and complex systems work. All these colonies work on simple rules that the individuals make. By the accumulation of lots of simple rules and lots of individuals, one can get the emergence of lots of complex properties.

Helen - Going back to your expedition, I presume it's rainforest that you're looking at, how will you know if the beetles are social rather than a group of beetles living together in a high concentration? What are the keys that you'll be looking for?

William - The key thing we'll want to see in the end, and this will unfortunately mean killing them, is the extent to which the females in particular are reproductive. If we got a hundred beetle sin one log, we'd collect them all and see if there is a queen beetle who is full of eggs, and lots of worker beetles who aren't. So we're looking for the extent to which reproduction is concentrated in one individual rather than being spread evenly across the whole colony. No-one knows that at all for this group at the moment.


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