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Getting Stung for Science in the Rain Forest

By Patrick Kennedy

A rainforest stream in Panama. A major hunting ground for tropical wasps, as they comb the vegetation for caterpillars. (Photo by Patrick Kennedy)
A rainforest stream in Panama. A major hunting ground for tropical wasps, as they comb the vegetation for caterpillars. (Photo by Patrick Kennedy)

Today was a momentous day for me. I was stung by a livid South American wasp for the 70th time. Even for people sticking their heads inside wasp nests for a living (which includes me), this requires some dedication. As one entomologist put it recently, the sting of this particular wasp “feels like spilling a beaker of hydrochloric acid on a paper-cut.” If you’re going to be stung on 70 separate occasions by Polistes canadensis, you’d better have an excellent reason.

It’s all National Geographic’s fault. Armed with a Young Explorers Grant, a set of collecting jars, several radio-antennae, and an epipen, I have embarked on an entomological mission across Central and South America in pursuit of a fascinating evolutionary mystery. Together with Pieter Botha from the University of Stellenbosch, I am currently in Panama for my PhD fieldwork, preparing to attach thousands of minute radio-transmitters to wasps on the lush banks of the Panama Canal. I feel like I had better explain!

Each wasp wears a tiny radio-tag, allowing us to track her movements over a network of colonies in the wild. She also gets a small makeover for her wings, so I can identify each wasp from her unique colour-code. (Photo by Patrick Kennedy)
Each wasp wears a tiny radio-tag, allowing us to track her movements over a network of colonies in the wild. She also gets a small makeover for her wings, so I can identify each wasp from her unique colour-code. (Photo by Patrick Kennedy)

I believe that wasps are not just those irritating things that try and make off with your jam sandwiches: they actually have incredible social lives. They live in complex societies typified by astonishing feats of cooperation. Sometimes, their societies erupt into civil war. To my eyes at least, it’s all very human. But more importantly still, they enable us to test theories about one of the most controversial parts of modern biology: the deep evolutionary origins of animal kindness.

Inside the nests of social insects (such as ants and wasps), individuals cooperate to help rear other members of their close family. This makes excellent sense, because every animal on Earth ultimately cares about just one thing: ensuring that as many copies of their own genes get transmitted successfully into the next generation. Since other members of your family share your genes, helping your parents and siblings reproduce can be a great way to help promote your genetic legacy.

Paper wasp colonies bristle with activity. Despite the appearance of harmonious cooperation, there are seething tensions in every colony that occasionally erupt into fights for the right to become queen. (Photo by Patrick Kennedy)
Paper wasp colonies bristle with activity. Despite the appearance of harmonious cooperation, there are seething tensions in every colony that occasionally erupt into fights for the right to become queen. (Photo by Patrick Kennedy)

However, in my lovely (if slightly painful) wasps, things are not so simple. These wasps apparently haven’t read the biology textbooks. They cooperate with a whole host of neighbouring nests, helping very distant relatives as well as their closet kin. On the face of it, this is a major conundrum for evolutionary biology. Finding the solution could have big implications for how we understand the evolution of altruism (self-sacrificing kindness to others) in the natural world.

Chasing wasps in the tropics means lunch breaks are normally in some breathtaking places! The forest floor, Colon Province, Panama. (Photo by Patrick Kennedy)
Chasing wasps in the tropics means lunch breaks are normally in some breathtaking places! The forest floor, Colon Province, Panama. (Photo by Patrick Kennedy)

With the help of National Geographic, I’m trying to unravel this evolutionary riddle by conducting fieldwork across the species’ range. I’m the first to admit that these wasps choose unusual places to live: I’ve found myself creeping through an abandoned leper colony with wasp-catching kit, crawling under bridges in mangrove swamps, descending into an underground army bunker, scouring a 17th century village in French Guiana, and peering over the precipice of a hydroelectric dam. Pieter and I have spent the past two months monitoring twenty-thousand baby wasps on the banks of the Panama Canal. I overheard one bewildered man in French Guiana call me “le chasseur des guêpes”–”the wasp-hunter.”

Carefully holding a wasp using washing-up gloves. (Photo by Patrick Kennedy)
Carefully holding a wasp using washing-up gloves. (Photo by Patrick Kennedy)

So, those radio-tags. By rigging up radio-antennae to many nests, I will be able to reveal in high-resolution where each individual wasp spends its time. This will give me a huge amount of information with which to tease apart this Darwinian enigma.

I am investigating the hypothesis that the wasps are acting like insect “investment bankers.” We know that they spread their altruistic “investments” across a whole portfolio of different nests, even though it means diverting help to more distant relatives who are less likely to carry their valuable genes. In theory, this may mean that if any one nest gets destroyed (whether by birds, parasites, army ants, starvation, or civil war) the wandering wasps don’t lose all their valuable helping effort. Investment bankers try to diversify their investments to different stocks and shares to minimise the risk of losing all their money. Together with my PhD supervisors (Dr Seirian Sumner and Dr Andy Radford at the University of Bristol), I am testing the idea that the wasps may be doing the same, diversifying their help across a whole set of distant relatives to dodge the extreme risks suffered by tropical wasp nests.

This is a radical hypothesis that has not been proposed before in any animal. Tantalisingly, it raises the prospect of deep links between the mathematics of evolutionary biology and the world of investment banking. The best way to put it to the test is to take it out into the field, which is why I’m out here in Panama being repeatedly injected by wasp venom. So, bring on the 71st sting!

A radio-tagged wasp pauses on a small nest, presumably before deciding which colony to help next. (Photo by Patrick Kennedy)
A radio-tagged wasp pauses on a small nest, presumably before deciding which colony to help next. (Photo by Patrick Kennedy)

 

Somewhere in here, there are wasps! Forest in Colon Province, Panama. (Photo by Patrick Kennedy)
Somewhere in here, there are wasps! Forest in Colon Province, Panama. (Photo by Patrick Kennedy)

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