Nature: Wasps watch over neighboring nests in a “ surprising act of altruism ”

In what experts have called a “ surprising act of altruism, ” some wasp colonies lend their spare workers to babysit children in nearby nests, a study finds.

British researchers studied some 20,000 baby neotropical wasps and their caregivers from 91 different colonies in Panama, including near the canal.

Paper wasps are so named for the gray and brown paper-like materials they produce from a mixture of chewed plant fibers and saliva and use to build their nests.

The team found that as colonies become more numerous, the utility of individual worker wasps decreases because they have a surplus of labor.

This frees up some of the workers to help their more distant relatives living in neighboring, smaller, worker-strapped settlements.

Such acts, however, are only selfless and altruistic, as they cost wasps time and energy. They also have social benefits.

When the wasps help their distant relatives, it increases the chances of survival of the DNA they share with the assisted colony.

“These wasps can act like wealthy family members lending a hand to their second cousins,” said author and biologist Patrick Kennedy of the University of Bristol.

“If there isn’t much more you can do to help your immediate family, you can turn your attention to the extended family,” he added.

“ By helping more distant relatives who are in greater need – those who live next door with fewer caregivers – workers can pass on more copies of their genes overall, ” the co-author and environmentalist explained. behaviorist Andy Radford, also from Bristol.

“We believe that similar principles of diminishing returns could explain seemingly paradoxical acts of altruism in many other social animals.

Dr Kennedy added: “ The fact that these paper wasps in Central and South America are helping in other colonies is really bizarre when you consider that most wasps, ants and bees are extremely hostile to strangers.

“To solve this puzzling behavior, we combined mathematical modeling with our detailed field observations. We ended up getting stung a lot. But it was worth it, as our results show that worker wasps can become redundant in the home.

“A wasp on a colony with few larvae but many other workers becomes almost useless – the best thing to do is to keep the larvae from other parents.

How apparently forms of “altruism” arise in nature has been an open question since the age of naturalist Charles Darwin – because, at first glance, helping others does not seem to provide a way for living things to pass on their genes.

However, explained Professor Radford, “in 1964, legendary biologist WD Hamilton discovered the cardinal rule of animal altruism.”

“A great help for your family because they share many of your genes. Copies of your genes will triumph in the population.

Professor Hamilton had also studied tropical paper wasps – but was confused, when examining polist wasps in Brazil, to see workers leaving close families in their own nests to help those in neighboring colonies, which were further away. .

The new findings, however, explain how paper wasps can afford to help their more distant relatives under certain circumstances – and gain an evolutionary advantage.

This study builds on previous work by co-author and behavioral ecologist Seirian Sumner of University College London, who found that more than half of the workers in a Panamanian wasp population helped out on multiple nests.

“Wasps offer incredible windows into the evolution of altruism,” she said.

“There is so much going on in a wasp nest: power struggles, self-sacrifice, groups fighting against all odds to survive.

“If we are to understand how societies change, we need to take a deeper look at wasps,” Professor Sumner concluded.

The full results of the study were published in the journal Nature Ecology & Evolution.