ZSL uses tiny “Oyster cards” to track wasps
Wednesday 24 January 2007
Female wasps have been fitted with mini “Oyster card” style tags so scientists can track their movements between nests.
ZSL scientists studying animal behaviour have been tracking the movements of the paper wasp in Panama with high-tech radio tags to find out why they drift from nest to nest.
Eusocial insects like the paper wasp (Polistes canadensis), including bumblebees and honey bees, have previously been observed drifting from nest to nest, but this is the first time scientists have been able to monitor them effectively enough to find out how much drifting goes on and why.
Antennae were placed on the entrances to 33 wasp nests while tags with unique identities were painlessly attached to the thoraxes of 422 female paper wasps. The antennae recorded the tag number each time a wasp flew in or out of a nest, in the same way Londoners touch-in and touch-out with their Oyster cards on the tube. This allowed researchers to accurately track and record their movements between different nests.
The research generated surprising results: the wasps drifted between nests at a rate 31 times higher than ever recorded before.
Scientists found that wasps drifted to nests on which their close relatives lived.
By observing the wasps, scientists found the drifters behaved as workers on the nests they visited, helping raise the young of their relatives. Females in eusocial insects like paper wasps are haplodiploid, which means they are genetically more closely related to their sisters than their own offspring. This means the drifting wasps are able to increase the chance of their genetic material being carried on, especially as predation tends to result in entire nests being wiped out.
ZSL scientist and report author Seirian Sumner said: “We were very surprised to find out that 56 per cent of the wasps drifted from nest to nest. Like the workers in most eusocial insect societies, these drifting wasps do not reproduce themselves, but instead pass on their genes by helping raise relatives. We were excited to discover that they did this be helping on several different nests, rather than just their home nest. Drifting behaviour in social insects has always been rather difficult to quantify and a puzzle to explain. The “mini-Oyster cards” have revealed a new level of understanding into this behaviour.”