Researchers at the University of Bristol in the UK have found that at least three species of caterpillars can sense the electric fields generated by predators and react accordingly. The findings were published in the latest issue of the Proceedings of the National Academy of Sciences on the 20th.
Previous studies have shown that many animals release static charges when moving. In this recent study, the team focused on caterpillars and wasps. Caterpillars have abundant bristles that can act as a form of electrostatic sensing "device." Wasps prey on caterpillars, and when they rapidly move their wings in the air, they may generate static charges.
To test these species, researchers first captured wasps and found that they did indeed produce an electric field when flapping their wings. Moreover, the amount of charge was easy to measure as the wings moved.
The researchers then captured over 200 caterpillars, including larvae of the crimson speckled moth, scarce vapourer moth, and European peacock butterfly. In the lab, the research team tested these caterpillars' ability to sense and react to artificially generated electric fields, which simulated the electric fields produced by wasps.
The results showed that all three caterpillar species had very noticeable reactions to the electric fields, with the bristles of the caterpillars reacting most strongly when the field matched the typical field produced by wasps. The researchers believe that the bristles of caterpillars have evolved to sense the electric fields of wasps and other predators.
