Caterpillars may sense threats using electric fields Premium

Caterpillars possess a unique sixth sense, electroreception, allowing them to sense electric fields and detect predators.

Caterpillars have a sixth sense that most land-based animals do not. They can sense electric fields around them with small bristles called setae on its body — a feat called electroreception. British researchers have discovered this in laboratory experiments and their findings were published recently in the Proceedings of the National Academy of Sciences.

They studied four species of caterpillars: cinnabar moth, scarce vapourer moth, European peacock butterfly, and common wasp.

Researchers have long known that aquatic and amphibious use electroreception to detect both predators and prey. Since 2013, scientists have also found electroreception in arthropods like bumblebees, hoverflies, and spiders. However, none of these land-based creatures use the ability to defend against predators.

Caterpillars, which are also arthropods, may break this mould, using electroreception to sense predatory insects nearby.

“It works exactly the same way as [brushing a] rubber balloon on your hair,” said first author Sam England. He is a postdoctoral researcher at the Museum für Naturkunde in Berlin and was at the University of Bristol before.

Static charges accumulate on both the balloon and the hair, leading to a mutual electrostatic attraction. The balloon can then move the hair without needing contact.

As an insect’s wings flap through the air, static charges build up on them. When it nears the caterpillar, the setae senses these charges by building up charges of its own. This mutual interaction gives rise to an oscillating electric field.