Earwigs Use Rotting Flesh Odor to Deter
It works with lizards, and probably on humans, too, but earwigs can’t successfully use disgusting smells to repel other insects. New research has found the earwig – a creepy looking, long-bodied creature with a dual-spiked tail – has more than one defensive maneuver.
Scientists used lizards to test out how edible earwigs can be, but the little green reptiles immediately spit the bugs out of their mouths. Within microseconds, earwigs squirt a horrid smelling substance much like rotting flesh into the lizard’s mouth. Not only were lizards reactive, they didn’t go near the earwigs again.
The ability of an insect to use a vile odor as a way of discouraging predators has not been thoroughly documented before.
Plants use odors to attract insect life, even what we might consider rancid or repugnant smells. The corpse flower, for example, uses an odor much like animal feces to attract a particular variety of fly. After feeding, the fly will spread fungal spores that benefit the plant.
But the earwig’s defense system is a new discovery, and investigators have found that the rotten smell is used to deter mammals, reptiles and birds. Other insects do not react to it, although the dimethyl sulfide released by earwigs may have another role for insects - it can act as a neurotoxin.