To deter a predator, kill its young!

Prey have evolved a suite of tricks to avoid falling victim to a predator. They may escape, hide, protect, become toxic/inedible or defend themselves. In principle, they could also scare the predator away, but this is risky when predators are big.

Recent work led by a Dutch research team and published in the July issue of Ecology Letters revealed that a plant-feeding thrips insect overcomes this differential size problem by killing the eggs of its enemy, a plant-inhabiting predatory mite. This infanticide poses a severe threat to these predators, which react by avoiding to lay their eggs and to forage for food at sites where their eggs are killed. Indeed, predation on thrips larvae near damaged predator eggs was almost 4 times lower than on other larvae. Hence, by killing eggs, vulnerable thrips larvae deter dangerous predators and thus reduce their own risk of being food for other insects. This mechanism makes one wonder who`s the predator and who`s the prey.