Plants and insects evolved independently to use cyanide as a defence mechanism reports a study in Nature Communications this week. The production of cyanide ― to fight off herbivores and predators ― is found in plants and insects, but how they both came to use this same defence technique has not been clear.

Niels Bjerg Jensen and colleagues study cyanide production in the Burnet moth (Zygaena filipendulae) larvae. Although the larvae can collect cyanide from the plant food they eat, the research shows that only three genes are needed by the larvae to produce cyanide glucosides the same way as plants. The authors therefore conclude that, over the past 420 million years, plants and insects have separately evolved to produce the same enzymes necessary for cyanide production in their defence against predators.