Research ArticleECOLOGY

Phenylacetonitrile in locusts facilitates an antipredator defense by acting as an olfactory aposematic signal and cyanide precursor

See allHide authors and affiliations

Science Advances  23 Jan 2019:
Vol. 5, no. 1, eaav5495
DOI: 10.1126/sciadv.aav5495

Abstract

Many aggregating animals use aposematic signals to advertise their toxicity to predators. However, the coordination between aposematic signals and toxins is poorly understood. Here, we reveal that phenylacetonitrile (PAN) acts as an olfactory aposematic signal and precursor of hypertoxic hydrogen cyanide (HCN) to protect gregarious locusts from predation. We found that PAN biosynthesis from phenylalanine is catalyzed by CYP305M2, a novel gene encoding a cytochrome P450 enzyme in gregarious locusts. The RNA interference (RNAi) knockdown of CYP305M2 increases the vulnerability of gregarious locusts to bird predation. By contrast, the elevation of PAN levels through supplementation with synthetic PAN increases the resistance of solitary locusts to predation. When locusts are attacked by birds, PAN is converted to HCN, which causes food poisoning in birds. Our results indicate that locusts develop a defense mechanism wherein an aposematic compound is converted to hypertoxic cyanide in resistance to predation by natural enemies.

This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial license, which permits use, distribution, and reproduction in any medium, so long as the resultant use is not for commercial advantage and provided the original work is properly cited.

View Full Text