Editors' ChoicePheromones

The Smell of Aggression

Science Signaling  19 Jan 2010:
Vol. 3, Issue 105, pp. ec21
DOI: 10.1126/scisignal.3105ec21

Aggressive behavior between males in a number of animal species is regulated by pheromones; however, the mechanisms involved are unclear. Social experience has effects on male aggression in Drosophila. For example, the group of Wang and Anderson showed that Cyp6a20, which encodes a cytochrome P450 protein, is more highly expressed in socially experienced, nonaggressive flies than in aggressive flies and that it is localized to cells sensitive to the male volatile pheromone 11-cis-vaccenyl acetate (cVA). The authors have now studied the effects of synthetic cVA on pairs of male files by videotaping their movements in a chamber and analyzing their behavior. cVA dose-dependently increased aggressive behavior between male flies without increasing their general locomotion. This response was dependent on the activity of olfactory sensory neurons (OSNs) that specifically expressed Or67d, which encodes a known receptor for cVA; mutation of Or67d blocked the response of files to cVA. Flies that had a mutation in Or83b, which encodes a co-receptor for olfactory receptors, were less aggressive in response to cVA than were control flies. Aggressive activity between flies was increased when the analyzed pair was surrounded by a high density of caged male flies, which would be expected to increase the concentration of volatile cVA in the chamber. In nature, aggressive, activity within a group of male flies leads to population dispersal. The authors found that synthetic cVA increased aggressive behavior in a group of flies surrounding a food source, which led to the dispersal of a number of flies. In contrast, flies in which Or67d-expressing OSNs were inactivated exhibited neither aggressive behavior nor dispersal in response to cVA. Further study of this pheromone-OSN pair should provide further insights into the mechanisms that control aggression.

L. Wang, D. J. Anderson, Identification of an aggression-promoting pheromone and its receptor neurons in Drosophila. Nature 463, 227–231 (2010). [PubMed]