Pheromonal and Behavioral Cues Trigger Male-to-Female Aggression in Drosophila

María De La Paz Fernández,Jean-Christophe Billeter,Joel D Levine,Joanne Y Yew,Edward A Kravitz,Klaus Dreisewerd,Yick-Bun Chan,Scott Waddell

doi:10.1371/journal.pbio.1000541

Abstract

Author SummaryAs in other species, the fruit fly Drosophila melanogaster uses chemical signals in the form of pheromones to recognize the species and sex of another individual. Males typically fight with other males and do not attack females. While the roles of pheromonal and other sensory cues in stimulating courtship towards females have been extensively studied, the signals that elicit aggression towards other males remain unclear. In this work, we use genetic tools to show that masculinization of female pheromones is sufficient to trigger aggression from wild type males towards females. Surprisingly, males also attacked females that displayed male patterns of aggression, even if they show normal female pheromonal profiles, indicating that pheromones are not the only cues important for identifying another animal as an opponent. By simultaneously manipulating pheromones and behavioral patterns of opponents, we can completely switch the behavioral response of males towards females and males. These results demonstrate that not only pheromonal but also behavioral cues can serve as triggers of aggression, underlining the importance of behavioral feedback in the manifestation of social behaviors.

Highlights

Aggression is a complex, innate behavior that likely evolved in the context of obtaining or defending resources [1,2,3]
By simultaneously manipulating pheromones and behavioral patterns of opponents, we can completely switch the behavioral response of males towards females and males
These results demonstrate that pheromonal and behavioral cues can serve as triggers of aggression, underlining the importance of behavioral feedback in the manifestation of social behaviors

Summary

Introduction

Aggression is a complex, innate behavior that likely evolved in the context of obtaining or defending resources [1,2,3]. A wide variety of sexually dimorphic cues might be used by a male in directing agonistic rather than reproductive behavior towards another fly. Drosophila cuticular hydrocarbons (CH) are sexually dimorphic; female surfaces are characterized by dienes like (Z,Z)-7,11 heptacosadiene and (Z,Z)-7,11 nonacosadiene that act as aphrodisiacs [12,14,15], while male surfaces include (Z)-7 tricosene [11,16,17] and 11-cis-vaccenyl acetate (cVA) [18,19,20] act as antiaphrodisiacs to other males. Pheromones that promote aggressive behavior have been identified in vertebrate and other invertebrate species [21,22,23,24,25], and cVA has been reported to modulate male aggressiveness in flies [26]. To what extent pheromonal or other cues are sufficient to trigger aggression in Drosophila remains largely unknown

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