Fighting fruit flies: A model system for the study of aggression

TLDR

Despite the importance of aggression in most animals, little is known about its proximate causes and control. The study develops a quantitative framework for studying aggression in Drosophila melanogaster, enabling detailed genetic analysis of aggressive behavior. The authors analyzed 73 experiments involving over 2,000 agonistic interactions among socially naive male flies, generating an ethogram, descriptive statistics, and temporal patterns through sequence analysis. In 30‑minute trials, flies averaged 27 agonistic interactions lasting about 11 s each, rarely reaching the highest intensity levels, and sequence analysis revealed recurrent patterns resembling courtship behaviors.

Abstract

Despite the importance of aggression in the behavioral repertoire of most animals, relatively little is known of its proximate causation and control. To take advantage of modern methods of genetic analysis for studying this complex behavior, we have developed a quantitative framework for studying aggression in common laboratory strains of the fruit fly, Drosophila melanogaster . In the present study we analyze 73 experiments in which socially naive male fruit flies interacted in more than 2,000 individual agonistic interactions. This allows us to ( i ) generate an ethogram of the behaviors that occur during agonistic interactions; ( ii ) calculate descriptive statistics for these behaviors; and ( iii ) identify their temporal patterns by using sequence analysis. Thirty-minute paired trials between flies contained an average of 27 individual agonistic interactions, lasting a mean of 11 seconds and featuring a variety of intensity levels. Only few fights progressed to the highest intensity levels (boxing and tussling). A sequential analysis demonstrated the existence of recurrent patterns in behaviors with some similarity to those seen during courtship. Based on the patterns characterized in the present report, a detailed examination of aggressive behavior by using mutant strains and other techniques of genetic analysis becomes possible.