Is variation in female aggressiveness across Drosophila species associated with reproductive potential?

TL;DR

The study explores how female aggression in fruit flies relates to reproductive traits, finding that more aggressive females tend to lay more eggs.

Contribution

This study is among the first to investigate the link between female aggression and reproductive traits across multiple Drosophila species.

Findings

Female aggression is correlated with ovariole number across Drosophila species.

Aggressive behaviors in females may be driven by a need for resources related to egg production or oviposition sites.

Abstract

Aggression is a key determinant of fitness in many species, mediating access to mates, food and breeding sites. Variation in intrasexual aggression across species is likely to be driven by variation in resource availability and distribution. While males primarily compete over access to mates, females are likely to compete over resources to maximize offspring quantity and/or quality, such as food or breeding sites. To date, however, most studies have focused on male aggression, and we know little about drivers of female aggression across species. To investigate potential reproductive drivers of female aggression, we tested the relationship between three reproductive traits and aggression in eight Drosophila species. Using machine learning classifiers developed for Drosophila melanogaster, we quantified aggressive behaviours displayed in the presence of yeast for mated and unmated females. We found that female aggression was correlated with ovariole number across species, suggesting that females who lay more eggs are more aggressive. A need for resources for egg production or oviposition sites may therefore be drivers of female aggression, though other potential hypotheses are discussed.

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