# Inbreeding strategies under social and sexual complexity: insights from female and male guppies

## TL;DR

The study explores how guppies make mating decisions in different social and sexual environments, finding limited evidence for inbreeding avoidance.

## Contribution

The research provides new empirical insights into how social and sexual complexity influence inbreeding strategies in guppies.

## Key findings

- Neither virgin nor experienced guppies showed mating preferences for relatives in simple social contexts.
- Females showed a weak, non-significant tendency to prefer related males in complex environments.
- Males did not show any preference for related or unrelated partners in any context.

## Abstract

Animals are typically expected to avoid mating with relatives due to the costs associated with incestuous matings. Yet for more than 4 decades, theoretical models have consistently suggested that animals may tolerate, or even prefer, mating with relatives under a broad range of conditions. However, empirical studies that evaluate inbreeding strategy under alternative social and sexual contexts remain scarce. Here, we investigate how experimental variation in sexual and social complexity influence precopulatory inbreeding avoidance behaviors in the guppy Poecilia reticulata, a species known to experience inbreeding depression. In an integrated set of experiments, we examined if sexual and affiliative behaviors of virgin and experienced females and males were differentially directed towards either related or unrelated individuals. In simple social context, neither virgin nor experienced females or males showed a preference for related or unrelated partners. In more sexually and socially complex free-swimming arenas, females appeared to respond slightly more to related males, but this effect was not statistically significant once corrected for multiple comparisons; male preference remained unchanged. Overall, these findings challenge previous reports of preference shifts between virgin and experienced female guppies and suggest that inbreeding avoidance behaviors may be less prevalent in complex social environments than previously thought.

Although animals are often expected to avoid inbreeding, theory suggests mating with relatives can sometimes be beneficial. We tested how social and sexual complexity affects guppies' mating decisions. In simple setups, neither females nor males preferred relatives or nonrelatives. In more naturalistic, free-swimming arenas, females showed a weak tendency to respond more to related males, while males showed no preference. These results suggest that inbreeding avoidance may be limited in guppies.