Clonal fish are more aggressive to distant relatives in a low resource environment

Kin selection explains conditions under which closely related individuals should be less antagonistic towards one another. One benefit of kin selection is a reduction in aggression towards kin in various social contexts, such as foraging. In the gynogenetic Amazon molly, females have been shown to differentiate between clone types, preferring to associate with clonal sisters to non-sisters, regulating their aggressive behaviours accordingly. We ask if Amazon mollies in resource-limited environments retain the ability to regulate aggressive behaviours according to relatedness. We found that focal females regulated their aggressive behaviours depending on partner type. Females spent more time behaving aggressively towards the heterospecific females than either of the clonal lineages, and towards non-sister clones compared to clonal sisters. We are able to confirm that kin discrimination is maintained, resulting in females showing more aggression towards heterospecific females and non-sister clones in a food-limited environment, and that this aggression scales with relatedness.