Abstract:
Behaviour can be altered by the presence of kin, and this is seen in multiple
organisms. This phenomenon is comparatively less studied in organisms that do not
show group-living behaviour, like Drosophila melanogaster. Our study examines how
the presence of kin affects behaviours in Drosophila melanogaster, with a focus on
how sex and mating status modulate these responses. We study dispersal,
aggregation, aggression, and mating behaviours in both a mate choice and nochoice
setup. We see that mating behaviours can be kin-biased depending on the
context in which mates interact. We also see that having been previously mated
leads to closer aggregation between related same-sex groups, and virgin flies do not
show this behaviour. We provide the first experimental proof that mating status and
relatedness can interact to modulate dispersal propensity, with related groups of flies
dispersing less than unrelated groups when mated but more when virgins. Mating
also leads to reduced dispersal speed and increased rest levels of females, which
has further implications in spatial sorting of populations. Our study shows that
traditionally ‘non-social’ organisms like the fruit fly can be used as models to
understand social behaviour between kin. We advocate for further experimental studies to elucidate the motivation behind complex group behaviours such as those we capture in our work.
