Kin-recognition shapes collective behaviors in the cannibalistic nematodePristionchus pacificus

Abstract

AbstractKin-recognition is observed across diverse species forming an important behavioral adaptation influencing organismal interactions. In most species, proximate level mechanisms are poorly characterized, but in the nematodePristionchus pacificusmolecular components regulating its kin-recognition system have been identified which determine its predatory behaviors. This ability prevents the killing of kin however, its impact on other interactions including collective behaviors is unknown. Utilizing pairwise aggregation assays between distinct strains ofP. pacificus, we observed aggregation between kin but not distantly related con-specifics. In these assays, only one strain aggregates with solitary behavior induced in the rival. Abolishing predation throughPpa-nhr-40mutations results in rival strains successfully aggregating together. Additionally, interactions betweenP. pacificuspopulations andCaenorhabditis elegansare dominated byP. pacificuswhich also disruptsC. elegansaggregation dynamics. Thus, aggregating strains ofP. pacificuspreferentially group with kin, revealing competition and nepotism as previously unknown components influencing collective behaviors in nematodes.