Kin-recognition is abundant in the natural world where it regulates diverse behaviors and social interactions. Some of the most striking examples of kin-recognition are found in organisms with the capability to harm or even kill their relatives. Here, it is fundamental to prevent the cannibalism of kin. Despite the prevalence of kin-recognition behaviors, many examples have only been described in non-model species currently lacking the necessary molecular, neurobiological, and evolutionary tools required to fully investigate these systems and the associated mechanisms. Furthermore, kin-recognition behaviors often act at the interface between neurobiology and immunology, making exploration of the behavioral processes additionally complex.
To overcome these challenges, we explore the kin-recognition system evident in the omnivorous roundworm, Pristionchus pacificus. This nematode has evolved teeth-like denticles and is capable of both feeding on bacteria and killing other nematode larvae, including those of its more famous cousin Caenorhabditis elegans. However, while P. pacificus kills other nematode species and strains, remarkably, it does not kill its own progeny or close relatives. We therefore investigate this kin-recognition system which protects larvae from the predatory adults. Firstly, we are identifying the signals transmitted by P. pacificus to indicate kin and prevent attack by their relatives. Secondly, we are elucidating the receptors and circuits behind the kin-recognition and predation decision. Finally, we are utilising a worldwide representation of P. pacificus from a vast library of strains to understanding the evolution of these processes.