Parasitism as a Driver of Trophic Niche Specialisation.

The population trophic niche of free-living species can be subdivided into smaller niches comprising individuals specialising on specific food items. The roles of parasites in creating these specialised subgroups remain unclear. Intrapopulation differences in parasite infections can develop from specialist individuals within populations. Their differences in morphology and habitat can increase their exposure to intermediate hosts via infected prey, altering their parasite fauna. However, we also suggest that parasite infections can drive this niche specialisation. Through mechanisms including parasite manipulation, altered host phenotypes, and/ or parasite-mediated competition, parasites can alter the resource availability of their hosts, altering their trophic niches. Thus, trophic niche specialisations could result from parasitism via varying influences on host traits, raising questions for future research.