Infection-related variation in cuticle thickness in the ant Myrmica scabrinodis (Hymenoptera: Formicidae)

Abstract

Cuticle quality is of vital importance in insects. It prevents desiccation, provides mechanical strength and protects against pathogens. The within-species variation of cuticular structure is affected by many factors. We investigated the relationship of the presence/absence of the ectoparasitic fungus Rickia wasmannii and cuticle thickness of its ant host Myrmica scabrinodis. Infected ants had thinner cuticle than uninfected ones, while there were also differences among populations. It is unclear whether reduced thickness is the host’s response, or whether the fungus infects preferentially colonies with ants that have a thin cuticle. Either way, within-species variation is linked to the presence of an epicuticular parasite.