Parasite load, body size, and age of wild-caught male field crickets (Orthoptera: Gryllidae): effects on sexual selection

Comparison of male Gryllus veletis and G. pennsylvanicus collected either by themselves or with one or more females showed that the paired males were significantly older and significantly less parasitized by gregarines (protozoan gut parasites) than were solitary males. Females are preferentially attracted to older males. The ability of less parasitized males to produce more spermatophores under laboratory conditions may also be important in the field. -from Author