Sex differences in frass production and weight change in Tenebrio molitor (Coleoptera) infected with cysticercoids of the tapeworm Hymenolepis diminuta (Cestoda).

In their intermediate host, parasites alter aspects of host physiology including waste production and body weight. Further, this alteration may differ between female and male hosts. To study this, a beetle (Tenebrio molitor)-tapeworm (Hymenolepis diminuta) system was used. Infected and uninfected male and female beetles were individually housed in vials without food. Each beetle's weight change and frass production were measured over 24 h periods at 3, 7, 12 and 16 days post-infection. Treatment (infection) had no effect on weight change, but males lost more weight than females. Further, infected females produced more frass than control females. Males on the day of infection had a higher food intake than females. These results suggest that males will be more exposed to infection than females and could explain why males had a higher median cysticercoid infection level.