Spermatophore production and spermatheca content in Tenebrio molitor infected with Hymenolepis diminuta.

Male and female Tenebrio molitor act as intermediate hosts for metacestodes of the rat tapeworm, Hymenolepis diminuta. It is known that the bean-shaped accessory glands of infected males exhibit an extended growth period and are significantly larger than those from noninfected males by day 10 after emergence. We wished to determine whether more material is transferred from these glands into the spermatophores. Here we report that the protein content and trehalase activity of spermatophores produced by bean-shaped accessory glands from infected males is elevated. However, protein transferred to the female spermatheca during mating was not affected by the infection status of the male. No evidence of transfer of trehalase to the spermatheca was detected but spermatheca from virgin, infected females contained significantly greater trehalase activity than those from noninfected females.