IMPAIRMENT OF THE CHEMICAL DEFENSE OF THE BEETLE, TENEBRIO-MOLITOR, BY METACESTODES (CYSTICERCOIDS) OF THE TAPEWORM, HYMENOLEPIS-DIMINUTA

The defensive glands of beetles, Tenebrio molitor, infected with metac estodes (cysticercoids) of Hymenolepis diminuta are everted less frequ ently upon stimulation, and contain less toluquinone (methylbenzoquino ne) and m-cresol, than glands of uninfected controls. These difference s, as shown in predation trials with wild rats, increase the likelihoo d that both cysticercoids and beetles will be ingested by the tapeworm 's definitive host. This is the first documented case of a parasite in hibiting the chemical defence of an intermediate host, and one of only a few reports of parasite-induced manipulation of host biology suppor ted by empirical evidence implicating facilitated parasite transmissio n between host species.