Experimental studies on the life-cycle ofRaillietiella gigliolii(Pentastomida: Cephalobaenida) in the South American worm-lizardAmphisbaena alba: a unique interaction involving two insects

Abstract

SUMMARYRaillietiella giglioliiis a cephalobaenid pentastomid which inhabits the lungs of the South American worm-lizardAmphisbaena alba. The host is a facultative inquiline of nests of the leaf-cutting antAtta cephaloteswhere it feeds occasionally (and possibly by accident) on ants but more often on beetles and their larvae which are themselves inquilines of ant nests. Ants store exhausted leaf-substrate in special underground chambers which serve as refuse dumps and it is here that larvae of the three-horned rhinoceros beetleCoetosis bilobafeed: these larvae are also known to be prey items ofA. alba. From observations of captive colonies ofAtta, we have demonstrated that pentastomid-egg contaminated faeces ofA. alba, introduced into the colony, are rapidly cut up and thrown onto the refuse dump, where, under natural circumstances they will be eaten byCoelosis. These larvae have an unusual and highly specialized gut physiology and parasite eggs will develop to an infective stage within the haemocoel in 70–96 days. Cockroaches are refractory to infection. Ants are the vital link in transmission since they literally deliver eggs to theCoelosislarvae. The strong trophic links which exist between the various components of the life-cycle offset a low fecundity of 100 eggs/female parasite/day but nonetheless maintain a high prevalence (86%) of infection.