Experimental studies on the life-cycle of Sebekia wedli (Pentastomida: Sebekidae).

Four young Nile crocodiles (Crocodylus niloticus) were infected with infective pentastome larvae obtained from naturally infected Mozambique bream, Oreochromis mossambicus, and red-breasted bream, Tilapia rendalli swierstrai in the Kruger National Park. At day 95 post infection one of the crocodiles died and three female and four male S. wedli were recovered from its lungs. One pair was found in copula but the uteri of the females were not yet developed. Males and females were of about equal size. After 226 d post infection the three remaining crocodiles were sacrificed. Two of these harboured no pentastomes but eight were taken from the lungs of the third. The sex ratio had shifted in favour of the females, seven females and one male being present. One of the females recovered from the crocodiles was placed in saline and produced 3,400 eggs. These were used to infect eight guppies, Poecilia reticulata. Within 31 d two infective stages of S. wedli had developed in one of the guppies thus completing the life-cycle of the pentastome. S. wedli recovered from experimentally infected final hosts were slightly smaller than those recovered from a wild-caught final host.