Untying a Gordian knot: the domestication and laboratory maintenance of a Gordian worm, Paragordius varius (Nematomorpha : Gordiida)

摘要

Twenty-one sand field crickets (Gryllus firmus) were infected with naturally collected cysts of the Gordian worm, Paragordius varius (Nematomorpha: Gordiida). The life cycle was completed by infecting laboratory-reared paratenic hosts with P. varius larvae. The life cycle has been maintained subsequently in the laboratory for numerous generations. This is the first time the life cycle of a member of the phylum Nematomorpha has been completed experimentally. Maturation within the definitive host took from 27 to 30 days post-exposure. The natural and laboratory life cycles of Paragordius varius vary in that a more easily maintainable paratenic host is used in the laboratory than is used in nature. The complete domesticated model life cycle is maintained easily and takes as few as 45 days. Data gathered from 46 laboratory-infected cricket hosts indicated that sex ratios of worms did not differ significantly from 1.0. Unlike most natural collections, the mean intensity of infection was above 1.0, and infection did not appear to preclude the host from mating.