EFFECTS OF LOW-TEMPERATURE ON THE DEVELOPMENT OF LEPTORHYNCHOIDES-THECATUS (ACANTHOCEPHALA) IN LEPOMIS-CYANELLUS (CENTRARCHIDAE)

The effect of low temperature on the development of Leptorhynchoides t hecatus (Acanthocephala: Rhadinorhynchidae) in Lepomis cyanellus (Cent rarchidae) was studied by infecting 28 fish with cystacanths reared in the laboratory. Fish were infected and maintained together at 12 C an d 4 were examined every 2 wk from 10 to 22 wk postinfection. Trunk len gths of recovered L. thecatus were used in conjunction with qualitativ e observations of gonadal development and gametogenesis to evaluate de velopment during the period of prepatency. The prepatent period was in excess of 22 wk in worms maintained at 12 C, nearly 3 times that of w orms maintained at 21 C. Results are consistent with known seasonal pa tterns of recruitment and maturation and suggest that retardation of g rowth is a mechanism by which natural populations of L. thecatus overw inter in vertebrate poikilothermic hosts.