The effects of computer-controlled shadow stimuli on the success of cercarial transmission by Cryptocotyle lingua (Digenea: Heterophyidae).
Pectoral fins from juvenile rainbow trout (Oncorhynchus mykiss) were used in a bioassay, the object of which was to quantify the effect of simulated shadow stimuli on the transmission success of the cercariae. For a period of 60 min, parasites and fins were exposed to a sequence of computer-controlled shadow stimuli, continuous light or total darkness, and subsequently the number of infections was counted. Trials were conducted with cercariae 1, 12 and 24 h old. Within the constraints of the experimental procedure, shadows were found to increase significantly the number of infections achieved by the 12-h-old parasites. As the cercariae aged, their ability to infect host tissue declined. The relevance of these results to transmission in the natural environment is discussed.
Rea
J G
JG
Department of Biological and Biomedical Sciences, University of Ulster, Jordanstown, Co. Antrim, N. Ireland.
Irwin
S W
SW
D000818:Animals; D003624:Darkness; D005393:Fish Diseases / Q000469:parasitology*; D006578:Heterophyidae / Q000502:physiology*; D008027:Light; D014201:Trematode Infections / Q000469:parasitology / Q000662:veterinary*; D014337:Trout / Q000469:parasitology*