The life cycles of Bunodera sacculata and B. luciopercae (Trematoda: Allocreadiidae) in Algonquin Park, Ontario

Abstract

Miracidia of Bunodera sacculata and Bunodera luciopercae develop into sporocysts in the gills of Pisidium variabile, where rediae are first produced after 60 to 70 days at 20C. Each redia has a well-developed pharynx, but neither gut nor lateral processes. Mature rediae, each with a birth pore and a degenerate pharynx, occur near the clam's gonad and contain ophthalmoxiphidiocercariae with a flame cell formula 2[(3+3+3) + (3+3+3)]. Cercarial stylets of B. sacculata and B. luciopercae are 15 and 18 long respectively. Only cercariae of B. sacculata have cystogenous glands. Infective metacercariae of B. sacculata develop in Daphnia similis and Moina affinis within 6 days and have well-developed reproductive structures unlike those of B. luciopercae, which develop within 12 days in Hyalella azteca and Crangonyx gracilis. Juvenile B. sacculata retain dark granules in the excretory bladder until they mature, which is within 3 weeks in the intestine of Perca flavescens. B. luciopercae juveniles, which expel the contents of the excretory bladder when they excyst, mature slowly, gradually moving from the gall bladder, where they first establish, to the intestine, where the first eggs are produced after 5 or 6 months. In B. sacculata spermatogenesis is abortive and reproduction parthenogenetic.