Meeting Abstract

69.5  Wednesday, Jan. 6  Reproductive biology of a bopyrid isopod, Probopyrus pandalicola, and its hyperparasite, Cabirops sp., parasitic on the river shrimp, Macrobrachium ohione CONNER, S.L.*; BAUER, R.T.; Univ. of Louisiana at Lafayette; Univ. of Louisiana at Lafayette sel6883@louisiana.edu

Macrobrachium ohione is a freshwater caridean shrimp that migrates to brackish-water estuaries to release its larvae, which require development in salt water. Postlarvae then migrate upstream to the adult freshwater habitat. Probopyrus pandalicola is a bopyrid isopod parasite in the gill chamber of M. ohione. Although both species require saline water for larval development, the bopyrid releases larvae both upriver and in the estuary. The typical positive correlation between parasite and host body size was not found in this study. Shrimps can become infected either as juveniles or as reproductive adults when in the estuary. Probopyrus pandalicola was itself found to be parasitized by another isopod, the hyperparasite Cabirops sp. Collection data indicate that the hyperparasite distribution is more limited to saline waters, unlike its bopyrid host. Light and SEM microscopy, as well as observations of live specimens indicate that the seven thoracic segments of the female hyperparasite develop into bilobed pouches used for incubating embryos and brooding epicaridium larvae. However, the developmental origin of the pouches, e.g. from oostegites, is still uncertain. The female vigorously contracts, possibly to circulate water among the embryos/larvae. After larval release, the female dies and its body is removed by the host shrimp. The female is often accompanied by multiple cryptoniscus larvae (presumptive males) which may metamorphose into adult females when the resident female dies.