Vol. 158, No. 1 February, 1980 THE BIOLOGICAL BULLETIN PUBLISHED BY THE MARINE BIOLOGICAL LABORATORY Reference: Biol. Bull., 158 : 1-15. (February, 1980; THE EFFECTS OF AN ISOPOD CASTRATOR, PROBOPYRUS PANDALICOLA, OX THE SEX CHARACTERS OF OXE OF ITS CARIDEAX SHRIMP HOSTS, PALAEMONETES PALUDOSUS J. THOMAS BECKi Department of Biological Science, Florida State Utm'crsity. Tallahassee, Florida 32306 Parasitic castration is the "destruction or alteration of gonad tissue, reproduc-tive behavior, hormonal balance or other modification of host reproductive effort above and beyond that which results from a nonselective use of host energy re-serves by the parasite" (Baudoin, 1975). Baudoin viewed parasitic castration as a parasite's adaptation and hypothesized that, as a result of the curtailment of host reproduction, the fitness of the parasite is increased due to increased host survivor-ship, increased host growth and/or increased energy available to the parasite. Parasitic castration of Crustacea was reviewed by Reinhard (1956), who dis-cussed the external and internal host modifications and also the theories attempt-ing to explain crustacean castration caused by rhizocephalan barnacles and epi-caridean isopods. Parasitic castration of crustacean hosts has been suggested as being due to: nutritional drain by the parasite (Reinhard. 1956); reduction in the titers of circulating reproductive hormones as a consequence of large blood losses to the parasite (Walker, 1977) ; secretion of toxic substances (Reinhard, 1956) ; indirect hormonal castration (Baudoin, 1975) ; or, in male hosts, decline or cessation of secretion by the androgenic glands ( Charniaux-Cotton, 1960). The parasitic castrator either retards the development of the gonads or actually destroys the sex cells, resulting in a complete atrophy of the gonad (Reinhard, 1956). Epicaridean isopods generally cause a lesser reduction of the gonads of the male than the female host, whereas the external secondary sex characters of the male host are modified more frequently and to a greater degree than those of the female (Reinhard, 1956). The effect of the castrator on the external sex charac-ters of the male host is usually referred to as a feminization or a juvenilization, as these characters are reduced in size and/or resemble those of the female host. In the bopyrid epicarideans, which infect decapod crustaceans, the effects on the host sex characters are varied. In fact, several workers have reported a lack of effect of bopyrid infection on host testes (Reverberi, 1941; Danforth, 1963; Codreanu, Codreanu, and Pike, 1965; Perez, 1923; Wenner, 1978; Reinhard, Von Brand, 1 Present address: 3124 Adwood Rd., Tallahassee, Florida 32312. 1 Copyright 1980, by the Marine Biological Laboratory Library of Congress Card No. A38-518 (ISSN 0006-3185)
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