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Parasitism of Leptasterias spp. (Echinodermata: Asteroidea) by the Ciliated Protozoan Orchitophrya stellarum (Scuticociliata)
William B. Stickle, Earl H. Weidner and Eugene N. Kozloff
Vol. 120, No. 1 (Winter, 2001), pp. 88-95
Stable URL: http://www.jstor.org/stable/3227229
Page Count: 8
You can always find the topics here!Topics: Testes, Starfish, Spermatozoa, Inlets, Bays, Gonads, Parasites, Species, Canals, Phagosomes
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The parasitic ciliate Orchitophrya stellarum was found in the testes of brooding, winter-spawning Leptasterias spp. from San Juan Island, Washington, but not in the testes of Leptasterias spp. from the Lynn Canal, Alaska. Dense populations of the ciliate were localized within the fuller areas of testes, where sperm counts were significantly reduced. The ciliates were loaded with phagosomes, some of which contained sperms in various stages of digestion. Leptasterias spp. are not as severely impacted by this ciliated protozoan parasite as Pisaster ochraceus. Leptasterias spp. may serve as seasonal hosts for O. stellarum; this ciliate lives in seawater and in ripe males of winter-brooding and spring-summer broadcasting sea stars. The wet weight of parasitized and non-parasitized males did not differ. The sex ratio did not deviate from the expected (1:1) in any population except at Point Louisa, Alaska, where males outnumbered females. Testis indexes of parasitized males from 2 of the 4 locations on San Juan Island, Washington were significantly reduced relative to non-parasitized males, indicating a loss of sperm output during spawning.
Invertebrate Biology © 2001 American Microscopical Society