Meeting Abstract

88.3  Friday, Jan. 7  First test of the protandric hypothesis in the bopyrid isopod hyperparasite Cabirops sp. CONNER, S.L.*; BAUER, R.T.; Univ. of Louisiana, Lafayette; Univ. of Louisiana, Lafayette saraelaporte@yahoo.com

Macrobrachium ohione was found to be infected by Probopyrus pandalicola which in turn was parasitized by another isopod, the rare hyperparasite Cabirops sp. The hyperparasite cryptoniscus larval stage settles into an uninfested bopyrid host, loses most external morphology and develops into a female stage. The mature female is little more than a chitinous bag full of embryos. Additional settling hyperparasite cryptonisci develop into dwarf males. The female produces only one brood before dying after which the host shrimp removes the dead female by grooming. An accompanying male Cabirops may then metamorphose into the female stage. Using histological investigation of internal morphology, we attempted to follow the progression from cryptoniscus larva to fully functional female, i.e., the rearrangement or reduction of male hyperparasite morphology with the concomitant development of the ovaries and embryo-filled lobes of females. Numerous specimens were examined and compared, including cryptoniscus larvae, males, and immature and mature females. Results presented here indicate the presence of testicular tissue in all cryptonisci associated with a single female. Immature females appear to be filled with only ovarian tissue which is not compartmentalized but rather fills all lobes and the body cavity. No other organs, including a digestive tract, were found in the immature females. The mature females are filled with embryos and/or epicaridium larvae indicating that fertilization may occur internally. A structure of unknown composition, which stains red indicating the presence of proteins, also develops in mature females. This “organ” can also be viewed externally as a dark streak. Further investigation using TEM is warranted. Cabirops sp. does appear to be protandric.