Meeting Abstract

69.6  Wednesday, Jan. 6  Reproductive biology and population ecology of the sea grass shrimp Ambidexter symmetricus. RASCH, J.A.*; BAUER, R.T.; Univ. of Louisiana, Lafayette; Univ. of Louisiana, Lafayette jennrasch@gmail.com

Ambidexter symmetricus is a caridean shrimp which dwells in sea grass meadows in tropical and subtropical waters. We collected samples at night from St. Joseph’s Bay in northwestern Florida by pushnet in 1986/87 and 2009, as well as from St. Andrew’s Bay in 2009. We examined the sexual morphology of males and females. Males of this species have the typical cincinnuli and appendix masculina, while females have the unusual feature of a theylcum. The presence of a theylcum is unique among carideans to the Processidae. Reproductive structures were observed with light microscopy and SEM. The theylcum may allow for short or long term storage of spermatophores by females. We examined the ovarian and embryonic condition of all females from each sample. We hope to determine if females in this subtropical population have seasonal or year-round reproduction. Our preliminary data indicates females can carry successive broods during their reproductive periods. We analyzed the population ecology of this species using past and current sampling data. We determined infestation rates of parasitic isopods for each sample, size of females at sexual maturity, and preliminary population structure, the latter of which is suggestive of partial protandric hermaphroditism. This type of sexual system is rare but has been documented in another member of the family. Knowledge of the reproduction and population ecology of this species can be used to answer larger questions about evolution not only this species, but along the several genera in the Processidae.