SREL Reprint #1915





Morphology and Evolutionary Implications of the Annual Cycle of Secretion and Sperm Storage in Spermathecae of the Salamander Ambystoma opacum (Amphibia: Ambystomatidae)

Department of Biology, Saint Mary's College, Notre Dame, Indiana 46556 (D.M.S., KM.J., L.C.R.);
Savannah River Ecology Laboratory, Drawer E, Aiken, South Carolina 29802 and
Institute of Ecology, University of Georgia, Athens, Georgia 30602 (J.D.K.)

ABSTRACT: Females of the marbled salamander, Ambystoma opacum, store sperm in exocrine glands called spermathecae in the roof of the cloaca. Eggs are fertilized by sperm released from the spermathecae during oviposition. Some sperm remain in the spermathecae following oviposition, but these sperm degenerate within a month and none persists more than 6 mo after oviposition. Thus, sperm storage between successive breeding seasons does not occur. Apical secretary vacuoles are abundant during the fall mating season and contain a substance that is alcian blue+ at pH 2.5. Production of secretary vacuoles decreases markedly after oviposition, and the glands are inactive by the summer months. Ambystoma opacum is a terrestrial breeder, and some mating occurs prior to arrival at pond basins where oviposition occurs. Mating prior to arrival at the ovipository site may prolong the breeding season, leading to fitness implications for both males and females. Females have opportunities for more matings, and the possibilities for sperm competition in the spermathe-
cae are enhanced.


SREL Reprint #1915

Sever, D.M., J.D. Krenz, K.M. Johnson, and L.C. Rania. 1995. Morphology and evolutionary implications of the annual cycle of secretion and sperm storage in spermathecae of the salamander Ambystoma opacum (Amphibia: Ambystomatidae). Journal of Morphology 223:35-46.

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