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Ultrastructure Of The Reproductive System Of The Black Swamp Snake (Seminatrix Pygaea). Part Iii. The Sexual Segment Of The Male Kidney., David M. Sever
Ultrastructure Of The Reproductive System Of The Black Swamp Snake (Seminatrix Pygaea). Part Iii. The Sexual Segment Of The Male Kidney., David M. Sever
Scholarship and Professional Work - LAS
In mature male snakes and lizards, a distal portion of the nephron is hypertrophied in relation to its appearance in females and immature males. This sexual segment of the male kidney apparently provides seminal fluid that is mixed with sperm and released into the female cloaca during copulation. In this article, we provide the first study at the ultrastructural level of seasonal variation in the sexual segment of the kidney of a squamate, the natricine snake Seminatrix pygaea. Previous workers have indicated that the sexual segment is secretory only when the testes are spermatogenically active. The sexual segment of the …
Reproductive Energetics Of Adult Male Yellow- Bellied Marmots (Marmota Flaviventris), Carmen M. Salsbury, K. B. Armitage
Reproductive Energetics Of Adult Male Yellow- Bellied Marmots (Marmota Flaviventris), Carmen M. Salsbury, K. B. Armitage
Scholarship and Professional Work - LAS
We examined the energy expenditure of adult male yellow-bellied marmots and its relationship to various female-defense characteristics critical to male reproductive success. Resting metabolic rates of males were estimated in the laboratory via oxygen-consumption analysis, and field metabolic rates were estimated using a doubly Labeled water technique. Male home-range size, number of females defended by males, dispersion of females in the habitat, and date into the active season were considered to be predictors of male energy expenditure in excess of maintenance costs (field metabolic rate minus resting metabolic rate). Energy expenditure was best explained by a defensibility index based on …