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Full-Text Articles in Life Sciences
The Evolution Of Copulation Frequency And The Mechanisms Of Reproduction In Male Anolis Lizards, Michele Johnson, Maria Lopez, Tara Whittle, Bonnie Kircher, A Dill, Divina Varghese, Juli Wade
The Evolution Of Copulation Frequency And The Mechanisms Of Reproduction In Male Anolis Lizards, Michele Johnson, Maria Lopez, Tara Whittle, Bonnie Kircher, A Dill, Divina Varghese, Juli Wade
Michele A Johnson
The evolution of many morphological structures is associated with the behavioral context of their use, particularly for structures involved in copulation. Yet, few studies have considered evolutionary relationships among the integrated suite of structures associated with male reproduction. In this study, we examined nine species of lizards in the genus Anolis to determine whether larger copulatory morphologies and higher potential for copulatory muscle performance evolved in association with higher copulation rates. In 10–12 adult males of each species, we measured the size of the hemipenes and related muscles, the seminiferous tubules in the testes, and the renal sex segments in …
Assessing Multiple Endpoints Of Atrazine Ingestion On Gravid Northern Watersnakes (Nerodia Sipedon) And Their Offspring, Lorin A. Neuman-Lee, Karen F. Gaines, Kyle A. Baumgartner, Jayme R. Voorhees, James M. Novak, Stephen J. Mullin
Assessing Multiple Endpoints Of Atrazine Ingestion On Gravid Northern Watersnakes (Nerodia Sipedon) And Their Offspring, Lorin A. Neuman-Lee, Karen F. Gaines, Kyle A. Baumgartner, Jayme R. Voorhees, James M. Novak, Stephen J. Mullin
Karen F. Gaines
Ecotoxicological studies that focus on a single endpoint might not accurately and completely represent the true ecological effects of a contaminant. Exposure to atrazine, a widely used herbicide, disrupts endocrine function and sexual development in amphibians, but studies involving live-bearing reptiles are lacking. This study tracks several effects of atrazine ingestion from female Northern Watersnakes (Nerodia sipedon) to their offspring exposed in utero. Twenty-five gravid N. sipedon were fed fish dosed with one of the four levels of atrazine (0, 2, 20, or 200 ppb) twice weekly for the entirety of their gestation period. Endpoints for the mothers included blood …
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
Carmen M. Salsbury
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 …