Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 4 of 4
Full-Text Articles in Life Sciences
Do Seasonal Glucocorticoid Changes Depend On Reproductive Investment? A Comparative Approach In Birds, S. Casagrande, L. Z. Garamszegi, W. Goymann, Jeremy W. Donald, C. D. Francis, M. J. Fuxjager, Jerry F. Husak, Michele A. Johnson, Bonnie K. Kircher, R. Knapp, L. B. Martin, E. T. Miller, L. A. Schoenle, Maren N. Vitousek, T. D. Williams, M. Hau
Do Seasonal Glucocorticoid Changes Depend On Reproductive Investment? A Comparative Approach In Birds, S. Casagrande, L. Z. Garamszegi, W. Goymann, Jeremy W. Donald, C. D. Francis, M. J. Fuxjager, Jerry F. Husak, Michele A. Johnson, Bonnie K. Kircher, R. Knapp, L. B. Martin, E. T. Miller, L. A. Schoenle, Maren N. Vitousek, T. D. Williams, M. Hau
Biology Faculty Research
Animals go through different life history stages such as reproduction, moult, or migration, of which some are more energy-demanding than others. Baseline concentrations of glucocorticoid hormones increase during moderate, predictable challenges and thus are expected to be higher when seasonal energy demands increase, such as during reproduction. By contrast, stress-induced glucocorticoids prioritize a survival mode that includes reproductive inhibition. Thus, many species down-regulate stress-induced glucocorticoid concentrations during the breeding season. Interspecific variation in glucocorticoid levels during reproduction has been successfully mapped onto reproductive investment, with species investing strongly in current reproduction (fast pace of life) showing higher baseline and lower …
The Evolution Of Copulation Frequency And The Mechanisms Of Reproduction In Male Anolis Lizards, Michele A. Johnson, Maria Veronica Lopez, Tara K. Whittle, Bonnie K. Kircher, A K. Dill, Divina Varghese, J. Wade
The Evolution Of Copulation Frequency And The Mechanisms Of Reproduction In Male Anolis Lizards, Michele A. Johnson, Maria Veronica Lopez, Tara K. Whittle, Bonnie K. Kircher, A K. Dill, Divina Varghese, J. Wade
Biology Faculty Research
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 …
The Burden Of Motherhood: The Effect Of Reproductive Load On Female Lizard Locomotor, Foraging, And Social Behavior, Michele A. Johnson, J. L. Caton, R. E. Cohen, J. R. Vandecar, J. Wade
The Burden Of Motherhood: The Effect Of Reproductive Load On Female Lizard Locomotor, Foraging, And Social Behavior, Michele A. Johnson, J. L. Caton, R. E. Cohen, J. R. Vandecar, J. Wade
Biology Faculty Research
The costs of reproduction, involving demands associated with both current and future reproductive efforts, may place a substantial burden on females. However, animals may minimize these costs by modifying their behavior across the reproductive cycle. We examined the effects of reproductive load on three types of behavior (locomotion, foraging, and social displays) in green anole lizards (Anolis carolinensis) by comparing egg, follicle, and oviduct mass and volume with field observational data. We found that female locomotor and social display behaviors decreased as reproductive load increased, suggesting behavioral modification in these traits, but we detected no relationship between foraging and …
The Evolution Of Social And Reproductive Monogamy In Peromyscus, Evidence From Peromyscus Californicus (The California Mouse), David O. Ribble
The Evolution Of Social And Reproductive Monogamy In Peromyscus, Evidence From Peromyscus Californicus (The California Mouse), David O. Ribble
Biology Faculty Research
The genus Peromyscus (deer mice) is an attractive group in which to study the evolution of social and mating behaviours. This genus includes over 50 species (Carleton, 1989) that are widely distributed across North and Central America from coast to coast and from the northern subarctic to Panama (Kirkland & Layne, 1989). The diversity in body sizes among Peromyscus ranges from 13 to 77 g (Millar, 1989) and exceeds that of most other genera. Phylogenetic relationships among species of Peromyscus are relatively well understood (Stangl & Baker, 1984), although the systematics of Peromyscus is an active area of study (e.g., …