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Theses/Dissertations

California Polytechnic State University, San Luis Obispo

Master's Theses and Project Reports

Testosterone

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Full-Text Articles in Life Sciences

Effects Of Testosterone On The Spatial Ecology, Coloration, And Brain Regions In Western Fence Lizards, Sceloporus Occidentalis, Rachel Catharine Wilson Sep 2015

Effects Of Testosterone On The Spatial Ecology, Coloration, And Brain Regions In Western Fence Lizards, Sceloporus Occidentalis, Rachel Catharine Wilson

Master's Theses and Project Reports

An organism’s spatial ecology allows for access to essential resources such as food, mates, and escape from predators. Home range size, or the total area an organism inhabits, varies in relation to numerous factors including seasonality. During the breeding season, home range size increases in males across taxa. In addition, males usually also have larger home range sizes than females. This implicates testosterone (T) as a possible mediator of this relationship. Indeed, T causes an increase in home range size of males in numerous species of lizards. In addition to T causing an increase in home range size, it ...


Territorial Behavior And Cortical Brain Plasticity In Adult Male Sceloporus Occidentalis, Daniel R. Pfau Mar 2014

Territorial Behavior And Cortical Brain Plasticity In Adult Male Sceloporus Occidentalis, Daniel R. Pfau

Master's Theses and Project Reports

The hippocampus is a brain region that can undergo tremendous plasticity in adulthood. The hippocampus is related to the formation of spatial memories in birds and mammals. In birds, plasticity in the hippocampus occurs when formation of such memories is directly relevant to survival or reproduction, such as for breeding or food caching. In reptiles, the homologues to the hippocampus are the dorsal and medial cortices (DC and MC). In several lizard, snake and turtle species, these structures have been related to spatial memory. Experimental investigations indicate that differences in DC volume are related to space use associated with differing ...


The Relationship Between Plasma Steroid Hormone Concentrations And The Reproductive Cycle Of The Northern Pacific Rattlesnake, Crotalus Oreganus, Craig Michael Lind Jun 2009

The Relationship Between Plasma Steroid Hormone Concentrations And The Reproductive Cycle Of The Northern Pacific Rattlesnake, Crotalus Oreganus, Craig Michael Lind

Master's Theses and Project Reports

To gain a better understanding of the role of steroid hormones in vertebrate reproduction, we quantified steroid hormone concentrations in a free ranging population of the Northern Pacific rattlesnake, Crotalus oreganus. Plasma steroid hormone concentrations were quantified for both male and female snakes throughout the active season (Mar-Oct). We measured testosterone (T), 5α-dihydrotestosterone (DHT), and corticosterone (B) concentrations in male and female snakes. 17β-estradiol (E2) and progesterone (P) were measured in females only. We also observed breeding behaviors (e.g. consortship, courtship, and copulation) in the field and measured testis and follicle size in male and female snakes from museum ...