In this study, pheromone and skin lipid samples collected from red-sided garter snakes (Thamnophis sirtalis parietalis) were exposed directly to either full-spectrum light or full-spectrum plus UVB light. In addition, female and male snakes were exposed to daily doses of either full-spectrum or full-spectrum and UVB light, after which the...
Vertebrates communicate with one another and coordinate intraspecific reproduction by using a variety of sexually dimorphic signals, such as plumage, ornaments, sounds, and/or scents. These sexual dimorphisms are maintained by physiological factors, typically sex-specific hormones (though see Chapter 3 for an exception). The purpose of the research in this dissertation...
Parasitic infections and immune challenges can affect host reproductive fitness and, ultimately, the evolution of host populations in a myriad of ways. The fitness implications of parasitic infections range from increased host mortality to subtle changes in reproductive investment. From alterations of behaviors, sexual signaling, and competitive ability to changes...
The benefits of reproduction are clear, but there are also costs. Much is known about the costs of reproduction in females, but only recently have male costs been investigated in any depth. These costs of reproduction may be minimized by appropriately modifying behavior, but there has been little research on...
A wide range of environmental and physiological factors influence the type and extent of sexual dimorphism found in animals. Influential factors include variable climate, competition for resources and mates, mate choice, and parental investment. In addition, some investigators attribute differences in body size to physiological factors influenced by genetic and...
Postcopulatory sexual selection—sperm competition and cryptic female choice—has become a major area of research over the past 40 years. Within this field there are many outstanding questions at every level of analysis, from proximate to ultimate. The fitness consequences for both sexes in the period after copulation and before fertilization...
Sperm competition is the post-copulatory analog of male-male combat, wherein sperm
from more than one male coincide in a female’s reproductive tract and compete with one
another for fertilization of a limited number of ova. Post-copulatory sexual selection,
such as sperm competition, can be a powerful driving force for the...
At a time when environmental conditions are rapidly changing, understanding how thermal extremes impact wildlife is imperative to fully understanding the consequences of climate change in natural ecosystems. While many organisms are currently impacted by rapidly warming and more erratic environmental conditions, identifying and investigating model species whose life histories...
This study investigated the effect of captivity on the chemical profiles of the female sexual attractiveness pheromone of the red-sided garter snake (Thamnophis sirtalis parietalis). Dorsal skin lipids were extracted from female garter snakes collected from the Interlake region of Manitoba, Canada. A comparison of captive and wild snakes was...
In animals, reproductive behaviors serve to attract individuals together during the
breeding season and to coordinate the behavioral and physiological states of individuals
so that mating can successfully occur. In snakes, the various reproductive behaviors
including courtship, mating, courtship inhibition, male combat and trailing are mediated
primarily by pheromones. Pheromones...