Thesis (Ph. D.)--University of Hong Kong, 2009. / Includes bibliographical references (p. 195-231). Also available in print.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

Thesis (Ph. D.)--University of Texas at Austin, 2009. / Title from PDF title page (University of Texas Digital Repository, viewed on Sept. 11, 2001). Vita. Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1975. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (p. 150-175).

Thesis (Ph. D.)--Illinois State University, 1996. / Title from title page screen, viewed May 25, 2006. Dissertation Committee: Charles F. Thompson, Angelo P. Capparella (co-chairs), Steven A. Juliano, Anthony J. Otsuka, Scott K. Sakaluk, David F. Weber. Includes bibliographical references (leaves 78-84) and abstract. Also available in print.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

Recently, it has been discovered that serotonin (5-HT) receptors exist as subtypes in the mammalian brain. At least two major subtypes that differ in their distribution, and affinity for serotonergic drugs, have now been described. These receptors have been labeled 5-HT₁, and 5-HT₂ receptors. The purpose of this thesis is to determine what roles the 5-HT₁, and 5-HT₂ receptors might play in the modulation of sexual behaviour in the female rat. The administration of the 5-HT₂ receptor antagonist pirenperone inhibited sexual receptivity in adult, ovariectomized Sprague Dawley rats that had been primed either chronically with estradiol benzoate (EB), or acutely with EB plus varying doses of progesterone (P). An inhibition occurred at peripherally administered doses of 50, 100 and 150, but not 25 µg/kg of pirenperone. Pirenperone also inhibited receptivity when administered intraventricularly at a dose of 15 µg/kg, however this dose of pirenperone was ineffective when administered peripherally. Increasing the dose of P did not attenuate the inhibitory effect of pirenperone. The 5-HT₂ antagonists ketanserin (2.5 mg/kg) and spiperone (250 µg/kg) also inhibited receptivity in females that had been primed with EB plus P. The inhibitory effect of pirenperone was attenuated by the 5-HT₂ agonist quipazine , however the 5-HT precursor 5-hydroxytryptophan (5-HTP) (20 mg/kg), and the 5-HT₁, agonists 5-methoxy-N,N-dimethytryptamine (5MeODMT) (200 µg/kg) and tryptamine (2 mg/kg) did not attenuate the effect of pirenperone. Quipazine, 5-HTP, and 5MeODMT did not effect receptivity in females that had been primed with EB plus P, however tryptamine inhibited receptivity. Whereas the nonselective 5-HT antagonist methysergide (3 mg/kg) failed to have an effect on receptivity in females that had been primed with EB, methysergide coadministered with quipazine facilitated receptivity. Pirenperone also inhibited proceptivity in females that had been primed with EB plus P. Although quipazine did not attenuate the inhibitory effect of pirenperone upon proceptivity, quipazine alone facilitated proceptivity in females that had been primed either with EB, or with EB and P. Methysergide did not effect proceptivity, and 5-HTP, 5MeODMT, and tryptamine were also ineffective with regards to proceptivity. The results of the present series of experiments are not entirely consistent with Meyerson's widely held theory of serotonergic inhibition , rather they suggest a dual role for 5-HT in female sexual behaviour. Therefore, a new theory regarding the role of 5-HT in sexual behaviour is proposed. Specifically, it is proposed that inhibitory effects of 5-HT are mediated by activity at 5-HT₁, receptors, whereas facilitatory effects are mediated by activity at 5-HT₂ receptors. / Arts, Faculty of / Psychology, Department of / Graduate

I consider the relationship between natal dispersal, the acquisition of breeding resources and the proximate maintenance of the mating system in a population of song sparrows (Melospiza melodia) resident on Mandarte Island, B.C.. The general hypothesis tested was that intrasexual competition for the resources that limit reproduction in each sex is the main factor affecting patterns of natal dispersal, territory turnover and mating system organization. This study reveals differences in the competitive ability of individuals and the consequences of these for natal dispersal, territory acquisition and the ability to monopolize mates. In this population, natal dispersal, territoriality and the mating system are related through the common mechanism of intrasexual competition for breeding resources. This competition affected reproduction within each sex, and in the opposite sex, raising potential conflicts of interest between mated males and females. I identify correlates of competitive ability, and consider how individuals of each sex maximize the number of young they raised. All suitable habitat was defended even at low density, resulting in high levels of competition for space. Song sparrows contested for territories year-round. Most settlers were yearlings, but several males were older and had previously owned a territory. Most floaters settled by evicting owners from all or part of their territories, in contrast to the assumption of most models of dispersal that floaters gain territories only after an owner's death. Relative age and dominance within cohorts affected recruitment and territorial status in the year following hatch in each sex. Differences in age also affected territorial and mating behaviour, particularly in males. Although competitive ability varied with age, differences in competitive ability between males persisted through life. Approximately 9% of male breeding attempts occurred after a male territory owner had evicted a neighbour and thereby gained access to an additional female. Polygynous males raised more young than monogamous males. Females vigorously defended their territories against female intruders, presumably to prevent polygyny by their mates. Females in polygynous groups often lost the aid of their mate, and raised fewer young, because polygynous males did not aid two females simultaneously. Adding supplemental food altered female time budgets, increased their ability to prevent settlement by female floaters, and increased their reproductive success. This suggests that females are constrained in the amount of time they can spend in territory defence by time spent foraging. The maintenance of monogamy was affected by differences in the abilities of individual males and females to defend their territories against intruders of the same sex. Dispersal distances were similar among sexes, in contrast to the usual pattern of female-biased dispersal in birds. Given the intense territorial behaviour of males and females, this study supports the hypothesis that biases in dispersal arise when territory establishment is substantially more difficult in one sex than the other. Dispersal on Mandarte was unrelated to inbreeding, common parentage, or reproductive success. However, emigrants from Mandarte were socially subordinate birds that must have outbred if they settled successfully. Female emigrants from local populations in the vicinity of Mandarte may settle more often than males. Dispersal occurred as young birds established ranges in the period following independence, from which they challenged or replaced owners. Adding food during the breeding period reduced dispersal in males and females in late summer and the following spring. Competitive ability probably affects dispersal from the natal population, the likelihood of settlement, and the time of settlement for those birds that remain in the natal population. / Science, Faculty of / Zoology, Department of / Graduate

No description available.

No description available.