Graduation date: 1992

In order to study sperm competition and mating dynamics in the snow crab Chionoecetes opilio, a genomic library was established with the goal of identifying highly polymorphic microsatellite markers. Six pairs of DNA primers were designed to amplify markers Cop3-4, Cop4-1, Cop5, Cop10, Cop24-3 and Cop111 by the polymerase chain reaction (PCR). All markers produced patterns as expected from single loci inherited in a mendelian fashion, except for Cop5 which revealed a multi-locus banding pattern. The cross-amplification of the six loci in seven additional crabs species revealed DNA polymorphisms at one or more loci for each species. Markers Cop3-4 and Cop24-3 were used to determine paternity of larvae of primiparous females both from the wild and from multiple mating experiments under laboratory settings. The two markers were also used to genotype the contents of female spermathecae in order to determine the number of number of male genotypes present. Spermathecal contents of wild-caught females were cut into several cross-sections and each section genotyped individually. Histological analysis of spermathecae was carried out to complement genetic data in order to elucidate patterns of sperm competition. Single paternity was observed for the progeny of all females. The analysis of laboratory females showed displacement was the mechanism by which single paternity was obtained by the last males to mate. The analysis of wild females revealed that their spermathecae contained on average the sperm of at least 3.7 males. Larvae appeared to be sired by males whose genotypes were found in the spermathecal cross-sections toward the blind-end of the spermathecae. This suggested that they were the first males to mate with females they guarded until oviposition, and females remated with other males thereafter. Also, a comprehensive account of the mating dynamics was carried out in a wild population of the Northwest Gulf of Saint Lawrence (Eastern Canada) and demonstrated the e

I studied the mating behaviour of Richardson’s ground squirrels (Urocitellus richardsonii) in 2007 and 2008, near Picture Butte, AB, Canada with the goals of evaluating multiple paternities within litters, sperm competition, and female mate choice. Eleven microsatellites and use of behavioural data to eliminate males who could not be putative sires based on their spatial and temporal remoteness from estrous females enabled exclusive assignment of paternity to 82.8% of 598 offspring with known maternity. The frequency of multiple paternities (26.4%, n=87 litters) in my population was lower than that reported for Richardson’s ground squirrels in a Manitoba population (80.0%, n=15 litters). Sperm competition was absent except in litters weaned by those females that mated again within 5 minutes of the first copulation, in which case sperm displacement was evident. Female choice was observed through avoidance of copulation, termination of copulation, and hide-then-run behaviour. / x, 98 leaves ;|c29 cm. --

Thesis (Ph.D.)--McMaster University, 2006. / Supervisor: Jianping Xu). Includes bibliographical references.

Thesis (M.S.) -- University of Montana, 2008. / Title from author supplied metadata. Description based on contents viewed on July 6, 2009. Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 1998. / Vita. Includes bibliographical references (leaves 156-171). Available also in a digital version from Dissertation Abstracts.

Thesis (M.S.)--State University of New York at Binghamton, Department of Biological Sciences, 2009. / Includes bibliographical references ( leaves 46-48).

Thesis (Ph. D.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on October 18, 2007) Vita. Includes bibliographical references.

The present series of studies was undertaken to determine the effects of peripherally and centrally administered alpha-melanocyte stimulating hormone (MSH) on lordosis and to investigate some of the mechanisms underlying these effects. The results of Experiments 1-5 (Section I) indicated that, when confounding factors were minimized, peripherally administered MSH facilitated receptivity. Centrally administered MSH was found to produce both a long and a short term inhibitory effect. Experiment 6 (Section II) tested the hypothesis that the facilitatory action of peripherally administered MSH was due to an MSH-induced release of progesterone or some other facilitatory adrenal steroid. Results indicated that, while adrenalectomy per se did not inhibit lordosis, it blocked the facilitatory action of MSH, supporting the hypothesis. In Experiments 7-9 (Section III), the role of estrogen and progesterone in the inhibitory actions of MSH was examined. The results of these studies suggested that both estrogen and progesterone are necessary for the short term inhibitory action of MSH. However, the long term inhibitory action of MSH appears to be due, in part, to an MSH-induced decrease in the availability of cytoplasmic progestin receptors. In Experiments 10-15 (Section IV), the role of serotonin in the production of the inhibitory actions of MSH was examined. Parachlorophenyl-alanine (PCPA), a serotonin depletor, was found to prevent the long term inhbitory action of MSH. In addition, the inhibitory effects of PCPA or pirenperone, a serotonin type II receptor antagonist, did not summate with the inhibitory action of MSH. This suggested that serotonin type II receptors were involved in the production of the inhibitory actions of MSH. In Experiment 12, quipazine, a serotonin type II agonist, was found to attenuate fully the short term Inhibitory action of MSH. However, quipazine did not fully attenuate the long term inhibitory action of MSH, suggesting that the short and long term inhibitory actions of MSH are mediated through different mechanisms. This possibility was supported by the results of Experiment 13, which indicated that 20 ng MSH produced a long term, but not a short term, inhibitory effect. The results of Experiment 14 indicated that subthreshold doses of pirenperone and of MSH, when administered together, would inhibit receptivity. Experiment 15 indicated that this inhibition could be attenuated by quipazine. Thus, the following conclusions can be drawn: 1) the facilitatory action of peripherally administered MSH is probably mediated by an MSH-induced release of progesterone from the adrenals, 2) the short term inhibitory action of MSH is mediated, to a large extent, by an MSH-induced decrease in serotonin type II activity, and 3) the long term inhibitory action of MSH is mediated, in part, by an MSH/serotonin-induced decrease in the availability of progestin receptors. In addition, it was hypothesized that: 1) progesterone acts in the MRF to increase serotonin type II activity. Thus, MSH-induced decreases in serotonin type II activity and in progestin receptors probably occur at this location, and 2) estrogen acts in the AH-POA to decrease serotonin type I activity. Therefore, any actions of MSH on serotonin type I activity or on estrogen receptors is likely to occur in this region. Finally, it was suggested that MSH plays a role in the induction and maintenance of pseudopregnancy, thereby providing MSH with a functional role in the regulation of receptive states. / Arts, Faculty of / Psychology, Department of / Graduate

The genetic relationship of anadromous (sockeye salmon) and non-anadromous (kokanee) Oncorhynchus nerka was examined in conjunction with the breeding behaviour of the two forms to determine: (1) if there is evidence of genetic divergence between the forms where they spawn sympatrically; (2) if such divergence is associated with significant premating isolation between the forms and; (3) if premating isolation results directly from the size difference between the forms (sockeye are much larger than kokanee at maturity). Both sexes exhibit spawning territoriality; females establish and defend particular nest sites until death or displacement, males defend access to specific females from other males until the female has spawned out, they are displaced, or leave to compete for additional mates. Size and prior access to resources (mates and/or specific areas) are significant factors in intrasexual aggression in both sexes, with size the major factor in males and prior access the major factor in females. Females accompanied by males larger than themselves lose weight at a faster rate than those accompanied by males smaller than themselves. Weight loss is related to egg loss, indicating females spawn at a faster rate when accompanied by large males. Male mate preference depends on the size of the male. Males of various sizes prefer females of their own size or larger over females smaller than themselves. In contrast, all sizes of males tested demonstrated no preference between females of their own size and those larger. Large males, which have the widest range of potential mates (because of male intrasexual competition and female choice), are the most selective and small males, which have the narrowest range of potential mates, are the least selective. There were significant differences in allele frequencies between sympatrically spawning sockeye and kokanee. However, there were no consistent differences between sockeye and kokanee at any of five polymorphic loci examined. The extent of genetic differentiation between sympatric forms appears to be less than that between neighbouring populations of the same form, judging from an examination of allele frequencies and/or allele compositions. There was extensive assortative mating by form between sockeye and kokanee, which was not totally accounted for by the large size difference. In the two systems examined, males preferred to mate with females of their own form. In sockeye, such preferences are expected because of the size difference between forms. In kokanee, such preferences are not expected based on size alone, suggesting the evolution of premating isolating mechanisms. The degree of premating isolation was positively correlated with the extent of genetic divergence between sympatric forms. The results of this study are related to existing models of sympatric speciation to hypothesize that sockeye and kokanee have diverged in sympatry. The probable differences in selection between the marine and freshwater environments coupled with the assortative mating resulting from their size difference may have caused subsequent genetic divergence. This divergence appears to have been followed by the evolution of premating isolation. / Science, Faculty of / Zoology, Department of / Graduate