published_or_final_version / abstract / toc / Clinical Psychology / Master / Master of Social Sciences

The neurons in the mesocerebrum of the right cerebral ganglion control the sexual behaviour of Helix aspersa maxima. The purpose of the present study was to examine the relationship between reproductive development and the development of these neurons. The growth of right mesocerebrum neurons was quantified by filling cells with hexamminecobalt chloride at different ages. The neurite growth phase preceded that of the penis by about four weeks. Total neurite length was linearly correlated with soma diameter as measured in wholemounts. Diameter measurements from sectioned material showed that postembryonic growth in three CNS populations was expressed as increases in soma diameters but not in neuron numbers. The growth rate of right mesocerebrum cells between 5-20 weeks of age was significantly greater than that of the other two populations. Right mesocerebrum development was unaffected by male reproductive tissue ablation. this study shows that growth and development of the right mesocerebrum neurons of H. aspersa maxima occurs relatively late, but is complete prior to the initiation of reproductive behaviour.

This thesis explores the psychosocial dynamics of sexual risk-taking in men who have sex with men, with particular focus on the dilemmas that gay men face in establishing trust in themselves and reasonable trust and intimacy with their sexual partners. As well, the practical function of this study is to analyze past and current social marketing efforts aimed at reducing the spread of HIV/AIDS, and to offer suggestions for how to approach a strategy to reduce HIV incidence in gay men and at the same time bolster efforts to assist men who have sex with men (MSM) in adhering to safer sex guidelines. In part, this thesis uses a sample of participants of the Vanguard Project cohort (St. Paul's Hospital, Vancouver, British Columbia), in order to explore the social meanings attributed by MSM towards sex, risk, intimacy, and attitudes toward HIV/AIDS. Through the use of first-person narratives, this thesis examines the concordance or discordance of MSM beliefs and behaviour with long-standing theoretical models of harm reduction methods concerning sexual risk. The study reveals that, in great measure, due to past life course events, many gay men suffer from a lack of trust in themselves, which results in a tendency to make irrational or unreasonable decisions concerning their long-term sexual health, and a lack of trust in other gay men. As welL through the misguided and often untruthful health models that advocate fewer sexual partners and rely upon the false assumption that all potential sex partners are carriers of contagion, the sense of mistrust has been reinforced. The lack of confidence in self and others further translates into a suspicion of the motives and/or efficacy of social institutions entrusted with community health development and maintenance, rendering their efforts even less effective. Moreover, traditional harm reduction messages, especially 'fear campaigns', often act as a deterrent, rather than as an incentive, to harm reduction. Of more appeal are supportive harm reduction messages delivered by someone whom the recipient trusts, especially when the social meanings of sex, risk, trust and intimacy are, for many gay men, less fixed and more contingent than for the population at large. This means that attempts to modify risky behaviour must acknowledge and negotiate multiple meanings, shifting values and changing social climates, as well as routine epidemiological concerns. The research identifies four key themes within a problematic of trust, risk and intimacy, and delineates the harm reduction social complexities experienced by gay men in the study group; these recurring themes deal with family and early sociahzation, internalized homophobia, contingency and instability of meanings of risk, trust and sex, and the toistworthiness of the messengers of harm reduction strategies. Out of these recurring themes come a number of recommendations for remedial programs aimed at both mid- and long-term reductions in HIV incidence. The recommendations are grounded in the recognition that homophobic and/or dysfunctional social conditions are, to a great extent, implicated in sexual risk behaviour, and therefore must be eliminated or ameliorated before meaningful harm reduction gains can be realized. The discussions with the gay men in the study reveal their need for positive role models and communal social support in their efforts to combat HIV infection, suggesting a need to rethink the meanings of what it is to be gay, a need to redevelop and revitalize what was once a vibrant and cohesive corrimunity, and bearing in mind the lessons of the past, a need to re-approach the task of sternming the tide of HIV infection in ways that are sensitive to the factors that adduce high-risk sexual behaviour.

The intent of this research thesis is the examination of post-secondary women’s positive experiences with pornography. Very little research has been conducted with women who enjoy pornography and yet recent statistics in Canada and the United States show that there is an increasing amount of female users of pornography (Cantor, Mares, & Hyde, 2003). This study presents an emerging grounded theory of the process through which a small group of post-secondary women come to label their experiences with pornography as positive. The study traces the experiences of four post-secondary women in Western Canada from their initial exposure to pornography to their current use of the material. Results showed the importance of personal control in the development of female sexual identity and the enjoyment of pornography. This study is embedded in a social constructionist theoretical framework and offers recommendations for further research in the area. iii / x, 179 leaves ; 29 cm

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Dart shooting, a bizarre component of mating behaviour seen in several species of terrestrial snails, has bewildered scientists for centuries. The hermaphroditic snail Helix aspersa pushes a calcareous "love dart", covered with mucus, through the skin of its partner at the end of an elaborate courtship. I address both why this dart shooting behaviour is performed and how it is controlled by the brain. I find that the dart cannot serve as a nuptial gift of calcium because it is rarely internalised by the recipient and contains only a small amount of calcium. However, most shot darts penetrate the skin and come into contact with the blood. I demonstrate that mucus, produced by the digitiform glands and carried on the dart, causes contractions in the female organs. The contractions suggest that more sperm will reach the sperm storage organ as a result of dart shooting, which is important in sperm competition because snails store sperm from several partners before laying eggs. This introduction of a bioactive substance can be explained by either mate choice or mate manipulation. My findings show that dart shooting is an optional component of mating behaviour, which supports the mate manipulation hypothesis. I conclude that the dart transfers a substance to manipulate the storage of the donated sperm. Many species transfer bioactive substances into conspecifics. I propose the term "allohormones" for such substances to distinguish them from hormones and pheromones. / To investigate how the central nervous system controls dart shooting and other mating behaviours, I used an in vivo approach. The right mesocerebrum has been proposed as the control centre for mating behaviour based on in vitro findings. I demonstrate, by electrically stimulating and recording from right mesocerebral neurones in the intact animal, that these neurones are involved in dart shooting and penial eversion. I also test the hypothesis that different neuropeptides mediate different mating behaviours, and I find that APGWamide is responsible for genital eversion. From my results, together with data obtained using other gastropods, I conclude that the anteromedial portion of the right cerebral ganglion is an evolutionarily conserved region for the control of mating behaviour.

This study investigates the colonization of Barbados, the seasonality of breeding, and the function of breeding plumes in the cattle egret Bubulcus ibis ibis. Colonization occurred around 1956, and the island now has 4 colonies. Numbers of birds at each colony are still increasing. Colonies are evenly spaced around the island. Plumage scores varied seasonally, and males had higher scores than females. Breeding activity peaked in July-August and November-March. Conspecific interference may force poorly plumed birds to breed when environmental conditions are poor. Chick mortality was primarily from starvation during periods of low breeding activity, and primarily from conspecific attack during high breeding activity. Fledging success did not increase with breeding activity. Plumage scores correlated positively in breeding pairs. Well-plumed males fed chicks more often than poorly plumed males and had the higher fledging success. Males contributed more to nest and nestling attendance when their mates were well plumed. Plumes appear to indicate the potential paternal care and the genetic quality of a mate.

This qualitative study investigated what factors impact Home-care professionals' ability to effectively discuss and intervene with older adults on the topic of intimacy and sexuality, and to generate a theoretical model for methods in which professionals deal with the subject matter. In depth interviews with nine Home-care professionals (social workers, occupational therapists, physiotherapists, nurses, home-care workers, team coordinators) from a Montreal CLSC who regularly intervene among older adults and utilize the Multiclientele Autonomy Assessment form, documentary evidence, and grounded theory analysis were utilized. Interviews centered on the professionals' conceptions of their roles and experiences as health and social service providers with regards to sexuality in later life. A theoretical model was developed describing (a) Home-care professionals' discomfort in inquiring and/or discussing the topic of sexuality with older adults, (b) phenomena that arose from those causal conditions, (c) strategies for facilitating intervention on the topic with older adults, (d) the consequences of those strategies. Implications for future research and practice are addressed.

During the final stage of courtship, the garden snail Helix aspersa attempts to stab its mating partner with a mucus-coated calcareous "love dart." I present evidence supporting two predictions of the most promising hypothesis for the adaptive significance of this behavior: that the dart serves to increase the reproductive success of the shooter by increasing the numerical representation of its sperm in the recipient's storage organ (the sperm loading hypothesis). First, I demonstrate that once-mated snails store more of the sperm transferred by successful shooters than by unsuccessful shooters. Second, I demonstrate that this biased storage results in higher paternity scores for successful shooters relative to unsuccessful shooters in the clutches of multiply mated recipients. Moreover, I present evidence that body size and mating order influence the outcome of sperm competition in snails. Finally, I propose a novel mechanism to explain the observed pattern of sperm utilization in H. aspersa based on the motility of stored allosperm.

The distribution of APGWamide-like and FMRFamide-like immunoreactive neurons involved in the mating behaviour of the terrestrial snail Helix aspersa have been investigated in the mesocerebrum by retrograde and anterograde labelling and immunostaining techniques. Retrograde labelling shows that 25-40 mesocerebral neurons have an axon in the penis nerve and a similar number of neurons have an axon in the nervus cutaneus pedalis primus dexter (NCPD). It was found that the mesocerebral neurons also project to the nervus cutaneus pedalis secundus dexter (NCSD), the medial lip nerves, the posterior lip nerve, the peritentacular nerve, and the pedal ganglion. Some mesocerebral neurons have multiple projections. Quantitative analysis using confocal laser scanning microscopy indicates that approximately half of the mesocerebral neurons projecting to the penis nerve contain APGWamide-like peptide and half of the mesocerebral neurons projecting to the NCPD contain FMRFamide-like peptide. Some mesocerebral neurons have both peptides. These results are generally in agreement with the hypothesis that the neurons projecting to the penis nerve contain APGWamide, while those projecting to the NCPD contain FMRFamide.