Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 18 of 18 for “"adult sex ratio"”.
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Sexual selections in the northern fall field cricket, Gryllus pennsylvanicus: a manipulation of the adult sex ratio
The operational sex ratio has long been considered an important constraint on the structure of mating systems. The effects of an experimentally manipulated sex ratio on mating behavior and selection were investigated in a polygynous species, Gryllus pennsylvanicus, where the potential exists for …
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Drivers of a Temporal Change in the Adult Sex Ratio of a Population of Roosevelt elk (Cervus elaphus roosevelti)
Ecological processes driving female-biased adult sex ratios (ASR, males:female) in ungulate populations have been addressed theoretically but empirical study is lacking. The female-substitution hypothesis asserts that a female-biased ASR reflects an overall fitness benefit to females and also males …
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Causes and consequences of mortality and mutilation in the Cape Peninsula baboon population, South Africa
… injury and mortality, in addition to an adult sex ratio strongly biased towards females. There was no data on the causes or the distribution of deaths and permanent injuries on the Peninsula to inform management decisions. The aim of this study was thus to: a) quantify the frequency, …
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Male reproductive success and population control in the Mediterranean fruit fly, ceratitis capitata
… males, despite this an understanding of the sexual selection processes that are involved is severely lacking. In this thesis I used the medfly as a model organism to investigate the context-dependent nature of male reproductive success. In Chapters 2 and 3 I investigate the effect of …
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The economics of tobacco control in some African countries
… variable used in the literature, the adult sex ratio, to instrument for the tobacco smoking status of Zambian households. But unlike previous studies, I relax the strict exclusion restriction and allow for the adult sex ratio to be correlated with the error term. That is, I allow the …
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Causes and consequences of sex ratio bias in Nazca boobies
… reproductive and demographic studies. The adult sex ratio at this colony has been significantly male biased for more than twenty years. Knowledge of the ontogeny of this bias provides critical context that allows proper framing of hypotheses regarding parental sex allocation, the relative …
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A dynamic white-tailed deer population simulator and lessons from its use
… virginianus). It is based on a dynamic age and sex-specific algorithm, unifying bioenergetic, sociological, hunter, and population characteristics. The system determines a management plan that will stabilize a population under the conditions specified. The system is also designed to be used for …
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Genetic Structure and Demographic Analysis of Key deer (Odocoileus virginianus clavium)
… individuals with a heavily skewed female-biased adult sex ratio. Furthermore, I combined genetic and contemporary demographic data to generate a species persistence model of the Key deer. Sensitivity tests within the population viability analysis brought to light the importance of fetal sex ratio …
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Sex-specific reproductive strategies in redfronted lemurs (Eulemur fulvus rufus, Primates, Lemuridae)
… monopolize a group of females. Due to male intrasexual competition, the sex ratio of groups of anthropoid primates is generally female-biased. Gregarious Malagasy lemurs deviate from theoretical expectations derived from sexual selection theory and from patterns found among anthropoids because …
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Encoding sex ratio information: automatic or effortful?
Operational Sex Ratio (OSR: the ratio of reproductively viable males to females in a given population) has been theorized and studied as a construct that may influence behaviors. The encoding of sex ratio was examined in order to determine whether the cognitive process underlying it is automatic or …
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Examining skewed sex ratio in the mountain plover (Charadrius montanus) population
Skewed sex ratios can have negative implications for population growth or persistence if not congruous for a species system. A skewed tertiary sex ratio (2.3 males per female) has been detected in the breeding population of a grassland shorebird experiencing population declines, the mountain plover …
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Examining skewed sex ratio in the mountain plover (Charadrius montanus) population
Skewed sex ratios can have negative implications for population growth or persistence if not congruous for a species system. A skewed tertiary sex ratio (2.3 males per female) has been detected in the breeding population of a grassland shorebird experiencing population declines, the mountain plover …
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Should I stay or should I go? Hormonal and demographic correlates of natal dispersal in a population of wild vervet monkeys
Natal dispersal is an important maturational milestone in the life of many primates and is associated with changes in the physical and social environment. To integrate into an unrelated group, an individual must abandon its known environment and face various challenges which can often be costly. …
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Extra-pair paternity within the female-defense polygyny of the lizard, Anolis carolinensis: Evidence of alternative mating strategies
Mate competition is a prominent component of sexual selection theory. Typically, males attempt to mate with the most females possible and females attempt to mate with the highest quality males possible. In the polygynous female-defense mating system of Anolis carolinensis, males compete directly …
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Essays on the economics of tobacco and alcohol control policy in Kenya
… the precedent of some other studies, the adult sex ratio is used as an instrumental variable for the tobacco and alcohol consumption status of households. However, the adult sex ratio may not meet the exclusion restriction. In order to address this concern, I change the specification of …
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Sex-specific Habitat Use and Responses to Fragmentation in an Endemic Chameleon Fauna
… field study reports a highly female-biased sex ratio in the Eastern Arc Endemic Usambara three horned chameleon, Trioceros deremensis, a large, sexually dimorphic species. This species is collected for the pet trade, and local collectors report males bring a higher price because only this …
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Reproductive traits, identity and host preferences of two genetic lines of the seedcorn maggot, Delia platura (Diptera : Anthomyiidae)
… whose dynamics are highly influenced by group sex ratio and density, we evaluated the effect of these two variables on the mating success, pre-oviposition period and fecundity of the two D. platura lines. By experimentally varying a mating group’s sex ratio and density, we observed an increase …
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Ecology and conservation of albatrosses and petrels at sea off Brazil
… primary moult timing. Based on molecular sexing and linear measurements, sexual size dimorphism was shown to vary according to species, with females in general smaller than males, more pronounced in bill measurements than in other traits, and more conspicuous in Giant Petrels (Macronectes …