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 20 of 24 for “"Size dimorphism"”.
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Queen size dimorphism in ants
… an important exception. The case of ant queen size dimorphisms has not been studied in sufficient detail, and thus this thesis aimed at elucidating causes and consequences of the different size of small (microgynous) and large (macrogynous)ant queens using the North American ant species …
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Genetic constraints on the evolution of sexual size dimorphism
… questions concerning the evolution of sexual size dimorphism (SSD). Fecundity selection is often suggested as the main causal factor underlying the prevalence of female-biased SSD, but this assumption has not been empirically tested. I selected female Drosophila melanogaster for increased or …
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Behavioural causes and consequences of sexual size dimorphism in an apex predator species.
… that result in corresponding variations in body sizes, including size dimorphism, is a particularly widespread feature of many animal populations. The increasing characterisation of consistent individual behavioural variations, unrelated to age or sex, is equally considered to have important …
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The breeding biology of Eudyptes penguins with particular reference to egg-size dimorphism
… chicks hatched from two eggs of similar size co-existed for up to 57 days. Chicks are raised successfully from 3% of all A-eggs laid by Rockhopper Penguins, and from 34% and 43% of all B-eggs laid by Rockhopper and Macaroni Penguins respectively. Only one chick can be reared from each …
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Evolution and development of morphological, allometric, and life history patterns in the spotted hyena (Crocuta crocuta)
… evolution and development of 'reversed' sexual size dimorphism (SSD) in spotted hyenas. My dissertation consists of four chapters following the introductory chapter. The first of these research chapters, Chapter 2, describes the ontogeny of morphological sexual dimorphism in spotted hyenas, and …
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Reproductive Biology and Conservation Genetics of the Alligator Snapping Turtle (Macrochelys Temminckii)
… of this study were to (1) determine gender size classes and assess sexual size dimorphism, (2) delineate the reproductive cycle of M. temminckii, particularly their sex steroid seasonality, and (3) evaluate possible genetic divergence between M. temminckii found in southwest Georgia and …
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Modelling the Interaction of Fishing with Size Structure, Dimorphism, and Egg Production of Clawed Lobsters
… and recruitment or to preserve specific size classes to increase reproductive output. Consequences of these strategies could include variation from a natural size structure of the population, exaggerated sexual dimorphism, skewed sex ratios, and suboptimal mating conditions. To examine …
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Mapping the Dorsal Skin Pigmentation Patterns of Two Sympatric Populations of Ambystomatid Salamanders, <em>Ambystoma opacum</em> and <em>A. maculatum</em> from Northeast Tennessee.
… a number of questions: i) the extent of sexual size dimorphism (SSD) in both species, ii) what traits influence the dorsal skin pigmentation and how, iii) whether gender differences in developmental stability occur, and iv) the extent of phenotypic variation within each species. The findings of …
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Foraging Ecology and Demography of Sternotherus Odoratus in a Southwestern Missouri Population
… of approximately 1161 stinkpots. Sexual size dimorphism was noted with females having larger carapace widths and greater masses, and males having smaller platron lengths. Stinkpots consumed algae, seeds, plant material, crayfish, molluscs, insects and fish. Sexual differences existed for …
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Ecology of the Eastern Massasauga (Sistrurus Catenatus Catenatus) From Carlyle Lake, Clinton County, Illinois
… range limit from 1999--2003. I found no sexual size dimorphism (SSD) present in either snout-vent length (SVL) or mass but SSD was present for tail length (TL). I observed variation in growth rates of cohorts and models predicted the 1998 and 1999 cohorts simultaneously matured in 2000. Contrary …
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A phylogeny of the genus Gasteracantha Sundevall, 1833 (Araneae, Araneidae) with an examination of sexually dimorphic characters in the subfamily Gasteracanthinae
… is followed by an analysis of the extreme sexual size dimorphism (eSSD) between Gasteracanthinae males and females, along with an examination of the evolution of several sexually dimorphic characters. Finally, taxonomic changes are proposed, suggestions around improving molecular and morphological …
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Ecology and conservation of albatrosses and petrels at sea off Brazil
… 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 spp.) and Diomedea albatrosses. Closely …
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An Assessment of the Effects of Sexual Selection and the Social Environment on Mating Behaviors in Two Tiger Beetle Species (Coleoptera: cicindelidae)
… and copulation durations were affected by female size, indicating that males may be capable of assessing female size once in physical contact with the female. The social environment of C. belfragei experiments did not affect guarding or copulation durations, but in C formosa, social context was …
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Cranial Sexual Dimorphism in Hispanics Using Geometric Morphometrics
… specific in that human groups differ in size. Sexual dimorphism in the cranium has been explored in American Whites and Blacks (Kimmerle et al., 2008), but little is understood concerning sexual dimorphism in Hispanics; the fastest growing US population (Martinez and Ariosto, 2011). A …
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Perch Selection by Male Dragonflies (Odonata, Anisoptera) Related to Competitive Ability and Species Composition
… dissertation research examined the role of male size in perch height selection, position on the perch, and competitive ability. Four hypotheses were tested: 1) Dragonfly species would vary by size and that territorial species would show sexual size dimorphism (SSD), 2) Perch height selection …
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The Design of Complex Weapons Systems in Scorpions: Sexual, Ontogenetic, and Interspecific Variation
… Given the complexity of these systems, I hypothesized that weaponry design is subject to selective forces arising from differences in usage between the sexes, during ontogeny, and among closely-related species occupying different habitats. In the first of three studies, I examined sexual …
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Microevolutionary processes in natural populations of the waterstrider Aquarius remigis
… and functional limitations. Optimal body size is determined by the net effect of selection acting throughout the life history of the organism. Body size is correlated between the sexes, and sexual size dimorphism (SSD) provides natural experiments in the evolution of traits constrained by …
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The evolution of mating systems in black scavenger flies (Diptera: Sepsidae)
… a comparative study of patterns of sexual size dimorphism and sex ratios at oviposition sites in conspecific populations that show great divergence in the expression of this trait. The results of this research support the pre-copulatory mate guarding hypothesis for the adaptive significance …
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Radiation in the genus Amazilia: A comparative approach to understanding the diversification of hummingbirds.
… 28 hummingbird genera (Chapter 2), and hypothesized that these structures aid in nectar-robbing of long-tubed corollas. I test this hypothesis and found that the association between nectar-robbing and bill serrations evolved several times independently within the family (Chapter 3). While the …
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Intrabrood Dominance Hierarchies in Juvenile Red-Cockaded Woodpeckers: The Role of Early Social Environment On Post-Fledging Survival and Natal Dispersal
… and heavier than females; however, the sexual size dimorphism in mass is only present in mixed-sex broods, suggesting that the subtle structural size advantage gives males a competitive advantage over their sisters. Conflict rates among siblings increased with decreasing targeted feeding rates, …
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