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 14 of 14 for “"Ontogenetic Shift"”.
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TROPHIC ECOLOGY OF JUVENILE LEAN AND SISCOWET LAKE TROUT (SALVELINUS NAMAYCHUSH) FROM U.S. WATERS OF LAKE SUPERIOR
… and niche overlap. I provide evidence that an ontogenetic shift in which Siscowet Lake Trout shift to feeding in deeper habitats at 400mm or age-5 facilitates resource partitioning between larger and older Lake Trout ecotypes.</p>
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Selected elements in Lake Michigan round goby (Neogobius melanostomus) reproductive physiology: spawning effort and determination of reproductive status of females and sperm competition in two reproductively distinct male morphs
… potential for flexible tactic expression, via ontogenetic shift, versus fixed tactic “choice.” There is evidence of an ontogenetic shift between these two morphs with smaller, younger males employing the sneak tactic and later transitioning to the parental tactic as they grow larger and older.
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The effects of individual-level differences in metabolic rate on foraging behavior and life history traits in honeybees
… rate was negatively correlated with age of ontogenetic shift and lifespan in wild-type bees as predicted by the Rate of Living hypothesis, it did not show any correlation with foraging parameters. In the phenotypic lines, metabolic rate affected life history parameters in the opposite …
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The biology, ecology and population trends of jacopever Helicolenus dactylopterus in South Africa
… indicated a selective benthic predator with an ontogenetic shift in diet from crustaceans to teleosts. To assess habitat preference, generalised linear models were fitted to broad and fine resolution abundance data from research trawls and video footage respectively. Trawl data indicated that H. …
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Towards an understanding of symbiont natural history through studies of crayfish and their annelid associates
… show that Cambarus crayfish display a consistent ontogenetic shift in resistance to the colonization of branchiobdellidans and this shift likely reflects underlying changes in the costs and benefits of symbiosis. I then show that this change in host resistance creates predictable patterns of …
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Herbivory by Parma mccullochi (Pomacentridae) : its role as an ecosystem engineer in temperate algal-dominated reefs
… achieve this, the diet of P. mccullochi and any ontogenetic differences, and its impact on the reef in terms of algal composition and algal recruitment were determined. P. mccullochi in the temperate reefs of Western Australia was found to be a strict herbivore, with its diet comprising almost …
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Comparative Biology of Sympatric Red Diamond and Southern Pacific Rattlesnakes in Southern California
… occasional lizards (7.5%) and birds, with no ontogenetic shift in prey type. Males averaged larger than females. Coastal snakes averaged larger and consumed a higher proportion of rodents and prey of larger body size than snakes from desert populations. Feeding occurred occasionally during …
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Thermal Tolerance of Age-0 Gulf of Mexico Striped Bass (<i>Morone saxatilis</i>): Ontogenetic and Genetic Effects
… Thermal tolerance challenges revealed a positive ontogenetic shift in thermal tolerance from the larval (CTM estimate 25.4°C<strong>±</strong>1.2°C) to the phase I juvenile stage (CTM estimate 35.8°C<strong>±</strong>0.7°C). Available water temperature data indicated that upper thermal tolerance …
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MULTIFACETED DRIVERS OF PERFORMANCE VARIATION IN ANIMAL POPULATIONS: INVASIVE PREDATOR, RESOURCE AVAILABILITY AND HYBRIDIZATION
… collected in alien crayfish-invaded sites. This ontogenetic shift can be interpreted as a local adaptation to the alien predator and suggests that frogs are able to recognise the predatory risk. If these responses are effective, escape strategies against the invasive predator may improve the …
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Comparisons of habitat use and diet of herbivorous kyphosids (Genus Kyphosus) in tropical and temperate reefs
… composition between all species (p < 0.001). An ontogenetic shift in was also present in the first two species (p < 0.001). K. sydneyanus and K. gladius consumed mostly brown macroalgae. However, K. sydneyanus consumed more Sargassum spp. (up to 44% in adults), while K. gladius generally had a …
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Biology, movement behaviour and spatial dynamics of an exploited population of smooth hound shark mustelus mustelus around a coastal marine protected area in South Africa
… Upogebia africana, Callichirus kraussi. No ontogenetic shift in diet was found for M. mustelus from Langebaan Lagoon. M. mustelus grow relatively rapidly, matured early (between 3 and 6 years) and attained a maximum observed age of 13 years. The movements of individual Mustelus mustelus in …
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Movement ecology of the bronze whaler shark (carcharhinus brachyurus) in southern Africa
… event could also provide evidence of an ontogenetic shift in migratory behaviour. Within False Bay, the declining temporal occurrence trend of Carcharodon carcharias, corresponded with an increase in C. brachyurus at several C. carcharias aggregation sites. Tracking of C. brachyurus …
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Studies on the diversity and distribution of marine ichthyoparasites in Southern Africa
… by host size. Multivariate analyses revealed an ontogenetic shift, driven by an increase in the prevalence and infection intensity of trophically transmitted taxa (Anisakis sp., Corynosoma australe, Hepatoxylon trichiuri, Molicola uncinatus), in infracommunity structure as well as in the …
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Spatial distribution of canopy gaps in a tropical forest landscape and its influence on the tree community
… as tree size increased, indicating a possible ontogenetic shift in the strength of species associations with slope. This pattern may be caused by a greater initial recruitment on moister slopes, and a progressive weakening of differential survival as trees grow and are better able to survive …