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 202 for “"Ants"”.
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Hybridization in Ants
… factors make hybridization act differently in ants than in other species: eusociality and haplodiploidy. These factors serve to reduce the costs of interspecific hybridization in ants while simultaneously allowing them to take advantage of certain benefits. Eusociality may mitigate the effects …
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The Mouthparts of Ants
… functions is the mandible closer muscle. In ants, this muscle is generally composed of distinct muscle fiber types that differ in morphology and contractile properties. Volume proportions of the fiber types are species-specific and correlate with feeding habits. Two biomechanical models …
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Queen size dimorphism in ants
Many polymorphisms are linked to alternative reproductive strategies. In animals, this is particularly common in males. Ant queens are 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 …
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Ants and spiders in grassland food webs
Eine Herauforderung ökologischer Forschung ist das Verständnis des Zusammenhangs von Nahrungsnetzinteraktionen und Ökosystemfunktionen. Aktuelle Studien weisen dem Fraßdruck durch invertebrate Räuber und den damit ausgelösten trophischen Kaskaden eine wichtige Rolle in terrestrischen Ökosystemen …
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Mechanisms for the Evolution of Superorganismality in Ants
… the proximate evolution of superorganismality in ants. Using focussed mechanistic experiments in O. biroi, in combination with comparative work from other ant species, I study three major aspects of ant social behaviour that provide insight into the origin, maintenance, and elaboration of …
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Aspects of the ecology of Namib Desert ants
Thirty-six species of ants were collected in the central Namib Desert, Namibia during the period 1981 to 1985. The ant fauna was dominated by the Myrmicinae, comprising 29 species, followed by the Formicinae, comprising six species and the Pseudomyrmecinae with one species. The dominance of the ant …
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Solving ANTS with loneliness detection and constant memory
In 2012, Feinerman et al. introduced the Ants Nearby Treasure Search (ANTS) problem [1]. In this problem, k non-communicating agents with unlimited memory, initially located at the origin, try to locate a treasure distance D from the origin. They show that if the agents know k, then the treasure …
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Simulating the evolution of recruitment behavior in foraging Ants
… foraging and recruitment behavior of harvester ants of the genus Pogonomyrmex. We optimized the behavior of these models using genetic algorithms over a variety of food distributions and colony sizes, and validated their behavior by comparison with data collected on harvester ants foraging for …
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The evolution and functional morphology of trap-jaw ants
… innovation in the diversification of “trap-jaw” ants: power-amplified mandibles used for prey capture, nest defense, and individual escape from predators. Insects are the most diverse and numerically abundant animal group on the planet. One feature that contributed to their evolutionary success …
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Sensory Ecology of Carbon Dioxide Perception in Leaf-cutting Ants
… ecology of CO2 perception in leaf-cutting ants. It begins with the ecological role of CO2 for leaf-cutting ants. Inside the subterranean nests of Atta vollenweideri large amounts of CO2 are produced by the ants and their symbiotic fungus. Measurements in field nest at different depths …
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Field Behavior Comparison of 8 Species of California Desert Ants
<p>Replicate colonies were observed at three study sites in southern California. Hourly activity was monitored during winter and spring.</p> <p>The time outside the nest ranged from strictly diurnal in Pogonomyrmex californicus to bimodal to nocturnal in Pheidole barbata. Four aspects of surface …
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The evolution of social traits and biodiversity in the ants.
… has shaped the evolution of life on Earth. The ants are the most numerically diverse of the eusocial Hymenoptera, and display wide variation in social complexity. This positions the ants as an ideal taxon in which to study social evolution in a comparative framework. Social evolution theory has …
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A macro- and micro-evolutionary investigation of African Camponotus ants
Camponotus than the cytochrome oxidase II gene, based on almost all measures of phylogenetic utility. The primary hypothesis proposed to account for this observation is that these two mitochondrial genes are evolving under different evolutionary constraints. Specifically, the cytochrome oxidase II …
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Comparison of Laboratory Rhythms in Several Species and Genera of Ants
… Veromessor, Formica, Myrmecocystus) of ants were compared, two of them represented by two species each. Under controlled temperatures, in alternating light and dark, there was more difference in phase of rhythm among than within genera. This evidence adds to previous field evidence for a …
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Assessing risk to native ecosystems: using exotic ants as a model
… frameworks, and apply this using exotic ants as a model. To assess the vulnerability of different ecosystems to exotic ant invasion, I replicated a sampling study conducted across the Auckland region in 2004, allowing a temporal aspect to be included in the analyses. I found open-canopy …
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The evolution of caste-specific morphology and colony structure in ants
An organism can adapt to its environment physiologically, behaviorally, and morphologically, but biological functions may conflict with each other and therefore constrain their evolution. Eusocial organisms live in colonies that possess morphologically distinct castes that divide biological roles …
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Prevalence and impacts of ants colonizing active bird nests in Illinois
… gradient. I found workers of eight species of ants in nests, and for three of these species (Tapinoma sessile, Temnothorax curvispinosus, and Crematogaster cerasi) there was evidence that at least part of their colonies inhabited the nest. Tapioma sessile was the most common species and …
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CRISPR/CASTE: Functional Genomic Studies of the Major Evolutionary Innovations of Ants
<p>Ants are social organisms that live in groups and depend intimately on their nestmates for growth and survival. Ants have evolved a number of highly sophisticated, social phenotypes that allow them to form coherent colonies. This thesis explores two particularly derived features of ant biology: …
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