54 research outputs found

    The ecology and population genetics of a complex of cryptic bumblebee species

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    Bumblebees are ecologically and economically important as pollinators, but some species are suffering severe declines and range contractions. In this thesis, three cryptic bumblebee species are studied to elucidate differences in their distribution, ecology and population genetics. As a result of their high morphological similarity, very little is known about the lucorum complex species: B. lucorum, B, cryptarum and B. magnus. In this study, their distributions across Great Britain were assessed using molecular methods, revealing that B. lucorum was the most abundant and most generalist of the three species, whereas B. magnus was the rarest and most specialised, occurring almost exclusively on heathland. Additionally, both B. magnus and B. cryptarum were more likely to be present at sites with cooler summer temperatures. Cryptic species represent interesting models to investigate the levels of niche differentiation required to avoid competitive exclusion. Characterising the niches of these species at a single site across the flight season revealed differences along three niche dimensions: temporal activity, weather sensitivity and forage-resource use. These species exhibited asymmetric niche overlap; a combination of ecological divergence and spatio-temporal heterogeneity may contribute to maintaining them in sympatry. Population genetic studies can be highly informative for understanding species ecology and for conservation management. The differences in habitat specialisation exhibited by these bumblebee species provide the opportunity to test conflicting hypotheses about links between dispersal and ecological specialisation: are habitat specialists selected to have low or high dispersal ability? Based on microsatellite analysis, the generalist B. lucorum had high levels of genetic diversity and little population structure across large spatial scales. The habitat specialist B. magnus had the lowest genetic diversity but similar levels of population differentiation to the moderate generalist, B. cryptarum. However, unlike B. cryptarum, B. magnus population differentiation was not affected by geographic distance, suggesting that this specialist species may maintain effective dispersal across large scales despite being restricted to a fragmented habitat. Bergmann’s rule is a well-known ecogeographic rule describing geographical patterns of body size variation, whereby larger endothermic species are found more commonly at higher latitudes. Ectotherms, including insects, have been suggested to follow converse Bergmann’s gradients, but the facultatively endothermic nature of bumblebees makes it unclear which pattern they should adhere to. This thesis reports caste-specific differences in body size between the three lucorum complex species in agreement with Bergmann’s rule: queens and males of B. cryptarum and B. magnus, which were found more commonly at higher latitudes and at sites with cooler temperatures, were larger than those of B. lucorum. Population genetic studies of invertebrates generally require the destruction of large numbers of individuals, which is often undesirable. Testing a variety of faecal collection and DNA extraction methods demonstrated that it is possible to obtain DNA of sufficient quality for genotyping from bumblebee faeces, without harming the individuals. This method would be valuable for studies of rare or declining bee species, for queens in reintroduction projects, and may be applicable to other arthropods. Overall this thesis contributes substantially to our knowledge of the ecology and population genetics of three important pollinator species. It provides data to inform species conservation, as well as understanding of ecosystem functioning and population dynamics. Furthermore, it successfully uses these cryptic species as a model to test several fundamental ecological theories

    Beyond brain size: Uncovering the neural correlates of behavioral and cognitive specialization

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    © Comparative Cognition Society. Despite prolonged interest in comparing brain size and behavioral proxies of "intelligence" across taxa, the adaptive and cognitive significance of brain size variation remains elusive. Central to this problem is the continued focus on hominid cognition as a benchmark and the assumption that behavioral complexity has a simple relationship with brain size. Although comparative studies of brain size have been criticized for not reflecting how evolution actually operates, and for producing spurious, inconsistent results, the causes of these limitations have received little discussion. We show how these issues arise from implicit assumptions about what brain size measures and how it correlates with behavioral and cognitive traits. We explore how inconsistencies can arise through heterogeneity in evolutionary trajectories and selection pressures on neuroanatomy or neurophysiology across taxa. We examine how interference from ecological and life history variables complicates interpretations of brain-behavior correlations and point out how this problem is exacerbated by the limitations of brain and cognitive measures. These considerations, and the diversity of brain morphologies and behavioral capacities, suggest that comparative brain-behavior research can make greater progress by focusing on specific neuroanatomical and behavioral traits within relevant ecological and evolutionary contexts. We suggest that a synergistic combination of the "bottom-up" approach of classical neuroethology and the "top-down" approach of comparative biology/psychology within closely related but behaviorally diverse clades can limit the effects of heterogeneity, interference, and noise. We argue that this shift away from broad-scale analyses of superficial phenotypes will provide deeper, more robust insights into brain evolution

    What does the honeybee see? And how do we know?

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    This book is the only account of what the bee, as an example of an insect, actually detects with its eyes. Bees detect some visual features such as edges and colours, but there is no sign that they reconstruct patterns or put together features to form objects. Bees detect motion but have no perception of what it is that moves, and certainly they do not recognize “things” by their shapes. Yet they clearly see well enough to fly and find food with a minute brain. Bee vision is therefore relevant to the construction of simple artificial visual systems, for example for mobile robots. The surprising conclusion is that bee vision is adapted to the recognition of places, not things. In this volume, Adrian Horridge also sets out the curious and contentious history of how bee vision came to be understood, with an account of a century of neglect of old experimental results, errors of interpretation, sharp disagreements, and failures of the scientific method. The design of the experiments and the methods of making inferences from observations are also critically examined, with the conclusion that scientists are often hesitant, imperfect and misleading, ignore the work of others, and fail to consider alternative explanations. The erratic path to understanding makes interesting reading for anyone with an analytical mind who thinks about the methods of science or the engineering of seeing machines

    Behavioural consistency and foraging specialisations in the Australasian gannet (Morus serrator)

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    This study reports behavioural consistency in Australian gannets, and give insights about its potential drivers. It contributes with the understanding of resource partitioning among individuals, crucial information for the conservation of this species. Also, it reveals ecological opportunity as a major component for foraging specialisations development in wildlife populations

    Latitude, longitude, and beyond:mining mobile objects' behavior

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    Rapid advancements in Micro-Electro-Mechanical Systems (MEMS), and wireless communications, have resulted in a surge in data generation. Mobility data is one of the various forms of data, which are ubiquitously collected by different location sensing devices. Extensive knowledge about the behavior of humans and wildlife is buried in raw mobility data. This knowledge can be used for realizing numerous viable applications ranging from wildlife movement analysis, to various location-based recommendation systems, urban planning, and disaster relief. With respect to what mentioned above, in this thesis, we mainly focus on providing data analytics for understanding the behavior and interaction of mobile entities (humans and animals). To this end, the main research question to be addressed is: How can behaviors and interactions of mobile entities be determined from mobility data acquired by (mobile) wireless sensor nodes in an accurate and efficient manner? To answer the above-mentioned question, both application requirements and technological constraints are considered in this thesis. On the one hand, applications requirements call for accurate data analytics to uncover hidden information about individual behavior and social interaction of mobile entities, and to deal with the uncertainties in mobility data. Technological constraints, on the other hand, require these data analytics to be efficient in terms of their energy consumption and to have low memory footprint, and processing complexity

    The role of visual adaptation in cichlid fish speciation

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    D. Shane Wright (1) , Ole Seehausen (2), Ton G.G. Groothuis (1), Martine E. Maan (1) (1) University of Groningen; GELIFES; EGDB(2) Department of Fish Ecology & Evolution, EAWAG Centre for Ecology, Evolution and Biogeochemistry, Kastanienbaum AND Institute of Ecology and Evolution, Aquatic Ecology, University of Bern.In less than 15,000 years, Lake Victoria cichlid fishes have radiated into as many as 500 different species. Ecological and sexual sel ection are thought to contribute to this ongoing speciation process, but genetic differentiation remains low. However, recent work in visual pigment genes, opsins, has shown more diversity. Unlike neighboring Lakes Malawi and Tanganyika, Lake Victoria is highly turbid, resulting in a long wavelength shift in the light spectrum with increasing depth, providing an environmental gradient for exploring divergent coevolution in sensory systems and colour signals via sensory drive. Pundamilia pundamila and Pundamilia nyererei are two sympatric species found at rocky islands across southern portions of Lake Victoria, differing in male colouration and the depth they reside. Previous work has shown species differentiation in colour discrimination, corresponding to divergent female preferences for conspecific male colouration. A mechanistic link between colour vision and preference would provide a rapid route to reproductive isolation between divergently adapting populations. This link is tested by experimental manip ulation of colour vision - raising both species and their hybrids under light conditions mimicking shallow and deep habitats. We quantify the expression of retinal opsins and test behaviours important for speciation: mate choice, habitat preference, and fo raging performance

    Creating Educational Experiences through the Objects Children Bring to School

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    The Scottish Curriculum for Excellence is framed, without visible theory, in language embedding the value of children’s experiences. In association with a policy encouraging practitioners to develop healthy home/school links, early childhood practitioners develop pedagogical practices in support of this curricular language of experience. One aspect coming into focus is children’s experiences in general rather than only those which take place within institutional walls. One way children introduce their out-of-school experiences into classrooms is by voluntarily bringing treasured objects from home to early childhood setting doors. By jointly engaging with John Dewey’s view that worthwhile educational experiences are developed through interactions and continuities, the pedagogic practices of twelve early childhood practitioners and the view that each child-initiated object episode could be viewed as part of a child’s experience this research aims to better understand practitioners’ development of educational experiences through their responses to the objects forty children voluntarily brought to school. In support of this aim three research questions focused on 1) what objects children brought? 2) what practitioners said and did with the objects? and 3) what practice similarities and differences were visible across two consecutive age groups: 3-5 year olds in a nursery (preschool) and 5-7 year olds in a composite Primary 1/2 class (formal schooling)? During an eight month period in 2009 data were collected by classroom observations, collection of photographic images and practitioner interviews in a government-funded, denominational, early childhood setting in a Scottish village school. Data were analysed for the physical and social properties of children’s objects, practitioner’s pedagogic practices when engaging with the brought-in objects and similarities and differences in object-related classroom behaviours as epitomised in the relationships in each classroom. The findings were that practitioners made use of three main pedagogical practices when engaging with children’s brought-in objects: transforming objects into educational resources, shaping in-school object experiences and building a range of relationships around these objects. While the broad patterns of practice used in both classrooms were similar the details of practice showed underlying framings of children and their futures were different in each classroom. It is argued that what Dewey’s views offer, in the context of these findings, is a theoretical framing of experience that opens new possibilities for practitioner’s individual and group reflections on their current practices and collaborative practice development. His is one of the languages of experience available as practitioners and policy makers around the world grapple with educational questions

    Population genetics of rhinoceros auklets throughout the North Pacific Ocean

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    Levels of gene flow among populations have a critical role in evolution and are affected by geographic, ecological, and behavioural barriers. Reductions in gene flow lead to population genetic structure. Seabirds have high potential for gene flow but, can show spatial genetic structure. Using molecular techniques, I examined levels of population genetic structure in rhinoceros auklets. I examined 424 individuals from 18 breeding colonies from Japan to California. Results from ten microsatellite markers showed significant genetic differentiation among and between North Pacific Ocean metapopulations. Isolation by distance, foraging segregation, site fidelity, oceanic conditions, and divergent breeding times are suggested to promote genetic differentiation for rhinoceros auklets. Using a population genetic approach, I tested if assignment tests could identify the genetic origin of rhinoceros auklets found at sea. From 124 birds of the eastern North Pacific Ocean, our research indicates assignment tests are limited with the current set of microsatellites
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