Undergraduate dissertations

Final Honours Project: Scarabaeinae Community Biology and Morphology in a Tropical Montane Cloud Forest

Abstract:

The Scarabaeinae are an important group in the conservation of rainforests, as biological indicators and as providers of ecosystem services. These two properties have been linked to both Scarabaeinae community structure and to the morphology of dung beetle species.

This study explores one of the potential drivers of community structure, resource utilisation: examining through field observations and novel methods of experimentation how different resources affect community composition. The results show clearly that certain resources, namely carrion, promote greater abundance, species richness and diversity than others. Patterns of specialisation and resources preference suggest that dung is most widely exploited, but further analysis suggests that specialisation on carrion, a more nutritious resource, may occur when interspecific competition outweighs the costs of carrion adaptations and reduced availability. It is suggested that low-nutrient resources are exploited opportunistically by many species in the absence of a better alternative, but rarely specialised on. The results of these finding for conservation are discussed.

Also studied are the effects of elevation and associated environmental gradients on patterns of morphology within three Scarabaeinae species. A novel approach is taken to measuring a number of morphological features, including facultatively dimorphic structures. However, no relationship is found between these gradients and any of the seven morphological parameters tested. This is contrary to many previous studies, and resource availability or microhabitat variation are suggested as possible explanations. This finding suggests community versatility to environmental change; this and other conservation implications are discussed.

View full pdf. Supervised by Darren J. Mann, Oxford University Museum of Natural History.

Extended Essay: Colony Collapse Disorder: Causes, Context and Economic Impact

Note that this was completed in early 2010, and there is much more recent research in this area.

Abstract:

Colony Collapse Disorder (CCD) is a new affliction affecting managed honeybee (Apis spp.) colonies around the world. Amid broad media and scientific interest, a number of causes have been proposed, but no single one is strongly linked with CCD. Instead, the emerging theme from studies is that interactions between pathogens, human management practices, and perhaps environmental conditions, are the root cause of CCD. As I discuss, the wide variety of stresses and strains on domesticated honeybees are constantly interacting, and CCD may just be another example of the many colony collapses that periodically occur within the global beekeeping community. Indeed, the occasional declines in domesticated pollinators are echoed by evidence of a worldwide decline in wild insect pollinators, a situation made more serious by their perceived economic importance. However, a direct link between pollinator decline and crop decline is bought into question by recent work, highlighting the risks of relying on such an assumption. This discussion notwithstanding, it is clear that there will be economic and conservation implications of declines in managed and wild insect pollinators, and future research should focus on the impacts of human disturbance and management practices.

View full pdf. Supervised by Dr Owen T. Lewis, University of Oxford

 

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