Here are some summaries and downloads of the best work from my education.
Unfortunately, due plagiarism rules, I am not allowed to publish my university work online. Here I have posted the abstracts/summaries. But if you are interested, and not an Exeter Biosciences student, then contact me personally and I can send you a copy.
Honours Research Project: ‘Stabilising sexual selection conflicts with directional natural selection in the cricket Gryllodes sigillatus’ - achieved 77%
Conflict between natural and sexual selection has long been theorised, with some empirical support. When conflict was originally proposed, it was assumed that natural selection was stabilising and sexual selection directional, but this is often incorrect. Natural selection is more commonly directional, while signal traits associated with female choice are sometimes under stabilising selection. How conflict is altered under these different selection pressures is yet to be studied. Cuticular hydrocarbons have roles in both desiccation resistance and sexual signalling, and have demonstrated multivariate stabilising sexual selection in crickets, making cricket hydrocarbon profile ideal for a comparative study. Using multivariate selection analysis and canonical analysis, conflict was found between directional natural selection and stabilising sexual selection on male cuticular hydrocarbon profile in the cricket Gryllodes sigillatus. The same dynamics underlying the traditional conflict model can be applied to other forms of conflict like those observed here, although the specifics of this will need further investigation. The results and success of this study offer opportunities for further research, beginning with replication of this study in other species and other traits, such as male call structure.
Dissertation in Evolution: ‘On the Phylogenetics of Cooperation’ - achieved 67%
Cooperation has been heavily studied in recent years, with many high profile papers speculating on the origin and maintenance of cooperation. Cooperative mechanisms are being increasingly found in all areas of life including microbes. This study looks to bring together many papers investigating the phylogenetics of cooperation, an area that has received less attention, in order to determine whether cooperation is typically an ancestral trait or if it is often the product of convergent evolution. Cooperation is found to typically be an ancestral trait, that has often been lost during the evolution of modern species. Further research is recommended into horizontal gene transfer and into primate phylogenies in relation to cooperation.
Evolutionary Genetics Experiment: ‘Sexual selection in the crop pest Tipula paludosa, with implications for Sterilised Insect Technique’ - achieved 82%
The larva of Tipula paludosa is a crop pest, and knowledge of sexual selection in this species could aid in designing pest control methods. 6 traits were measured for selection in males captured autumn 2009 in Cornwall, using mating status at time of capture as a fitness correlate; co-variance between the traits was also measured. Weight was found to be the only trait significantly selected on, and of several proposed reasons for this, ability to pin females down and initiate mating was seen as the most likely explanation. The only significant co-variance found was between abdomen length and weight; it is proposed that this is because the abdomen is the most stable place to concentrate mass in a crane fly body. These findings can aid the design of a sterilised insect technique (SIT) method for population control, by increasing the abdomen length – and therefore weight – of the sterilised males released. Searching literature for possible explanations for the results highlighted a distinct lack of research into sexual selection in the Tipulidae, despite an obvious diversity in mechanisms from one species to the next. Further research in this area is strongly recommended.
The following projects together earned the ‘Chris Campbell Award for Outstanding Coursework’.
Environmental Science Fieldwork - achieved 100%:
Geology Fieldwork Pembroke - achieved 100%: