Macroparasites have a central place in wildlife ecology because they have the potential to regulate host populations through effects on reproduction and/or survival. However, there remains a paucity of studies investigating parasite-host relationships in .wild animals. This thesis focussed on the transmission and impact of a gastrointestinal nematode of Svalbard reindeer (Rangifer tarandus platyrhunchus), Marshallagi marshalli. The overall aim of the thesis was to test whether M marshalli is transmitted during the Arctic winter and to quantify the impact of over-winter parasitism on the fitness of Svalbard reindeer. To do this, parasite burdens needed to be manipulated during winter, at a time when reindeer cannot be caught. Therefore, a delayed-release intra-ruminal bolus system was developed, to enable administration of the bolus up to six months before reducing worm burdens. By removing parasite burdens at the start of winter and monitoring re-infection rates of larval and adult nematode stages, the over-winter transmission strategy of M marshalli was experimentally demonstrated. Further laboratory-based experiments provided support to the hypothesis of a one-year time delay in the production of eggs to the recruitment of parasites to the host population. They also demonstrated that eggs and larvae can withstand exposure to sub-zero temperatures. Contrary to expectation, a long-term, individual-based, capture-recapture experiment revealed no significant differences in body mass and pregnancy rates between animals treated with anthelmintics overwinter and non-treated animals, suggesting that nematode infection during winter does not significantly affect fitness of Svalbard reindeer. This thesis provides base-line data on a parasite-host interaction in the Arctic and may contribute to a better general understanding of the circumstances and environments in which parasites may negatively impact on host fitness.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:660110 |
| Date | January 2012 |
| Creators | Carlsson, Anja Morven |
| Publisher | Lancaster University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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