Climate change is altering the phenology of bumblebees in parts of the UK, with worker activity recorded during winter. This presents a unique set of physiological challenges to bumblebees, as they are typically exposed to exclusively summer conditions. The aim of this thesis was to assess the capacity for winter activity and survival in the UK-native bumblebee Bombus terrestris audax (Harris, 1780) (Hymenoptera: Apidae) and the commercially imported B. t. dalmatinus Dalla Torre, 1882 (Hymenoptera: Apidae). Cold tolerance assessments indicated that both subspecies were physiologically ill-adapted to winter temperatures. However, both species were found to undergo Rapid Cold Hardening (RCH); the first evidence of RCH in Hymenoptera. Thermal activity thresholds (CTmin, chill coma and chill coma recovery) were significantly lower in B. t. audax than B. t. dalmatinus. However, only B. t. dalmatinus was able to lower these thresholds as a result of acclimation. This highlights the potential for competition between the subspecies. Field experiments showed a lack of winter-active bumblebees in Birmingham, and an inability of commercial colonies to survive winter. Finally, this thesis presents the first evidence to suggest that sublethal neonicotinoid exposures impair bumblebee activity at low temperatures. Results are discussed in the light of climate change, pesticide use and the bumblebee pollinators in future climate scenarios.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:646174 |
| Date | January 2015 |
| Creators | Owen, Emily Louise |
| Publisher | University of Birmingham |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://etheses.bham.ac.uk//id/eprint/5802/ |
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