Bumblebee ecophysiology: assessing the impacts of climate change and pesticide use on Bombus terrestris audax and B. t. dalmatinus

Owen, Emily Louise (2015). Bumblebee ecophysiology: assessing the impacts of climate change and pesticide use on Bombus terrestris audax and B. t. dalmatinus. University of Birmingham. Ph.D.

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Abstract

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.

Type of Work:	Thesis (Doctorates > Ph.D.)
Award Type:	Doctorates > Ph.D.
Supervisor(s):	Supervisor(s) Email ORCID Hayward, Scott UNSPECIFIED UNSPECIFIED Bale, Jeffrey S UNSPECIFIED UNSPECIFIED
Licence:
College/Faculty:	Colleges (2008 onwards) > College of Life & Environmental Sciences
School or Department:	School of Biosciences
Funders:	Biotechnology and Biological Sciences Research Council
Subjects:	G Geography. Anthropology. Recreation > GE Environmental Sciences Q Science > QH Natural history > QH301 Biology Q Science > QL Zoology
URI:	http://etheses.bham.ac.uk/id/eprint/5802

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