Dr Penelope Whitehorn

Biological and Environmental Sciences 3A141 University of Stirling Stirling FK9 4LA United Kingdom

Research

I’m an applied ecologist with field experience in a range of different environments, and interests in the dynamics and conservation of threatened mammal and insect populations. My research has focused on pollinating insects, particularly the impacts of isolation, inbreeding and parasitism on bumblebees in Scotland. I am now especially interested in the effects of insecticides on pollinators.

Current research project:

‘Determining the exposure to, and effects of, sublethal doses of neonicotinoid insecticides in bumblebees and other pollinators in arable, soft-fruit growing and urban areas’

Neonicotinoid insecticides are among the most widely used pesticides globally. Their systemic nature means that they occur in both the pollen and nectar of treated plants, where they can be consumed by bees and other beneficial pollinators. Evidence is mounting to suggest that such exposure to trace levels of neonicotinoids produce sublethal effects in the non-target invertebrates, which may have substantial impacts at the population level. This project is initially investigating the doses of neonicotinoids that bumblebee colonies are exposed to when naturally foraging in different landscape types.

Previous research projects:

‘The effect of the neonicotinoid imidacloprid on bumblebee colony growth and queen production’

This study found that bumblebee colonies exposed to field realistic doses of imidacloprid and left to forage under natural conditions had a reduced nest growth and an 85% drop in queen production. This suggests that the small doses that bumblebees receive when feeding upon the nectar and pollen of seed treated crops, such as oil seed rape, do indeed have significant impacts on wild bumblebee populations.

‘The impact of inbreeding and parasitism on bumblebees’

Several bumblebee species have suffered dramatic population declines in recent years, predominantly as a result of changes in farming practises. Populations of the rarer species have become isolated and are suffering from inbreeding and a loss of genetic diversity. My thesis demonstrated the costs of inbreeding in laboratory reared bumblebees living under natural conditions. The data illustrated that inbreeding exacts a considerable cost in bumblebees due to the production of diploid males. Genetically impoverished populations may be further stressed due to decreased immune competence and higher susceptibility to parasites. My thesis investigated this, using Hebridean island populations of Bombus muscorum, and found that prevalence of the gut parasite Crithidia bombi was higher in populations with lower genetic diversity. These results suggest that as insect populations lose heterozygosity, the impact of parasitism will increase, pushing threatened populations closer to extinction.

Other previous research experience includes biodiversity research and awareness in the Eastern Arc mountains in Tanzania, managing large game in South African reserves and investigating the effects of poaching on large mammal populations in Malawi. I have also worked on a study of sylvatic plague in prairie dogs and the associated conservation of the black footed ferret in the US.

© University of Stirling FK9 4LA Scotland UK • Telephone +44 1786 473171 • Scottish Charity No SC011159
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