Flowers for health: the importance of flower diversity and composition for maintaining the health and disease resistance of bumblebee pollinators

Lead Research Organisation: University of Sussex
Department Name: Sch of Life Sciences


Bumblebees are amongst the most ecologically and economically important groups of pollinators, but many species are suffering serious declines. Out of 25 bumblebee species in the UK, for example, 2 have gone extinct and 8 decreased substantially in abundance since 1940, while 13 species have gone extinct in at least one European country and four across the entire region. Reasons for the declines include habitat loss and nutritional stress, pesticide exposure, and both existing and emerging diseases. The importance of bumblebees for crop pollination and sustainable food production means that their declines are of economic as well as conservation significance. Britain's already vulnerable bumblebee populations currently face additional risks from emerging diseases, including pathogens which spillover from honeybees and from commercially produced bumblebee colonies which are imported for crop pollination. However, the roles of flower diversity and composition in maintaining the health and resistance to disease of bumblebees is unclear, and a strong understanding of this is crucial to inform the provision of flower resources in conservation and agricultural schemes. This project will investigate the effects of the diversity and composition of flower resources on the health and disease resistance of bumblebees, including rare bumblebee species. It will combine controlled laboratory experiments to precisely determine the impact of food resources on bees, field experiments in managed habitats that provide different levels of food resource, and the examination of parasite levels in wild bumblebees in different environments, to disentangle the role and ecological significance of flower diversity and composition for bumblebee health and disease resistance. The results will provide a substantial advance in our understanding of the importance of food resources and nutritional stress in the susceptibility of bumblebees to disease. The project will deliver the evidence for appropriate management of habits for bumblebee conservation, thereby supporting bee biodiversity and their ecosystem services for sustainable food production, and will provide a first-class training experience for the student that will encompass academic research, public engagement and practical conservation skills.


10 25 50
Description Bumblebees are ecologically and economically important pollinating insects that are suffering widespread decline due to multiple interacting factors, including pathogen pressure and lack of flowers. The health and survival of both adult and larval bees depends solely on the availability of floral resources. These resources (pollen and nectar) vary in nutritional value and availability. Bumblebees can regulate their nutritional intake by foraging selectively on flowers to achieve an optimum diet, which is important for their development, reproduction and disease resistance. Fundamental differences in life history traits suggest different bumblebee species have different nutritional needs. Despite this, previous research on diet has focused on only a small number of generalist species. This project investigated the relationship between diet and pathogen infections in bumblebees, with a particular focus on some of the more specialist species. The main findings were: 1) Techniques to rear two specialist, long-tongued bumblebee species were developed and laboratory experiments with them revealed that different species have different nutritional requirements. 2) In the wild, floral resource availability was found to differ widely in flower abundance and composition across the landscape, with gardens containing the greatest species richness of flowers and having the largest, healthiest bees, despite increased parasitism, while farmland consistently provided the least floral resources. However, habitats were complementary to each other in resource provision. 3) Interspecific differences were found in bee health across habitats, with floral resources having a substantial effect on bumblebee health and pathogen dynamics, but these effects appearing to vary between species.
Exploitation Route The results demonstrate the importance of nutrition for the resistance of bumblebees to pathogens and of studying a variety of different species in order to understand the full effects of nutritional stress on bumblebee health. This will inform the selection of plant species for the conservation of pollinators, in particular by evidencing the complementarity of a diversity of species and habitats for maintaining pollinator communities. This will have benefits both for the environment and for the ecosystem services that pollinators provide to agriculture.
Sectors Agriculture, Food and Drink,Environment

Description The results are initially informing management of conservation areas for pollinators by the project's partner organisation, the Bumblebee Conservation Trust. They will then be able to be used more widely for pollinator conservation following publication in academic journals.
First Year Of Impact 2020
Sector Agriculture, Food and Drink,Environment
Impact Types Societal

Description Bumblebee Conservation Trust 
Organisation Bumble Bee Conservation Trust
Country United Kingdom 
Sector Charity/Non Profit 
PI Contribution Provision of expertise and data to inform the partners strategies for the conservation of bumblebees and other pollinators in the UK, the provision of the floral resources that are required for the maintenance of UK bumblebee populations and the ecosystem services they provide.
Collaborator Contribution Provision of training and expertise to the research student in public engagement, pollinator ecology, floral identification and ecology, and conservation; training and assistance in engagement with end-users and land owners.
Impact Three publications, doi: 10.1016/bs.aiip.2020.09.003, 10.1007/s00040-020-00792-3, 10.1007/s13592-019-00707-7
Start Year 2015