Abstract
Supplemental feeding of wildlife populations can locally increase the density of individuals, which may in turn impact disease dynamics. Flower strips are a widely used intervention in intensive agricultural systems to nutritionally support pollinators such as bees. Using a controlled experimental semi-field design, we asked how density impacts transmission of a virus and a trypanosome parasite in bumblebees. We manipulated bumblebee density by using different numbers of colonies within the same area of floral resource. In high-density compartments, slow bee paralysis virus was transmitted more quickly, resulting in higher prevalence and level of infection in bumblebee hosts. By contrast, there was no impact of density on the transmission of the trypanosome Crithidia bombi, which may reflect the ease with which this parasite is transmitted. These results suggest that agri-environment schemes such as flower strips, which are known to enhance the nutrition and survival of bumblebees, may also have negative impacts on pollinators through enhanced disease transmission. Future studies should assess how changing the design of these schemes could minimize disease transmission and thus maximise their health benefits to wild pollinators.
Highlights
Understanding the spread of disease is of fundamental importance in wildlife ecology [1,2]
To test if there was an effect of bumblebee density on the time taken for a bumblebee colony to become infected with Crithidia, a Cox proportional hazard model was fitted, with the response variable ‘number of days until Crithidia detected within a colony’
Pathogen identity had a strong influence on disease transmission dynamics, with increased viral transmission being driven by higher density, in contrast with no impact of density on the transmission of a trypanosome parasite
Summary
Understanding the spread of disease is of fundamental importance in wildlife ecology [1,2]. One area where the understanding of mechanisms behind disease transmission is important is supplemental feeding of wildlife, which is a frequently used management intervention to help support declining populations [18]. Such feeding can alter host behaviour and physiology in ways that could influence disease transmission. One important case of supplemental feeding is the use of wildflower strips as a source of forage for flower visiting taxa in agricultural areas, which has been widely advocated as a strategy to mitigate habitat loss and improve pollinator populations [23,24,25] Such schemes are incorporated as funded strategies under agri-environment schemes in the European Union Our results have important implications for future management strategies to improve wild bee populations on agricultural land
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Proceedings of the Royal Society B: Biological Sciences
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
