EN65CH11_Cameron ARjats.cls December 6, 2019 23:29 Annual Review of Entomology Global Trends in Bumble Bee Health Sydney A. Cameron1,∗ and Ben M. Sadd2 1Department of Entomology, University of Illinois, Urbana, Illinois 61801, USA; email:
[email protected] 2School of Biological Sciences, Illinois State University, Normal, Illinois 61790, USA; email:
[email protected] Annu. Rev. Entomol. 2020. 65:209–32 Keywords First published as a Review in Advance on Bombus, pollinator, status, decline, conservation, neonicotinoids, pathogens October 14, 2019 The Annual Review of Entomology is online at Abstract ento.annualreviews.org Bumble bees (Bombus) are unusually important pollinators, with approx- https://doi.org/10.1146/annurev-ento-011118- imately 260 wild species native to all biogeographic regions except sub- 111847 Annu. Rev. Entomol. 2020.65. Downloaded from www.annualreviews.org Saharan Africa, Australia, and New Zealand. As they are vitally important in Copyright © 2020 by Annual Reviews. Access provided by Illinois State University on 01/03/20. For personal use only. natural ecosystems and to agricultural food production globally, the increase All rights reserved in reports of declining distribution and abundance over the past decade ∗ Corresponding author has led to an explosion of interest in bumble bee population decline. We summarize data on the threat status of wild bumble bee species across bio- geographic regions, underscoring regions lacking assessment data. Focusing on data-rich studies, we also synthesize recent research on potential causes of population declines. There is evidence that habitat loss, changing climate, pathogen transmission, invasion of nonnative species, and pesticides, oper- ating individually and in combination, negatively impact bumble bee health, and that effects may depend on species and locality.