Open AccessArticle
Overwintering Honey Bee Colonies: Effect of Worker Age and Climate on the Hindgut Microbiota
by
1, 2, 2 and 1,2,*
1
Graduate Interdisciplinary Program in Entomology and Insect Science, University of Arizona, P.O. Box 210036, Tucson, AZ 85721, USA
2
USDA-ARS Carl Hayden Bee Research Center, 2000 East Allen Road, Tucson, AZ 85719, USA
*
Author to whom correspondence should be addressed.
Academic Editor: Silvio Erler
Received: 11 February 2021
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Revised: 1 March 2021
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Accepted: 2 March 2021
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Published: 5 March 2021
Simple Summary
The honey bee is managed worldwide for use in pollinating crops and producing honey. Healthy overwintered colonies are paramount to meeting spring agricultural pollination demands, but beekeepers typically report high rates of winter colony loss. Although many factors affect winter survival, the gut microbiome, demonstrated to facilitate healthy metabolism and physiology, is understudied in this context. Here, we investigate how overwintering climate (warm versus cold) alters the honey bee gut microbiome. In both climates, the gut bacteria were generally stable during overwinter. However, microbiota changes in the warm climate suggest compromised host physiology. The abundance of fungus increased two-fold in the warm climate and was strongly associated with potentially harmful bacteria. The life expectancy of worker bees in warm climates was low compared to that known for cold climates. Our results indicate that colony loss in warm climates is associated with shortened life expectancy of overwintering workers, and alterations in the gut microbiome. We suggest that overwintering in warm climates can worsen preexisting conditions of disease, parasites, and poor nutrition, increasing winter colony loss. Ultimately, our results provide new insights into overwintering honey bee management strategies.