Honey bee colony performance and health are enhanced by apiary proximity to US Conservation Reserve Program (CRP) lands

Vincent A Ricigliano,Brendon M Mott,Amy S Floyd,William Fitz,Kirk E Anderson,William G Meikle,Duan C Copeland,Patrick W Maes

doi:10.1038/s41598-019-41281-3

Abstract

Honey bee colony performance and health are intimately linked to the foraging environment. Recent evidence suggests that the US Conservation Reserve Program (CRP) has a positive impact on environmental suitability for supporting honey bee apiaries. However, relatively little is known about the influence of habitat conservation efforts on honey bee colony health. Identifying specific factors that influence bee health at the colony level incorporates longitudinal monitoring of physiology across diverse environments. Using a pooled-sampling method to overcome individual variation, we monitored colony-level molecular biomarkers during critical pre- and post-winter time points. Major categories of colony health (nutrition, oxidative stress resistance, and immunity) were impacted by apiary site. In general, apiaries within foraging distance of CRP lands showed improved performance and higher gene expression of vitellogenin (vg), a nutritionally regulated protein with central storage and regulatory functions. Mirroring vg levels, gene transcripts encoding antioxidant enzymes and immune-related proteins were typically higher in colonies exposed to CRP environments. Our study highlights the potential of CRP lands to improve pollinator health and the utility of colony-level molecular diagnostics to assess environmental suitability for honey bees.

Highlights

Insect pollinators are crucial for the maintenance of biodiversity[1,2] and agricultural crop production which represents an estimated economic value of ~$15 billion annually in the United States alone[3]
We evaluated the link between foraging environment, colony performance, and gene expression diagnostics of 50 pooled bees sampled from the center of the brood nest
Within the context of this study, we showed that performance and biomarkers associated with adequate nutrition were positively influenced by foraging proximity to Conservation Reserve Program (CRP) land

Summary

Introduction

Insect pollinators are crucial for the maintenance of biodiversity[1,2] and agricultural crop production which represents an estimated economic value of ~$15 billion annually in the United States alone[3]. We evaluated the link between foraging environment, colony performance, and gene expression diagnostics of 50 pooled bees sampled from the center of the brood nest This sampling approach relies on the strong association between spatial distribution of worker tasks within the colony and associated nutritional physiology[40,41,42]. The western honey bee is adapted to survive seasonal changes in forage quality and availability by storing simple sugars in the hive and complex nutrient stores within the bodies of long-lived workers These workers become a nutrient storage caste referred to as diutinus bees which synthesize protein-rich food for a new cohort of brood following extended forage dearth[47]. To further explore the utility of colony-level molecular biomarkers, we measured the transcript expression of vg-like gene homologs implicated in life-span regulation and response to oxidative stress[50]

Methods

Results

Discussion

Conclusion