Honey bees overwintering in a southern climate: longitudinal effects of nutrition and queen age on colony-level molecular physiology and performance

Vincent A Ricigliano,Amy S Floyd,Kirk E Anderson,Mark J Carroll,Duan C Copeland,Brendon M Mott

doi:10.1038/s41598-018-28732-z

Vincent A Ricigliano, Amy S Floyd + Show 4 more

Open Access

https://doi.org/10.1038/s41598-018-28732-z

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Abstract

Honey bee colony nutritional ecology relies on the acquisition and assimilation of floral resources across a landscape with changing forage conditions. Here, we examined the impact of nutrition and queen age on colony health across extended periods of reduced forage in a southern climate. We measured conventional hive metrics as well as colony-level gene expression of eight immune-related genes and three recently identified homologs of vitellogenin (vg), a storage glycolipoprotein central to colony nutritional state, immunity, oxidative stress resistance and life span regulation. Across three apiary sites, concurrent longitudinal changes in colony-level gene expression and nutritional state reflected the production of diutinus (winter) bees physiologically altered for long-term nutrient storage. Brood production by young queens was significantly greater than that of old queens, and was augmented by feeding colonies supplemental pollen. Expression analyses of recently identified vg homologs (vg-like-A, -B, and -C) revealed distinct patterns that correlated with colony performance, phenology, and immune-related gene transcript levels. Our findings provide new insights into dynamics underlying managed colony performance on a large scale. Colony-level, molecular physiological profiling is a promising approach to effectively identify factors influencing honey bee health in future landscape and nutrition studies.

Highlights

Honey bee (Apis mellifera) colony loss occurs primarily during the winter regardless of climate
Supplemental feeding with natural pollen led to a 16.3% increase in brood production compared to exclusively artificial feed, but this increase was not statistically significant (F1,105 = 1.608, P = 0.208, Supplementary Fig. S2)
We detected an interaction between diet and evaluation time point on brood production (F2,210 = 3.782, P = 0.024; Supplementary Fig. S2), suggesting that the efficacy of artificial feed formulations are impacted by season-dependent, nutritional landscape dynamics

Summary

Introduction

Honey bee (Apis mellifera) colony loss occurs primarily during the winter regardless of climate. The western honey bee is adapted to survive seasonal differences in temperature and forage dearth by storing simple sugars in the hive and more complex nutrient stores within the bodies of long-lived workers. This cohort of workers transforms physiologically into a nutrient storage caste referred to as “diutinus” bees[10]. Following extended forage dearth, the nutrients stored in diutinus bees are used to synthesize food for a new cohort of brood This colony-level nutritional economy is reliant on the production and conservation of internal storage molecules, predominantly vitellogenin, a nutritionally-regulated protein that is highly expressed during the fall www.nature.com/scientificreports/. Colonies with young queens have larger adult populations and increased productivity compared to colonies with older queens[50,55,56,57]

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