Low-Temperature Stress during Capped Brood Stage Increases Pupal Mortality, Misorientation and Adult Mortality in Honey Bees.

Qing Wang,Lin Chen,Bingfeng Zhou,Zachary Y. Huang,Xinjian Xu,Shujing Zhou,Xiangjie Zhu,Olav Rueppell

doi:10.1371/journal.pone.0154547

Abstract

Honey bees (Apis mellifera) are key pollinators, playing a vital role in ecosystem maintenance and stability of crop yields. Recently, reduced honey bee survival has attracted intensive attention. Among all other honey bee stresses, temperature is a fundamental ecological factor that has been shown to affect honey bee survival. Yet, the impact of low temperature stress during capped brood on brood mortality has not been systematically investigated. In addition, little was known about how low temperature exposure during capped brood affects subsequent adult longevity. In this study, capped worker broods at 12 different developmental stages were exposed to 20°C for 12, 24, 36, 48, 60, 72, 84 and 96 hours, followed by incubation at 35°C until emergence. We found that longer durations of low temperature during capped brood led to higher mortality, higher incidences of misorientation inside cells and shorter worker longevity. Capped brood as prepupae and near emergence were more sensitive to low-temperature exposure, while capped larvae and mid-pupal stages showed the highest resistance to low-temperature stress. Our results suggest that prepupae and pupae prior to eclosion are the most sensitive stages to low temperature stress, as they are to other stresses, presumably due to many physiological changes related to metamorphosis happening during these two stages. Understanding how low-temperature stress affects honey bee physiology and longevity can improve honey bee management strategies.

Highlights

Honey bee (Apis mellifera) is one of the most important pollinators because of its major role in pollination [1], ecosystem stability and biodiversity [2,3,4]
Low Temperature Effects on Honey Bees affected by many stressors
Temperature is the main ecological factor affecting the development of honey bee brood [13]

Summary

Introduction

Honey bee (Apis mellifera) is one of the most important pollinators because of its major role in pollination [1], ecosystem stability and biodiversity [2,3,4]. Low Temperature Effects on Honey Bees affected by many stressors. These include extreme temperatures [5, 6], poor nutrition [7, 8], pesticides [9, 10], parasites and pathogens [11, 12]. Temperature is the main ecological factor affecting the development of honey bee brood [13]. Honey bees have been known to regulate their nest temperatures with high precision [14, 15]. To ensure normal brood development, colonies spend much energy to maintain brood nest temperature in the range of 32–36°C [13, 16]

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Conclusion