The effects of heat exposure on honey bee (Apis mellifera) microbial community and physiology

The honey bee (Apis mellifera) is essential for agricultural production and human food security. Despite their importance, honey bees face ongoing peril due to several environmental factors. Colder temperatures and reduced forage availability contribute to high colony mortality rates over winter. However, comparable mortality rates occur during summer indicating that higher temperatures negatively affect colony maintenance and worker physiology. To assess the effects of heat exposure on honey bee physiology and behavior, sets of newly emerged workers were maintained at different temperatures. Gut microbial composition was compared between differing rearing temperature treatments. Worker pollen consumption rates and vitellogenin concentration were also evaluated in response to rearing temperature. Heat exposure is expected to negatively affect honey bee workers suggesting the underlying factors by which colony mortality is induced during summer.