The effects of heat stress on honey bee (Apis mellifera) physiology and health

The honey bee (Apis mellifera) is essential for agricultural production and agricultural sustainability. Despite their importance, honey bees face decline populations due to several environmental factors. Ongoing climate change induced temperature increases are potentially a ubiquitous stressor threatening honey bee survival. Increasing colony mortality rates during summer indicate that higher temperatures negatively affect colony maintenance and worker physiology. To assess the effects of developmental and post-eclosion heat stress on honey bee physiology and behavior, sets of worker brood and newly emerged workers were maintained at an optimal rearing temperature or a temperature regime simulating a heat wave. Heat stress negatively impacted worker pollen consumption rates and hypopharyngeal gland size. Gut microbiota were also altered in response to elevated rearing temperatures. These findings suggest that climatic warming constitutes a major underlying factor by which colony mortality is induced during summer.