The effects of heat exposure on drone competence

Ongoing and expected global temperature increases threaten many organisms, including pollinators critically important for human food production. The honey bee (Apis mellifera) exhibits numerous negative outcomes of temperature-related stress. Drone brood may be particularly vulnerable since they require a narrow range of rearing temperatures for optimal development and are exposed to greater fluctuations in temperature. Since drones undergo key physiological processes during development, heat stress may negatively affect resulting adult outcomes. To assess the consequences of heat stress on drone performance, drones were maintained at supra-optimal temperatures during development. Reproductive competence, cognition, flight performance, and navigation were evaluated between different rearing temperatures. Heat exposure during development is expected to reduce sperm viability, learning and memory capabilities, maximal flight performance, and impair navigational capacities. These outcomes will elucidate sub-lethal effects resulting from climatic warming on honey bee drones.