Effect of shipping boxes, attendant bees, and temperature on honey bee queen sperm quality (Apis mellifera)

The fertility and fecundity of the queen are vital to the success of a honey bee colony (Apis mellifera L.). Young mated queens are shipped worldwide to meet the demand of the beekeeping industry. Since little is known about the conditions experienced by queens in transit from breeders to beekeepers and the importance of these conditions on the queens' reproductive potential, we conducted a two-part study. First, queen shipments from the USA and Canada to Canadian beekeepers were monitored to measure thermal conditions during shipment. A total of 39 shipments were followed in 2017 and 2018. Monitoring revealed variable temperatures during shipment, with occasional periods of lows (10-15 degrees C) and highs (30-36 degrees C). Second, young mated queens were placed in different shipping boxes with or without attendant bees and exposed to one of three temperatures (6 degrees C, 26 degrees C, and 40 degrees C) for 2 h. We then compared the thermoregulation within shipping boxes, and the viability of sperm in each queen's spermatheca. Our results show that both low and high temperatures significantly decrease sperm viability, and that the addition of loose attendant bees within shipment boxes helps maintain the temperature at 26 degrees C when exposed to low temperature and delays the temperature increase when temperatures are high. The study shows the potential to improve current honey bee shipping methods in order to mitigate variable conditions experienced by bees during transportation.