Effects of hive entrance orientation on honey bee colony activity

In an effort to determine the effects of the orientation of hive entrance on honey bee colony activity and temperature, hives were placed facing different cardinal directions (3-5 hives per direction). Hive weight was recorded every 5 minutes and temperature every 30 minutes from April 2019 to June 2020. Daily weight data were analyzed using piecewise regression. In southern Arizona from December to March, hives facing east started daily flight activity 50 minutes earlier than hives facing west, and ended flight activity 57 minutes earlier than hives facing south. During that period east-facing hives also lost only 62 g per d while north-facing hives lost about 100 g per d. East-facing hives were also about 7°C cooler on average than west-facing hives, although that may have been due to the movement of bee clusters within the hive. From December to March hives facing east also had significantly lower morning weight loss due to departing foragers than hives facing north (indicating more foragers) but higher weight loss from April-June 2020. Most effects were observed from December to March, probably due to restricted daylight hours and lower ambient temperatures. No significant effects were observed with respect to visually-estimated adult bee numbers (frames of bees) or the surface areas of sealed brood. We recommend hive orientation be taken into account in the design of field experiments that involve monitoring colony activity.