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 had the lowest daily hive weight loss, 62 g per d compared to 100 g per d for north-facing hives. East-facing hives were also about 7 degrees C cooler on average than west-facing hives, suggesting that lower hive weight loss was due to lower food consumption which was directly related to lower colony cluster temperatures. 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 to 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 the sealed brood. We recommend hive orientation be taken into account in the design of field experiments that involve monitoring colony activity.