DOI: 10.5061/dryad.jq2bvq88s
title: Effects of hive entrance orientation on honey bee colony activity

description: 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.
description: On 1 April 2019, 20 mature bee colonies (at least one year old)
 were identified in an apiary north of Tucson, Arizona, USA (Latitude:
 32.55°; Longitude: -111.35°). All hives were queen right with no visible
 signs of disease. Each hive contained a minimum of 1 kg honey bees in 1-2
 painted, 10-frame, wooden Langstroth boxes (43.7 l capacity) (Mann Lake
 Ltd., Hackensack, MN) with migratory wooden lids. Hives were placed on
 stainless steel electronic scales (Tekfa model B-2418 and Avery
 Weigh-Tronix model BSAO1824-200) (max. capacity: 100 kg, precision: ±20g)
 and linked to 16-bit dataloggers (Hobo UX120-006M External Channel
 datalogger, Onset Computer Corporation, Bourne, MA) with weight recorded
 every 5 minutes. A temperature sensor (iButton Thermochron, precision
 ±0.06°C) enclosed in plastic tissue embedding cassettes (Thermo Fisher
 Scientific, Waltham, MA) was stapled under the center of the top bar on
 the 5th frame in the bottom box of each hive and set to record every 30
 min. Hives were arranged in a square pattern around a central box that
 contained the batteries and electronic gear. Hives within such a group
 were 0.5- 1 m apart and groups were &gt;3 m apart.
 Prior to the start of the experiment, the frames of bees (FOB)
 was visually estimated (Delaplane et al. 2013). Hives were randomly
 assigned a treatment group, with hives in a given group having the
 entrance facing the same cardinal direction (east, north, south or west).
 Because the size of the honey bee colony may be expected to impact data on
 hive weight and temperature, and because a clumped distribution of bee
 colony sizes may occur even in randomly-assigned treatment groups
 (Hurlbert 1984) care was taken to avoid a clumped distribution by
 selecting a design with the least clumping. To adjust the hive entrance
 orientation to a new orientation, hives were slowly moved and rotated into
 position over a period of 2-10 d, depending on how much the hive had to be
 moved. Care was taken to avoid moving hives in a way that would confuse
 returning foragers. Hives were inspected on 21 June, 18 July, 14 August,
 12 September and 10 October, 2019, and on 27 February and 19 June, 2020.
 During each inspection, FOB was visually estimated, all frames containing
 sealed brood were photographed, and hive queen status was determined.
 Missing or supersedure queens were replaced. All queens except two were
 replaced at least once between April and December 2019. The area of sealed
 brood per frame was estimated from the photographs using ImageJ version
 1.47 software (W. Rasband, National Institutes of Health, USA) or
 CombCount (Colin et al. 2018). During the course of the experiment the
 number of hives in each treatment group changed as hives died and were
 replaced, but each group had at least three hives throughout the
 experiment.
description: Missing values are entered as -999.  Hive
 weights are in kg. Hive temperatures are in degrees
 Celsius. Brood surface area is in square
 centimeters.