Power was turned on at 1000 h and remained on continuously for 28 days, except for 4-h periods on days 7, 14, and 21 when the hives had to be removed from the chambers for weighing and recording of cell contents. Daily flight and foraging activity were determined by recording the number of foraging bees returning to each hive, and the number of foraging bees that were carrying pollen (with the exceptions of days 7, 14, and 21). These observations were conducted during a one-hour period between 1100 and 1200 h by an observer who counted incoming bees during alternating 4 min periods in each runway, separated by a 1 min rest period, making a total of six observation periods per hive during the 1 h interval. Internal colony brood nests and ambient temperatures in the microwave anechoic chamber were measured continuously (except for days 13-16 when the monitoring unit malfunctioned, and during the 4-h examinations of days 7, 14, and 21) with a gallium-arsenide fiberoptic temperature monitoring unit (5) and recorded on an Omniscribe chart recorder (model B5237-5). Colony brood nest and ambient temperatures in the sham chamber were monitored continuously with copper-constantan thermocouples (Omega models SCPSS-020E-6 and SCPSS-062E-6, respectively) connected to electronic ice point references (Omega model MCJ-T), and recorded with an Omniscribe chart recorder (except on days 9—10 and 21-23 because of equipment malfunction). Humidity was monitored continuously with a recording hygrothermograph (Bendix model 594) located inside the sham chamber. Ambient temperature and humidity inside the laboratory which housed the chambers was also monitored with a hygrothermograph.
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