At the end of each week of exposure (days 1,7, 14, 21, and 28), both colonies were removed from the anechoic chambers and placed outside the laboratory in front of their respective entrance runways (to receive returning foragers) for 4-h periods to permit comb examinations. Single frames of comb were removed alternately between microwave and sham colonies at ~ 20 min intervals, brushed free of bees, then taken to an incubator room (34 °C and 50% RH) where the contents of all cells were mapped on a clear acetate sheet affixed over the comb. Contents were discriminated by different color dots placed on the sheet with a felt tip marking pen (Sharpie) to denote eggs, larvae, capped brood, honey and nectar, pollen, or empty cells. Frames of comb were returned immediately to their respective colonies after examination, and microwave exposure was resumed immediately after the comb examinations were completed. On days 1, 14, 21, and 28 of the study each colony (including the plywood base) was weighed on a platform balance. On the final day of the experiment, adult populations in each colony were estimated by removing all bees and placing them into a preweighed container to obtain the total weight. Then 5 subsamples of 40 bees were weighed to generate a mean weight that was used to extrapolate the total population.
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