6.2.2. Recommendations for incubator temperature for maintaining adult workers in the laboratory
Frames of brood should be maintained at 34.5°C for optimal brood development (Heran, 1952; Crailsheim et al., 2012); whereas, we recommend keeping adults at 30°C, based on optimal respiration at 32 °C (Allen, 1959) and honey bee thermal preference of 28°C (Schmolz et al., 2002). Generally these recommendations are also appropriate when performing experiments; however, further adjustments to temperature may be required. For example, a recent study investigating acute oral toxicity of chemicals to honey bees under laboratory conditions suggested that these evaluations should be performed at both 25 and 35°C to account for the wide range of temperatures to which honey bees are exposed (Medrzycki and Tosi, 2012). When obtaining newly-emerged honey bees from a brood frame maintained at 34.5°C in an incubator, young honey bees (i.e. individuals 0 to 24 hours old) should be transferred from a caged frame containing brood to one or more cages that are maintained at 30°C. More details on obtaining newly emerged honey bees from brood comb are provided in section 4.2.