Metabolic effects of anesthetics (cold, CO2, and isoflurane) and captivity conditions in isolated honey bee (Apis mellifera) foragers under different ambient temperatures

Abstract

Acclimation and anesthesia are necessary steps when manipulating live honey bees, Apis mellifera, in laboratory. Although cold and carbon dioxide exposure are commonly used to temporarily immobilize honey bees, they are known to influence the bees’ physiology and behavior in various ways. We investigated the effect of captivity conditions and anesthesia methods on the non-flight metabolic rate in honey bee foragers under different ambient temperatures (25, 30, or 35 °C) by using flow-through respirometry. Honey bees experienced a significant drop in metabolic rate as they acclimate to captivity at normal laboratory temperature (25 °C), but did not show much change at higher temperatures. We found that cold and carbon dioxide exposure greatly affected honey bees’ metabolic rates during and after recovery from the anesthesia regardless of the ambient temperatures. Compared to these traditional anesthesia methods, isoflurane at the dose tested is an alternative anesthetic with a) less effect on honey bees’ metabolic rate, b) an adjustable recovery time that depends on ambient temperature, and c) visible sign of life displayed by anesthetized honey bees.