A honey bee (Apis mellifera) colony’s brood survival rate predicts its in vitro-reared brood survival rate

Abstract

Rearing honey bee, Apis mellifera L., larvae in vitro is a popular risk assessment tool because many uncontrollable factors (e.g., weather conditions, food availability) that bias field studies can be eliminated in the laboratory. However, modern in vitro rearing techniques suffer variable survival rates and OECD guidelines specify a minimum of 70% survival to adult emergence in the untreated negative controls for the test to be considered valid. We hypothesized that the colony from which larvae are sourced for in vitro-rearing risk assessments may affect the survival percentage of those larvae in vitro. To test this hypothesis, we compared the survival rates of brood reared in vitro to that of brood reared by their parental colony to determine if source colony affects brood survival in vitro. Colony-reared and in vitro-reared brood survival percentages were calculated for each of the 14 colonies. There was not a statistically detectable difference in the survival percentage to adult emergence of colony-reared and in vitro-reared bees. Furthermore, the colony-reared brood survival percentage at day 11 (prepupal stage) was predictive of the survival percentage to adult emergence of in vitro-reared bees. We suggest that the 11-day brood survival percentage should be used when selecting suitable colonies for use as source colonies for in vitro-rearing risk assessments. Based on our results, colonies with brood survival percentages of ≥ 80% are suitable colonies from which to source larvae for in vitro-rearing risk assessments.