Honeybee (Apis mellifera) Larval Toxicity Test, Repeated Exposure (OECD GD 239)
The Honeybee Larval Toxicity Test, Repeated Exposure according to OECD Guidance Document 239 is a chronic laboratory assay designed to evaluate the effects of chemicals on honeybee larvae (Apis mellifera) when exposed repeatedly over their development. This test provides critical information on potential sublethal and cumulative impacts on larval survival and colony health.
In this study, newly hatched larvae are continuously fed a diet containing the test substance at defined concentrations under controlled laboratory conditions. The exposure is maintained throughout the larval development period until pupation or emergence as adult bees.
Key endpoints include larval survival, developmental progression, pupation success, and adult emergence. Observations may also include morphological abnormalities or delayed development. The results are used to establish concentration–response relationships and to determine endpoints such as the No Observed Effect Concentration (NOEC) and the Lowest Observed Effect Concentration (LOEC).
This test is essential for comprehensive environmental risk assessment of chemicals, particularly plant protection products, by providing insights into potential chronic effects on honeybee larvae and subsequent colony viability.
