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Development and validation of a bumble bee adult chronic oral test
Citation:
Exeler, N., N. Hanewald, A. Zicot, E. Soler, A. Kling, S. Vinall, K. Dressler, V. Tanzler, S. Kimmel, D. Lehmann, M. Patnaude, AND A. Cabrera. Development and validation of a bumble bee adult chronic oral test. 2019 International Conference on Pollinator Biology, Health and Policy, Davis, CA, July 17 - 20, 2019.
Impact/Purpose:
This presentation describes an effort to develop and validate a standardized chronic toxicity test for adult bumble bees.
Description:
The regulation of pesticide uses is based on the local Risk Assessment frameworks, including a specific framework for pollinators. These frameworks rely on data from honey bee toxicity in a three-tiered process, from laboratory to semi-field to field settings, and exposure estimates based on application rates or refined via residue levels in nectar and pollen. In recent years, concerns about the risk to other bees such as bumble bees have been the driver for the development of new methods to address toxicity and exposure with selected surrogate species. Here, we present the results from the second international ring test for a bumble bee adult chronic oral test. Nine European laboratories conducted the 10 d test with Bombus terrestris workers while 3 US laboratories conducted the test with B. impatiens. Along with biological observations and consumption measurements, the stock solutions and feeding diets were confirmed for the concentration of dimethoate. There were 5 and 7 dimethoate test levels for the European and US ring test, respectively. The LC50 endpoints derived from this test were on average 0.468 and 0.258 mg a.s./kg of diet for B. terrestris and B. impatiens, respectively. Similarly, the LDD50 endpoints derived from the test were on average were 0.093 and 0.032 µg a.s./bee/d for B. terrestris and B. impatiens, respectively. Our results indicate the test design is robust and replicable, and after a two-year effort, a validation report is in preparation to initiate the process to develop it into an OECD Guideline document. Disclaimer: This presentation does not represent U.S. EPA policy.