4.12 Impact of pesticide residue on Japanese Orchard Bees (Osmia cornifrons) development and mortality

Ngoc Phan, Ed Rajotte, David Biddinger
LD 50 data sets (of which 11 were insecticides), discrete LD 50 values were determined for both honeybees and bumblebees. For all of those 18 data sets the ratio of honeybee contact LD 50 values divided by bumblebee contact LD 50 value was lower than one, demonstrating that honeybees were more sensitive to the test substances than bumblebees. Similarly, lower or similar oral sensitivity of bumblebees vs. honeybees was determined ( Figure 2 ). Where the endpoint was the maximum dose tested, a
more » ... m dose tested, a ratio of 1:1 was rare because the endpoint is adjusted according to actual dose consumption. For 12 (and 11 of those were insecticides) of the 52 acute oral LD 50 data sets, discrete acute oral LD 50 values were determined for both honeybees and bumblebees. Only for one insecticide a higher acute oral bumblebee sensitivity compared to honeybees was determined (for two different formulations). For this insecticide, higher tier semifield data with B. terrestris is available and results do not indicate any negative impact on bumblebees or their colony development at the maximum intended use rate. B. terrestris worker bees are about 3-times heavier in terms of body weight than A. mellifera worker bees. Therefore, lower or similar contact and oral sensitivity of the bumblebee species vs. the honeybee was also found in terms of body weight. Conclusions Overall, the ECPA company data evaluation indicates for a wide range of plant protection products that bumblebees are not more sensitive than honeybees based on acute toxicity assessment supporting similar previous findings 2, 3 . References Arena M, Sgolastra F (2013): A meta-analysis comparing the sensitivity of bees to pesticides. Ecotoxicology 23: 324-334. Thompson HM (2001): Assessing the exposure and toxicity of pesticides to bumblebees (Bombus sp.). Apidologie 32: 305-321. Thompson H (2015): Extrapolation of acute toxicity across bee species. Integrated Environmental Assessment and Management 12 (4): 622-626.
doi:10.5073/jka.2018.462.051 fatcat:dzyx4bkapbfilfzrtpsyyh72bq