Risk assessment for chemicals in the United States relies upon the honey bee (Apis meliffera L. [Hymenoptera: Apidae]) as a surrogate for other bee species. There is uncertainty in extrapolating honey bee toxicity data to bumble bees due to differences in life history strategies, food consumption, and nest structure. Here we evaluated the design of a queenless bumble bee microcolony test that could be considered for generating larval toxicity data. Three microcolony studies were conducted with Bombus impatiens to evaluate the effects of exposure to 1) diflubenzuron in pollen, 2) dimethoate in pollen, and 3) dimethoate in sucrose. Immature drone bee emergence, worker survival, pollen, and sucrose utilization were measured throughout the study duration. For dimethoate, a 10-d chronic adult bumble bee study was also conducted to compare microcolony endpoints to toxicity endpoints on individual adults. Microcolonies exposed to 10 mg diflubenzuron/kg pollen produced fewer adult drones despite no effects on worker survival. Microcolonies treated with dimethoate at ≥3 mg a.i./kg pollen and ≥0.1 mg a.i./kg sucrose solution produced fewer drones. Exposure to dimethoate in the 10-d chronic adult study resulted in direct mortality to the adult workers at ≥0.1 mg a.i./kg diet. Results from the 10-d study suggest direct effects of dimethoate on workers in the microcolony will alter provisioning of diet to the brood, resulting in lower drone production in the microcolony. Our data suggest that the microcolony study is only appropriate to assess brood effects to bumble bees for substances with low toxicity to adults, as demonstrated with diflubenzuron.

中文翻译：

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大黄蜂（Bombus spp. [Hymenoptera: Apidae]）育雏试验用于评估农药效果的效用

美国对化学品的风险评估依赖于蜜蜂（Apis meliffera L. [Hymenoptera: Apidae]）作为其他蜜蜂物种的替代物。由于生活史策略、食物消耗和巢结构的差异，将蜜蜂毒性数据外推到大黄蜂存在不确定性。在这里，我们评估了可考虑用于生成幼虫毒性数据的无蜂王大黄蜂微菌落试验的设计。用凤仙花进行了三项微菌落研究，以评估暴露于 1) 花粉中的除虫脲、2) 花粉中的乐果和 3) 蔗糖中的乐果的影响。在整个研究期间测量未成熟的雄蜂出现、工人存活、花粉和蔗糖利用。对于乐果，还进行了一项为期 10 天的慢性成年大黄蜂研究，以比较个体成年人的微菌落终点与毒性终点。尽管对工人生存没有影响，但暴露于 10 mg diflubenzuron/kg 花粉的微菌落产生的成年无人机较少。用≥3 mg ai/kg 花粉和 ≥0.1 mg ai/kg 蔗糖溶液处理的小菌落产生较少的雄蜂。在 10 天慢性成人研究中暴露于乐果导致成年工人在≥0.1 mg ai/kg 饮食中直接死亡。为期 10 天的研究结果表明，乐果对小群落中的工人的直接影响将改变对育雏的饮食供应，从而导致小群落中的无人机产量降低。我们的数据表明，微群落研究仅适用于评估对大黄蜂的育雏效应对成人低毒性的物质，