2012年夏天,我们在安大略省南部发起了一项大规模的野外实验,加拿大,以确定暴露于clothianidin种子处理的油菜(油菜籽油菜)是否对蜜蜂有任何不利影响。在开花期间,将菌落放置在clothianidin种子处理或对照油菜田中,然后将其移至养蜂场,周围没有用新烟碱类处理过的种子生长的作物。殖民地体重增加,蜂蜜生产,害虫发病率,蜜蜂死亡率,成人人数,在整个夏季和秋季,对每个菌落的密封育苗量进行了评估。蜂蜜样品,蜂蜡,花粉,定期收集花蜜,并分析样品中的噻虫胺残留物。这些终点中的几个也在2013年春季进行了测量。总的来说,在暴露期间和之后,菌落很旺盛,我们发现,暴露于clothianidin种子处理的油菜对任何终点测量都没有影响。在高峰开花期间,蜜蜂在测试田上大量觅食,残留物分析表明,蜜蜂暴露于花粉中低水平(0.5-2ppb)的噻虫胺。在开花结束时从对照蜂巢收集的一些花粉样品中检测到低水平的clothianidin,说明了在农业景观中对自由放养的蜜蜂进行完全受控的野外研究的困难。处理和对照蜂巢的越冬成功率没有显着差异,与2012-2013年冬季安大略省和加拿大养蜂人的越冬菌落损失率相似。我们的结果表明,暴露于用噻虫胺处理过的种子生长的油菜对蜜蜂的风险较低。
In summer 2012, we initiated a large-scale field experiment in southern Ontario, Canada, to determine whether exposure to clothianidin seed-treated canola (oil seed rape) has any adverse impacts on honey bees. Colonies were placed in clothianidin seed-treated or control canola fields during bloom, and thereafter were moved to an apiary with no surrounding crops grown from seeds treated with neonicotinoids. Colony weight gain, honey production, pest incidence, bee mortality, number of adults, and amount of sealed brood were assessed in each colony throughout summer and autumn. Samples of honey, beeswax, pollen, and nectar were regularly collected, and samples were analyzed for clothianidin residues. Several of these endpoints were also measured in spring 2013. Overall, colonies were vigorous during and after the exposure period, and we found no effects of exposure to clothianidin seed-treated canola on any endpoint measures. Bees foraged heavily on the test fields during peak bloom and residue analysis indicated that honey bees were exposed to low levels (0.5-2 ppb) of clothianidin in pollen. Low levels of clothianidin were detected in a few pollen samples collected toward the end of the bloom from control hives, illustrating the difficulty of conducting a perfectly controlled field
study with free-ranging honey bees in agricultural landscapes. Overwintering success did not differ significantly between treatment and control hives, and was similar to overwintering colony loss rates reported for the winter of 2012-2013 for beekeepers in Ontario and Canada. Our results suggest that exposure to canola grown from seed treated with clothianidin poses low risk to honey bees.