A systems approach to understanding the impacts of sublethal doses of neonicotinoids on bumblebee and honeybees

新烟碱类杀虫剂现在是世界上使用最广泛的杀虫剂之一，通常用于保护一系列开花作物，如油菜和向日葵，防止食草动物。在英国，2010年有127万公顷的农作物被新烟碱处理，其中最常用的类型是氯硫菌素、吡虫啉和甲氧西林。大多数被用作种子调味剂，作物在生长过程中吸收这种化合物，从而保护自己免受食草性害虫的侵害。新烟碱也被用作软果类作物的叶面喷雾，并作为花卉、水果和蔬菜作物的园艺用喷雾剂或颗粒剂广泛销售。由于它们是系统化学物质，在处理过的作物的花蜜和花粉中发现了低浓度的新烟碱，因此它们被传粉者消耗。它们也是水溶性和持久性的，因此可以在经过处理的作物附近的树篱/田野边缘野花中发现可检测到的数量。越来越多的证据表明，蜜蜂暴露在新烟碱类化合物中会产生亚致命影响，比如导航能力降低，这在实验室测试中或在田间试验中不会被检测到，在田间试验中，蜂箱被直接放置在经过处理的开花作物旁边。只有当蜜蜂在远处觅食时，它们才会显现出来，就像自然界中发生的那样。PIREAD PI最近的一项研究表明，将熊蜂巢暴露在吡虫啉水平下，这种水平的吡虫啉存在于种子处理的油菜的花蜜和花粉中，导致新蜂王的产量减少85%(Whitehorn等人)。2012年)。无论是野生大黄蜂的蜂巢还是经过管理的蜂群，都有相当大一部分可能在经过处理的开花作物的觅食范围内，因此这类杀虫剂似乎可能是引起人们广泛讨论的野生蜜蜂数量下降的主要原因。迫切需要了解新烟碱对大黄蜂在田间条件下的行为和群体水平表现的亚致命性影响。该项目将量化在英国耕地的农作物和野花中发现的新烟碱的含量，并将其输入花卉资源分布的景观地图(从2013年开始的一个平行项目BB/J014753/1中制作)。我们将量化蜜蜂和熊蜂群体在农田中自然觅食时接触到的新烟碱的剂量，然后继续评估这种暴露对熊蜂群体表现的可能影响。将通过实证研究和建模方法来审查风险暴露和影响。奥斯本博士和贝希尔博士开发了一个蜜蜂群体的综合模型，该模型预测了蜜蜂在真实或模拟的环境中的觅食行为和群体表现。在BB/J014753/1项目中，我们将为大黄蜂群体开发该模型的一个版本。这些模型将使我们能够预测蜜蜂和大黄蜂的工作人员将在哪里觅食，从而预测它们的暴露情况，并将其与放置在地面上的真实巢穴接收到的信息进行比较。然后，我们将利用Rothamsted独特的谐波雷达设备，研究暴露在现实磁场水平下的新烟碱是否会改变或损害觅食行为。这些数据将被用来为蜜蜂和大黄蜂开发一个子模型，其中包括新烟碱对蜂群成功预测的影响，该模型将在野外实验中用真实的大黄蜂群体进行测试，并可作为用户的风险评估工具。最后，数据和模型结果将使我们能够制定管理建议，将新烟碱类化合物对受管理的蜜蜂和野生熊蜂种群的影响降至最低。

Neonicotinoid insecticides are now among the most widely used pesticides in the world, and are routinely used to protect a range of flowering crops such as oilseed rape and sunflowers against herbivores. In the UK, 1.27 million ha of crops were treated with neonicotinoids in 2010, with clothianidin, imidacloprid and thiamethoxam being the most frequently used types. Most are used as a seed-dressing, with the crop plant absorbing the compound as it grows, and hence becoming protected against herbivorous pests. Neonicotinoids are also used as foliar sprays on soft fruit crops, and are widely sold as sprays or granules for garden use on flowers, fruit and vegetable crops. As they are systemic chemicals, low concentrations of neonicotinoids are found in nectar and pollen of treated crops, and hence they are consumed by pollinators. They are also water soluble and persistent, so that detectable quantities are found in hedgerow / field margin wildflowers near treated crops. Evidence is mounting that exposure of bees to neonicotinoids produces sublethal effects such as reduced navigational ability that would not be detected in laboratory assays, or in field trials where hives are placed immediately adjacent to a treated flowering crop. They are only apparent when bees are foraging at distance across the landscape, as occurs in nature. A recent study by the lead PI demonstrated that exposure of bumblebee nests to levels of imidacloprid which are known to occur in the nectar and pollen of seed-treated oilseed rape resulted in an 85% reduction in output of new queens (Whitehorn et al. 2012). A substantial proportion of both wild bumblebee nests and managed honeybee colonies are likely to be within foraging range of a treated, flowering crop, so it seems likely that this class of insecticide may be contributing substantially to the much-discussed declines in wild bee populations. There is an urgent need to understand the sublethal impacts of neonicotinoids on behaviour and colony-level performance of bumblebees under field conditions. This project will quantify the levels of neonicotinoids found in crops and wildflowers in UK arable farmland, and feed these into landscape maps of the distribution of floral resources (produced in a parallel project, BB/J014753/1, starting 2013). We will quantify the doses of neonicotinoids that honeybee and bumblebee colonies are exposed to when naturally foraging in farmland, before going on to assess the likely impacts of this exposure on bumblebee colony performance. Exposure and impacts will be examined by both empirical studies and modelling approaches. Drs Osborne and Becher have developed an integrative model of a honeybee colony, which predicts forager behaviour and colony performance when placed into a real or simulated landscape. In project BB/J014753/1 we will develop a version of this model for bumblebee colonies. These models will enable us to predict where both honeybee and bumblebee workers will forage, and thus predict their exposure, which will be compared to that received by real nests placed in the landscape. We will then examine whether exposure to neonicotinoids at realistic field levels alters or impairs foraging behaviour using Rothamsted's unique harmonic radar facility. These data will be used to develop a sub-model for both honeybees and bumblebees which includes impacts of neonicotinoids in predictions of colony success, which will be tested with real colonies of bumblebees in field experiments, and can be used as a risk assessment tool by users. Finally, the data and model results will enable us to develop management recommendations to minimise the impacts of neonicotinoids on both managed honeybees and wild bumblebee populations.