Floral resource diversification promotes solitary bee reproduction and may offset insecticide effects – evidence from a semi-field experiment

Pollinator declines in agricultural landscapes are driven by multiple stressors, but potential interactions of these remain poorly studied. Using a highly replicated semi-field study with 56 mesocosms of varying wild plant diversity (2-16 species) and oilseed rape treated with a neonicotinoid, we tested the interacting effects of resource diversity and insecticides on reproduction of a solitary wild bee. Compared to mesocosms with oilseed rape monocultures, availability of resources from wild plants complementing oilseed rape doubled brood cell production. In addition, bee reproduction increased due to plant diversity and identity effects. Exposure to neonicotinoid-treated oilseed rape reduced bee larval to adult development by 69%, but only in mesocosms with oilseed rape monocultures. Availability of complementary flower resources can thus offset negative effects of neonicotinoid-treated oilseed rape on wild bee reproduction. Policy should encourage the implementation of diverse floral...

农业景观中的传粉者衰退现象由多重胁迫因子共同驱动，但这些胁迫因子间的潜在交互作用仍未得到充分研究。本研究依托一项高重复率半田间试验，设置56个配置梯度野生植物多样性（2~16种）的中型实验生态箱（mesocosm），并采用经新烟碱类杀虫剂（neonicotinoid）处理的油料油菜作为实验材料，以此探究资源多样性与杀虫剂对独居野生蜂繁殖的交互影响效应。相较于仅种植单一片油料油菜的中型实验生态箱，搭配野生植物蜜源以补充油料油菜资源的生态箱，其蜂群的巢室产量提升了一倍。此外，植物多样性与物种组成效应同样可提升蜂类繁殖成功率。暴露于经新烟碱类杀虫剂处理的油料油菜环境中，会使蜂类幼虫到成虫的发育存活率降低69%，但该抑制效应仅出现在单一种植油料油菜的生态箱中。由此可见，互补性花源资源的供给能够抵消经新烟碱类杀虫剂处理的油料油菜对野生蜂繁殖的负面影响。政策应鼓励推广多样化花源……