Gillespie Sandra, Long Rachael, Williams Neal
Department of Biology, Simon Fraser University, 8888 University Drive, Burnaby B.C. Canada, V5A 1S6.
Department of Entomology, University of California, Davis, CA 95616.
J Econ Entomol. 2015 Dec;108(6):2511-7. doi: 10.1093/jee/tov225. Epub 2015 Jul 30.
Pollination in crops, as in native ecosystems, is a stepwise process that can be disrupted at any stage. Healthy pollinator populations are critical for adequate visitation, but pollination still might fail if crop management interferes with the attraction and retention of pollinators. Farmers must balance the direct benefits of applying insecticide and managing irrigation rates against their potential to indirectly interfere with the pollination process. We investigated these issues in hybrid onion seed production, where previous research has shown that high insecticide use reduces pollinator attraction. We conducted field surveys of soil moisture, nectar production, pollinator visitation, pollen-stigma interactions, and seed set at multiple commercial fields across 2 yr. We then examined how management actions, such as irrigation rate (approximated by soil moisture), or insecticide use could affect the pollination process. Onions produced maximum nectar at intermediate soil moisture, and high nectar production attracted more pollinators. Insecticide use weakly affected pollinator visitation, but when applied close to bloom reduced pollen germination and pollen tube growth. Ultimately, neither soil moisture nor insecticide use directly affected seed set, but the high correlation between pollinator visitation and seed set suggests that crop management will ultimately affect yields via indirect effects on the pollination process.
与原生生态系统一样，作物授粉是一个可在任何阶段受到干扰的逐步过程。健康的传粉者种群对于充足的访花至关重要，但如果作物管理干扰了传粉者的吸引和留存，授粉仍可能失败。农民必须在施用杀虫剂和管理灌溉率的直接益处与它们间接干扰授粉过程的可能性之间取得平衡。我们在杂交洋葱种子生产中研究了这些问题，此前的研究表明，大量使用杀虫剂会降低对传粉者的吸引力。我们在两年内对多个商业田地的土壤湿度、花蜜产量、传粉者访花、花粉 - 柱头相互作用和结实情况进行了实地调查。然后，我们研究了灌溉率（以土壤湿度近似）或杀虫剂使用等管理措施如何影响授粉过程。洋葱在中等土壤湿度下产生的花蜜最多，高花蜜产量吸引了更多传粉者。杀虫剂的使用对传粉者访花的影响较小，但在接近开花期施用时会降低花粉萌发和花粉管生长。最终，土壤湿度和杀虫剂使用都没有直接影响结实情况，但传粉者访花与结实之间的高度相关性表明作物管理最终将通过对授粉过程的间接影响来影响产量。
