Past insecticide exposure reduces bee reproduction and population growth rate

Pesticides are linked to global insect declines, with impacts to biodiversity and essential ecosystem services. In addition to well-documented direct impacts of pesticides at the current stage or time, potential delayed “carryover” effects from past exposure at a different life stage may augment impacts to individuals and populations. We investigated the effects of current exposure and the carryover effects of past insecticide exposure on the individual vital rates and population growth of the solitary bee, Osmia lignaria. Bees in flight cages freely foraged on wildflowers, some treated with the common insecticide, imidacloprid, in a fully crossed-design over two years, with insecticide exposure or no exposure in each year. Insecticide exposure reduced reproduction, directly to foraging adults and via carryover effects from past exposure. Repeated exposure across two years additively impaired individual performance, leading to a nearly four-fold reduction in bee population growth. Expos...

农药与全球昆虫种群衰退密切相关，会对生物多样性及关键生态系统服务造成负面影响。除当前阶段已被充分证实的农药直接暴露影响外，过往不同生命阶段暴露所产生的潜在延迟“遗留（carryover）”效应，可能会加剧对昆虫个体及种群的危害。本研究探究了当前杀虫剂暴露以及过往暴露遗留效应对独居蜂——紫壁蜂（Osmia lignaria）的个体生命参数及种群增长的影响。本研究采用完全交叉设计，在两年周期内设置每年杀虫剂暴露与非暴露两种处理；飞行笼中的独居蜂可自由采食野花，部分野花经常用杀虫剂吡虫啉（imidacloprid）喷施处理。杀虫剂暴露会直接降低觅食成虫的繁殖能力，同时通过过往暴露的遗留效应进一步抑制繁殖。连续两年的重复暴露会对个体表现产生累加性损害，最终导致独居蜂种群增长量下降近四倍。暴露[原文未完成]