Bellile Katie G, Vonesh James R
Virginia Commonwealth University, Center for Environmental Studies, Richmond, VA 23284-3050, U.S.A.
Virginia Commonwealth University, Department of Biology, Richmond, Virginia 23284-2012, U.S.A..
J Vector Ecol. 2016 Jun;41(1):123-7. doi: 10.1111/jvec.12203.
Mosquito egg traps, aquatic habitats baited with oviposition attractant and insecticide, are important tools for surveillance and control efforts in integrated vector management programs. The bioinsecticide Bacillus thuringiensis subsp. israelensis (Bti) is increasingly used as an environmentally friendly alternative to chemical insecticides and the combination of Bti with a simple oviposition attractant like leaf litter to create an effective egg trap seems appealing. However, previous research suggests that Bti may itself alter oviposition, and that leaf litter may dramatically reduce Bti toxicity. Here we present results from field experiment designed to link the effects of litter and Bti on mosquito oviposition habitat selection and post-colonization survival to production of adult mosquitoes. Tripling litter increased Culex spp. oviposition nearly nine-fold, while Bti had no effect on oviposition. Neither factor altered egg survival, thus larval abundance reflected the effects of litter on oviposition. Both Bti and litter reduced larval survival by ∼60%. We found no evidence that increased litter reduced Bti toxicity. Adult production was dependent upon both litter and Bti. In the absence of Bti, effects of litter on oviposition translated into three-fold more adults. However, in the presence of Bti, initial increases in oviposition were erased by the combined negative effects of Bti and litter on post-colonization survival. Thus, our study provides field evidence that combined litter and Bti application creates an effective ovitrap. This combined treatment had the highest oviposition and the lowest survival, and thus removed the greatest number of mosquitoes from the landscape.
蚊卵诱捕器，即使用产卵引诱剂和杀虫剂诱饵的水生栖息地，是综合病媒管理计划中监测和控制工作的重要工具。生物杀虫剂苏云金芽孢杆菌以色列亚种（Bti）越来越多地被用作化学杀虫剂的环保替代品，将Bti与简单的产卵引诱剂（如落叶）结合以制造有效的诱卵器似乎很有吸引力。然而，先前的研究表明，Bti本身可能会改变产卵行为，并且落叶可能会显著降低Bti的毒性。在此，我们展示了田间实验的结果，该实验旨在将落叶和Bti对蚊子产卵栖息地选择以及定殖后存活的影响与成蚊的产生联系起来。落叶量增加两倍使库蚊属的产卵量增加了近九倍，而Bti对产卵没有影响。这两个因素均未改变卵的存活率，因此幼虫数量反映了落叶对产卵的影响。Bti和落叶均使幼虫存活率降低了约60%。我们没有发现证据表明落叶量增加会降低Bti的毒性。成蚊的产生取决于落叶和Bti。在没有Bti的情况下，落叶对产卵的影响转化为成虫数量增加了两倍。然而，在有Bti的情况下，产卵的最初增加被Bti和落叶对定殖后存活的综合负面影响所抵消。因此，我们的研究提供了田间证据，表明同时应用落叶和Bti可制造出有效的诱卵器。这种联合处理具有最高的产卵量和最低的存活率，因此从环境中清除的蚊子数量最多。
