Department of Ecology and Environmental Science, Assam University, Silchar, India.
Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Belfast, UK.
Pest Manag Sci. 2020 Feb;76(2):609-616. doi: 10.1002/ps.5556. Epub 2019 Aug 21.
Predatory biological control agents can be effective natural means of managing pests, vectors and invasive species. However, the strength of predator-prey interactions can be regulated through context-dependencies that often remain unquantified. In particular, refuge effects can influence the efficacy of biological agents towards target species, and such effects are often driven by prey size and search area differences. In this study, we quantify the prey preferences of two predaceous notonectids, Anisops breddini and Anisops sardeus, towards four different aquatic larval instar stages of the medically important mosquito Culex quinquefasciatus across variations in surface area and water depth.
Consumption rates differed significantly among the four larval sizes but not between the notonectids. Search area variations also elicited differences in consumption rates. Both predators tended to prefer second-instar mosquito prey among surface area and water depth variations, while generally avoiding the largest (fourth instar) and smallest (first instar) prey instar stages. For both predators, differential selectivity traits were emergent across surface area variations and water depth, with refuge effects for small prey generally greatest at intermediate-large depths with high surface areas. We thus demonstrate that predatory impacts of notonectids towards mosquito larvae differ significantly according to prey size, and likely peak at intermediate size classes.
Different mosquito size classes often coexist and compete, selectivity has important implications for adult mosquito proliferations. Further, in ephemeral aquatic habitats where surface areas and water depths are highly variable spatiotemporally, the efficacy of notonectids in controlling mosquito prey may differ substantially. © 2019 Society of Chemical Industry.
掠食性生物防治剂可以是管理害虫、病媒和入侵物种的有效自然手段。然而，捕食者-猎物相互作用的强度可以通过上下文依赖来调节，而这些上下文依赖通常是无法量化的。特别是，避难所效应可以影响生物防治剂对目标物种的效果，而这种效应通常是由猎物大小和搜索区域差异驱动的。在这项研究中，我们量化了两种捕食性龙虱，Anisops breddini 和 Anisops sardeus，对四种不同的水生幼虫阶段的医学上重要的蚊子 Culex quinquefasciatus 的猎物偏好，这些幼虫阶段的大小不同，表面积和水深也不同。
四种幼虫大小的消耗率有显著差异，但龙虱之间没有差异。搜索区域的变化也引起了消耗率的差异。两种捕食者在表面积和水深的变化中都倾向于选择第二龄蚊子幼虫，而通常避免最大（第四龄）和最小（第一龄）的幼虫期。对于两种捕食者，在表面积的变化和水深方面，都出现了不同的选择性特征，对于小猎物的避难所效应通常在中等-大水深和大表面积时最大。因此，我们证明了龙虱对蚊子幼虫的捕食影响根据猎物大小而有显著差异，并且可能在中等大小的类群中达到峰值。
不同大小的蚊子幼虫通常共存和竞争，选择性对成年蚊子的繁殖有重要影响。此外，在表面积和水深在时空上高度变化的短暂水生栖息地中，龙虱控制蚊子猎物的效果可能会有很大的不同。© 2019 化学工业协会。
