Department of Ecology and Environmental Science, Assam University, Silchar, India.
Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Medical Biology Centre, Belfast, UK.
Pest Manag Sci. 2019 Oct;75(10):2610-2617. doi: 10.1002/ps.5368. Epub 2019 Mar 13.
Context-dependencies can modulate the strength of predatory interactions and often remain unquantified. In particular, differences in water depth within aquatic systems could influence predator efficiencies towards prey which utilise three-dimensional space through the water column. Differences in prey size could drive prey size-refuge effects, influencing the efficacy of natural enemies towards vector species. We thus quantify the predatory impact of two notonectid predators, Anisops breddini and Anisops sardeus, towards four different larval instars of Culex quinquefasciatus prey across a water depth gradient, using functional responses (FRs).
Consumption rates differed significantly between the predators, and interspecific differences in responses to variations in water depth were emergent. Both notonectids were able to handle C. quinquefasciatus prey across all instar stages, yet predation rates were generally higher towards early as opposed to late instar prey. Anisops sardeus was most voracious, and differential predation rates of this species were most pronounced in shallow waters. Type II FRs were displayed by notonectids in the majority of treatments; however, Type III FRs were emergent in specific treatment groups, with potential implications for prey population stability. Both capture rates and handling times were often greater at greater depths, and thus maximum feeding rates reduced as depth increased. Our results further demonstrate substantial predatory impacts of notonectid predators towards mosquito, and quantify biotic and abiotic context-dependencies which modulate their impact.
Given notonectids are capable of aerial dispersal between ephemeral aquatic habitats of varied volumes, their promotion in aquatic systems could help reduce proliferations of medically important mosquitoes. © 2019 Society of Chemical Industry.
语境依赖性可以调节捕食相互作用的强度，而且通常无法量化。特别是，水生系统中水深的差异可能会影响到通过水柱利用三维空间的猎物的捕食者效率。猎物大小的差异可能会产生猎物大小避难所效应，从而影响天敌对病媒物种的效力。因此，我们通过功能反应（FR）量化了两种龙虱捕食者（Anisops breddini 和 Anisops sardeus）对四个不同的 Culex quinquefasciatus 幼虫龄期的捕食影响，水深梯度。
两种捕食者的消耗率存在显著差异，并且对水深变化的种间差异是明显的。两种龙虱都能够处理所有龄期的 C. quinquefasciatus 猎物，但捕食率通常对早期而非晚期猎物更高。Anisops sardeus 最贪婪，该物种的差异捕食率在浅水中最为明显。龙虱在大多数处理中表现出 II 型 FR，但在特定处理组中出现了 III 型 FR，这可能对猎物种群稳定性有影响。在较大的深度下，捕获率和处理时间通常更大，因此最大进食率随着深度的增加而降低。我们的结果进一步证明了龙虱捕食者对蚊子的巨大捕食影响，并量化了调节其影响的生物和非生物语境依赖性。
鉴于龙虱能够在不同体积的短暂水生栖息地之间进行空气传播，它们在水生系统中的推广可能有助于减少医学上重要蚊子的泛滥。© 2019 化学工业协会。
