Domingos A R, Arcifa M S
Laboratório de Limnologia, Departamento de Biologia, Faculdade de Filosofia Ciências e Letras de Ribeirão Preto - FFCLRP, Universidade de São Paulo - USP, Av. Bandeirantes, 3900, CEP 14040-901, Ribeirão Preto, SP, Brazil.
Braz J Biol. 2016 Jul 11;0:0. doi: 10.1590/1519-6984.10815.
Notonectids are widely distributed in freshwaters and can prey on zooplankton in temperate lakes. However, its role in structuring the zooplankton community is unknown in tropical lakes. Thus, our objective was to study the notonectid Martarega uruguayensis in a Brazilian tropical shallow lake to evaluate its potential as a zooplankton predator. Its horizontal distribution was analized in the lake throughout one year in fortnightly samplings. Backswimmers were more abundant (mean density 162.9 ± 25.8 ind.m-2) in the cool-dry season, with a strong preference by the littoral zone (mean density 139.9 ± 17.5 ind.m-2). Laboratory experiments were undertaken with young and adult notonectid and the two most abundant cladocerans, Daphnia gessneri and Ceriodaphnia richardi, as prey. Predation by backswimmers in the laboratory showed that only juveniles fed on microcrustaceans (mean ingestion rate of 1.2 ± 0.2 Daphnia and 1.0 ± 0.2 Ceriodaphnia per predator per hour), without size selectivity. Adult insects probably have difficulties in detecting and manipulating small planktonic organisms. On the other hand, young instars might influence zooplankton community, especially in the littoral zone of the lake. This study does contribute to a better understanding of trophic interactions in tropical shallow lakes and is the first to investigate the predation of a notonectid on microcrustaceans from Lake Monte Alegre.
仰泳蝽广泛分布于淡水环境中，能够捕食温带湖泊中的浮游动物。然而，其在热带湖泊浮游动物群落结构中的作用尚不清楚。因此，我们的目标是研究巴西热带浅水湖泊中的乌拉圭玛塔仰泳蝽，以评估其作为浮游动物捕食者的潜力。我们通过每两周一次的采样，对该湖泊中仰泳蝽的水平分布进行了为期一年的分析。仰泳蝽在凉爽干燥季节更为丰富（平均密度为162.9±25.8只/平方米），并且对沿岸带表现出强烈偏好（平均密度为139.9±17.5只/平方米）。我们以年轻和成年仰泳蝽以及两种数量最多的枝角类动物——格斯纳水蚤和理查德圆囊溞作为猎物进行了实验室实验。实验室中仰泳蝽的捕食情况表明，只有幼体以小型甲壳类动物为食（每个捕食者每小时平均摄食率为1.2±0.2只格斯纳水蚤和1.0±0.2只理查德圆囊溞），且没有大小选择性。成年昆虫可能难以察觉和捕捉小型浮游生物。另一方面，幼虫可能会对浮游动物群落产生影响，尤其是在湖泊的沿岸带。这项研究有助于更好地理解热带浅水湖泊中的营养相互作用，并且是首次对蒙特阿莱格雷湖中的仰泳蝽捕食小型甲壳类动物进行调查。
