Abundance of Odonata in different microhabitats at an oxbow lake in the Peruvian Amazon

ABSTRACT The relationship between Odonata and vegetation in Amazonia has been studied primarily in streams. In this study, I examined the abundance of adult Odonata in two vegetation types (shrubs and herbs) surrounding an oxbow lake in the Peruvian Amazon. Daytime visual samplings of Odonata were carried out in time blocks along transects in each habitat. Thirteen taxa were identified. Five species were similarly abundant in both habitats, three used mainly herbs, and one mainly shrubs, with no variation among time blocks. The results suggest that most Anisoptera and Zygoptera are adapted to unshaded areas of the lake. Some Odonata also were observed during sunless days with light rainfall, suggesting they are adapted to rainy conditions in tropical climate.摘要 亚马孙地区蜻蜓目（Odonata）与植被的关联研究既往多聚焦于溪流生境。本研究针对秘鲁亚马孙流域某牛轭湖（oxbow lake）周边的两种植被类型（灌木层与草本层）内蜻蜓目成虫的种群丰度展开调查。研究于各生境的样带（transects）内按时段区块开展蜻蜓目成虫的日间目视采样，共鉴定出13个分类单元（taxa）。其中5个物种在两种生境中的丰度相当，3个物种主要栖息于草本层，1个物种偏好灌木层，且各时段区块间无显著差异。研究结果显示，绝大多数差翅亚目（Anisoptera）与束翅亚目（Zygoptera）均适应该牛轭湖的无遮蔽区域。此外，团队在阴天伴小雨的天气中也观测到部分蜻蜓目成虫，表明它们能够适应热带气候下的多雨环境。