Functional feeding groups of Brazilian Ephemeroptera nymphs: Ultrastructure of mouthparts

Abstract

In order to assign 18 mayfly taxa found in streams in the Macaé River basin into Functional Feeding Groups, the anatomy of their feeding apparatus was examined through scanning electron microscopy. Also, habitat preference and field observations of feeding behaviour were made to assure FFG assignment. Ephemeropteran taxa were classified into five FFGs: Passive Filterers - Hylister plaumanni; Active Filterer - Lachlania boanovae and Campylocia sp.; Brushers - Askola froehlichi, Farrodes carioca, Hagenulopsis spp., Massartela brieni, Miroculis froehlich, Miroculis sp., and Thraulodes spp; Grazers - Cloeodes spp., Americabaetis spp., Camelobaetidius spp.and Baetodes spp.; Scrapers - Leptohyphes pereirae, Leptohyphes spp., Tricorythodes spp. and Tricorythopsis spp. Species of the three best represented mayfly families in south-east Brazil were assigned to different FFGs (Leptophlebiidae - Brushers; Baetidae - Grazers and Leptohyphidae - Scrapers), with one exception, Hylister plaumanni (Leptophlebiidae; Active filterers). This information is useful to understand the role of mayflies in stream ecosystems, and to help the development of ecological theories for tropical streams.