Análise da composição e abundância dos dípteros da macrofauna de solo em liteira de uma floresta de terra firme

Abstract

Most Diptera have their larval stages attached to the soil and have saprophytic habits. When adults, some continue feeding on plants and small dead insects, contributing to the decomposition of organic matter, an important fact for the soil and good plant development. The present work aims to identify the saprophytic adult diptera present in litter in an upland area. The individuals were collected at the Ferreira Penna Scientific Station, in Caxiuanã, Melgaço-PA, in June, October and November 2001, using Winckler extractors, Pitfall traps and manual collections from leaves retained in decomposition bags. The collected insects were taken to the laboratory and kept in 80% alcohol for identification. We observed in the first collection in June (Winckler and Pitfall/October (decomposition bags), a greater presence of diptera belonging to the fanu1iasPhoridae (60.86 %), Cecidomyiidae (12.56 %) and Drosophilidae (9.90 %) and a small amount of other diptera, among them few individuals of the Sciaridae family (2.65 %). In the second collection in November, (Winckler & Pitfall) the most representative families were Cecidomyiidae, Sciaridae, Phoridae and Drosophilidae, in decreasing order of abundance. Most of the insects of these families have saprophytic habits, both in larval and adult stages. It can be concluded that these insects, among diptera, are the most participatory in soil decomposition. It is important to note the variation in abundance of the Sciaridae, which increased in frequency during the drier periods. These data are not yet conclusive but may be indicative of different responses of insect groups to moisture gradations.