Diversidade de himenópteros sociais (Hymenoptera: aculeata) com redução do esforço amostral e o custo-benefício em uma floresta ombrófila densa de terra-firme na Amazônia

Abstract

The Amazon is considered one of the biomes with the greatest biodiversity in the world, but this enormous diversity is still little known and studied. Hymenoptera is one of the largest groups of insects, in terms of diversity, with more than 153 thousand species, among the main representatives and the best known, the social Hymenoptera have their greatest diversity in Brazil, with greater concentration in the Amazon region. In this way, the richness and composition of the fauna of social Hymenoptera collected with a Malaise trap in an ombrophilous forest in the Central Amazon was investigated. In addition, the possibility of reducing the sampling effort was studied by reducing the number of traps and the time of permanence of the traps, as well as its impact on cost-benefit in a survey of this size in a dense rainforest of terra-firme in 25 km² of the Central Amazon. For this, a sampling was carried out from September to November 2014 with two Malaise traps per plot, in 30 terrestrial plots of 250 m in length of the trail system in the 25 Km² Biodiversity Research Program (PPBio) grid, in the Reserve Ducke, Manaus, Amazonas, Brazil. The reduction of the sampling effort was based on the maintenance of taxonomic patterns (similarity in richness and composition) in view of the reduction of the Malaise trap permanence time in the field, and through the reduction of the number of traps per plot. In total, 63 social species were collected, being 11 species of Apidae, 31 of Formicidae and 21 of Vespidae. Social wasps represented the most abundant group and ants the richest. About 60% of the Hymenoptera collected were considered singleton or unique. It was possible to reduce the duration of the Malaise trap in the field from 72 to 48 hours, without significant loss of the maximum observed diversity, since there is high similarity (80%) to the maximum effort of 72 hours of sampling, either for richness or composition. Regarding the reduction of traps, the decrease from two to one trap directly impacted the sampled diversity, indicating the use of two traps per sampling point for a satisfactory collection of the studied groups. A savings of 28.3% is estimated with the reduction of the sampling effort and the time the traps remain, allowing resources to be invested more efficiently.