Diversidade de besouros escarabeíneos copro-necrófagos (Coleoptera: Scarabaeidae: Scarabaeinae) e a dispersão secundária de sementes por Canthon (Peltecanthon) staigi (Pereira, 1953) em uma área de Floresta Atlântica no Nordeste do Brasil

Abstract

Dung beetles (Coleoptera: Scarabaeidae: Scarabaeinae) have more than 6,200 species described, which are predominantly coprophagous. Due to their feeding and breeding activities they are suggested as bioindicators and play important ecological roles. This study aim to know the diversity of copro-necrophagous dung beetles and to evaluate the secondary seed dispersal capacity by Canthon staigi in an area of Atlantic Forest in Northeast Brazil. The following hypotheses were formulated: the richness and abundance of these beetles is higher in the rainy season; there is a difference in species composition between seasons; Canthon staigi is an efficient secondary spreader of small seeds. The six collections of beetles and seeds were carried out at the Mata do Buraquinho Wildlife Refuge, three during the dry season and three in the rainy season, in 2018. Forty pitfalls were used, baited with human faeces and rotted bovine spleen for beetles and ten collectors (1x1m) for seed rain. Seeds and beetles were screened and only C. staigi individuals were kept alive for laboratory tests. The abundance and richness data between the seasons were compared using one-way ANOVA. Five tests of secondary dispersion

of seeds were carried out in the Laboratory of Ecology Applied to Conservation - LEAC- UFPB. For this, the seeds, previously classified in four size classes were inserted in

portions of 15g of fresh bovine feces and placed in each of the ten terrariums. The terrariums were adapted of plastic trays (43 x 30 x 8cm) with soil, each containing five beetles. Records of quantities of seeded and seedless balls were made. Also, the observation of the types of horizontal or vertical movements was made. Of the 1,184 individuals collected from nine species, 756 (63.9%) of the nine species were recorded for the rainy season and 428 (36.2%) of six species were recorded for the drought. A significant difference was found in both abundance and richness between the seasons. Canthon staigi was the most abundant species in both seasons, being Canthon sp., Coprophanaeus ensifer and Coprophanaeus cyanescens recorded only in the rainy season, which indicates that there was difference in the composition of the species between the seasons. In 107 balls of feces produced, displacement of 42 balls with seeds was registered, 91% of the dispersion of small seeds (<6 mm) was recorded. According to these results, we can conclude that the richness and abundance of beetle beetles are higher in the rainy season and that the composition of these species is different between dry and rainy seasons. In addition, we conclude that Canthon staigi is an secondary spreader of small seeds and can act directly in the processes of ecological succession, thus contributing to biodiversity conservation studies, especially in tropical ecosystems.