Variabilidade espaço-temporal de Scarabaeinae (Coleoptera: scarabaeidae) em quatro localidades com diferentes níveis de alteração no Rio Grande do Sul, Brasil

Abstract

Insects represent more than half of the animal species described in the world, and the order Coleoptera is one of the best known because comprehends insect that are easily collected and identified, making it appropriate for studies of ecology and conservation. The main goal of this research is to evaluate and compare the spatiotemporal variability of Scarabaeinae species (Coleoptera: Scarabaeidae) in four localities of Rio Grande do Sul. It was also aimed to compare the diversity of Scarabaeinae among the studied localities with different phytophysiognomies: two areas of environmental protection - Turvo State Park and Moreno Fortes Biological Reserve, both located northwest of the state; and two areas located in remnant fragments not isolated from Deciduous Seasonal Forest, in the municipalities of Santa Maria and Silveira Martins; to increase the list of species of Scarabaeinae recorded for Rio Grande do Sul: specifically those of the region of Upper Uruguay, for which there are still no records; to correlate abundance and richness with the seasonality of species of Scarabaeinae during the period of one year; To compare the diversity of species of Scarabaeinae using traps arranged at different height levels and to correlate abundance and richness with climatic variables (temperature and rainfall). The main justification for the study is the scarcity of data about the Coleoptera of the Scarabaeidae family occurring in the fragments of Atlantic Forest in southern Brazil and the need to increase the research involving this group, making possible the contribution to the knowledge of the characteristics of certain environments. Samplings were carried out from May 2016 to July 2017 in the four areas mentioned above, through pitfall traps and aerial traps baited with human excrement. The captured insects were identified at the species level using entomological dichotomic keys described for genera of Scarabaeinae and consultation with specialists. Scarabaeinae species were analyzed for their diversity through Shannon-Wiener (H) and Simpson diversity indexes. For an evaluation of the similarity of the Scarabaeinae fauna between the areas the Jaccard and Morisita indexes were used and the richness was estimated through the indicator Jackknife 1. A total of 5,533 individuals belonging to 46 species were collected. Among the four sites sampled Canthidium aff. trinodosum (Boheman, 1858) (20.71%), Eurysternus parallelus Castelnau, 1840 (14.82%), Onthophagus catharinensis Paulian, 1936 (12.09%), Scybalocanthon nigriceps (Harold, 1868) (7.61 %), Eurysternus caribaeus (Herbst, 1789) (7.49%), and Canthon rutilans cyanescens Harold 1868 (7.22%) were the species with higher abundance and together represented 69.94% of the individuals collected. Dois Irmãos das Missões had the higher richness and Santa Maria the higher abundance, while Silveira Martins presented the lowest values. The greatest similarity occurred between Derrubadas and Dois Irmãos das Missões, Dois Irmãos das Missões and Silveira Martins had the lowest similarity. Only 11 species (23.9%) occurred in all sites, while 14 species were restricted to only one. The abundance and richness of Scarabaenae were positively correlated with site temperature. The list of Scarabaeinae for the state is expanded, with 128 registered species.