The bee fauna (Hymenoptera, Apoidea) in Cerrado and Cerrado-Amazon Rainforest transition sites in Tocantins state, Northern Region of Brazil

Abstract: Two sites located in Tocantins State, Brazil, were selected for the bee’s community survey. One of them was mostly covered by Cerrado vegetation and the other one is located in the Cerrado-Amazon Rainforest ecotone. Five expeditions were performed in each site throughout a 12-month period, between 2019 and 2020. The total of 771 bee specimens were collected and distributed into four families. Apidae presented the greatest species abundance and richness, it was followed by Halictidae, Megachilidae and Andrenidae, respectively. Trigona pallens (Fabricius) (Apidae) was the species presenting the greatest abundance in both sites, it totaled 118 specimens, which corresponded to 26.9% of the total abundance of individuals belonging to tribe Meliponini. In general, the community presented several species with few individuals and few species with many individuals. Bee collections were performed by using three different methodologies, among them one finds sampling based on the entomological net method, which allowed collecting the largest number of both individuals and species in comparison to the other used methods. Based on the frequency and abundance classes, only few species were classified as very frequent (VF) and very abundant (VA) in both sites based on the frequency and abundance classes. Most species were constant (W) in both regions, and there was a small number of dominant species (D); moreover, more than 70% of the sampled species were considered accidental (Z). According to the present study, either Cerrado or Cerrado-Amazon Rainforest studied sites presented higher species richness than other sites in these biomes sampled in Brazil.

摘要：本研究选取巴西托坎廷斯州的两处样地开展蜂类群落调查。其中一处样地以塞拉多（Cerrado）植被为主要覆盖类型，另一处样地位于塞拉多-亚马逊雨林生态交错带。2019至2020年间，在为期12个月的周期内对两处样地各开展5次野外采样，共计采集到771号蜂类标本，隶属于4个蜂科。其中蜜蜂科（Apidae）的物种丰度和丰富度均居首位，其后依次为隧蜂科（Halictidae）、切叶蜂科（Megachilidae）与地蜂科（Andrenidae）。淡色无刺蜂（Trigona pallens (Fabricius)）隶属于蜜蜂科，是两处样地中丰度最高的物种，共计采集到118号标本，占麦蜂族（Meliponini）总个体数的26.9%。总体而言，该蜂类群落呈现出“多数物种个体稀少，少数物种个体众多”的分布特征。本次蜂类标本采集采用三种不同方法，其中基于昆虫网的采样法相较其余两种方法，采集到的个体数与物种数均为最多。依据频度和多度等级划分标准，两处样地中仅极少数物种被划为频度极高（very frequent, VF）且多度极高（very abundant, VA）类群。多数物种在两个区域均为恒有种（constant, W），仅存在少量优势种（dominant, D）；此外，超过70%的采样物种被归类为偶见种（accidental, Z）。本研究结果显示，本次调研的塞拉多样地与塞拉多-亚马逊雨林交错带样地的物种丰富度，均高于巴西境内已报道的同生物群落其他样地。