Abundance and species richness of euglossini (hymenoptera: apidae) in different fragments in the municipality of Mojuí dos Campos, Pará, Brazil

Abstract

The bees of the Euglossini tribe (Hymenoptera: Apidae) are extremely important in the pollination of Neotropical forests and because they are sensitive to changes in their habitat, they are considered excellent bioindicators of environmental quality. In this context, the present study aimed to (i) to compare the species richness and abundance of Euglossini between fragments of forest, pasture and soy plantation; (ii) identify the preference for chemical baits; and (iii) assess the edge effect on species richness and abundance of individuals. The study was carried out in the municipality of Mojuí dos Campos, Pará, Brazil, in three distinct fragments: forest fragment, pasture and soybean plantation. Six chemical baits were used to attract males: eugenol, eucalyptol, vanillin, benzyl benzoate, methyl cinnamate and geraniol. A total of 1668 individuals were collected in 4 genera and 11 species. There is a significant difference in the abundance of Euglossini between the environments (F_{(2, 24)} = 4,1007; p = 0.029), the highest abundance occurred in the pasture area (866-52%). There was a significant difference in both abundance (F_{(5, 156)} = 15.811; p < 0.001) and in the species richness (F_{(5, 156)} = 70.039; p < 0.001) of Euglossini among the baits. Vanillin proved to be the most attractive bait and geraniol the least attractive. There is no significant difference in abundance (F_{(2, 24)} = 1,8505; p = 0.178) and Euglossini species richness (F_{(2, 24)} = 0.299; p = 0.744) between the border, intermediate and center transects , which may be related to the proximity between the areas and the bees' ability to fly long distances. Another factor that can influence this result is the dispersal capacity of these bees, and they can explore nearby localities. Climatic factors, difference in substance volatility, age range of populations, isometric purity and composition of substances and supplies from natural sources may have influenced this outcome. Although the results show a high degree of degradation in the studied area, it is necessary to carry out further studies, taking into account the size of the fragments and the number of Eulaema nigrita in relation to other species in order to obtain more accurate data on the impacts of different soil uses on the diversity of Euglossini bees.