WITHIN-HABITAT HETEROGENEITY OF EUGLOSSINE BEE POPULATIONS:A RE-EVALUATION OF THE EVIDENCE

Authors: TONHASCA, A - UENF,CAMPOS, BRAZIL; BLACKMER, JACQUELYN; ALBUQUERQUE, G - UENF,CAMPOS, BRAZIL

Submitted to: Journal of Tropical Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/1/2002
Publication Date: 12/30/2002
Citation: TONHASCA, A.J., BLACKMER, J.L., ALBUQUERQUE, G.S. WITHIN-HABITAT HETEROGENEITY OF EUGLOSSINE BEE POPULATIONS:A RE-EVALUATION OF THE EVIDENCE. JOURNAL OF TROPICAL ECOLOGY. 2002. v. 18: 929-933.

Interpretive Summary: Euglossine bees are important pollinators in the neotropics. Pollination by male bees occurs when they visit flowers to collect floral fragrances. Synthetic products that mimic these fragrances have been used in studies of euglossine bee ecology and population structure. The ability of euglossine bees to disperse and find isolated flowers and distant baits suggests that bees are attracted to floral odors from a wide area, and potentially different habitats. According to this hypothesis, individuals collected at baiting stations are part of the same pool of bees and representative of the habitat. Other researchers have suggested that attraction of bees to concentrations of resources (or baits) does not necessarily represent the habitat, but only particular microhabitats. To test these hypotheses we conducted studies on within-habitat distributions of euglossine bees at several sites from an area of approximately 230 km2 around the village of Sossego de Imbé, Rio de Janeiro State, Brazil. Bees were collected using bait stations that were ran simultaneously at two or three sampling stations at three sites. Based on our collections, we suggest analysis should take into consideration the relative abundance of the species and give less importance to the numerical differences between collections. The Morisita index of similarity was used for this purpose. This analysis showed that there was some variability between sampling stations in the number of individuals collected, but the euglossine bee communities within sites were similar.

Technical Abstract: Euglossine bees (Hymenoptera: Apidae: Euglossini) are considered keystone species in the neotropics because of their role as pollinators of several plant species, particularly orchids. Pollination by male bees occurs when they visit flowers to collect essential oils. Synthetic products that mimic these oils have been used in studies of euglossine bee ecology and population structure. The ability of euglossine bees to disperse and find isolated flowers and distant baits suggests that bees are attracted to fragrances from a wide area that may include different habitats. According to this hypothesis, individuals collected at baiting stations are part of the same pool of bees and representative of the habitat. Other researchers have suggested that attraction of bees to concentrations of resources (or baits) does not necessarily represent the habitat, but only particular microhabitats. To test these hypotheses we conducted studies on within-habitat distributions of euglossine bees at several sites from an area of approximately 230 km2 around the village of Sossego de Imbé, Rio de Janeiro State, Brazil. Bees were collected using bait stations on six occasions when samples were collected simultaneously at two or three sampling stations at three sampling sites. Based on our collections, we suggest that a better analysis of homogeneity between samples should take into consideration the relative abundance of the species and give less importance to the numerical differences between collections. This was accomplished by the Morisita index of similarity. This analysis showed that there was some variability between sampling stations in the number of individuals collected, but the euglossine bee communities within sites were similar.