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ARS Home » Pacific West Area » Maricopa, Arizona » U.S. Arid Land Agricultural Research Center » Pest Management and Biocontrol Research » Research » Publications at this Location » Publication #202634

Title: Behavioral Ecology of Euglossine Bees of the Atlantic Rain Forest

item Blackmer, Jacquelyn

Submitted to: International Congress of Scientific Knowledge
Publication Type: Abstract Only
Publication Acceptance Date: 10/5/2006
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Before the colonization of Brazil, the Atlantic Forest extended from Rio Grande do Norte to Rio Grande do Sul. As recently as 1832, Charles Darwin described it as "a forest which in the grandeur of all its parts could not be exceeded." It is now highly fragmented and only 8% of its former size, with the states of Bahia and Espírito Santo having only 1-2% of their rain forests remaining. The Atlantic Forest consists of very diverse habitats from the mangroves and restingas along the coastal reaches, the dense forests inland, to the high altitudinal grasslands that exceed 1800 m in elevation. Because of its biological diversity, endemism and number of endangered species, the Atlantic Forest is considered to be one of the most threatened habitats in the world. There is an incredible diversity of species in the Atlantic Forest and many of these species are found nowhere else on earth. It has been estimated that there are approximately 250 species of mammals, 55 of which are endemic; 340 species of amphibians, 90 of which are endemic; more than 1000 species of birds, 188 of which are endemic; and more than 20,000 species of trees, one-half of which are endemic to the Atlantic Forest. The high biodiversity in the Atlantic Forest is a function of the extreme variations in latitudinal span, elevation, and differences in coastal versus inland forests in the region. The flora of the region is incredibly rich and one of the most diverse groups of plants in the Atlantic Forest is the orchids. In the high mountain areas (> 1000 m elevation) of Macaé de Cima, RJ over 230 orchid species from 26 genera have been described and it has been estimated that more than 300 species in 70 genera probably exist in this region alone. At lower elevations, orchid diversity is likely to be similar. In the New World Tropics there are ~ 700 species of orchids that are pollinated exclusively by a group of bees known as the orchid bees. It has been shown that such intricate associations are highly vulnerable to habitat loss and with the fragmentation of the Atlantic Forest one might expect that such relationships would suffer and possibly result in a decrease in species diversity and abundance. One of the largest remnants of the Atlantic forest (Desengano) in the northern portion of the state of Rio de Janeiro was selected as our study site. This area is characterized by an edge of secondary vegetation that gradually shifts into a semi-deciduous primary tropical rain forest. The forest is surrounded by cattle ranches, abandoned pastures and second-growth vegetation. The objective of our study was to compare the abundance and diversity of euglossine bees within a highly fragmented area of the Atlantic forest and test the hypothesis that fragmentation and forest degradation affect species composition. Sampling sites were selected within an area of ~ 230 km2 around the village of Sossego do Imbé. Nine sites were sampled every two months over 10-day periods. Four of the sites were located in second growth forest contiguous with the main forest; two sites consisted of scrubby vegetation and second growth forest that was contiguous with the main forest; three sites were in fragments that were separated from the main forest and were 14, 156, and 200 ha in size. Synthetic compounds resembling orchid fragrances or other natural substances were used to attract male bees. We collected more than 3,600 specimens represented by at least 21 species (nearly double the number of previously collected euglossine bees in the state of Rio de Janeiro). Certain species like Euglossa analis and Eulaema nigrita demonstrated distinct preferences for secondary undisturbed and scrubby, disturbed areas, respectively; however, when all species were considered, we found no clear difference in species diversity or abundance across nine locations that varied in their degree