Keywords: Apis mellifera, Brachygastra mellifica, competition for pollination, Meliponinae, pollination, foraging preference.
Insects visiting avocado flowers were collected over the course of five research trips to Mexico, in the states of Michoacan, Mexico,
Puebla, Veracruz and Chiapas. Most of the specimens were identified at the species level, and the amount and distribution of pollen on their bodies were determined. 80th the density and behavior of species found to carry a large amount of avocado pollen were observed on the avocado bloom. In commercial orchards sprayed with potent insecticides, only a small number of visitors of a few species were observed, most of them honeybees (Apis mellifera). In contrast, on unsprayed traes (in small plots, backyards, etc) large numbers of visitors of numerous species were usually observed. More than 1,000 individual insects, of about 100 species, were coIlected on avocado bloom, most of them of the orders Hymenoptera, Diptera, CoIeoptera and Heteroptera. Apparently, some of the visitor species did not pollinate the avocado flowers, but most of them did contribute to its pollination. The following species were found to be effective pollinators of avocado: the honeybee, 8 to 10 species of stingless bees (Apidae, Meliponinae) and the. Mexican honey wasp" (Brachygastra mellifica). These species were the main pollinators of the three avocado races: Mexican, Guatemalan and West Indian. Honeybees were active on the avocado bloom at most sites; however, in some cases they abandoned the avocado bloom lo collect nectar and pollen from nearby competing flowers. The stingless bee species and the Mexican honey wasp showed a greater preference for the avocado bloom. We assume that the original pollinators of the avocado, before the introduction of the honeybee to the American continent, were stingless bee and wasp species, which are better adapted for its pollination.