Two-year study of male orchid bee (Hymenoptera: Apidae: Euglossini) attraction to chemical baits in lowland south-eastern Peru
Journal of Tropical Ecology
1985
Journal Article
1
37-54
Explorer's Inn animals invertebrates arthropods insects bees plants orchids Orchidaceae pollination flowers field techniques diversity Madre de Dios Bibliography
A number of male bee pollinators of orchids were attracted and captured, using chemical baits reassembling natural orchid scents, at locations in both forest subject to flooding and on terra firma in the TRZ. 38 species of bees were attracted by these chemical substances and collected in the two locations; of these, 11 were significantly more common in one of the habitats than in the other. A great variation was found in the number and types of chemical baits that interested the bees, and there were two seasonal periods of abundance of individuals and species of bees using the chemical baits. The greatest success was achieved at the end of the first month of the rainy season, and the least success was during the dry season. Individual body size by species was associated with seasonal activity, though other factors such as floral phenology and parasitoids could also have been involved. The number of euglossine bee species found in the TRZ was similar to that found in other forested areas of Costa Rica, Panama and central and eastern Brazil. This homogeneity of species richness contrasts notably with other groups of insects such as: Odonata, Lepidoptera, Diptera (Asilidae and Tabanidae) and Coleoptera (Cicindelidae), in which the numbers of species found in the TRZ are the highest in the world (when compared with areas of similar size). Of the total of 20 baits that were tried, four did not attract any bees, 11 attracted just a few and five were the main attractors. Males of a total of 39 orchid pollinating bee species, belonging to the genera Eufriesia, Euglossa, Eulaema and Exaerete, were found in the ZRT. Only Eulaema polyzona was not attracted by any chemical bait, and two species: Euglossa perviridis and Exaerete dentata, were collected with baits other than the five best. As in Costa Rica and Panama, there is considerable species variation in the types and range of chemical substances to which the bees were attracted. Some species such as Euglossa despecta and E. mixta were attracted by a particular bait, while species like E. augaspis were attracted by the five most effective baits. With regard to seasonal changes in chemical attraction, it was found that of the six commonest species, three of the ones that were the first arrivals at one or two chemical attractants, Euglossa imperialis, E. mixta and Eulaema meriana showed no significant difference in any of the five temporal comparisons of frequency of chemical attraction. Species that were attracted to a wider range of baits, such as Euglossa augaspis and E. chalybeata, showed significant differences for the five seasonal comparisons that were carried out.