Algumas observações sobre o comportamento de algumas especies do genero Trigona (Alpidae - Meliponini)

Abstract

Various methods were developed to study the diurnal flight patterns of Trigona bees, insects that inflict considerable damage in plantations of Eucalyptus citriodora Hook, by boring and gouging the stems until resin exudes. By marking bees with fluorescent powder, it was found that the bees stayed in the vicinity of their work, the collection of resin, until their hind tibiae were packed with resin. This behavior was seen when over 50 per cent of those recapture, returned within 30 minutes. It was found that four species of Trigona collected resin produced by E. citriodora: Trigona (Trigona) silvestriana Vachal, Trigona (Partamona) cupira Smith, Trigina (Partamona) testacea musarum Cockerell, and Trigona (Trigona) ferricauda Cockerell. The larger bees T. silvestriana, were most active at 08.00 h and stopped flying by 18.00 h. The other bees had two peaks of activity, one at 06.00 h and a second at 17.00 h, with flight ceasation at 18.00 h. It was noted that T. silvestriana collected more resin per bee during 15-18.00 hours, the time trees were diminishing their resin production, this also was the time of the least T. silvestriana activity. It would seem that, even though less bees flew to the trees, each bee stayed at its task for a longer time, thus the nest continued to receive an adequate supply of resin. The beginning and end of daily bee flight is controlled by light; in the region of sunrise is about 05.30 h and darkness begins at about 18.00 h. Even though E. citriodora trees exude more resin during mid-day, there is a significant accumulation of resin during the night. Accordingly the smaller sized Trigona bee species seemed more specialized in their resin-collecting activities then T. silvestriana; diurnal activity of the smaller bees being early in the morning when the most resin has accumulated, and in the evening when T. silvestriana has decreased it's like activity. Several types of baits were tested in order to find one that would attract bees and induce them to take the bait back to their nest. Among 20 baits tested, the most satisfactory were resin extracted from Eucalyptus citriodora mixed with sugar; bees wax and honey, pine extract, agar, and honey, and, macadamia extract mixed with wax, honey, oil and saponifying agent. Unfortunately, none of these baits could compete with resin exuding from their natural host, E citriodora. It is believed that if a usable bait were found, sub-lethal insecticide doses could be included in the baits. In this manner, bees would carry small amounts of the baits back to their nests and in time, the nests would be eliminated as doses of the insecticides would slowly augument.