O Comportamento de defesa das abelhas africanizadas (Hym.: apidae) e sua relação com a variação na quantidade de veneno produzido pelas operárias

Abstract

The crossing of the africanized bees with the european ones resulted in a highly defensive hybrid in brazil. The acid gland and the stinging apparatus are structures directly involved in development of the bees' behaviour of defense, by being responsable of the production and also the injection of the venom. To evaluate the defensive behaviour, the same was measured according to the methodology related in the usual literature and decomposed as in: "time to hit the first sting, the time the bees took to enrage, the distance of chase and the number of stings left in the artificial enemy". The morphological variations analyzed in the gland are considered to be from genetic origin and they directly influenced the amount of produced venom. This produced venom amount was evaluated by its dry weight, by breaking the reservatory and spilling its content on a histological pre-weighted coverslip with the identical numeration as the established for the gland. The set was introduced in a drying oven for 24 hours, weighted again and, by the difference, the value of the dry weight of venom was obtained. To verify if the amount of venom produced could influence the africanized bees' defense behaviour, the dry weight of the venom was compared with the variables of behaviour by using the spearman correlation test (rs). Regarding the results obtained for the defensive behaviour, it was observed that, for the first variable, 70% of the colonies analyzed presented great defensive capacity, when for the second variable 50% were more defensive and for the third one, 50% were for the colonies and for the number of stings 50% were more efficient in this variable. For variations in gland morphology, to length of the main glandular duct (mdl) there was a variation from 5,8 ± 1,7mm to 9,6 ± 3,5mm. To the length of the extra ramification (rl), when there, the variation went from 0,1 ± 0,1mm to 1,0 ± 0,1 mm and for total glandular length (mdl + rl) = (tgl), 6,0mm to 11,0mm. The frequency of ramification varied from 0% to 93,3% in 2, 4 and 8 beehives. To weight of dry venom, the beehive 2 got the maximum weight of 0,00060 ± 0,00050 and the minimum weight was obtained (0,00022 ± 0,00016) in the beehive 6, with an overall average of 0.00035 ± 0.00012 venom produced. About the behaviour variables correlated to the amount of venom produced (dry weight), the "time the bees took to enrage" was significant, while the other ones, "time to hit the first sting, the distance of chase and the number of stings left in the artificial enemy", weren't, according to the sequential development of behavior analyzed in africanized bees in dourados-ms. It is considered that the africanized bees of the region still present a defensive behaviour very similar to the behaviour of first africanized bees introduced to this country.