Controle de temperatura pelas abelhas africanizadas (Apis mellifera l.) em colmeias sob condições de sol e sombra no Semiárido Nordestino

Abstract

The temperature control in Apis mellifera is realized by the bees themselves through behavioral adjustments in order to keep the temperature at optimum levels. Unfavorable climatic conditions such as high temperatures and intense solar radiation can cause overheating of the colonies and consequently damage to beekeeping. The objective of this work was to evaluate how africanized bees (Apis mellifera L.) control temperature under different conditions, exposed and protected from direct solar radiation in a semiarid environment. Three colonies of Africanized bees housed in Langstroth hives that were changed every 3 months were used, total of twelve colonies. The internal temperatures and humidity of the three colonies were recorded using thermohygrometer. The body surface temperature of the bees was measured in three parts of the bee's body, head, chest and abdomen, using a mini infrared thermometer. Observations of the social behavior of ventilation were classified into four levels ranging from none to high ventilatory activity. When the hives were in the shade the internal temperature of the hives remained within the range considered optimal, while in the sun, this condition was not reached. In the shade, the bees managed to keep the relative humidity stable. In the sun, there was an increase in internal humidity as the bees carried water to the hive in order to lower the internal temperature. The ventilation behavior was much more expressive in hives than in the sun, since in the shade only few bees were recruited for this task. The bees that were in the shade, managed to maintain their body temperatures at relatively normal levels, while the bees that was in the sun, had a considered increase of its temperatures. The chest temperature is the highest, followed by the head and abdomen. The mechanisms of temperature control used at colony level and at individual level in the shade were, low ventilation activity and heat transfer to the head, respectively. In the sun, at colony level were distribution of water in the hive and high activity of ventilation and at the individual level transfer of heat to head and abdomen and use of water to wet the body surface. The results obtained in this work, represent a mean collected data of individuals surface temperature of the bees and data of temperature and humidity inside the hives, which constitute important subsidies for an understanding of three fundamental principles for a beekeeping, or abandonment of the bees In drought, a low productivity in the semi-arid and a need of construction of cans for the supply of shade in the apiaries