Ecologia urbana de uma abelha nativa: respostas comportamentais de colônias de uruçu amarela (Melipona flavolineata, Apidae, Meliponini) às variações climáticas em um gradiente de urbanização

Abstract

Urbanization can generate changes in the structure of the environment, also affecting physical- chemical processes. These changes over time have caused the loss of habitats and with them the reduction of populations of stingless bees, which are a group of insects important for the maintenance of ecosystems. Stingless bee populations, unlike the Apis genus, are at risk of reducing their population because they are not very flexible to changes and their possibility of adapting to urbanized areas is very low. For this reason, our study aimed to know the urban ecology of the stingless bee species Melipona flavolineata, measuring their responses in foraging behavior and posture to climatological parameters in environments with different degrees of urbanization (agroforestry-semi- urban and urban). We observed 12 colonies of M. flavolineata for five months. The observations were weekly, alternating internal and external activity. The rate of foraging (weekly average) was evaluated from 7:00 am to 11:00 am (time of greatest foraging) and bees were counted back to the colony, parallel to this process, data of temperature, relative humidity, luminosity and barometric pressure were recorded. The laying rate (weekly average) was assessed for four consecutive days in the corresponding week. The results showed that the climatological parameters had a high variation in the three collection points, affecting the performance of the bees. Barometric pressure and relative humidity had a positive and significant effect on pollen collection. Relative humidity and temperature had a positive and significant effect with the nectar foraging; barometric pressure had a negative, non- significant effect. The laying rate was higher as the relative humidity was added, showing a positive relationship; barometric pressure had a positive, but not significant, effect. The relationships between the foraging rate and the laying rate; as well as the relationship between the pollen foraging rate and the nectar foraging rate, were positive and significant and did not differ between environments, just by the amplitude of the data. Thus, we conclude that the stingless bee M. flavolineata is a species that is not tolerant of completely urbanized areas, and its capacity to adapt to environments with unfavorable environmental conditions is very limited, as its activities are restricted by high climatic variations and probably by the scarcity of food resources. In this sense, it would be good to implement studies of the urban ecology of smaller species, and to add in the studies of responses to climatic factors the barometric pressure parameter which, according to our results, affects the behavior of stingless bees