Agrotóxicos e fisiologia de guildas alimentares de morcegos em diferentes paisagens

Abstract

The loss and fragmentation of habitats is one of the greatest threats to biodiversity and the maintenance of ecosystem services, and may have physiological implications for the wild fauna. The objective of this thesis was to evaluate how changes in the landscape may impact the health of bats from different trophic guilds. In Chapter 1, a bibliographic review was made addressing the state of the art regarding bats and pesticides. It was observed that research on the topic is concentrated in the Northern Hemisphere, mainly in the USA. Only 5% of the world's species have been studied, predominantly insectivorous species. Insecticides were the most searched pesticides, mainly organochlorines. Thus, the knowledge about the effects of pesticides on bats is still insufficient for a risk assessment of their populations or their use as bioindicators. In Chapter 2, a method for determining residues of 48 types of pesticides by gas chromatography coupled with mass spectrometry in bat muscle was presented. The miniaturized extraction method makes feasible the analysis when the volume of sample is limited. In addition, by using fewer reagents, it reduces the cost, impact on the environment and on the health of researchers, making it possible, therefore, to carry out this type of evaluation on bats as bioindicators. In Chapter 3, an assessment was made of the physiological changes linked to different lands use and occupation profiles. Bats were collected from a protected area, the Serra do Cipó National Park (PARNA Cipó), MG, Brazil, and an area with intense agricultural activity, in the municipality of Uberaba, MG, Brazil. Despite the differences in land use and occupation between the studied areas, bats showed similar responses. However, it was found that trophic guilds are affected differently. Frugivorous bats in both areas showed lower activity of the enzymes SOD, CAT and GST and low concentrations of MDA, which can be explained by the greater intake of antioxidants from the diet, in addition to the lower production of reactive oxigen species (ROS). Histopathological analysis of the liver revealed that the animals had similar prevalences in the two areas, with some differences related to the guilds. Hematophagous bats from PARNA Cipó had a higher prevalence of steatosis and, together with frugivorous bats from Uberaba, had higher frequencies of ballooning degeneration, suggesting that these animals are subjected to anthropogenic factors capable of inducing disturbances in hepatic metabolism. Hematophagous bats from Uberaba had a higher prevalence of portal inflammation, and insectivorous bats from Uberaba had a higher prevalence of lobular and portal inflammation. Although the profiles of use and occupation of the areas are different, the health status of the animals is similar, with some differences between trophic guilds. These differences seem to be related to the way each group responds to environmental changes, in addition to aspects of biology and ecology specific to each guild. Considering that bats from different trophic guilds present different physiological responses to changes in the landscape, the importance of knowing the responses of each guild to measure the losses related to the ecosystem services provided by these animals is emphasized, as well as determining which guilds or species can be used as bioindicators of environmental quality.