Effects of anthropogenic stress on stingless bees Melipona mandacaia inhabiting urban and natural environments

Abstract

Bees play a crucial role as pollinators, significantly contributing to ecosystem health. However, they face growing threats from human activities. This study uses biomarkers to evaluate the health status of Melipona mandacaia, a stingless bee native to the Caatinga biome, as indicators of anthropogenic stress. Bees were collected from the unique Caatinga biome, which had no recorded human pressure, and from an urban area with high human pressure. These bees were then analyzed for various biomarkers to assess the different levels of anthropogenic stress. The biomarkers included cholinesterases (ChE) to assess neurotoxicity, catalase (CAT) to measure antioxidant responses, glutathione S-transferases (GST) for detoxification pathways, and lipid peroxidation (LPO) as an indicator of oxidative stress. The results reveal that ChE inhibition may be associated with stress levels due to human activities showing an inhibition pattern with increased stress levels (up to 54.4 % inhibition), while the remaining biomarkers showed mixed responses across the different stress-level areas. In addition, the use of a principal component analysis (PCA) allowed a separation between the different groups and the weigh of the measured variables to each anthropogenic stress group. The integrated biomarker response (IBR) index was applied showing a clear distinction among groups. The obtained results could be partly explained by the beekeeping practices in some locations, which may have mitigated the effects of anthropogenic stressors to a certain degree, especially in HS. These findings underscore the importance of monitoring wild bee health in the Caatinga and demonstrate the value of a multifaceted biomarker approach for understanding the impacts of anthropogenic stressors on bee populations in varied environments and the effects of beekeeping.