Oxidative stress in honey bees (Apis mellifera) and small carpenter bees (Ceratina calcarata) across different landscapes

Abstract

Oxidative stress (OX) is a state of imbalance between antioxidants and reactive oxygen species, which are the byproducts of oxidative phosphorylation in the mitochondria. Honey bees (Apis mellifera) and small carpenter bees (Ceratina calcarata) are two important pollinators. However, it is unclear how pollinators respond to the abiotic stress in different landscapes at different management levels. Conventional, organic and roadside use different pesticides and pest control management practices. The roadside landscape habitats are unmanaged systems with potentially minimum exposure to agrochemicals and high traffic-related pollutants. Conventional farms represent direct agrochemical inputs, and organic farms restrict synthetic pesticide usage. Oxidative stress as levels of lipid peroxidation and protein carbonylation was quantified in individual bees of adult and larval stages and among three landscapes. Furthermore, pesticide residues were determined using chromatographic analysis. Results from the lipid assay show that bees collected from organic and roadside landscapes exhibited the lowest and highest OX levels, respectively. The protein carbonylation assay indicated a significant difference between conventional and organic farms. Similarly, a greater number of pesticides were detected in conventional farms compared to other habitats. Overall, these findings show that variation in pesticide residue profiles across landscapes is associated with different OX responses in bees, which will be a valuable foundation for monitoring pollinator health across different landscapes. It also showed that small carpenter bee is an emerging model system to study OX and insect physiology.