Efectos de la exposición a dosis sub-letales de Clorpirifos sobre biomarcadores de estrés oxidativo en abejorros nativos (Bombus pauloensis).

CECCHETTO FRANCO; CRUPKIN ANDREA; VILLALBA, A.; MAGGI MATIAS; MIGLIORANZA, K.S.B.

Congreso; VIII Congreso Argentino de la SETAC; 2022

Bees (Family Apidae), including the native bumblebee Bombus pauloensis, are key to biodiversity, ecosystem stability, and food production. Currently, these pollinators are threatened by a combination of factors, including excessive pesticide use. The latter, through mechanisms like oxidative stress, affects organism survival and, at sublethal levels, affect their physiology, impairing their chance to cope with environmental challenges. The objective of this study is to determine the impact of environmentally relevant sublethal doses of the insecticide chlorpyrifos on adult workers of B. pauloensis. In Argentina, chlorpyrifos is the most used insecticide in agriculture and it is being phased out. Exposure trials to commercial chlorpyrifos in sucrose syrup were conducted using workers from commercial colonies, which were exposed to different concentrations (200, 20, and 10 ng/ml) and times (24, 48, and 72 hours). Individuals from each treatment group (N=6) were sacrificed, then the activity of the antioxidant enzymes Glutathione-S-Transferase (GST) and Catalase (CAT), and lipid peroxidation (LPO) levels were evaluated in total tissues. Here, are shown previous but also novel results of an ongoing study. GST activity at 24 hours showed to be higher with the increase of the dose. At 48 hs, this trend reversed, with the lowest value observed in the 200 ng/ml group, indicating possible enzyme inhibition. The interaction between the factors time and dose was statistically significant. CAT activity did not show clear trends among dose groups, although slightly lower absolute levels were found at 48 and 72 hs. LPO levels were similar among treatments at 24 hs, different at 48 hs were the 200 and 20 ng/ml groups showed significant lower levels, but aversely, at 72 hs the 200 ng/ml group showed the highest LPO levels with respect to the other groups. Again, the interaction between dose and time was significant. This increased lipid peroxidation appears to coincide with the possible inhibition of GST activity observed at longer time points in the 200 ng/ml group. However, further assessment of other oxidative stress biomarkers and the target enzyme affected by chlorpyrifos (Acetylcholinesterase) is needed to improve the effects framework. This study represents the first analysis of sublethal effects of an insecticide on native bees in Argentina and highlights the potential of B. pauloensis as a model organism.Keywords: Native bees, chlorpyrifos, biomarkers, oxidative stress