Mortality, Immobility and Biochemical Acute Effects of Thiacloprid on two Populations of Hyalella curvispina Amphipods From North Patagonia Argentina

KIRILOVSKY EVA RUTH; CARRASCO NATACHA; BONGIOVANNI, GUILLERMINA A.; ANGUIANO OLGA LILIANA; FERRARI ANA

Congreso; SETAC Latin America 14th Biennial Meeting; 2021

SETAC Latin America

Thiacloprid (TCP) is a neonicotinoid insecticide widely used in the Valley of Río Negro River as pest control for fruit production. The aim of this study was to evaluate TCP acute effects in two different populations of the amphipod Hyallela curvispina, from a pristine site (LB) and an agricultural one (FO) located in North Patagonia Argentina. Both populations have shown differences in susceptibility to anticholinesterasic insecticides in previous studies.Amphipods from LB and FO were exposed to increasing concentrations (0-100 mg/L) of TCP (Calypso ®, Bayer), lethality and immobility were measured every 24 h for four days and 96 h LC50 and EC50 values were determined. In addition, amphipods were exposed to sublethal and lethal concentrations of TCP (LB: 0.02-2, FO: 0.02-100 mg/L), and enzymatic activity of glutathione-S-transferase (GST) and carboxylesterase (CE), and reduced glutathione content (GSH) were measured spectrophotometrically in surviving individuals at 48 and 96 h.TCP 96h-LC50 for LB was 0.42 (0.21-0.78) mg/L, while for FO it was 44.2 (15.6-134.8) mg/L, two orders of magnitude higher. Immobility 96h-EC50 value for LB was 0.14 (0.07-0.23) mg/L, and for FO, 0.14 (0.06-0.26) mg/L. GST activity in LB was not significantly affected by TCP. In FO it showed a tendency to increase at 2 mg/L and a significant increase with 20 and 100 mg/L (50 and 60% vs. control), and after 96 h with 0.2 and 2 mg/L (42 and 35%). There were no significant differences in CE activity in LB after 48 h, while all tested concentrations decreased after 96 h (48, 53 and 51%, respectively). CE activity increased in FO after 48 h exposure to 0.2; 2 and 100 mg/L TCP (28, 93 and 57 %, respectively) while no significant differences with controls were observed after 96 h. No significant differences were found in GSH content between exposed and control amphipods from both populations.Higher LC50 levels in FO compared to LB could be a sign of tolerance to TCP due to a history of use in this agricultural frame. However, both populations showed the same immobility response, which would most likely hinder the chances of survival in the wild. This highlights the importance of immobility as a biomarker of effect. The increase in GST and CE activities, even at sublethal concentrations, could be linked to a protective response in FO amphipods. The results obtained in this study constitute further evidence of the impact from continued neonicotinoid applications on autochthonous species.