Behavioral and Physiological Response of the Wild Grayish Baywing (Agelaioides badius) After Chronic Exposure to Imidacloprid Treated Seeds

MARIA BELEN POLISERPI; BRODEUR, JULIE CÉLINE

Congreso; SETAC LatinAmerica 14th Biannual Meeting; 2021

The imidacloprid (IMI) is a neonicotinoid insecticide largely used in seed treatment in many countries, including the Argentinean Pampa Region. The consumption of IMI treated seeds is a hazard for farmland birds, even if only a part of the bird?s diet is composed of treated seeds. In this context, the objective of the present study was to characterize the effects of IMI in the wild grayish baywing (Ageliaioides badius) in a realistic scenario in which birds feed chronically on treated seeds as a portion of their daily diet. To address this issue, baywings were fed for 32 days with IMI treated seeds with 2.5 and 15 % of a regularly used concentration (3 g IMI/ kg seed), simulating the consumption of the 2.5 or 15% of their daily diet as treated seeds. Seeds were sprayed with the product Confidor® OD, and treatment concentrations were 0.075 g IMI/kg seed (Low dose) and 0.45 g IMI/kg seed (High dose). The effects exerted by IMI on birds were evaluated in a variety of behavioral, physiological, hematological, genotoxic, and biochemical parameters during and after exposure. In both treatments, delayed mortality was observed: 60% (N=7) of individuals died in the High-dose group within 15 days, and 8% (N=1) in the Low-dose group after 30 days. The mean survival time for the High-dose group was 12,5 days. High-dose birds significantly decreased their feed intake rate by 20% the first three days, compared to the other groups. High-dose birds also decreased their body weight the first week (p˂ 0.05). Birds treated with the High dose had lower escape reactions and lower response to a predator?s sound (p˂ 0.05). Birds exposed to the higher IMI treatment, experienced reduced mobility in the cage the first two weeks, while the Lower-dose group experienced reduced mobility in the fourth week of exposure (p˂ 0.05). No alterations in the hematological or genotoxicity parameters were observed in treated birds after 32 days of exposure. After the 32 days of exposure, glutathione S transferase activity in the plasma of treated birds decreased, and the cholinesterases activity increased in the liver of treated birds (p˂ 0.05). This study highlights that consumption of only 2.5% of bird?s daily diet as IMI treated seeds, is sufficient to generate sublethal effects and death. In the field, these effects may have consequences on wild birds affecting their capacity to search for refuge or escape from a predator, representing a risk to farmland bird populations.