S14 - Session P5 - Insect community composition and functional groups within models regarding distinct pesticide managements

Authors: Rodrigo Araujo *, Carlos de Melo, Claudio Salas, Cristián Valdez, Monika Ruiz, Anibal Valencia

Chilean Lettuce crops correspond to the leafy vegetable species with a higher percentage of production under traditional farming concepts, with a range of 6n10 applications of insecticides per production cycle. Thus, our objective was to evaluate the influence of pesticides usage in different lettuce horticultural systems and how it affects the composition and functioning of the entomological communities associated with this agroecosystem. Four traditional managements with ≥ eight pesticide applications (high) per crop cycle and three integrated pest managements with ≤ two applications (low) per crop cycle were selected in the "Pan de azucar", Coquimbo Region, Chile. The insect sampling was conducted for 7 months using the yellow pan traps. In relation to the entomological community were evaluated: Abundance, species richness, Simpson dominance, Shannon-Weaver Diversity (SWD), equitability, and the same variables but considering only the functional groups found (considering functional traits performed by each insect family based on the exploitation of the same resource in a similar way). To compare localities and different managements (predictors), we analyzed variable models (GLMN~95% significance) using community attributes as response variables. All variables had an effect in relation to the date of a colleague, as would be expected, but only species richness, SWD, and equitability (p=0.000) had an effect in relation to areas with different managements. The ecological attributes calculated with functional groups were not efficient to verify the effect of management in the areas. species richness was still the only variable that showed an effect between area management and seasonality (p=0.004). The most evident differences were in species richness being 47% higher and 17% for equitability between Low to High pesticide application areas. Species composition increasingly differed between the studied sites as management intensity increased. We conclude that small reductions in management intensity can have a significantly positive impact on insect biodiversity.