Adapting pesticides effect studies to stingless bees: a colony level feeding study with Melipona quadrifasciata

• Ano de defesa: 2019
• Autor(a) principal: Santos, Camila Camata
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Biblioteca Digitais de Teses e Dissertações da USP
• Palavras-chave em Português: Dimethoate; Dimetoato; Estudo de semi-campo; Exposição oral; Meliponini; Native pollinators; Oral exposure; Polinizadores nativos; Semi-field study
• Link de acesso: http://www.teses.usp.br/teses/disponiveis/41/41134/tde-04112019-095823/

Pesticides effects on pollinators and representativeness of native species in ecological risk assessment and studies are an increasing concern. Stingless bees are especially important in Brazil, a major agricultural producer. Given the lack of colony-level data, a feeding study methodology for Melipona quadrifasciata was proposed and tested with the toxic standard dimethoate. Free foraging colonies at five sites were offered sugar syrup containing 0 (C), 75 (T1), 100 (T2) and 200 (T3) μg dimethoate/Kg and assessed weekly up to five weeks after exposure. Dimethoate concentration was analytically verified in the artificial syrup and honey from colonies. Pollen from pots was identified throughout the experiment. Actual concentrations in the syrup were 75-117% of nominal levels and low dissipation/dilution occurred in honey pots during the study. Mean numbers of foragers, brood, honey pots, proportions of brood mortality and incomplete honey pots, behavior and colony survival were significantly affected in T3 colonies, compared to control. Transient effects on brood mortality and incomplete pots (T1) or on number of new cells (T2) were observed at the lowest concentrations, but were rapidly recovered and may not be treatment related. Pollen diversity varied between sites, but no clear treatment differences were observed. The proposed methodology allowed identification of suitable parameters for colony-level studies using M. quadrifasciata, and of the no-observed effect concentration (nominal: 100 μg/Kg)