Efeitos do herbicida glifosato no comportamento da espécie de abelha Tetragonisca angustula (Latreille, 1811)

Abstract

The stingless bees (Hymenoptera: Apidae: Meliponini) are important pollinators of native flora, as well as species of economic interest. However, some factors have been affecting the survival of these insects, such as the indiscriminate use of pesticides. The objective of the study was to evaluate the oral toxicity of the herbicide glyphosate in Tetragonisca angustula. To carry out this research, protocol number 213 of the Organization for Economic Cooperation and Development (OECD) was followed. Three treatments were applied, with concentrations: 0 μl/mL(T1); 19.75 μl/mL (T2); 39.5 μl/mL (T3) and 79 μl/mL (T4). The mortality and sub-lethality of the bees was evaluated at one, six, 12, 24, 48, 72 and 96 hours after exposure to the stressor, observing behavioral variations during the evaluations. The data were submitted to statistical analysis in the R Core Team software, generating Kaplan-Meier survival curves that were compared using the Logrank test, dose-response analysis to estimate the median lethal concentration (LC50) of the herbicide. The mortality rates of bees exposed to glyphosate were: 75% (T4); 50% (T3); 13.8% (T2) and 0% (T1). The Logrank test showed significance between the survival curves (p<0.01), indicating that there was a statistical difference between the tested concentrations. The glyphosate LC50 (42.57 ± 4.40 ul/mL) was similar to the highest recommended field dosage (39.5 ul/mL). The bees showed changes in behavior from the first hour of evaluation. The results of this research certify that glyphosate in a commercial formulation can compromise the survival of T. angustula individuals at the dosages recommended by the manufacturer, as well as promote behavioral changes, indicating possible sublethal effects that still require more detailed investigations.