Physiological selectivity and tolerance of social wasps exposed to Malathion

Insect pest infestations are a worldwide problem as a result of human actions. Among them, Aedes aegypti stands out as vector of several diseases. Like other pests, A. aegypti has become resistant to the insecticide used for its control, thus harming the local fauna of non-target insects. Therefore, the aim of this study was to study the physiological selectivity of social wasps exposed to Malathion, as well as to investigate possible resistance to this insecticide. Adults of the swarming species Polybia platycephala and Protopolybia sedula and the independent species Polistes versicolor were exposed to four Malathion concentrations. Overall, Malathion was more selective to P. versicolor and more toxic to P. platycephala, and despite the decrease in the concentration of the product recommended by the manufacturer, which in theory would be sublethal doses, social wasps still exhibited high mortality rates. In comparing the mortalities of species collected in an area where there is no application of the insecticide with an area where there is regular application, the data showed an indication that populations of non-target insects are also becoming resistant to insecticides, especially in urban environments.