Chlorantraniliprole-mediated toxicity and changes in sexual fitness of the Neotropical brown stink bug Euschistus heros

Abstract

Chlorantraniliprole is a diamide insecticide that has been widely used against lepidopteran pests. However, the actions of this compound on non-targeted insect pests such as the Neotropical brown stink bug Euschistus heros (Hemiptera: Pentatomidae) have not received attention. Here, we assessed the susceptibility of E. heros to chlorantraniliprole as well as the potential chlorantraniliprole-mediated changes in the sexual fitness of E. heros. Newly emerged (≤24 h old) individuals were exposed for 48 h to dry residues of chlorantraniliprole, and mortality was recorded. To assess the sexual fitness of E. heros, we tested four couple combinations: untreated male and female; untreated male and treated female; treated male and untreated female; and treated male and female. Chlorantraniliprole caused low mortality regardless of the developmental stage assessed (e.g., 3rd, 4th, 5th, and adults). However, sublethal exposure (i.e., at the concentration of 0.56 µg/cm2) to chlorantraniliprole affected the sexual fitness of stink bug couples. While treated males coupled with untreated females exhibited a higher number of matings, untreated males coupled with treated females exhibited a higher mean survival time. These treated females coupled with untreated males showed a higher oviposition peak and shorter egg incubation time but a delay in their peak of fertility. Curiously, the untreated females coupled with treated males exhibited higher daily fecundity, which potentially represents chlorantraniliprole-induced hormesis which may have contributed to the recent outbreaks of E. heros observed in Brazilian soybean fields.