Sublethal indoxacarb exposure alters pheromone production and ovarian development in the yellow peach moth, Conogethes punctiferalis

Abstract

The Conogethes punctiferalis, a major pest of peach and other fruit trees, causes significant damage by boring into fruits during its larval stage. Indoxacarb, a sodium channel blocker insecticide, has been widely applied in agriculture and horticulture for pest control, particularly against larval pests. However, its effects on adult insects remain largely unexplored. Present study employed C. punctiferalis as model to investigate the toxic effects of indoxacarb on adult moths. The results showed that sublethal exposure to indoxacarb significantly reduced the release of sex pheromones, reduced female attraction to males, and lowered mating success rate. Further investigations indicated that exposure to sublethal indoxacarb resulted in a significant decrease in Ca²⁺ levels in the pheromone gland (PG), subsequently affecting the activities of calcineurin and acetyl-CoA carboxylase as well as affecting the expression levels of genes related to sex pheromone biosynthesis. Physiological assays revealed that indoxacarb exposure significantly reduced trehalose content, hexokinase activity, and pyruvic acid content in the PG. Moreover, ovarian development was hindered as the exposure led to reduced ovarian size and vitellogenin (Vg) content. Transcriptomic analysis revealed change in genes linked to ovarian development, including Vg, vitellogenin receptor (VgR), and genes related to lipid metabolism. In conclusion, this study demonstrates that indoxacarb exerts a dual regulatory effect on adult C. punctiferalis, inhibiting both sex pheromone biosynthesis and ovarian development. These findings provide novel insights into the mechanisms by which sublethal pesticide exposure influences adult moths.