Hormetic-like feeding alterations and intergenerational effects of afidopyropen in the cotton leafhopper Amrasca...

Sublethal insecticide exposure is frequent in agricultural environments as a consequence of natural compound degradation and variable efficacy, often leading to diverse physiological and behavioral responses in pests. These effects may extend across generations but remain poorly understood in leafhoppers, key targets of insecticide applications. Afidopyropen, a novel systemic insecticide with potent feeding-inhibitory properties, has proven effective against sap-sucking pests. In this study, we evaluated its toxicity to the cotton leafhopper Amrasca biguttula and assessed sublethal impacts on feeding behavior and life-history traits using electropenetrography (EPG) and two-sex life table analysis.

Bioassays confirmed strong toxicity against 3^rd-instar nymphs [median lethal concentration (LC₅₀) = 4.67 mg a.i. L^-1 at 168 h]. EPG identified six characteristic waveforms, including A2 and A3 representing active ingestion with and without watery salivation, respectively. Afidopyropen exposure caused a dose-dependent increase in nonprobing duration and suppression of active ingestion, culminating in complete feeding inhibition at 106.9 mg a.i. L^-1. Remarkably, sublethal exposure reduced feeding activity in the parental generation but significantly enhanced it in the F₁ progeny. Correspondingly, developmental and reproductive parameters were significantly modified in the F₁ generation derived from treated parents.

This study provides the first evidence of insecticide-mediated feeding alterations and intergenerational hormetic effects in A biguttula, highlighting the potential risks of pest resurgence and elevated crop damage following sublethal afidopyropen exposure. These findings emphasize the need for careful risk assessment and judicious integration of afidopyropen into integrated pest management programs. © 2025 Society of Chemical Industry.