Transgenerational effects of peppermint essential oil on life table parameters and antioxidant enzymes in Callosobruchus maculatus.

Cowpea weevil (Callosobruchus maculatus) causes critical losses by affecting the quantity and quality of stored cowpea grains. The aim of this study was (a) to analyze peppermint (Mentha piperita) essential oil (EO) chemical constituents, (b) to explore its effects on the female and male adults, (c) to investigate whether exposure of parental generation (F(0)) influences life table parameters and antioxidant enzyme activities in subsequent generations (F₁ and F₂). GC-MS analysis identified 52 volatile compounds in the peppermint EO, with isopulegol (26.613%), L-menthone (20.284%), cis-menthone (8.528%), eucalyptol (5.855%), camphene (5.754%), camphor (4.882%), and D-carvone (3.984%) as major constituents. The EO exhibited vigorous adulticidal activity, with males more susceptible (LC₠₀ = 1.894 ppm) than females (LC₠₀ = 3.349 ppm). Sublethal EO exposure significantly reduced fecundity and affected key life table parameters (GRR, R0, r, and λ). Notably, LC₁₀ in F₁ and LC₃₀ in F₂ generations resulted in decreased GRR, R₀, and r, while λ increased. Enzyme assays revealed substantial modulation of glutathione S-transferase (GST), catalase (CAT), and superoxide dismutase (SOD) activity, particularly at LC₃₀ and in the F(2) generation, indicating a possible oxidative stress response mechanism. These findings indicate that sublethal EO exposure can induce immediate and transgenerational physiological stress in C. maculatus, supporting the potential of peppermint EO as a botanical insecticide in sustainable pest management.