Long-Term Selection with α-Solanine Enhances Tolerance and Drives Multilevel Physiological Remodeling in Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae)

Abstract

Simple Summary The fall armyworm feeds on many crops and encounters diverse plant defensive chemicals. We examined whether repeated exposure to α-solanine, a defensive compound associated with potato, changes how this insect performs and responds physiologically. A line maintained for 12 generations on an α-solanine-containing diet became more tolerant to the compound. Under α-solanine exposure, the selected insects developed faster and showed higher pupation, adult emergence, and egg hatch rates, while pupal mass and egg production remained similar to the unselected line. The selected line also showed faster population turnover and distinct patterns of detoxification-enzyme activity, metabolism, and expression of detoxification- and stress-related genes. Its metabolic response to α-solanine was smaller than that of the unselected line, and its response to potato foliage was also altered. These findings show that sustained exposure to one plant defensive compound can produce coordinated changes across survival, development, reproduction, and physiology, helping explain how a pest that feeds on many crops adjusts to challenging plant chemistry.