Steroidal glycoalkaloids (GAs) are key plant defense compounds, yet their effects on insect gut physiology are not fully understood. We investigated how purified α-chaconine and Solanum tuberosum leaf extract influence the gut function and growth of the mealworm Tenebrio molitor. Larvae were exposed to sublethal doses of GAs, and gut contractility, midgut digestive enzyme activity and body weight were analysed over time. Both α-chaconine and potato extract caused a rapid decrease in digestive enzyme activity 2 h after exposure, followed by a clear increase above control levels after 24 h, indicating a time-dependent compensatory response of the digestive system. Gut contractility was significantly enhanced in treated larvae, and larvae exposed to both treatments exhibited a body weight loss over 72 h. These results show that potato glycoalkaloids strongly modulate the gut physiology of T. molitor while allowing continued growth, highlighting both the plasticity of insect digestive responses and the need to consider sublethal, gut-centered effects when evaluating glycoalkaloids as candidates for bioinsecticidal agents.
Slocinska et al. (Thu,) studied this question.