Medicinal aromatic plants modulate Tenebrio molitor and Zophobas morio biochemical responses

Abstract Insects provide a sustainable, high-quality protein source, thus incorporating agri-food by-products into their farming aligns with circular economy principles. This study explored the effects of supplementing wheat bran substrates for Tenebrio molitor and Zophobas morio (Coleoptera: Tenebrionidae) larvae with medicinal aromatic plant (MAP) distillation residues (agri-food by-products from rock samphire, oregano, industrial hemp, linseed and olive paste). We assessed heat shock response, MAPK activation, apoptosis, and antioxidant defense in larval samples. Increased Bcl-2 levels in T. molitor suggested that MAPs may inhibit apoptosis; however, MAPs also suppressed heat shock response, mitogen-activated protein kinases (MAPK) activation, and antioxidant enzyme activity. Combined with previous observations of decreased larval growth and higher mortality, these results indicated MAPs-induced oxidative stress that exceeds the insects’ ability for compensatation. Overall, our findings revealed notable physiological stress and negative impacts on insects’ welfare due to dietary MAPs, thus highlighting the need for further research to clarify their safe application.