Methyl linolenate as a feeding stimulant for the 28-spotted potato ladybird, Henosepilachna vigintioctopunctata? A molecular docking approach

The 28-spotted potato ladybird, Henosepilachna vigintioctopunctata is a key pest of Solanum melongena in Asian countries. In order to develop reliable tools to control this pest, it is important to explore the feeding activity and understand the influence of potential feeding stimulants present in the host plants for the pest development. Here we focused on a modern approach integrating feeding assays, GC-MS analysis and molecular docking, in order to shed light on potential feeding stimulants from young, mature and senescent eggplant leaves, routing the development of H. vigintioctopunctata larvae. As a general trend, food utilization indices showed best results when beetles fed on mature leaves, if compared to pests fed on young or senescent leaves. High feeding index and larval survivability were noted when beetles fed on mature leaves, followed by marked total lipid level deterioration. GC-MS analysis identified the main presence of methyl linolenate in S. melongena leaf extract. Therefore, we evaluated this compound using a novel approach based on a combination of bioinformatics and feeding assays, to identify potential compounds affecting the metamorphosis of H. vigintioctopunctata. A correlation between the deprival of lipids and larval growth was argued considering the marked interaction between methyl linolenate and ecdysone protein receptor. Overall, this research provides useful knowledge to understand the importance of feeding stimulants routing larval growth and development in H. vigintioctopunctata.