Untargeted metabolomics and detoxification of parthenium weed phytotoxins across life stages of Zygogramma bicolorata Pallister (Coleoptera: Chrysomelidae)

Abstract

This study investigates the metabolomic profiles across various life stages of the Parthenium beetle, Zygogramma bicolorata Pallister (Coleoptera: Chrysomelidae), and its host plant, Parthenium hysterophorus L. (Asterales: Asteraceae). As a promising biocontrol agent for the invasive Parthenium weed, understanding these profiles is essential. The analysis identified 2,588 metabolites in fourth-instar larvae (n = 15), 2,369 in larval feces (n = 15), 636 in adult females (n = 15), 929 in female feces (n = 15), and 3,161 in Parthenium leaves (n = 15 plants). Enrichment analysis based on chemical structure revealed distinct differences in chemical classes across the four groups: fourth instar larvae, larval feces, adult females, and female feces. A comparative analysis of metabolic pathways across all groups identified 11 pathways common to all, five shared only by larvae and adult females, seven exclusive to larvae, and one unique to adult females. Metabolomic profiles of larvae, adult females, and their feces contained a range of compounds, including terpenoids, flavonoids, amino acids, pseudo-guaianolides, carbohydrates, and phenolic acids. Among these, seven potential phytotoxic compounds—caffeic acid, vanillic acid, ferulic acid, chlorogenic acid, quinic acid, anisic acid, and parthenin—were also detected in the host plant P. hysterophorus. These findings highlight significant differences in the metabolic profiles of Z. bicolorata and its host plant, providing new insights into the insect's detoxification mechanisms. This study enhances our understanding of the complex biochemical interactions between Z. bicolorata and Parthenium, contributing valuable knowledge for biocontrol applications.