eng International Academy of Ecology and Environmental Sciences Arthropods 2224-4255 2025-12-1 14 4 174 186 2 article Preeti Subba 1 2 Soumya Majumder 1 2 Malay Bhattacharya 1 2 Molecular Biology and Tissue Culture Laboratory, Department of Tea Science, University of North Bengal, Rajarammohunpur, Siliguri, Darjeeling, West Bengal, India Looper caterpillars, Biston suppressaria and Hyposidra talaca, are the major folivorous insect pests of tea plants in India. They cause 40-90% economic losses during severe infestations and have become unmanageable, presenting a substantial challenge to stakeholders. Chemical profiling of an organism holds great significance in exploring an organism's biology, behavior, and ecological interactions necessary for developing effective pest mitigation strategies. So, this research was aimed to analyze the gut metabolomes of these looper pests using GC-MS analysis. The results determined a total of twenty-eight metabolites in the gut of these pests that included fatty acids as major metabolites followed by alkanes, alcohols, and terpenoids. Among detected fatty acids, hexadecanoic acid, methyl ester; ethyl (9Z,12Z)-9,12-octadecadienoate, and stearic acid are the primary metabolites for pheromone biosynthesis. Moreover, the upregulation of these fatty acids is also associated with pesticide stress response in many lepidopteran pests. In addition, ten common compounds were obtained that indicate their shared habitat, i.e., tea plants. Squalene, a precursor molecule forthe synthesis of many steroidal hormones, was detected as one of the major metabolites in this study, highlighting the important role of microbes in the synthesis of squalene in these pests' guts. Hence, our study hypothesized that gut microbes mediated plant-derived sterol biosynthesis in these pests. Moreover, the detection of the fluorinated metabolites in the gut extracts indicated the possible contribution of the gut microorganisms towards the breakdown of pesticides (fluorinated). Thus, targeting these gut bacteria interferes with the physiological function of the looper pestsand facilitates the development of effective pest management strategies. http://www.iaees.org/publications/journals/arthropods/articles/2025-14(4)/first-report-on-gut-metabolites.pdf tea looper chemical ecology GC-MS fatty acids pheromones detoxification pest management