Thermotolerance response mechanisms of Tuta absoluta and its microbiota under short-term high-temperature stress

Global warming-induced extreme high temperatures pose severe challenges to the adaptive evolution of invasive insects, while the thermotolerance response mechanisms of most invasive insects and the changes in their resident microorganism in response to high-temperature stress underexplored. This study systematically investigated the thermotolerance response mechanism of the major invasive pest Tuta absoluta (Tomato Leafminer) and the impact of short-term high-temperature stress on its resident microorganism (including gut, reproductive glands, mouthparts, etc.), particularly on the endosymbiont Wolbachia. Gradient heat shock experiments (26℃, 36℃, 44℃) revealed that 44℃ treatment for 3 hours significantly reduced female adult survival rate to 20.33%, while 36℃ had no significant effect; female adult lifespan showed no significant differences after different temperature treatments; the activities of three antioxidant enzymes (Catalase CAT, Peroxidase POD, and Superoxide Dismutase SOD) did not change significantly under high temperature, suggesting its thermotolerance does not rely on the traditional antioxidant system. 16S rRNA gene sequencing indicated that high temperature significantly altered the microbial community structure: Proteobacteria accounted for over 83.62%, the abundance of the symbiont Wolbachia in the high-temperature female adult group significantly increased to 70.40% (ambient temperature group < 42.18%), and microbial α-diversity (Shannon index decreased by 64%) and function were altered. KEGG analysis showed that microbiota pathways related to carbohydrate metabolism and energy metabolism were significantly activated under heat stress, accompanied by enrichment of antibiotic biosynthesis genes, implying that Wolbachia may enhance heat tolerance by regulating host energy homeostasis and suppressing pathogens. This study reveals the responses of T. absoluta and its resident microorganism to short-term high-temperature heat shock, laying a theoretical foundation for further investigation into the influence of symbiotic bacteria like Wolbachia on the thermotolerance of T. absoluta.