Abstract

Heat stress profoundly affects insect physiology and fitness, yet the adaptive mechanisms in predatory insects remain poorly understood. In this study, we examined the responses of Arma chinensis —an ecologically important predatory natural enemy—to heat stress (38 ℃ and 44 ℃ for 1 h daily over five consecutive days) using integrated physiological, microbiomic, and transcriptomic analyses. Heat stress significantly increased body weight and enhanced thermal tolerance, as indicated by a prolonged median lethal time (LT₅₀). Gut microbiota analysis further revealed temperature-induced shifts in community structure, with notably higher abundances of Priestia and Longimicrobium under high-temperature stress. Transcriptome sequencing identified 121 key heat-responsive genes, including heat shock proteins (Hsps) and genes associated with proteostasis, DNA repair, and metabolic reprogramming. Weighted gene co-expression network analysis (WGCNA) highlighted CRYAA as a central hub gene. Integrated correlation analysis revealed significant associations between specific microbial taxa and host transcriptional responses. Collectively, these findings provide comprehensive insights into the integrated adaptive strategies of A. chinensis under thermal stress and suggest potential molecular and microbial markers for enhancing thermal tolerance in biological control agents.