Chironomids commonly dominate macroinvertebrate assemblages in aquatic habitats and these non-biting midges are known for their ability to tolerate contaminants. Studies regarding the interplay between gut microbiota and host detoxification ability is currently a point of interest. Cytochrome P450s (P450s) are critical metabolic enzymes in which a subset is involved in xenobiotic detoxification. In this study, we first conducted an integrated global investigation of P450s based on the whole genomic sequence of Propsilocerus akamusi and retrieved a series of 64 P450 genes which were further classified into 4 clans and 25 families on the basis of phylogenetic relationships. With assistance of RNA-Seq and RT-qPCR validation, the expression profile of screened PaP450s in guts was compared between chlorpyrifos-challenged larvae with deficient gut microbiota (GD) and those with a conventional gut community (CV). An increasing prevalence of chlorpyrifos from sublethal to lethal dosages induced a greater mortality rate of individuals coupled with remarkable downregulation of 14 P450s in GD larval guts when compared to CV ones. Moreover, it turned out that the decreased level of PaCYP3998B1 and PaCYP3987D1 might imply impaired host endogenous detoxification capability potentiated by gut dysbiosis, reflected by a remarkably severe mortality in GD larvae treated with lethal chlorpyrifos. Collectively, our study unveiled candidate P450 genes that might be mediated by gut symbionts in chlorpyrifos-challenged P. akamusi larvae, possibly facilitating further understanding of the detoxified mechanism that chironomids might employ to alleviate poisonousness.

Gut microbial community research has garnered considerable attention due to its pivotal role in shaping diverse insect hosts’ life-history traits, with key studies confirming that insect gut microbiota is vital for core physiological processes including growth, nutrient metabolism, nitrogen fixation, pheromone biosynthesis, and environmental adaptation. Findings highlight that integrating insect ecology understanding with gut microbial community characterization is indispensable for innovative pest management strategies. Notably, S. frugiperda, a globally destructive agricultural pest causing substantial annual economic losses, has been extensively investigated. Its host range is extremely wide, from staple food crops such as corn and rice to various cash crops. This review systematically synthesizes the prevalent diversity of its gut’s dominant microbes, clarifies the important mechanism of gut microbiota in host stress adaptation (providing direct evidence for explaining the pest’s stress resistance formation), draws the key conclusion that host–microbe interaction mechanisms can serve as key pest management targets to guide more targeted control technologies. We also discuss current limitations such as inadequate microbial function verification and unclear host–microbe molecular mechanisms while outlining future directions including focusing on microbial community dynamic changes under multiple environmental stresses and functional microbe screening and application.

Chironomids are abundant aquatic macroinvertebrates with known pollutant tolerance, but the molecular effects of chlorantraniliprole (CAP) remain unclear. In this study, we exposed Propsilocerus akamusi larvae to LC₁₀ and LC₅₀ of CAP, sampled at 48 h and 144 h, and integrated biochemical assays, metabolomics, and transcriptomics to profile stress responses. Our results showed that CAP elevated antioxidant enzymes and protein carbonyls, indicating severe oxidation, especially at LC₅₀. At 48 h, LC₁₀ activated JNK-mediated antioxidative and drug metabolism pathways, whereas LC₅₀ altered glycolysis, cofactor biosynthesis, and fatty acid metabolism. At 144 h, LC₁₀ enriched proteasome and oxidative phosphorylation pathways; chaperones PaHsp70 and PaHsp90 were upregulated by 4.14- and 2.08-fold, respectively, and were negatively correlated with lipid and carbohydrate metabolites, indicating a metabolic shift toward protein repair. In contrast, LC₅₀ CAP triggered protein processing in the endoplasmic reticulum (ER) and TCA cycle dysregulation, with upregulation of PaCalreticulin linked to energy crisis markers, reflecting severe energy collapse. After knockdown of PaHsp70, the survival rates of chironomid larvae exposed to LC₁₀ and LC₅₀ CAP significantly decreased from 80.8% to 65.8% and from 43.3% to 28.3%, respectively. Collectively, our results revealed that low CAP concentrations triggered early detoxification followed by proteasome- and Hsp-mediated strategies to sustain protein homeostasis whereas high concentrations directly disrupted core metabolism and ultimately caused energy collapse and lethal ER stress in chironomid larvae. These findings provide mechanistic insights into the chronic effects of CAP on aquatic insects.