Although Telenomus remus, a promising parasitoid of Spodoptera frugiperda, had been successfully reared on the eggs of Corcyra cephalonica in some countries, reports from China have argued that it is infeasible. Notably, studies from China have indicated that Spodoptera litura eggs could be a candidate host. Therefore, to further evaluate the potential of using S. litura eggs as hosts, we compared the development and parasitism of T. remus on the eggs of S. frugiperda and S. litura at temperatures between 20–32 °C. Our results showed that T. remus developed successfully on both host eggs at all of the tested temperatures, and the developmental duration and thermal requirements at each stage were similar between the two host species. The number of parasitized eggs was greater for S. litura than for S. frugiperda. Meanwhile, the emergence rate exceeded 86.6%, and it was significantly higher for S. litura than that for S. frugiperda, except at 29 °C. This study is the first time estimating the thermal requirements of T. remus at each stage. Moreover, we also recorded the morphological characteristics of T. remus at each stage. Our results demonstrate that S. litura eggs are more suitable than S. frugiperda eggs as an alternative host for the mass-rearing of T. remus in China. Understanding the thermal requirements and biological parameters contributes greatly to predicting the generation time and providing a reference for the mass-rearing and storage of the parasitoid.

Phenolic compounds, abundant secondary metabolites in plants, profoundly influence soil ecosystems, plant growth, and interactions with herbivores. In this study, we explore the intricate relationships between phenolics, soil microbes, and gall formation in Ageratina adenophora (A. adenophora), an invasive plant species in China known for its allelopathic traits. Using metabolomic and microbial profiling, significant differences in soil microbial composition and metabolite profiles were observed between bulk and rhizosphere soil samples. Phenolics influenced bacterial communities, with distinct microbial populations enriched in each soil type. Additionally, phenolics impacted soil metabolic processes, with variations observed in Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis between different soil treatments. Analysis of phenolic content in plant and soil samples revealed considerable variations, with higher concentrations observed in certain plant tissues and soil types. Bioactive phenols extracted from plant and soil samples were identified using gas chromatography/mass spectrometry (GC-MS), providing insights into the diverse chemical composition of these compounds. Furthermore, the effects of phenolics on plant growth and gall formation were investigated. Phenols exhibited both stimulatory and inhibitory effects on plant growth, with optimal concentrations promoting emergence but higher concentrations hindering growth. Gall formation was influenced by phenolic concentrations, leading to structural alterations in stem tissue and gall morphology. Histochemical analysis revealed starch and lipid accumulation in gall tissues, indicating metabolic changes induced by phenolics. The presence of phenolics disrupted tissue structures and influenced vascular bundle orientation in gall tissues. Overall, our study highlights the multifaceted roles of phenolic compounds in soil ecosystems, plant development, and gall formation, facilitating the utilization of secondary metabolites in agriculture.

Cathepsin L protease, which belongs to the papain-like cysteine proteases family, is an important player in many physiological and pathological processes. However, little was known about the role of cathepsin L in ladybird beetles (Coccinella septempuctata Linnaeus) during diapause. Here, we analyzed the characteristics of cathepsin L (CsCatL) in the females of C. septempunctata and its role during the diapause of the ladybeetle. CsCatL was cloned and identified from beetle specimens by rapid amplification of cDNA-ends (RACE). The cDNA sequence of CsCatL was 971 bp in length, including an 843 bp open reading frame encoding a protein of 280 amino acids. It was identified as the cathepsin L group by phylogenetic analysis. Knockdown of CsCatL by RNA interference led to decreased expression levels of fatty acid synthase 2 (fas 2) genes and suppressed lipid accumulation. Furthermore, silencing the CsCatL gene distinctly reduced diapause-related features and the survival of female C. spetempunctata under diapause-inducing conditions. The results suggested that the CsCatL gene was involved in fatty acid biosynthesis and played a crucial role in the survival of adult C. septempunctata during the diapause preparation stage.