Development Of Silkworm Research Articles

Toxic Effect of Methyl-Thiophanate on Bombyx mori Based on Physiological and Transcriptomic Analysis

Background/Objectives: The utilization of methyl-thiophanate (MT) in vegetables and fruits is widespread due to its broad efficiency, yet its potential impact on silkworm growth remains uncertain. This study aims to examine the effects of MT on the growth of silkworms. Specifically, we assessed the weights of fifth-instar larvae that were fed mulberry leaves saturated with three concentrations (2.5, 5, and 10 mg/mL) of MT, as well as the weights of a control group. Methods: TEM was used to show the status of the silkworm midgut after MT supplementation. Oxidative stress was evaluated in the presence of MT. Furthermore, a transcriptomic sequencing experiment was conducted to investigate the mechanism through which the development of silkworms is induced by MT. Results: Our findings indicate that the supplementation of MT hindered larval growth compared to the control group, suggesting a toxic effect of MT on silkworms. The transmission electron microscopy (TEM) results show that MT supplementation induced autophagy in the silkworm midgut. MT was also found to induce oxidative stress in silkworms through the activation of reactive oxygen (ROS), superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) activities. Subsequent transcriptomic analysis revealed 1265 significantly differentially expressed genes (DEGs) in response to MT. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis indicated that these DEGs were associated with antioxidant defense, detoxification processes, lysosome biogenesis, and metabolic pathways. Conclusions: These findings suggest that MT toxicity in silkworm larvae is mediated through the induction of oxidative stress and alterations in metabolism. This study contributes to our understanding of the impacts of MT exposure on silkworms and provides insights into potential pesticides for use in mulberry gardens.

Transcriptome and Metabolome Analysis of BmFAMeT6 Overexpression in Bombyx mori.

Background/Objectives: The gene-encoding farnesyl diphosphate O-methyltransferase 6 (FAMeT 6) is a member of the farnesyl diphosphate O-methyltransferase family. Our previous studies have demonstrated its influence on juvenile hormone levels in third instar silkworm larvae. Methods: we utilized transcriptomic and metabolomic techniques to investigate the changes in third instar larvae at 0, 12, and 24 h following BmFAMeT6 overexpression. Results: (1) The differentially expressed homologous genes were enriched in detoxification-related pathways at all three time points. (2) Transcription factor analysis of DEGs indicated a predominant presence of ZF-C2H2. (3) The metabolite-related network suggested that BmFAMeT6 may influence the metabolism of silkworm larvae through the ABC transporters, purine metabolism, and tyrosine metabolism pathways. (4) The differential gene count, differential metabolite count, and types of metabolites at the three time points indicated a shift in the regulatory focus within the larvae as time progresses, with the inflection point of regulation occurring at the third instar larval stage, 12 h. Conclusion: In summary, our research indicates that the regulatory role of BmFAMeT6 occurs within the context of the domestic silkworm's own growth and development regulation.

Impact of Host Plants on Growth, Development and Economic Characters of Eri Silkworm (Samia ricini Boisd.)

Impact of Host Plants on Growth, Development and Economic Characters of Eri Silkworm (Samia ricini Boisd.)

Sublethal effects of nitenpyram on the development of silkworm

The utilization of nitenpyram for aphid and whitefly control may induce environmental contamination and negative repercussions on non-target organisms. Formerly, we found that nitenpyram would pollute the peripheral and sub-peripheral areas of the adjacent mulberry orchard. Under acute toxicity conditions, nitenpyram induced oxidative damage in silkworms, affected biological metabolism, synthesis, immunity, and signal transduction. Considering the impact of nitenpyram mist drift on mulberry leaves, we investigated the effects of low concentrations of nitenpyram on silkworms. The results showed that silkworms exposed to 0.17 mg/L, 0.35 mg/L and 0.70 mg/L of nitenpyram (1/40 LC50, 1/20 LC50 and 1/10 LC50) showed obvious poisoning symptoms. The cocoon weight and cocoon shell weight decreased gradually with increases in the concentration, and these decreases prolonged the growth and development time of silkworms and induced the detoxification enzymes carboxylesterase (CarE) and glutathione-S-transferase (GST) to cope with the stress damage caused by nitenpyram. Exposure to low concentrations of nitenpyram downregulates genes involved in the drug metabolism-other enzymes and peroxisome pathway in silkworms. Additionally, through injection of miRNA mimics and inhibitors, we discovered that detoxifying enzyme pathway genes are influenced by bmo-miR-3382-3P, bmo-miR-3213-5P and bmo-miR-133, regulating the immune response of silkworms. This study provides an overall view of the toxicity and detoxification metabolism of nitenpyram in silkworm, and provides a reference for environmental assessment.

Effects of high temperature on the growth performance and midgut autophagy of thermotolerant and thermosensitive silkworm strains.

High temperature stress has long-term negative effects on the growth and development of silkworm (Bombyx mori). Different silkworm varieties show the different tolerance to high temperature. The induction of autophagy is linked to increased thermotolerance in diverse ectothermic organisms. However, the function of autophagy in the thermotolerant and thermosensitive silkworm strains under high-temperature conditions remains unclear. The thermotolerant Liangguang NO.2 and thermosensitive Jingsong × Haoyue strains were used to explore the role of autophagy in thermotolerance. Here, we firstfound that the larval body weight gain was increased in the thermosensitive Jingsong × Haoyue strain, but there was no difference in the thermotolerant Liangguang NO.2 strain under high temperature conditions. High temperature stress had a negative influence on the cocoon performance in both the Liangguang NO.2 and Jingsong × Haoyue strains. Additionally, the autophagy-related gene Atg5 mRNA expression in the Liangguang NO.2 strain was upregulated by high temperature, while the expression of Atg12 mRNA was reduced in the Jingsong × Haoyue strain. Titers of 20-Hydroxyecdysone and the ultraspiracle 1 mRNA expression in the Liangguang NO.2 strain were upregulated by high temperature, which might be associated with the induction of autophagy. These results demonstrate the potentially regulatory mechanism of autophagy in silkworms' tolerance to high temperature, providing a theoretical basis for exploring the physiological mechanism of thermotolerance in insects.

In vitro Evaluation of Bio Control Agents and Botanicals against Mulberry Root Rot Pathogen Lasiodiplodia theobromae

Mulberry root rot is fast spreading disease caused by L. theobromae. The pathogen can be managed by synthetic fungicides. However, enormous use of synthetic fungicides leads to residual toxicity which affects the growth and development of silkworm. In this context, an attempt was made to use potential bio control agents for the management of this pathogen. Seven fungal and five bacterial bio agents evaluated out of them T. viride (Tv – B2), T. harzianum (Th - 44), B. subtilis (Bs - M) and (Bs - O) proved as best for inhibition of mycelial growth of the pathogen. Out of eleven botanical extracts used, garlic proved best at 15 per cent and 20 per cent and agave at 20 per cent concentration against root rot causing pathogen L. theobromae.

Climate change and its impact on sericulture

Climate change refers to the global phenomenon of rapid transformation in natural climate patterns like rain, wind, heat and more. Climate change poses a significant challenge to the existence of species and the stability of ecosystems on a global scale. The escalation in the Earth's atmospheric temperature is predominantly influenced by the heightened levels of greenhouse gases (GHG), including carbon dioxide (72%), methane (18%) and nitrous oxide (9%). (Bora et al., 2022). Agriculture is directly dependent on climate change and weather in India. The climate change viz., temperature, rainfall and carbon dioxide showed impact on crop growth and production in the country (Ram et al., 2016). Temperature fluctuations impact silkworm behavior, development, survival, growth and reproduction as highlighted by Neelaboina et al. in 2018. Silkworms are ectothermic organisms meaning that, their body temperature closely aligns with their surrounding environment. Consequently, alterations in temperature can significantly impact insect behavior, distribution, development, survival, growth and reproduction. Elevated air temperatures particularly during the 4th and 5th larval instars pose a significant climatic challenge that can adversely affect both silkworms and cocoon crops. The issues arising from these unfavorable conditions can be effectively mitigated by adhering to the recommended silkworm rearing technologies as outlined by Tripath et al. (2017).

Pre-extension Demonstration and Popularization of Silk Production Technologies in South Ethiopia

The study was conducted in Shebadino, Tula and Wondogenet districts of Sidama regional state of southern Ethiopia from 2018 to 2023 with the objectives of to evaluate the performance of silk production technologies at various levels of silk production with stakeholders/beneficiaries. The study also aimed to create awareness and develop confidence among silkworm producers, development agents, agricultural experts and policy makers for wider dissemination. Nine kebeles’ (the lowest administrative level), were selected from three (3) districts for the purposes of this study. Five (5) farmers from each kebele were selected, totaling 45 farmers, for technology pre-scale up and promotion. Three rounds of theoretical and practical training were given to these farmers after they were selected. Training in the third round focused on managing row silk and cocoons after harvest, with a first round that covered broad knowledge and the importance of sericulture. Of the farmers who were chosen and trained, 95.6 percent were women who began raising silk worms, producing cocoons, and processing row silk. Each farmer received 30 kilograms of castor seed and 50 disease-free adult moths for pre-scaling up and promotion of the technology. During the first year of the study period, 90%, 50%, and 40% of the disease-free moths that were disseminated laid eggs and developed into cocoons at Shebadino, Tula sub city and Wondogenet districts respectively. Sericulture is very beneficial to young people, particularly women, in terms of providing a variety of employment options and viable income without affecting their regular agricultural activities or the existing sociocultural equilibrium. Sericulture technology with its package used, knowledge and skill of the farmers (users) on the technology upgraded, continuous follow up assured by DAs and experts. This study highlights the significance of sericulture for rural development and offers insightful information for its dissemination.

BmC/EBPZ gene is essential for the larval growth and development of silkworm, Bombyx mori.

The genetic male sterile line (GMS) of the silkworm Bombyx mori is a recessive mutant that is naturally mutated from the wild-type 898WB strain. One of the major characteristics of the GMS mutant is its small larvae. Through positional cloning, candidate genes for the GMS mutant were located in a region approximately 800.5kb long on the 24th linkage group of the silkworm. One of the genes was Bombyx mori CCAAT/enhancer-binding protein zeta (BmC/EBPZ), which is a member of the basic region-leucine zipper transcription factor family. Compared with the wild-type 898WB strain, the GMS mutant features a 9bp insertion in the 3'end of open reading frame sequence of BmC/EBPZ gene. Moreover, the high expression level of the BmC/EBPZ gene in the testis suggests that the gene is involved in the regulation of reproduction-related genes. Using the CRISPR/Cas9-mediated knockout system, we found that the BmC/EBPZ knockout strains had the same phenotypes as the GMS mutant, that is, the larvae were small. However, the larvae of BmC/EBPZ knockout strains died during the development of the third instar. Therefore, the BmC/EBPZ gene was identified as the major gene responsible for GMS mutation.

From phyllosphere to insect cuticles: silkworms gather antifungal bacteria from mulberry leaves to battle fungal parasite attacks

BackgroundBacterial transfers from plants to insect herbivore guts have been well investigated. However, bacterial exchanges between plant phyllospheres and insect cuticles remain unclear, as does their related biological function.ResultsHere, we report that the cuticular bacterial loads of silkworm larvae quickly increased after molting and feeding on the white mulberry (Morus alba) leaves. The isolation and examination of silkworm cuticular bacteria identified one bacterium Mammaliicoccus sciuri that could completely inhibit the spore germination of fungal entomopathogens Metarhizium robertsii and Beauveria bassiana. Interestingly, Ma. sciuri was evident originally from mulberry leaves, which could produce a secreted chitinolytic lysozyme (termed Msp1) to damage fungal cell walls. In consistency, the deletion of Msp1 substantially impaired bacterial antifungal activity. Pretreating silkworm larvae with Ma. sciuri cells followed by fungal topical infections revealed that this bacterium could help defend silkworms against fungal infections. Unsurprisingly, the protective efficacy of ΔMsp1 was considerably reduced when compared with that of wild-type bacterium. Administration of bacterium-treated diets had no negative effect on silkworm development; instead, bacterial supplementation could protect the artificial diet from Aspergillus contamination.ConclusionsThe results of this study evidence that the cross-kingdom transfer of bacteria from plant phyllospheres to insect herbivore cuticles can help protect insects against fungal parasite attacks.2Gz4BRurS3WWiYBnkN9F_dVideo

Structural Insights into the Substrate Binding of Farnesyl Diphosphate Synthase FPPS1 from Silkworm, Bombyx mori.

Farnesyl diphosphate synthase (FPPS) is an important enzyme involved in the juvenile hormone (JH) biosynthesis pathway. Herein, we report the crystal structure of a type-I Lepidopteran FPPS from Bombyx mori (BmFPPS1) at 2.80 Å resolution. BmFPPS1 adopts an α-helix structure with a deep cavity at the center of the overall structure. Computational simulations combined with biochemical analysis allowed us to define the binding mode of BmFPPS1 to its substrates. Structural comparison revealed that BmFPPS1 adopts a structural pattern similar to that of type-II FPPS but exhibits a distinct substrate-binding site. These findings provide a structural basis for understanding substrate preferences and designing FPPS inhibitors. Furthermore, the expression profiles and RNA interference of BmFPPSs indicated that they play critical roles in the JH biosynthesis and larval-pupal metamorphosis. These findings enhance our understanding of the structural features of type-I Lepidopteran FPPS while providing direct evidence for the physiological role of BmFPPSs in silkworm development.

Cytotoxicity of AuCu-Cu2S Nanocomposites: Implications for Biological Evaluation of the Nanocomposite Effect on Bombyx mori Silkworms and Cell Lines.

AuCu-Cu2S nanocomposites are unique materials with exceptional properties that have recently received a lot of interest. However, little is known about their potential toxicity in terrestrial organisms and their subsequent effects on the environment. Therefore, it is essential to develop effective methodologies for evaluating AuCu-Cu2S nanocomposites in biological systems. This study reports the biological evaluation of the AuCu-Cu2S nanocomposite from animal and cell entity levels. The Bombyx mori silkworm was used as a model organism to study the effects of different concentrations of AuCu-Cu2S on silkworm development. Transcriptome analysis was also carried out to examine the genetic modulation exerted by the treatment. Moreover, biocompatibility and cytotoxicity of AuCu-Cu2S were evaluated in human bronchial epithelial cells 16HBE, human lung adenocarcinoma, and the insect Spodoptera frugiperda cell sf9 cell lines. The results showed that although AuCu-Cu2S at ≤400 ppm can prolong the eating habit of silkworms and promote the weight of the cocoon layer, there was an increase in silkworm mortality and a decrease in moth formation at a concentration of ≥800 ppm. The genetic regulation by AuCu-Cu2S treatment showed varying effects in the silkworm, primarily related to functions such as transport and catabolism, metabolism of cofactors and vitamins, xenobiotic biodegradation, amino acid, and carbohydrate. 16HBE, PC-9, and sf9 treated with 300 ppm of AuCu-Cu2S showed viability percentages of 60, 20, and 90%, respectively. Thus, AuCu-Cu2S at low concentrations serves as a safe and biocompatible material for the sf9 cell lines but is lethal to 16HBE and PC-9. This research could aid in understanding the biological effects and biocompatibility of AuCu-Cu2S nanocomposites, particularly in the field of biochemistry; however, the mechanisms involved need further exploration.

Comparative analysis of gut bacteria of silkworm Bombyx mori L. on exposure to temperature through 16S rRNA high throughput metagenomic sequencing

Global warming is one of the serious threats that adversely affects the development and reproduction of silkworms. The ideal temperature for silkworms to carryout normal life activities is 20–30 °C. Certain bivoltine silkworms that are raised in tropical regions are thermotolerant. But, prolonged exposure to high temperatures may be fatal. In the present study, fifth instar larvae of bivoltine silkworm were exposed to heat shock at 40 ± 2 °C for a short period of one hour per day to examine the changes in the gut microflora. The study used high throughput sequencing to evaluate the impact of intestinal microbes of silkworms in response to high temperature. The findings demonstrated that elevated temperature has a negative impact on the intestinal microbes of silkworm compared to the control which were reared under the optimum temperature (25 ± 3° C). Four hundred and fifty eight (458) species of microbes were reported in the control group whereas only 434 species were reported in the temperature exposed group. The digestive process of silkworms may also be impaired by heat shock due to their effect on digestive enzymes. So, the results indicated that heat shock has an impact on the intestinal microflora of silkworms that control the activity of associated digestive enzymes which affects the digestion and nutritional intake, eventually impacting the growth and development of silkworm larvae and cocoons produced. The morphometric parameters of silkworm larvae and cocoons also showed a considerable drop when exposed to heat shock.

M6A writer gene fl(2)d regulates the metamorphosis of silkworm Bombyx mori

The N6-methyladenosine (m6A) is one of the most abundant posttranscriptional modifications on RNAs, which is mediated by its effector proteins—writers, readers, and erasers. Female-Lethal(2)D (Fl(2)d) is one of the key writers to stabilize the interaction between another two writers Methyltransferase-like 3 (METTL3) and Methyltransferase-like 14 (METTL14). Here with dsRNA transfection, fl(2)d was knocked down in the BmN4 cell lines of silkworm, the expression of 61 genes were significantly increased, and 86 genes were significantly decreased after fl(2)d repression, which encoded proteins related to catalytic, hydrolase activity or in metabolism of nucleic acid. To elucidate the functional role of fl(2)d during silkworm development, dsRNA of which was injected into the hemolymph of the 2-d-old fourth instar larvae, the mounting process of silkworm was delayed, the expression level of genes in metabolism, RNA processing and ecdysone signaling pathway decreased significantly after fl(2)d knockdown, such as genes encoded Ubiquitin protein ligase E3C, the nuclear pore complex protein Nup98-Nup96, and the m6A reader YTHDF3, as well as Broad Complex isoform 2 (BRC-Z2), Fushi Tarazu Factor-1 (FTZ-F1), lactate dehydrogenase (LDH) and the ecdysone-induced protein 74EF isoform A (E74A). Total m6A level of RNAs also decreased after fl(2)d repression. These indicated that decreased level of fl(2)d and YTHDF3 decay the m6A level and translation of their target genes, which might lead to the retardation of metamorphosis, and resulted in the delayed mounting of silkworm.

Effects of different diets on the growth and development of young silkworms

To investigate the impact of different diets on the growth and development of the silkworm Bombyx mori (L.; Lepidoptera: Bombycidae), we conducted an analysis of differentially expressed genes (DEGs) between larvae fed an artificial diet (referred to as the AD group) and those fed mulberry leaves (referred to as the ML group) during the first, second, and third instars using RNA sequencing (RNA-Seq) technology. Our results revealed that the DEGs primarily belonged to pathways associated with lipid metabolism, carbohydrate metabolism, amino acid metabolism, the endocrine system, the nervous system, the digestive system, the immune system, and oxidation–reduction processes. Notably, in the AD group, there was a decrease in transcript levels of genes related to amino acid metabolism synthases, while the transcript levels of antimicrobial peptide genes were up-regulated. Furthermore, genes associated with cytochrome P450 (CYP) enzymes exhibited down-regulation in the AD group. These observed changes likely contributed to the delayed growth and compromised robustness observed in the AD group. Overall, these findings provided valuable insights into the mechanisms underlying the differences in growth, development, disease resistance, and adversity resistance between silkworms fed an artificial diet and those fed mulberry leaves.

Low concentration of indoxacarb interferes with the growth and development of silkworm by damaging the structure of midgut cells

As an important economic insect, Bombyx mori plays an essential role in the development of the agricultural economy. Indoxacarb, a novel sodium channel blocker insecticide, has been widely used for the control of various pests in agriculture and forestry, and its environmental pollution caused by flight control operations has seriously affected the safe production of sericulture in recent years. However, the lethal toxicity and adverse effects of indoxacarb on silkworm remain largely unknown. In this study, the toxicity of indoxacarb on the 5th instar larvae of silkworm was determined, with an LC50 (72 h) of 2.07 mg/L. Short-term exposure (24 h) to a low concentration of indoxacarb (1/2 LC50) showed significantly reduced body weight and survival rate of silkworm larvae. In addition, indoxacarb also led to decreased cocoon weight and cocoon shell weight, but had no significant effects on pupation, adult eclosion, and oviposition. Histopathological and ultrastructural analysis indicated that indoxacarb could severely damage the structure of the midgut epithelial cells, and lead to physiological impairment of the midgut. A total of 3883 differentially expressed genes (DEGs) were identified by midgut transcriptome sequencing and functionally annotated using GO and KEGG. Furthermore, the transcription level and enzyme activity of the detoxification related genes were determined, and our results suggested that esterases (ESTs) might play a major role in metabolism of indoxacarb in the midgut of B. mori. Future studies to examine the detoxification or biotransformation function of candidate genes will greatly enhance our understanding of indoxacarb metabolism in B. mori. The results of this study provide a theoretical basis for elucidating the mechanism of toxic effects of indoxacarb on silkworm by interfering with the normal physiological functions of the midgut.

Response of Silkworm (Bombyx mori L.) Breeds to Temperature and BmNPV Stress

Silkworm Bombyx mori L. is one of the most important domesticated insects, which produces luxuriant silk thread in the form of cocoon by consuming mulberry leaves during larval period. The growth and development of silkworm is greatly influenced by environmental conditions. The seasonal differences in the environmental components considerably affect the genotypic expression in the form of phenotypic output of silkworm crop. Bombyx mori nucleopolyhedrovirus (BmNPV) is a pathogen that causes great economic losses in sericulture. In the present investigation, twelve bivoltine silkworm breeds (WM, ND5, NB4D2, U-4, PO1, ND3, U-6, CSR2, SH6, SPO, U-3 and NSP) were studied for temperature and BmNPV stress. After third and fourth moult silkworm larvae were treated with BmNPV inoculum at 25±1⁰C and 30±1⁰C temperature respectively. Increased mortality was observed at 30±1⁰C when compared to 25±1⁰C. However, with respect to breeds the highest total mortality was recorded in breed PO1 and least in breed U-3. Silkworm breed U-3 may have the ability to tolerate BmNPV incidence and can be exploit for evolving disease-tolerant silkworm hybrids.

The silkworm (Bombyx mori) gut microbiota is involved in metabolic detoxification by glucosylation of plant toxins

Herbivores have evolved the ability to detoxify feed components through different mechanisms. The oligophagous silkworm feeds on Cudrania tricuspidata leaves (CTLs) instead of mulberry leaves for the purpose of producing special, high-quality silk. However, CTL-fed silkworms are found to have smaller bodies, slower growth and lower silk production than those fed mulberry leaves. Here, we show that the high content of prenylated isoflavones (PIFs) that occurred in CTLs is converted into glycosylated derivatives (GPIFs) in silkworm faeces through the silkworm gut microbiota, and this biotransformation is the key process in PIFs detoxification because GPIFs are found to be much less toxic, as revealed both in vitro and in vivo. Additionally, adding Bacillus subtilis as a probiotic to remodel the gut microbiota could beneficially promote silkworm growth and development. Consequently, this study provides meaningful guidance for silk production by improving the adaptability of CTL-fed silkworms.

THE IMPACT OF MICROCLIMATE FACTORS ON SILK THICKNESS UNIFORMITY AND OPTIMAL CONTROL THROUGH A MECHATRONIC SYSTEM

This study investigates the influence of microclimate factors on the uniformity of silk thickness and explores the application of a mechatronic system for optimal control and maintenance. As environmental conditions vary on a daily and seasonal basis, managing temperature and relative humidity becomes crucial for consistent cocoon production. The review delves into the significant role of temperature and humidity in the growth and development of silkworms, highlighting the potential of a mechatronic system for regulating the microclimate. Additionally, the research addresses the creation of an optimal microclimate during cocoon wrapping and examines the impact of temperature and humidity on the quality parameters of the resulting cocoon.

Bombyx mori Ecdysone Receptor B1 May Inhibit BmNPV Infection by Triggering Apoptosis.

Bombyx mori nucleopolyhedrovirus (BmNPV) is a serious threat to sericulture. Nevertheless, no effective control strategy is currently available. The innate immunity of silkworm is critical in the antiviral process. Exploring its molecular mechanism provides theoretical support for the prevention and treatment of BmNPV. Insect hormone receptors play an essential role in regulating host immunity. We found a correlation between Bombyx mori ecdysone receptor B1 (BmEcR-B1) and BmNPV infection, whereas the underlying mechanism remains unclear. In this study, the expression patterns and sequence characteristics of BmEcR-B1 and its isoform, BmEcR-A, were initially analyzed. BmEcR-B1 was found to be more critical than BmEcR-A in silkworm development and responses to BmNPV. Moreover, RNAi and an overexpression in BmN cells showed BmEcR-B1 had antiviral effects in the presence of 20-hydroxyecdysone (20E); Otherwise, it had no antiviral activity. Furthermore, BmEcR-B1 was required for 20E-induced apoptosis, which significantly suppressed virus infection. Finally, feeding 20E had no significant negative impacts on larval growth and the cocoon shell, suggesting the regulation of this pathway has practical value in controlling BmNPV in sericulture. The findings of this study provide important theoretical support for understanding the mechanism of the silkworm innate immune system in response to BmNPV infection.