The invasive fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), poses a significant threat to China's agricultural sector, necessitating sustainable biological control strategies. The generalist predatory stink bug, Arma chinensis (Fallou) (Hemiptera: Pentatomidae), shows potential for controlling S. frugiperda, but the temperature-dependent efficacy is unclear. We evaluated the functional response of adult female A. chinensis to 3rd instar S. frugiperda across five temperatures (18, 23, 28, 33, and 38 °C) and five prey densities (10, 20, 30, 40, and 50 larvae per dish) under laboratory conditions. Logistic regression and model fitting via maximum likelihood estimation confirmed a consistent type II functional response at all temperatures. Temperature significantly modulated predation efficiency, with peak performance at 28 to 33 °C, characterized by the highest attack rate (0.064 to 0.067 h-1) and shortest handling time (0.918 to 0.942 h). Supra-optimal temperature (18 and 38 °C) increased handling time and reduced predation capacity, suggesting that temperature significantly modulates predation performance. The field experiment demonstrated that A. chinensis significantly suppressed S. frugiperda populations under optimal temperatures, with higher efficacy at low to moderate densities, validating the inverse density-dependent predation. This study demonstrates that temperature significantly modulates the predation capacity of A. chinensis, and identifies 28 to 33 °C as the optimal thermal range for predation on S. frugiperda larvae.

Plant secondary metabolites (PSM) influence the susceptibility of insect herbivores to entomoviruses, but the apoptosis mechanism is not clear. Among plant hosts screened, the level of coumarin is correlated with NPV-mediated mortality, with high coumarin levels associated with high mortality and low coumarin levels with low mortality. Flow cytometry and morphological experiments showed that coumarins increased the apoptosis rate in NPV-infected larvae. miRNA transcriptomic analysis of coumarin-exposed larvae identified downregulation of miR-8 and miR-6497-3p, which negatively correlate with expression of pro-apoptotic kinases MAPK and ASK1. In addition, miR-9c-5p is upregulated, suppressing the apoptosis inhibitor 14-3-3 protein zeta. Our study suggests plant coumarins increase the susceptibility of larvae to NPV through miRNA-mediated regulation of apoptotic pathways. These findings suggest viral biocontrol efforts may be more successful on certain host plants, and provide molecular insight into how plant defense chemicals synergize with entomoviruses to control agricultural pests.

Spodoptera frugiperda Smith (Lepidoptera: Noctuidae) is a worldwide invasive pest. Microplitis pallidipes Szépligeti (Hymenoptera: Braconidae) is an endoparasitoid of this pest. However, the melanization immune response of this pest to M. pallidipes, has not yet been explored. We found that the parasitism of S. frugiperda by M. pallidipes severely inhibited hemolymph melanization and phenoloxidase activity of larvae. Transcriptomic and proteomic analysis indicated that 1128 genes and 594 proteins were significantly altered in expression following parasitism. These included 12 of the 23 candidate genes involved in melanization in S. frugiperda (i.e., 7 recognition protein genes, 10 prophenoloxidase (PPO) cascade genes, and 6 melanin synthesis genes). Eight of these 12 melanization genes were significantly downregulated in S. frugiperda larvae 24 h or 48 h after treatment with siRNAs. Of these, RNAi knockdown of PPO1, PPO2 and TH (tyrosine hydroxylase) increased parasitism rate by 13.3 %-23.3 % and decreased hemymphatic melanization rate by 36.7-66.7 %. Our results provide insight into the melanization response of S. frugiperda and identify genes that appear to play a key role in this process. These findings shed light on the mechanisms by which insect herbivores respond to parasitism, and have applied implications for the biological control of insect pests by parasitic wasps.

Novel pest population control strategies that use natural products to disrupt the host-seeking behaviors of pests are imperative in modern pest management. Odorant-binding proteins (OBPs), which are responsible for odorant recognition and signal transduction in the pest olfactory system, play key roles in host localization. We previously reported that ethyl oleate (EO) exhibits significant repellent properties against the highly destructive polyphagous crop pest Tetranychus cinnabarinus; however, the molecular mechanism remains unknown. In the present study, two OBPs (TcinOBP1 and TcinOBP2) from T. cinnabarinus were identified and their EO-induced expression profiles were detected. The results suggested that TcinOBP1 exhibited significant upregulation at 15 min and gradual decrease at 45 min post-EO-treatment. Microscale thermophoresis (MST) showed that the recombinant TcinOBP1 protein displayed a strong binding affinity to EO (Kd = 32.3 mu M). RNA interference (RNAi) analysis demonstrated that a significant inhibition of TcinOBP1 transcript led to a remarkable reduction in the sensitivity of T. cinnabarinus to the repellent activity of EO. Furthermore, computational simulations indicated that TcinOBP1 employed five alpha-helices and three disulfide bridges, forming a hydrophobic pocket composed of several nonpolar and polar amino acid residues to bind with EO, and hydrophobic interactions was the dominating driving force. Among these residues, six amino acid residues (Leu83, Trp132, Glu147, Ile148, Met190, and Ile194) were confirmed to be essential for the binding of TcinOBP1 to EO through site-directed mutagenesis and binding assays. These results demonstrated that TcinOBP1 is likely involved in mediating the responses of T. cinnabarinus to EO. This finding provides new insights into the olfactory molecular mechanism of OBPs with chemicals in mites and reveals that TcinOBP1 serves as a novel target for developing new and efficient mite control strategies.

The tri-trophic interaction of plants, insect herbivores, and entomoviruses is an important topic in ecology and pest control. The susceptibility of insect herbivores to entomoviruses (e.g., nucleopolyhedroviruses) is influenced by host plants; however, the role of plant secondary metabolites in determining such susceptibility is poorly understood. Metabolomic analyses of Brassica oleracea, Glycine max, and Ipomoea aquatica plants, which differ in how they affect the susceptibility of Spodoptera exigua to nucleopolyhedroviruses among 14 plants, suggested that the plant secondary metabolites genistein, kaempferol, quercitrin, and coumarin play a role in influencing nucleopolyhedroviruses susceptibility. Subsequently, transcriptomic analysis of caterpillars, treated with nucleopolyhedroviruses alone or with one of these four phenolics, identified four genes (CYP340K4, CXE18, GSTe, and GSTe1) that were significantly downregulated by the phenolics. Functional characterization of these genes suggested that their downregulation significantly increased larval sensitivity to nucleopolyhedroviruses and altered aspects of the immune response. Our findings provide new insight into the role of plant defense metabolites in influencing the interactions between insect herbivores and entomopathogens and identify plant secondary metabolites as potential synergists of viral agents for the control of agricultural pests.

Plant secondary metabolites are crucial in affecting the interactions between insect herbivores and entomoviruses. However, there is limited knowledge regarding the impact of such metabolites on the susceptibility of insect herbivores to entomoviruses. In this study, we adopted the allicin, caterpillars (Spodoptera exigua) and nucleopolyhedrovirus (SeMNPV) as a system, and found that allicin significantly increased the mortality of S. exigua larvae infected with SeMNPV by 36.03–59.45

为明确温度对异色瓢虫(Harmonia axyridis)各虫态捕食桃蚜(Myzus persicae)能力的影响,设定 18、23、28、33℃四个温度处理,测定不同虫态(龄)异色瓢虫(1-4 龄幼虫和成虫)在不同猎物密度条件下对桃蚜的捕食量,并分析其捕食功能反应和寻找效应.结果显示:不同温度下各虫态异色瓢虫对桃蚜的捕食功能反应属于Holling Ⅱ型.在18-33℃条件下,随着温度的升高,各虫态异色瓢虫对桃蚜的捕食量逐渐增加.在33℃条件下,异色瓢虫的捕食能力(a/Th)最强,理论最大捕食量(1/Th)最高.同一温度下,异色瓢虫对桃蚜的捕食能力、理论最大捕食量均表现为4 龄幼虫＞成虫＞3 龄幼虫＞2 龄幼虫＞1 龄幼虫.4 龄异色瓢虫幼虫在4 个温度处理下对桃蚜的理论最大捕食量(1/Th)分别为 90.909、200.000、333.333、500.000 头.各虫态异色瓢虫对猎物的寻找效应均随温度的升高而增加,随猎物密度的增加而降低.综上,在一定温度范围内,各虫态异色瓢虫对桃蚜的捕食能力、日最大捕食量和寻找效应均随温度的升高而增加.

Natural acaricides are potential biorational mite control alternatives to conventional chemical acaricides. However, little is known about the molecular mechanism of defense response to natural acaricides in mites. We previously reported significant acaricidal properties of ethyl oleate (EO) against Tetranychus cinnabarinus (here referred to as a sibling species of two-spotted spider mite, Tetranychus urticae ), a highly polyphagous pest devastating crops in fields and greenhouses worldwide. In this study, we explored the molecular responses of T. cinnabarinus exposed to EO using RNA-Seq and differentially expressed gene (DEG) analysis. A total of 131, 185, and 154 DEGs were identified in T. cinnabarinus after 1, 6, and 24 h of EO treatment. In addition, 36 putative detoxification-related DEGs, including 10 cytochrome P450s (P450s), three glutathione S-transferases (GSTs), nine UDP-glycosyltransferases (UGTs), eight esterases (ESTs), and six ATP-binding cassette transporters (ABC transporters), were identified. Interestingly, the upregulation of these detoxification-related genes might be the main defense response of T. cinnabarinus exposed to EO. A quantitative real-time PCR analysis indicated that the expression profiles of 19 random DEGs were consistent with the RNA-Seq results. These findings serve as valuable information for a better understanding of the acaricide-mite interaction and molecular mechanisms involved in the defense response of T. cinnabarinus against EO.

Microplitis pallidipes Szépligeti (Hymenoptera: Braconidae) is an important parasitic wasp of second and third-instar noctuid larvae such as the insect pests Spodoptera exigua, Spodoptera litura, and Spodoptera frugiperda. As in other insects, M. pallidipes has a chemosensory recognition system that is critical to foraging, mating, oviposition, and other behaviors. Odorant-binding proteins (OBPs) are important to the system, but those of M. pallidipes have not been determined. This study used PacBio long-read sequencing to identify 170,980 M. pallidipes unigenes and predicted 129,381 proteins. Following retrieval of possible OBP sequences, we removed those that were redundant or non-full-length and eventually cloned five OBP sequences: MpOBP2, MpOBP3, MpOBP8, MpOBP10, and MpPBP 429, 429, 459, 420, and 429 bp in size, respectively. Each M. pallidipes OBP had six conserved cysteine residues. Phylogenetic analysis revealed that the five OBPs were located at different branches of the phylogenetic tree. Additionally, tissue expression profiles indicated that MpOBP2 and MpPBP were mainly expressed in the antennae of male wasps, while MpOBP3, MpOBP8, and MpOBP10 were mainly expressed in the antennae of female wasps. MpOBP3 was also highly expressed in the legs of female wasps. Temporal profiles revealed that the expression of each M. pallidipes OBP peaked at different days after emergence to adulthood. In conclusion, we identified five novel odorant-binding proteins of M. pallidipes and demonstrated biologically relevant differences in expression patterns.

以草地贪夜蛾Spodoptera frugiperda为寄主,研究了不同温度下淡足侧沟茧蜂Microplitis pallidipes对草地贪夜蛾寄生和生长发育的影响,并建立了淡足侧沟茧蜂发育速率与温度的关系模型.结果表明:在试验温度范围内,淡足侧沟茧蜂均能在草地贪夜蛾幼虫体内完成发育,23℃和32℃时,淡足侧沟茧蜂对草地贪夜蛾寄生率最高(>60％),20℃和26℃时,淡足侧沟茧蜂结茧率最高(>90％).随着温度的升高,淡足侧沟茧蜂的发育历期(卵-幼虫期、蛹期和成虫期)明显缩短.Logistic曲线和线性模型均可拟合淡足侧沟茧蜂发育速率与温度的关系,但在卵-幼虫期和蛹期阶段,线性模型的拟合效果较好,成虫阶段两种模型均可;卵-幼虫、蛹和成虫的发育起始温度依次为10.2℃、15.08℃和5.43℃,有效积温依次为110.27日·度、81.10日·度和107.53日·度.

Host plants have an effect on the susceptibility of lepidopteran insects to nucleopolyhedrovirus (NPV), but the role of the protein in peritrophic membrane (PM) of larvae has not been investigated. We determined a key PM gene (SeIIM8 gene) in Spodoptera exigua (Hubner), which plays a role in protecting against NPV infection. Then we quantified the activity of chitin synthase (SeCHS), the content of insect intestinal mucin (SeIIM) and the expression of their genes in S. exigua fed one of four foods (artificial diet, Brassica oleracea (L.), Glycine max (L.), or Ipomoea aquatica (Forsskal)) with or without inoculation of Spodoptera exigua multiple nucleopolyhedrovirus (SeMNPV). Our results showed that the larval mortality was highest for NPV-infected with siRNA-injected larvae, intermediate for NPV-infected larvae, and lowest for uninfected larvae. The SeCHS activity, SeIIM content, and their relative gene expressions of S. exigua fed G. max or artificial diet were lower compared to caterpillars fed other diets. The relative SeCHS and SeIIM8 gene expression levels of larvae depended on the interaction of NPV treatment, diet, and time. This study concluded that plants affected the susceptibility of insects to NPV by altering the enzyme activity and gene expression of insects.

[目的]明确植物次生代谢物对甜菜夜蛾Spodoptera exigua生长发育及解毒酶的影响,探索利用植物次生物质防控甜菜夜蛾的潜在途径.[方法]本研究选用3种含量(0.01％、0.1％和1.0％)的槲皮素、山奈酚和香豆素,分别与人工饲料混合均匀后饲养甜菜夜蛾3龄初幼虫,观察植物次生代谢物对幼虫生长发育的影响;并测定幼虫取食添加0.1％的槲皮素、山奈酚和香豆素的人工饲料24、48和72 h后,幼虫羧酸酯酶(Caboxylesterase,CarE)、谷胱甘肽-S-转移酶(Glutathione-S-transferase,GSTs)和 P450 解毒酶活性.[结果]添加不同次生物质的人工饲料显著影响甜菜夜蛾幼虫生长和解毒酶活性.与对照组相比,3种次生代谢物均显著提高了幼虫死亡率.幼虫取食添加1％槲皮素的人工饲料后,蛹重显著降低,发育历期明显延长.而取食添加0.l％山奈酚的人工饲料后,可诱导幼虫CarE活性显著增强,0.1％槲皮素和0.1％香豆素对幼虫CarE活性均有显著抑制作用.添加槲皮素对幼虫GSTs活性无显著性影响,添加0.1％山奈酚和0.1％香豆素可诱导幼虫GSTs活性显著升高.0.1％槲皮素和0.1％香豆素可促进幼虫P450活性增强但未达到显著水平,但0.1％山奈酚处理48 h后,幼虫P450活性显著降低.[结论]植物次生代谢物种类与含量对甜菜夜蛾生长发育及解毒酶活性存在不同程度的影响.

Rice-fish co-culture system has a history of more than 2,000 years in Asia and has been recognized as one of FAO's Globally Important Agricultural Heritage Systems (GIAHS). To date, few studies have explored rice-fish co-culture effects on the relationship between predator-prey aggregations and associated tri-trophic cascades of predatory spiders, insect herbivores and rice. Indeed, predators have been shown to increase prey spatial aggregation but it is still not clear how fish (tertiary consumers) affect aggregations and interactions of their prey on multiple trophic levels (i.e. predatory spiders and rice insect herbivores). Here, we conducted a 2-year experiment to measure the abundance and distribution of herbivores (leafrollers, stemborers and planthoppers) and their predators (spiders) along with rice yield in rice-fish co-culture versus monoculture-rice (fish free) systems in eastern China. We analysed spatial aggregations of herbivores and predators using geostatistics and used correlations to examine tri-trophic interactions. Results showed that co-culture enhanced predatory spider and herbivore spatial aggregations, which in turn increased biocontrol of herbivores by predators, decreased herbivore damage and increased rice productivity. Synthesis and applications. Fish presence increased spatial aggregation of two different trophic levels, which enhanced a tri-trophic cascade of predatory spiders, insect herbivores and rice in co-culture systems. Our approach linking spatial aggregations of herbivores and predators with trophic cascades can be applied to study trophic interactions in other ecosystems. Incorporating fish into monoculture paddy fields can increase both natural pest control by predatory spiders and crop productivity via aggregation, and thus increase multiple ecosystem services.

【目的】克隆萝卜蚜Lipaphis erysimi（Kaltenbach）的三磷酸腺苷合酶f亚基（ATP synthases subunit f,LeATPf）基因，并利用RNA干扰技术抑制该基因表达，分析复配RNA干扰剂对萝卜蚜的防治效果，推动以RNA干扰为核心的害虫绿色防控新技术。【方法】利用同源克隆技术获得萝卜蚜LeATPf基因的全长cDNA，通过RNA干扰技术沉默其基因表达；采用浸叶法测定不同浓度的复配RNA干扰剂对萝卜蚜的杀虫效果，并通过田间小区试验测定RNA干扰剂对萝卜蚜的虫口减退率和田间防治效果。【结果】萝卜蚜LeATPf基因编码长度为324bp的cDNA序列，与其它5种蚜虫的ATPf基因同源性在88%以上，且LeATPf基因主要在2龄期萝卜蚜中表达；喷施RNA干扰剂可有效抑制LeATPf基因的表达，且高浓度的RNA干扰剂（200.00 mg/L）对萝卜蚜的室内杀虫效果与吡虫啉处理组无显著差异（P＞0.05）；在田间试验中，中高浓度的RNA干扰剂（50.00、100.00和200.00mg/L）在处理后第3和第7天对萝卜蚜的虫口减退率和防治效果与吡虫啉处理组无显著差异（P＞0.05），但在处理后14d对萝卜蚜的虫口减退率和防治效果显著高于吡虫啉处理组（P＜0.05）。【结论】针对LeATPf基因设计并配置的中高浓度的RNA干扰剂对萝卜蚜的防治效果与吡虫啉相当，但是其药效持续性优于吡虫啉；LeATPf基因是开发萝卜蚜RNA干扰制剂的良好靶标基因。

The use of ground cover vegetation is becoming a prominent way of promoting biodiversity and associated ecosystem services in Chinese orchards. Despite the large number of studies that have addressed the effects of ground cover vegetation on promoting natural enemy populations and related pest control, it is still unclear whether enhanced natural pest control can increase yield and reduce the use of pesticide. We performed an experiment comparing three cover vegetation practices (ryegrass, clover and hairy vetch) versus a bare ground control in commercial pear orchards in the Yangtze River Delta of East China (YRDEC), China. Natural enemy density (predator and parasitoid abundance), invertebrate herbivore performance (piercing-sucking herbivore abundance and branch-boring and fruit-boring percentage), pesticide input, and pear fruit yield were recorded. The results indicated that cover vegetation decreased herbivore abundance and boring percentage by 50% and 64%, respectively, thus decreasing pesticide use by 26%. We also found that cover vegetation increased the abundance of natural enemies by 621%, and increased pear fruit yield by 7%. Piecewise structural equation modelling confirmed that increased natural enemy densities, decreased herbivore performance by 102%, pesticide use by 51% and increased fruit yield by 10%. This study suggests that the use of ground cover vegetations, especially with clover and hairy vetch, is an effective way of promoting biocontrol services and associated ecosystem services in pear orchards.

The effects of plant volatiles on parasitoids are important with regards to the tri-trophic interactions among host plants, insect herbivores, and their natural enemies. However, the effects of plant volatiles on the important parasitoid (Microplitis pallidipes Szépligeti; Hymenoptera: Braconidae) of noctuids have not been determined at the molecular, laboratory, and outdoor scales with complementary approaches. The odorant binding protein 8 of M. pallidipes (MpOBP8) with an open reading frame of 459 bp was cloned and successfully expressed in Escherichia coli (Eubacteriales: Enterobacteriaceae). The purified protein MpOBP8 had a relatively high binding capacity to the plant volatile β-ionone (Ki value was 28.86 μM) in the fluorescence competitive binding assay. Meanwhile, Y-tube olfactometer experiments indicated that β-ionone selectively attracts the parasitic wasp as the ratio of M. pallidipes selecting β-ionone vs. control was 2:1. Likewise, field screenhouse experiments verified the above results as the ratio of M. pallidipes selecting β-ionone vs. control was close to 2:1. This study suggested that β-ionone is a plant volatile that attracts the parasitoid M. pallidipes, and MpOBP8 may play a key role in the discrimination of M. pallidipes in searching for hosts via β-ionone. In general our results suggest that β-ionone has the potential to enhance the biocontrol effect of parasitoids on insect herbivores.

This uploaded file is a dataset for "Plants regulate cellular immunity of caterpillars to an entomovirus".

It has been reported that host plants are able to mediate the interactions between insect herbivores and entomoviruses, but how plants affect growth, development, detoxifying enzymes and metabolic enzymes of herbivores infected by entomoviruses has only rarely been studied so far. We compared growth, development duration, activity of a detoxifying enzyme (carboxylesterase) and a metabolic enzyme (acetylcholinesterase) of a caterpillar (Spodoptera exigua) infected with an entomovirus (SeMNPV) or left non‐infected that were fed one of four plants (Ipomoea aquatica, Brassica oleracea, Glycine max or Zea mays). Developmental duration was shorter but growth (length, mass) and enzyme activities were higher in NPV‐infected caterpillars fed I. aquatica or B. oleracea than those fed G. max or Z. mays. This study suggests that host plants influence the growth impacts of entomoviruses on herbivores by affecting the enzymes of herbivores.

Natural pesticides are potential alternatives to conventional chemical pesticides. Recently, studies on pesticide–pest interactions have combined empirical biochemical measurements and practical field experiments. In this study, we performed laboratory and field efficacy analysis and biochemical characterization of two phytochemicals (2,4-di-tertbutylphenol (DTBP) and ethyl oleate (EO)) for carmine spider mite Tetranychus cinnabarinus control. DTBP and EO controlled mites by inhibiting egg hatchability and showed significant residual toxicity in laboratory tests. The control efficacy was confirmed in eggplant and cucumber field trials in three provinces in China. Oxidative stress induced by antioxidant enzymes (superoxide dismutase and peroxidase) and detoxification metabolism (involving carboxylesterase and/or mixed-function oxidase) may be involved in the response of mites to DTBP and EO. This study demonstrates the potential of DTBP and EO as effective acaricides for the control of spider mites and provides researchers a better understanding of acaricide–mite interactions.

RNA干扰（RNAi）是生物体内源基因发生转录后特异性降解的一种生理现象,广泛存在于生物体内。RNAi主要由小干扰RNA诱发阻碍目的基因的翻译或转录,造成目标信使RNA沉默。RNAi具有高效、特异性强等优点,被广泛应用于昆虫基因功能研究,并显示出了开发新型病虫害管理策略的巨大潜力。主要阐述了RNAi的沉默机制,双链RNA转入昆虫体内的几种方式,以及RNAi技术在不同目昆虫中研究的最新进展。最后,对RNAi技术存在的不足之处进行了简单总结,还对RNAi技术在害虫防治中的应用进行了展望,以期为该技术广泛应用于农业害虫防治提供理论支持。