Virtual Issue

昆虫生防与生态Insect biocontrol and ecology

Default Latest Most Read

Please wait a minute... For Selected: Download Citations EndNote Ris BibTeX Toggle Thumbnails Select Regional selection of insecticides and fungal biopesticides to control aphids and thrips and improve the forage quality of alfalfa crops PAN Fan, GAO Li-jie, ZHU Kai-hui, DU Gui-lin, ZHU Meng-meng, ZHAO Li, GAO Yu-lin, TU Xiong-bing, ZHANG Ze-hua 2023, 22 (1): 185-194.   DOI: 10.1016/j.jia.2022.08.070 Abstract （268）      PDF in ScienceDirect       The efficacies of biological and conventional chemical insecticides against two major insect pests of alfalfa (aphids and thrips) were compared in three sites across China’s alfalfa belt.  In addition, the persistence of the residues of chemical insecticides in alfalfa and their influence on the quality of alfalfa hay were examined.  Efficacy varied among the different biological and chemical insecticides.  The chemical insecticides were significantly more effective than biopesticides in a short time-frame.  The efficacy period of biopesticides was significantly longer than that of chemical insecticides, and the corrected mortality rate of aphids in all regions was above 50% at 14 days after application.  The analysis of pesticide residues showed that the residual doses of all the pesticides were within the allowed ranges after the safe period.  The acid detergent fiber and neutral detergent fiber contents in alfalfa hay were higher and the protein content was lower in chemical insecticide treatments than in biopesticide treatments in Hebei.  The relative feeding value of alfalfa hay treated with Metarhizium anisopliae IPP330189 was the highest among the treatments.  Compared with chemical insecticides, the yield of alfalfa hay was higher in the biopesticides treatments.  Biopesticides show a stronger control effect on insect populations and also a better improvement in the quality of alfalfa hay than chemical insecticides.  This study provides a basis for exploring and developing a comprehensive control regime for alfalfa insect pests in the different alfalfa-growing regions in China, and for reducing chemical insecticide usage and improving forage quality. Reference | Related Articles | Metrics Select Estimation of the potential geographical distribution of a new potato pest (Schrankia costaestrigalis) in China under climate change XIAN Xiao-qing, ZHAO Hao-xiang, GUO Jian-yang, ZHANG Gui-fen, LIU Hui, LIU Wan-xue, WAN Fang-hao 2023, 22 (8): 2441-2455.   DOI: 10.1016/j.jia.2022.08.023 Abstract （365）      PDF in ScienceDirect       Global food security is threatened by the impacts of the spread of crop pests and changes in the complex interactions between crops and pests under climate change.  Schrankia costaestrigalis is a newly-reported potato pest in southern China.  Early-warning monitoring of this insect pest could protect domestic agriculture as it has already caused regional yield reduction and/or quality decline in potato production.  Our research aimed to confirm the potential geographical distributions (PGDs) of S. costaestrigalis in China under different climate scenarios using an optimal MaxEnt model, and to provide baseline data for preventing agricultural damage by S. costaestrigalis.  Our findings indicated that the accuracy of the optimal MaxEnt model was better than the default-setting model, and the minimum temperature of the coldest month, precipitation of the driest month, precipitation of the coldest quarter, and the human influence index were the variables significantly affecting the PGDs of S. costaestrigalis.  The highly- and moderately-suitable habitats of S. costaestrigalis were mainly located in eastern and southern China.  The PGDs of S. costaestrigalis in China will decrease under climate change.  The conversion of the highly- to moderately-suitable habitat will also be significant under climate change.  The centroid of the suitable habitat area of S. costaestrigalis under the current climate showed a general tendency to move northeast and to the middle-high latitudes in the 2030s.  The agricultural practice of plastic film mulching in potato fields will provide a favorable microclimate for S. costaestrigalis in the suitable areas.  More attention should be paid to the early warning and monitoring of S. costaestrigalis in order to prevent its further spread in the main areas in China’s winter potato planting regions. Reference | Related Articles | Metrics Select Analysis of sex pheromone production and field trapping of the Asian corn borer (Ostrinia furnacalis Guenée) in Xinjiang, China DENG Jian-yu, LAN Chen-yi-hang, ZHOU Jun-xiang, YAO Yu-bo, YIN Xiao-hui, FU Kai-yun, DING Xin-hua, GUO Wen-chao, LIU Wen, WANG Na, Fumin WANG 2023, 22 (4): 1093-1103.   DOI: 10.1016/j.jia.2022.08.042 Abstract （296）      PDF in ScienceDirect       Identifying the sex pheromone systems of local pest populations facilitates their management, especially for moth species that show significant geographic variation in sex pheromone communication.  We investigated the pheromone production and behavioral responses of the Asian corn borer (Ostrinia furnacalis Guenée; ACB) in Xinjiang, China.  The ACB produces three compounds: (Z)-12-tetradecenyl acetate (Z12-14:Ac) and (E)-12-tetradecenyl acetate (E12-14:Ac) which are two sex pheromone compounds, and n-tetradecyl acetate (14:Ac) which has variable roles in mediating behavioral responses.  The ratios of these three compounds produced in female gland are geographically distinct among different populations.  Quantitative analysis of pheromone production showed that the proportions of Z12-14:Ac in the E/Z isomers (i.e., Z and E12-14:Ac) and the proportions of 14:Ac in the ternary blend respectively averaged 60.46% (SD=5.26) and 25.00% (SD=7.37), with their probabilities normally or near-normally distributed.  Trapping experiments in a cornfield indicated that deploying the E/Z isomers and the three compounds in rubber septa close to their gland ratios yielded the most captured males, while other ratios that deviated from the gland ratios showed reduced field captures.  The ternary blend was significantly more attractive to males than the E/Z isomers in the field, indicating a functional role of 14:Ac as the third pheromone component used by the local population.  Additionally, the dose-response test demonstrated that the application of the three compounds at dosages between 200 and 350 μg attracted significantly more males compared to other dosages.  Therefore, the characterization of this local ACB pheromone system provides additional information about its geographic variation and serves as a basis for optimizing the pheromone-mediated control of this pest in Xinjiang.  Related Articles | Metrics Select Population genetic variation and historical dynamics of the natural enemy insect Propylea japonica (Coleoptera: Coccinellidae) in China WANG Meng-qi, ZHANG Hong-rui, XI Yu-qiang, WANG Gao-ping, ZHAO Man, ZHANG Li-juan, GUO Xian-ru 2023, 22 (8): 2456-2469.   DOI: 10.1016/j.jia.2022.08.025 Abstract （422）      PDF in ScienceDirect       Propylea japonica (Coleoptera: Coccinellidae) is a natural enemy insect with a wide range of predation in Chinese mainland and is commonly used in pest management.  However, its genetic pattern (i.e., genetic variation, genetic structure, and historical population dynamics) is still unclear, impeding the development of biological control of insect pests.  Population genetic research has the potential to optimize strategies at different stages of the biological control processes.  This study used 23 nuclear microsatellite sites and mitochondrial COI genes to investigate the population genetics of Propylea japonica based on 462 specimens collected from 30 sampling sites in China.  The microsatellite dataset showed a moderate level of genetic diversity, but the mitochondrial genes showed a high level of genetic diversity.  Populations from the Yellow River basin were more genetically diverse than those in the Yangtze River basin.  Propylea japonica has not yet formed a significant genealogical structure in China, but there was a population structure signal to some extent, which may be caused by frequent gene flow between populations.  The species has experienced population expansion after a bottleneck, potentially thanks to the tri-trophic plant–insect–natural enemy relationship.  Knowledge of population genetics is of importance in using predators to control pests.  Our study complements existing knowledge of an important natural predator in agroecosystems through estimating its genetic diversity and population differentiation and speculating about historical dynamics. Reference | Related Articles | Metrics Select MRUNet: A two-stage segmentation model for small insect targets in complex environments  WANG Fu-kuan, HUANG Yi-qi, HUANG Zhao-cheng, SHEN Hao, HUANG Cong, QIAO Xi, QIAN Wan-qiang 2023, 22 (4): 1117-1130.   DOI: 10.1016/j.jia.2022.09.004 Abstract （366）      PDF in ScienceDirect       Online automated identification of farmland pests is an important auxiliary means of pest control.  In practical applications, the online insect identification system is often unable to locate and identify the target pest accurately due to factors such as small target size, high similarity between species and complex backgrounds.  To facilitate the identification of insect larvae, a two-stage segmentation method, MRUNet was proposed in this study.  Structurally, MRUNet borrows  the practice of object detection before semantic segmentation from Mask R-CNN and then uses an improved lightweight UNet to perform the semantic segmentation.  To reliably evaluate the segmentation results of the models, statistical methods were introduced to measure the stability of the performance of the models among samples in addition to the evaluation indicators commonly used for semantic segmentation.  The experimental results showed that this two-stage image segmentation strategy is effective in dealing with small targets in complex backgrounds.  Compared with existing state-of-the-art semantic segmentation methods, MRUNet shows better stability and detail processing ability under the same conditions.  This study provides a reliable reference for the automated identification of insect larvae. Reference | Related Articles | Metrics Select Accurate recognition of the reproductive development status and prediction of oviposition fecundity in Spodoptera frugiperda (Lepidoptera: Noctuidae) based on computer vision LÜ Chun-yang, GE Shi-shuai, HE Wei, ZHANG Hao-wen, YANG Xian-ming, CHU Bo, WU Kong-ming 2023, 22 (7): 2173-2187.   DOI: 10.1016/j.jia.2022.12.003 Abstract （225）      PDF in ScienceDirect       Spodoptera frugiperda (Lepidoptera: Noctuidae) is an important migratory agricultural pest worldwide, which has invaded many countries in the Old World since 2016 and now poses a serious threat to world food security. The present monitoring and early warning strategies for the fall army worm (FAW) mainly focus on adult population density, but lack an information technology platform for precisely forecasting the reproductive dynamics of the adults. In this study, to identify the developmental status of the adults, we first utilized female ovarian images to extract and screen five features combined with the support vector machine (SVM) classifier and employed male testes images to obtain the testis circular features. Then, we established models for the relationship between oviposition dynamics and the developmental time of adult reproductive organs using laboratory tests. The results show that the accuracy of female ovary development stage determination reached 91%. The mean standard error (MSE) between the actual and predicted values of the ovarian developmental time was 0.2431, and the mean error rate between the actual and predicted values of the daily oviposition quantity was 12.38%. The error rate for the recognition of testis diameter was 3.25%, and the predicted and actual values of the testis developmental time in males had an MSE of 0.7734. A WeChat applet for identifying the reproductive developmental state and predicting reproduction of S. frugiperda was developed by integrating the above research results, and it is now available for use by anyone involved in plant protection. This study developed an automated method for accurately forecasting the reproductive dynamics of S. frugiperda populations, which can be helpful for the construction of a population monitoring and early warning system for use by both professional experts and local people at the county level. Reference | Related Articles | Metrics Select Monitoring the little fire ant, Wasmannia auropunctata (Roger 1863), in the early stage of its invasion in China: Predicting its geographical distribution pattern under climate change  ZHAO Hao-xiang, XIAN Xiao-qing, GUO Jian-yang, YANG Nian-wan, ZHANG Yan-ping, CHEN Bao-xiong, HUANG Hong-kun, LIU Wan-xue 2023, 22 (9): 2783-2795.   DOI: 10.1016/j.jia.2022.12.004 Abstract （253）      PDF in ScienceDirect       Invasive alien ants (IAAs) are among the most aggressive, competitive, and widespread invasive alien species (IAS) worldwide.  Wasmannia auropunctata, the greatest IAAs threat in the Pacific region and listed in “100 of the world’s worst IAS”, has established itself in many countries and on islands worldwide.  Wild populations of W. auropunctata were recently reported in southeastern China, representing a tremendous potential threat to China’s agricultural, economic, environmental, public health, and social well-being.  Estimating the potential geographical distribution (PGD) of W. auropunctata in China can illustrate areas that may potentially face invasion risk.  Therefore, based on the global distribution records of W. auropunctata and bioclimatic variables, we predicted the geographical distribution pattern of W. auropunctata in China under the effects of climate change using an ensemble model (EM).  Our findings showed that artificial neural network (ANN), flexible discriminant analysis (FDA), gradient boosting model (GBM), Random Forest (RF) were more accurate than categorical regression tree analysis (CTA), generalized linear model (GLM), maximum entropy model (MaxEnt) and surface distance envelope (SRE).  The mean TSS values of ANN, FDA, GBM, and RF were 0.820, 0.810, 0.843, and 0.857, respectively, and the mean AUC values were 0.946, 0.954, 0.968, and 0.979, respectively.  The mean TSS and AUC values of EM were 0.882 and 0.972, respectively, indicating that the prediction results with EM were more reliable than those with the single model.  The PGD of W. auropunctata in China is mainly located in southern China under current and future climate change.  Under climate change, the PGD of W. auropunctata in China will expand to higher-latitude areas.  The annual temperature range (bio7) and mean temperature of the warmest quarter (bio10) were the most significant variables affecting the PGD of W. auropunctata in China.  The PGD of W. auropunctata in China was mainly attributed to temperature variables, such as the annual temperature range (bio7) and the mean temperature of the warmest quarter (bio10).  The populations of W. auropunctata in southern China have broad potential invasion areas.  Developing strategies for the early warning, monitoring, prevention, and control of W. auropunctata in southern China requires more attention. Reference | Related Articles | Metrics Select Diurnal emission of herbivore-induced (Z)-3-hexenyl acetate and allo-ocimene activates sweet potato defense responses to sweet potato weevils XIAO Yang-yang, QIAN Jia-jia, HOU Xing-liang, ZENG Lan-ting, LIU Xu, MEI Guo-guo, LIAO Yin-yin 2023, 22 (6): 1782-1796.   DOI: 10.1016/j.jia.2023.02.020 Abstract （252）      PDF in ScienceDirect       The sweet potato weevil (Cylas formicarius (Fab.) (Coleoptera: Brentidae)) is a pest that feeds on sweet potato (Ipomoea batatas (L.) Lam. (Solanales: Convolvulaceae)), causing substantial economic losses annually.  However, no safe and effective methods have been found to protect sweet potato from this pest.  Herbivore-induced plant volatiles (HIPVs) promote various defensive bioactivities, but their formation and the defense mechanisms in sweet potato have not been investigated.  To identify the defensive HIPVs in sweet potato, the release dynamics of volatiles was monitored.  The biosynthetic pathways and regulatory factors of the candidate HIPVs were revealed via stable isotope tracing and analyses at the transcriptional and metabolic levels.  Finally, the anti-insect activities and the defense mechanisms of the gaseous candidates were evaluated.  The production of (Z)-3-hexenyl acetate (z3HAC) and allo-ocimene was induced by sweet potato weevil feeding, with a distinct circadian rhythm.  Ipomoea batatas ocimene synthase (IbOS) is first reported here as a key gene in allo-ocimene synthesis.  Insect-induced wounding promoted the production of the substrate, (Z)-3-hexenol, and upregulated the expression of IbOS, which resulted in higher contents of z3HAC and allo-ocimene, respectively.  Gaseous z3HAC and allo-ocimene primed nearby plants to defend themselves against sweet potato weevils.  These results provide important data regarding the formation, regulation, and signal transduction mechanisms of defensive volatiles in sweet potato, with potential implications for improving sweet potato weevil management strategies. Reference | Related Articles | Metrics Select Cadmium (Cd) exposure through Hyphantria cunea pupae reduces the parasitic fitness of Chouioia cunea: A potential risk to its biocontrol efficiency YAN Shan-chun, WU Hong-fei, ZHENG Lin, TAN Ming-tao, JIANG Dun 2023, 22 (10): 3103-3114.   DOI: 10.1016/j.jia.2023.04.032 Abstract （203）      PDF in ScienceDirect       Heavy metal contamination has been regarded as an environmental variable that affects the efficiency of pest biological control, but the parasitic fitness of parasitoids under heavy metal stress is poorly understood.  Herein, the effect of Cd exposure through the host pupa of Hyphantria cunea on the parasitic fitness of Chouioia cunea was investigated, and the mechanism by which Cd exposure affects the interaction between H. cunea and C. cunea from the perspective of innate immunity in host insect and the oxidative status in the parasitoid offspring was explored.  Our results indicated that Cd can be transferred from the H. cunea pupae to the parasitoid offspring, and the transfer coefficient reflected biological amplification.  There were no significant differences in the rates of parasitism success and offspring emergence between the untreated and Cd-treated groups.  However, after parasitizing Cd-accumulated pupae, the parasitic fitness of offspring wasps (e.g., the number, individual size and life span) decreased significantly.  Under Cd exposure, the cellular and humoral immunity of H. cunea pupae decreased significantly.  Compared with the untreated group, the H2O2 content of parasitoid offspring in the Cd-treated group was significantly increased.  Cd exposure significantly inhibited superoxide dismutase activity in parasitoid offspring, but the contents of ascorbic acid and glutathione were significantly increased by Cd stress.  Taken together, these results indicate that Cd exposure reduces the cyclic utilization efficiency of C. cunea on H. cunea pupae.  The oxidative status of parasitoid offspring triggered by Cd exposure could be responsible for the reduced parasitic fitness of C. cunea on Cd-accumulated H. cunea pupae. Reference | Related Articles | Metrics Select A mite parasitoid, Pyemotes zhonghuajia, negatively impacts the fitness traits and immune response of the fall armyworm, Spodoptera frugiperda Yanfei Song, Tai’an Tian, Yichai Chen, Keshi Zhang, Maofa Yang, Jianfeng Liu 2024, 23 (1): 205-216.   DOI: 10.1016/j.jia.2023.05.022 Abstract （319）      PDF in ScienceDirect       Parasitoids are key regulators in ecological communities and widely used as agents in biocontrol programmes.  The fall armyworm, Spodoptera frugiperda, recently invaded multiple continents and caused substantial economic losses in agriculture.  Pyemotes zhonghuajia, a newly identified mite parasitoid, has shown potential for controlling various agricultural insect pests.  Therefore, this study tested the performance of P. zhonghuajia in parasitising S. frugiperda.  We also investigated the sublethal effects of parasitism by P. zhonghuajia on host fitness traits, transgenerational impacts, and cellular and humoral immunity.  Our result showed that the fifth-instar larvae of S. frugiperda parasitised by 40 P. zhonghuajia were all dead (i.e., a lethal effect), while parasitism by 5 or 10 P. zhonghuajia was considered sublethal since many S. frugiperda survived to adulthood and produced offspring after mating.  The sublethal influences from parasitism by P. zhonghuajia resulted in reduced pupal weight, adult emergence rate and fecundity, but increased developmental time and longevity.  Parasitism at both lethal (40 mites) and sublethal (10 mites) levels impaired the cellular and humoral immunity of S. frugiperda.  This study presents the first empirical evidence that mite parasitoids can negatively influence host immunity.  Moreover, it provides insights into the biocontrol potential of mite parasitoids and their interactions with hosts. Reference | Related Articles | Metrics Select Possible source and migration pathway for early-summer immigrants of the oriental armyworm, Mythimna separata, arriving in northern Japan Akira OTUKA, Tokumitsu NIIYAMA, JIANG Xing-fu 2023, 22 (11): 3474-3488.   DOI: 10.1016/j.jia.2023.06.001 Abstract （144）      PDF in ScienceDirect       The first generation of the oriental armyworm, Mythimna separata (Walker), arrives every year in northern Japan in mainly late May to early June.  Analyses of weather maps suggested that this moth’s immigration source could be eastern China, but the accuracy of those analyses was very limited due to the lack of a current standard trajectory analysis.  The management of migratory insect pests such as M. separata benefits from the identification of the migration source(s) and pathway(s) of the pests.  The present study provides a trajectory analysis for M. separata.  Backward trajectories from trap sites in northern Japan were calculated with the HYSPLIT System developed by the U.S. National Oceanic and Atmospheric Administration, taking the flight speed of M. separata and the limitation of low ambient temperature at flight height into account.  The ending times of the moth’s short and long trajectories were set at dusk on the day before and two days before the possible arrival date, respectively.  The results suggested two types of possible migration pathway: a multi-step pathway from Northeast China, the Korean Peninsula, and eastern Russia, which are destination areas of the first-generation’s migration, and a direct pathway from seasonal main emigration areas in eastern China such as Jiangsu and Shandong provinces.  These findings contribute to our understanding of the migration ecology of M. separata and can be used for the development of methods to predict the migration of this insect. Reference | Related Articles | Metrics Select Thelytokous Diglyphus wani: A more promising biological control agent against agromyzid leafminers than its arrhenotokous counterpart DU Su-jie, YE Fu-yu, XU Shi-yun, WAN Wei-jie, GUO Jian-yang, YANG Nian-wan, LIU Wan-xue 2023, 22 (12): 3731-3743.   DOI: 10.1016/j.jia.2023.06.002 Abstract （188）      PDF in ScienceDirect       Diglyphus wani (Hymenoptera: Eulophidae) is a dominant parasitoid that attacks agromyzid leafminers.  Two reproductive types occur in D. wani: arrhenotoky (in which virgin females produce only male offspring; and virgin females mate with males to produce bisexual offspring) and thelytoky (in which virgin females produce female offspring).  As a potential biological control agent, exploring the differences in the relevant biological parameters of both strains is necessary.  In this study, comparisons between the two strains of D. wani were performed by evaluating the life table and host-killing rate.  The thelytokous strain exhibited significantly better life table parameters than its arrhenotokous counterpart.  Higher values for the intrinsic rate of increase, finite rate of increase, net reproductive rate, and fecundity were found in the thelytokous strain.  The thelytokous strain also performed better than the arrhenotokous strain in terms of net parasitism, host-feeding, host-stinging, and total host-killing rates.  Thus, populations of the thelytokous strain could grow fast and kill more hosts.  In conclusion, the thelytokous strain of D. wani may be the more promising biological agent against agromyzid leafminers compared to its arrhenotokous counterpart.  Also, since the thelytokous strain of D. wani is only known to produce females, it should be given priority in future biocontrol applications owing to the cost savings of breeding only females. Reference | Related Articles | Metrics Select Acaricidal effect of the antimicrobial metabolite xenocoumacin 1 on spider mite control Jiaxing Wei, Hong Yan, Jie Ren, Guangyue Li, Bo Zhang, Xuenong Xu 2024, 23 (3): 948-959.   DOI: 10.1016/j.jia.2023.06.008 Abstract （189）      PDF in ScienceDirect       The two-spotted spider mite, Tetranychus urticae Koch, is one of the most harmful pests in many agroecosystems worldwide.  To effectively manage this pest, there is an urgent need to develop novel bio-active acaricides that support integrated pest management strategies targeting T. urticae.  In this study, we explored the acaricidal effects of xenocoumacin 1 (Xcn1) on T. urticae and its predator Neoseiulus californicus using the highly purified compound.  Xcn1 was extracted and purified from the cell-free supernatant of the Xenorhabdus nematophila CB6 mutant constructed by the easy promoter activated compound identification (easyPACId) method.  When the concentration of Xcn1 exceeded 100 μg mL–1, the survival rate of spider mite adults declined to below 40% and the fecundity was decreased by 80% at six days post-application.  At concentrations of 25 and 50 μg mL–1, Xcn1 significantly impeded spider mite development by inhibiting the molt.  However, neither concentration had any adverse effects on the survival or reproduction of the predatory mite N. californicus.  The results from laboratory and semi-field experiments consistently demonstrated the effectiveness of the antimicrobial metabolite Xcn1 in controlling pest mites at both the molecular and physiological levels.  Our study offers a promising possibility that combines the compatible biocontrol agents of Xcn1 and predatory mites for integrated pest mite control. Reference | Related Articles | Metrics Select Tissue distribution of cadmium and its effect on reproduction in Spodoptera exigua Honghua Su, Menglu Wu, Yong Yang, Yan Deng, Yizhong Yang, Qingming Sun 2024, 23 (1): 195-204.   DOI: 10.1016/j.jia.2023.08.010 Abstract （168）      PDF in ScienceDirect       Vegetable fields are often contaminated by heavy metals, and Spodoptera exigua is a major vegetable pest which is stressed by heavy metals mainly by feeding.  In this study, cadmium accumulation in the tissues of S. exigua exposed to cadmium and its effects on the growth and development of the parents and the offspring were investigated.  Under the stress of different concentrations of cadmium (0.2, 3.2, and 51.2 mg kg–1), the cadmium content in each tissue of S. exigua increased in a dose-dependent manner.  At the larval stage, the highest cadmium accumulation was found in midgut in all three cadmium treatments, but at the adult stage, the highest cadmium content was found in fat body.  In addition, the cadmium content in ovaries was much higher than in testes.  When F1 S. exigua was stressed by cadmium and the F2 generation was not fed a cadmium-containing diet, the larval survival, pupation rate, emergence rate and fecundity of the F2 generation were significantly reduced in the 51.2 mg kg–1 treatment compared to the corresponding F1 generation.  Even in the F2 generation of the 3.2 mg kg–1 treatment, the fecundity was significantly lower than in the parental generation.  The fecundity of the only-female stressed treatment was significantly lower than that of the only-male stressed treatment at the 3.2 and 51.2 mg kg–1 cadmium exposure levels.  When only mothers were stressed at the larval stage, the fecundity of the F2 generation was significantly lower than that of the F1 generation in the 51.2 mg kg–1 treatment, and it was also significantly lower than in the 3.2 and 0.2 mg kg–1 treatments.  The results of our study can provide useful information for forecasting the population increase trends under different heavy metal stress conditions and for the reliable environmental risk assessment of heavy metal pollution. Reference | Related Articles | Metrics Select Invasion of fall armyworm led to the succession of maize pests in Southwest China Zezheng Fan, Yifei Song, Shengyuan Zhao, Kongming Wu 2024, 23 (4): 1300-1314.   DOI: 10.1016/j.jia.2023.09.016 Abstract （186）      PDF in ScienceDirect       The invasive fall armyworm Spodoptera frugiperda (J. E. Smith) invaded Asia in 2018, colonizing the tropical and southern subtropical regions as well as migrating with the monsoons into Northeast Asia during spring and summer.  This has resulted in widespread infestations, with significant impacts on maize production in various Asian countries.  Previous studies have shown that the invasion of this pest can alter the species relationships of maize pests, but the actual impact on maize pest management is still unclear.  This study investigated the changes in maize pest occurrence and pesticide use in the annual breeding areas of S. frugiperda in Yunnan Province and the Guangxi Zhuang Autonomous Region of China during 2017–2021, based on surveys and interviews with small farmers in maize production.  The results showed that S. frugiperda has emerged as the dominant species among maize pests after invasion and colonization, replacing traditional pests such as Ostrinia furnacalis, Spodoptera litura, Agrotis ypsilon, and Rhopalosiphum maidis.  The variety of pesticides used for maize pest control has changed from chlorpyrifos, lambda-cyhalothrin, and acetamiprid to emamectin benzoate-based pesticides with high effectiveness against S. frugiperda.  Furthermore, the frequency of maize pest chemical applications has increased from an average of 5.88 to 7.21 times per season, with the amounts of pesticides used in summer and autumn maize being significantly higher than in winter and spring maize, thereby increasing application costs by more than 35%.  The results of this study clarified the impact of S. frugiperda invasion on maize pest community succession and chemical pesticide use in tropical and south subtropical China, thereby providing a baseline for modifying the regional control strategies for maize pests after the invasion of this relatively new pest. Reference | Related Articles | Metrics Select Characterization of Domeless receptors and the role of BdDomeless3 in anti-symbiont-like virus defense in Bactrocera dorsalis Wei Zhang, Shaoyang Li, Rong Li, Jinzhi Niu, Jinjun Wang 2024, 23 (4): 1274-1284.   DOI: 10.1016/j.jia.2023.10.003 Abstract （153）      PDF in ScienceDirect       The Janus kinase/signal transducers and activators of transcription (JAK/STAT) signaling pathway play a pivotal role in innate immunity.  Among invertebrates, Domeless receptors serve as the key upstream regulators of this pathway.  In our study on Bactrocera dorsalis, we identified three cytokine receptors: BdDomeless1, BdDomeless2, and BdDomeless3.  Each receptor encompasses five fibronectin-type-III-like (FN III) extracellular domains and a transmembrane domain.  Furthermore, these receptors exhibit the increased responsiveness to diverse pathogenic challenges.  Notably, only BdDomeless3 is upregulated during symbiont-like viral infections.  Moreover, silencing BdDomeless3 enhanced the infectivity of Bactrocera dorsalis cripavirus (BdCV) and B. dorsalis picorna-like virus (BdPLV), underscoring BdDomeless3’s crucial role in antiviral defense of B. dorsalis.  Following the suppression of Domeless3 expression, six antimicrobial peptide genes displayed decreased expression, potentially correlating with the rise in viral infectivity.  To our knowledge, this is the first study identifying cytokine receptors associated with the JAK/STAT pathway in tephritid flies, shedding light on the immune mechanisms of B. dorsalis. Reference | Related Articles | Metrics Select A dicistrovirus increases pupal mortality in Spodoptera frugiperda by suppressing protease activity and inhibiting larval diet consumption Meixue Sun, Tong Li, Yingjie Liu, Kenneth Wilson, Xingyu Chen, Robert I. Graham, Xianming Yang, Guangwei Ren, Pengjun Xu 2024, 23 (8): 2723-2734.   DOI: 10.1016/j.jia.2023.12.030 Abstract （94）      PDF in ScienceDirect       Understanding interactions between viruses and their hosts is conducive to enabling better application of viruses as biocontrol agents.  Certain viruses carried by parasitic wasps enhance the parasitic efficiency of wasp-larvae by protecting them against the immune system of their Lepidopteran host.  However, the relationship between prey pests and viruses found in predatory natural enemies remains unclear.  Herein, we report the interaction between Arma chinensis virus-1 (AcV-1), originally isolated from a predatory natural enemy, Arma chinensis (Hemiptera: Pentatomidae), and one of its prey species, Spodoptera frugiperda (Lepidoptera: Noctuidae).  The results showed that the AcV-1 virus appeared harmful to the novel host S. frugiperda by inhibiting larval diet consumption and increasing pupal mortality.  Meanwhile, sequencing data indicated that the virus altered the gene expression profiles of S. frugiperda.  KEGG analysis showed that the proteasome and phagosome pathways related to protein degradation and immune response were significantly enriched.  Although the expression levels of digestive enzyme genes did not change significantly, the total protease activity of AcV-1 virus-positive individuals was significantly decreased, suggesting that the virus inhibited diet consumption of S. frugiperda via the down-regulation of digestive enzyme activities.  These results indicate that a virus initially isolated in a predatory natural enemy can decrease the fitness of its prey species.  The virus was found to impact the host proteasome and phagosome pathways related to protein degradation and immunity, providing a potential mechanism to enhance controlling efficiency. Reference | Related Articles | Metrics Select Induced CTL-S15 gene expression by Bacillus thuringiensis declines susceptibility in Spodoptera exigua Jianqiang Bao, Yuxuan Chen, Suwan Jiang, Rui Liu, Xi Zhang, Fangzheng Zhang, Zhiwei Chen, Chen Luo, Hailong Kong 2024, 23 (9): 3078-3088.   DOI: 10.1016/j.jia.2024.01.024 Abstract （120）      PDF in ScienceDirect       It has been reported that C-type lectins (CTLs), which are pattern recognition receptors of the insect innate immunity response, may compete with Cry toxin for the receptor alkaline phosphatase to decrease its toxicity in insects.  However, to date, which CTLs affect larval susceptibility to Bt in Spodoptera exigua is not clear.  In this study, 33 CTL genes were identified from S. exigua.  Based on the number of carbohydrate-recognition domains (CRDs) and the domain architectures, they were classified into three groups: (1) nineteen CTL-S (single-CRD), (2) eight immulectin (dual-CRD) and (3) six CTL-X (CRD with other domains).  RT-qPCR analysis revealed that expression levels of SeCTL-S15, IML-4 and CTL-X6 were upregulated after challenge with Bt and Cry1Ab.  Tissue and developmental stage expression analysis showed that only SeCTL-S15 was mainly expressed in the midgut and larva, respectively.  Knockdown of SeCTL-S15 significantly increased Bt susceptibility, as indicated by reduced survival and larval weight.  These results suggest that CTL-S15 might play a vital role in the low susceptibility of larvae to Bt in S. exigua.  Our results provide new insights into CTL function in insects. Reference | Related Articles | Metrics