Acta Entomologica Sinica

Expression and functional analysis of the heat shock protein Hsp70 genes in Myzus persicae (Hemiptera: Aphididae) under high and low temperature stress

LIU Jia-Rui, MENG Jian-Yu, DONG Xiang-Li, LI Zhi-Mo, YANG Chang-Li, ZHANG Chang-Yu

2025, 68(7): 877-886. doi:10.16380/j.kcxb.2025.07.001

Abstract ( 65 )

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【Aim】To explore the role of heat shock protein Hsp70 genes of Myzus persicae in response to high and low temperature stress. 【Methods】 RT-qPCR was used to detect the relative expression levels of eight MpHsp70 genes (MpHsp70-1, MpHsp70-2, MpHsp70A1, MpHsp70B2, MpHsp68a, MpHsp68b, MpHsc70-4 and MpHsp70) in different wingless adult tissues (head, midgut, embryo and cuticle) and wingless adults under high temperature (36 ℃) and low temperature (4 ℃) stress for different duration (0, 30, 60, 90, 120 and 150 min), respectively. RNAi was used to silence two key MpHsp70 genes (MpHsp70A1 and MpHsp68a), and the survival rate and number of nymphs produced of wingless adults were observed and calculated at 120 min under high temperature treatment (36 ℃) and 30 min under low temperature treatment (4 ℃).【Results】 The eight MpHsp70 genes were expressed in different wingless adult tissues of M. persicae, and the expression levels of MpHsp70, MpHsp70A1, MpHsp70B2, MpHsc70-4 and MpHsp68b in the cuticile were significantly higher than those in the other tissues. The expression levels of MpHsp70-1, MpHsp70-2 and MpHsp68a in the embryo of M. persicae were significantly higher than those in other tissues. High and low temperature stress had significant induction effect on the expression of MpHsp70 genes in wingless adult of M. persicae. The expression levels of MpHsp70-1, MpHsp70A1, MpHsp70-2, MpHsp68a and MpHsp68b all increased and then decreased under 4 ℃ stress, and reached the highest at 30 min under 4 ℃ stress, which were significantly higher than those of the control. Under 36 ℃ stress, the expressions levels of MpHsp70-1, MpHsp70A1, MpHsp70-2, MpHsc70-4, MpHsp68a and MpHsp68b increased first and then decreased. The expression level of MpHsp70-1 reached the highest at 60 min after 36 ℃ stress, and those of the other genes reached the highest at 120 min after 36 ℃ stress. After the silence of MpHsp68a, the survival rate and number of nymphs produced of M. persicae under high and low temperature stress were significantly decreased and those after the silence of MpHsp70A1 under high temperature stress were extremely significantly decreased as compared with those of the control group. 【Conclusion】MpHsp70 genes of M. persicae can respond to high and low temperature stress, and play an important role in the molecular mechanism of resistance to temperature stress of M. persicae.
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Venom-gland transcriptomic analysis of the predatory stink bug, Picromerus lewisi (Hemiptera: Pentatomidae)

LI Jin-Meng, SU Qi, LI Wen-Hong, WANG Han-Cheng, TIAN Xu, WANG Qing, ZHANG Xing-Hong, DONG Xiang-Li

2025, 68(7): 887-897. doi:10.16380/j.kcxb.2025.07.002

Abstract ( 36 )

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【Aim】 Picromerus lewisi is a significant predatory natural enemy insect distributed in multiple countries of Asia, such as China, Korea and Japan, primarily used for controlling lepidopteran pests. Venom plays a crucial role in causing rapid paralysis and death of preys during hunting. The aim of this study is to understand the transcriptomic characteristics of the venom glands of P. lewisi, explore the diversity of toxins in P. lewisi, and establish a foundation for further research on the composition and function of the venom in P. lewisi.【Methods】Transcriptome sequencing was conducted on the venom glands of adults and the 5th instar nymphs of P. lewisi collected from Qianxinan Prefecture, Guizhou Province using the high-throughput Illumina NovaSeq 6000 platform. The resulting data were annotated using the NR, NT, Pfam, KOG/COG, Swiss-Prot, KEGG and GO databases. Gene expression in the venom gland samples of P. lewisi was assessed using the FPKM method, and DESeq was employed for the differential expression analysis of venom gland transcriptomes between adult and the 5th instar nymph. The differentially expressed genes (DEGs) between the adult and the 5th instar nymphal venom gland transcriptomes were screened using the criteria of |log₂(Fold change)|>1 and P<0.05, followed by GO functional enrichment analysis and KEGG pathway enrichment analysis of the identified DEGs. The 33 215 transcripts obtained from the sequenced venom gland transcriptomes of adults and the 5th instar nymphs of P. lewisi were subjected to BLAST comparisons in the UniProt database.【Results】Transcriptome sequencing of the venom glands of adults and the 5th instar nymphs of P. lewisi assembled to 22 242 unigenes with an average length of 949 bp. A total of 15 364 unigenes were annotated to the NR, NT, Pfam, Swiss-Prot, GO, KOG/COG and KEGG databases, corresponding to 10 closely related species including three species of true bugs and two species of spiders. A total of 344 DEGs were screened between the venom gland transcriptomes of adults and the 5th instar nymphs of P. lewisi, with 218 genes up-regulated and 126 genes down-regulated. A total of 443 sequences encoding 33 distinct types of toxin-related proteins were identified.【Conclusion】The transcriptome data from the venom glands of both the 5th instar nymphs and adults of P. lewisi were sequenced and obtained in this study. Differential proteins between the venom gland transcriptomes of adults and the 5th instar nymphs were screened, and sequences associated with toxin proteins were identified. This research lays a theoretical foundation for the identification of components in the venom of P. lewisi and the investigation of their biological functions.

Expression characteristics of the cuticle protein gene TmAbd4 and its role in endocuticle formation in Tenebrio molitor (Coleoptera: Tenebrionidae)

WANG Hao-Ran, LIU Gao-Hua, CHANG Nan, SHI Xue-Kai, YU Rong-Rong, ZHANG Yu-Ping

2025, 68(7): 898-906. doi:10.16380/j.kcxb.2025.07.003

Abstract ( 26 )

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【Aim】 To investigate the molecular characteristics of the endocuticle structural glycoprotein gene (TmAbd4) and its role in endocuticle formation in Tenebrio molitor, and so as to provide a theoretical basis for screening the key target genes involved in the growth and development of T. molitor. 【Methods】 The full-length cDNA sequence of TmAbd4 was obtained based on the transcriptome database of T. molitor, and the functional domains of TmAbd4 were analyzed using bioinformatics tools. RT-qPCR was employed to detect the expression levels of TmAbd4 in different tissues (integument, fat body, Malpighian tubules, foregut, midgut and hindgut) of the 13th instar mature larvae and in the integument of the 1-15-day-old mature larvae of T. molitor. After the silence of TmAbd4 in the 13th instar mature larvae of T. molitor by RNAi, the microstructure of the integument was observed using hematoxylin and eosin staining (H&E), and the ultrastructure of the integument was observed through transmission electron microscopy (TEM). 【Results】 The full-length cDNA sequence of TmAbd4 of T. molitor was 506 bp, with an open reading frame (ORF) of 396 bp, encoding 131 amino acids. TmAbd4 contained a signal peptide, a chitin-binding domain 4 (ChtBD4), and a conserved RR-1 motif, classifying it within the RR-1 subclass of the CPR family. TmAbd4 was specifically highly expressed in the integument, and was significantly highly expressed in the integument of the first 3 d after the molting of the 13th instar mature larvae. Injection of dsTmAbd4 caused no visible abnormal phenotypes in T. molitor from molt to pupal stage, however, the endocuticle was observed significantly thinner compared to the dsGFP-injected control group. 【Conclusion】TmAbd4 belongs to the RR-1 subclass of the CPR family and is highly expressed in the integument of T. molitor, with significantly higher expression during endocuticle formation. Silencing of TmAbd4 did not impair the ability of the larvae to molt into the pupal stage, however, it led to a significant reduction in endocuticle thickness, indicating that TmAbd4 involves the formation of endocuticle.

Genetic analysis of the red compound eye mutant in Grapholita molesta (Lepidoptera: Tortricidae)

WU Ai-Hua, ZHENG Yi-Ming, ZHANG Wen-Lin, WANG Yi-Fei, MA Rui-Yan, LI Xian-Wei

2025, 68(7): 907-913. doi:10.16380/j.kcxb.2025.07.004

Abstract ( 29 )

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【Aim】To investigate the inheritance mode of a mutant with red compound eye of Grapholita molesta. 【Methods】 A stable population for a red compound eye natural mutation of G. molesta was constructed indoors by reciprocal crossing of the red compound eye mutant and the black compound eye wild type to obtain F₁ generation, F₁ generation self-crossing to obtain F₂ generation, and backcrossing of F₁ female and male with male and female mutant to obtain BC₁ generation, and self-crossing of F₂ generation red compound eye individuals, and the inheritance mode of red compound eye was explored via the number of female and male offspring showing different compound eye phenotypes. 【Results】The red compound eye mutant of G. molesta at female and male pupal and adult stages has red compound eye that can be easily distinguished from the wild type, whose compound eye is black. F₁ adults had black compound eyes. The segregation ratio of wild type to mutant in F₂ generation adults was 3.24∶1. The segregation ratios of wild type to mutant in BC₁ generation adults were 1.13∶1 and 1.05∶1, which obtained from F₁ female crossed with mutant male and F₁ male crossed with mutant female, respectively. All the progenies of self-crossing in F₂ generation, which showed mutant phenotype, had red compound eye. In all treatments, the average number of female and male adults of offspring ranged from 8.4 to 13.0 individuals, and had no significant difference. 【Conclusion】The red compound eye mutant phenotype of adult G. molesta is controlled by a single gene on the autosomal recessive allele.

Effects of cold storage duration on the biology of Spodoptera litura (Lepidoptera: Noctuidae) and the metabonomic characteristics of its pupae

TIAN Xu, WANG Han-Cheng, LI Jin-Men, ZHOU Feng, WANG Qing, MENG Jian-Yu, ZHANG Xing-Hong, GAO Gui, SU Qi

2025, 68(7): 914-925. doi:10.16380/j.kcxb.2025.07.005

Abstract ( 26 )

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【Aim】 To explore the effects of low-temperature storage for varying duration on the survival, growth and development of Spodoptera litura pupae, and investigate the changes in metabolites of S. liturapupae subjected to low-temperature treatment over different time periods. 【Methods】The pupae of S. litura were subjected to treatment at 10 ℃ for varying duration (5, 10, 15, 20 and 25 d), and their developmental duration, emergence rates of female and male adults, next generation hatching rate and number of eggs laid per female were measured using conventional feeding methods. Targeted metabolomics was employed to analyze the changes in metabolites within the pupae at different treatment time. 【Results】The duration of S. litura pupae stored at 10 ℃ for varying duration was extended. The emergence rates of both female and male adults gradually decreased with extended cold storage time, while the oviposition period was reduced from 5.80 to 2.76 d. Additionally, the longevity of female and male adults was gradually shortened and the hatching rate of the offspring was gradually declined, and the number of eggs laid per female diminished gradually from 750.00 to 133.00 grains. Metabolomic analysis of S. litura pupae identified a total of 872 metabolites. In the comparison group with longer cold storage duration (processing for 20 d vs processing for 25 d), the differential metabolites were primarily classified into lipids and amino acids, along with their derivatives, with most metabolites enriched in the metabolic pathways of tyrosine, tryptophan and phenylalanine. In the comparison group with shorter cold storage duration (processing for 5 d vs processing for 10 d), the differential metabolites spanned a wider range of categories, with significant enrichment in the metabolic pathways of tryptophan, tyrosine and 2-oxocarboxylic acid. Among the pathways with the highest enrichment by metabolites in the comparison between the control group at room temperature and the treatment group under 10 ℃ for 25 d, only sorbitol, glutathione and taurine were highly expressed in the treatment group under 10 ℃ for 25 d. 【Conclusion】Among the tested storage duration (5－25 d), the optimal storage duration for S. litura pupae at 10 ℃ ranges from 15 to 20 d. This storage condition minimally impacts their development, and the metabolites produced under this treatment are diverse. The enriched metabolites are predominantly concentrated in various amino acid metabolic pathways. These findings provide valuable insights into the cold resistance mechanisms of S. litura pupae at low temperatures.

Effects of high-fat diet on the growth, development and economic traits of the silkworm, Bombyx mori

LI Jia, CHEN Xin-Yi, SHAN Yu-Xi, MIAO Wang-Long, ZHAN Li-Jie, YAN Hai-Hang, XU Ping-Zhen, WU Yang-Chun

2025, 68(7): 926-934. doi:10.16380/j.kcxb.2025.07.006

Abstract ( 35 )

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【Aim】High-fat diet has been proven to induce various diseases such as hyperlipidemia, posing a threat to human health. This study investigated the effects of high-fat diet on the growth and development, economic traits, lipid metabolism and immune function of Bombyx mori by adding soybean oil to mulberry leaves, to evaluate the feasibility of using B. mori to construct a hyperlipidemia disease model for human health research. 【Methods】 The day-0 4th instar and day-0 5th instar larvae of B. mori were fed with high-fat diets (mulberry leaves treated with 0.5%, 1.0% and 2.0% soybean oil, respectively) until maturity. The body weight of various day-old larvae and the cocoon layer rate were measured. The triglyceride contents in the fat body and serum of the 5th instar larvae of B. mori fed with the mulberry leaves treated with 0.5% soybeal oil were detected using a triglyceride test kit. Oil red O staining was used to observe the morphological changes and average optical density values of lipid droplets. Real-time fluorescence quantitative PCR was used to analyze the transcription levels of eight immune-related genes (BmCecD2, BmCecA, BmCecB, BmCecE, BmCec-CBM2-2, BmSpz1, BmDual and BmKayak) in the 5th instar larval fat bodies. 【Results】Compared with the control group (fed with regular mulberry leaves), high-fat diet (nulberry leaves treated with 0.5%, 1.0% and 2.0% soybean oil, respectively) significantly inhibited the body weight gain of B. mori larvae and significantly reduced the cocoon layer rate. Compared with the control, a high-lipid diet (mulbery leaves treated with 0.5% soybean oil) significantly increased the triglyceride content in the fat body and serum of the 5th instar larvae of B. mori, resulted in abnormal morphology of fat body and accumulation of lipid droplets, and significantly down-regulated the expression levels of the tested eight innate immune-related genes in the fat body of the 5th instar larvae. Among them, the expression levels of BmCecE, BmDual and BmKayak were down-regulated by more than 90%.【Conclusion】The high-fat diet leads to slow growth, delayed development, decreased economic traits, disrupted lipid metabolism and weakened immune regulatory function in B. mori. Among them, the increase in triglyceride content is similar to the physiological and pathological characteristics of human hyperlipidemia. This study provides a theoretical basis for constructing disease models using insects.

Repellent activities of three plant-derived compounds against adult Tribolium confusum (Coleoptera: Tenebrionidae) and their effects on its olfaction-related genes

SHI Dan-Ni, CHANG Jing, KANG Peng, MA Chong-Yong, LI Hai-Ping

2025, 68(7): 935-946. doi:10.16380/j.kcxb.2025.07.007

Abstract ( 55 )

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【Aim】To elucidate the repellent activities of three plant-derived compounds neochamaejasmine A, thymol and azadirachtin against adult Tribolium confusum and their effects on its olfaction-related genes. 【Methods】 The relative electroantennogram (EAG) response values of T. confusum adults to 0.005, 0.05, 0.5, 5 and 50 μg/μL neochamaejasmine A, thymol and azadirachtin were measured. The olfactory behavior responses of T. confusum adults to neochamaejasmine A, thymol and azadirachtin at the concentrations of 0.5, 5 and 50 μg/μL were studied by Y-tube olfactometer. Impregnated filter paper method was used to determine the repellent rates of 20, 30, 40, 50 and 60 mg/L neochamaejasmine A, thymol and azadirachtin to T. confusum adults. Transcriptomes of the head of T. confusum adults treated with median lethal concentration (LC₅₀)(28.37 mg/L) neochamaejasmine A, LC₅₀(51.05 mg/L) thymol and LC₅₀(42.20 mg/L) azadirachtin were sequenced and comparatively analyzed using RNA-Seq. 【Results】The relative EAG response value of T. confusum adults was proportional to the concentrations of neochamaejasmine A, thymol and azadirachtin. At the maximum concentration of 50 μg/μL, neochamaejasmine A, thymol and azadirachtin resulted in the relative EAG response values of T. confusum adults of 1.61, 2.69 and 2.34 mV, respectively, and the selection rates of 86.48%, 73.89% and 78.33%, respectively. The repellent rates (74.67% and 80.82%, respectively) of 60 mg/L thymol to T. confusum adults were the highest at 2 and 4 h, and the repellent grades reached grades Ⅳ and Ⅴ, respectively. After treatment with thymol, neochamaejasmine A and azadirachtin, there were 569, 597 and 661 differentially expressed genes in the head transcriptomes of T. confusum adults, respectively, 412, 434 and 498 differentially expressed genes were annotated with GO function, respectively, and the differentially expressed genes were identified to 26, 33 and 32 KEGG pathways, respectively, compared with the control group. Thirteen, four and five olfaction-related genes with differential expression were found after treatment with thymol, neochamaejasmine A and azadirachtin, respectively. 【Conclusion】In this study, the repellent activities of the three plant-derived compounds to T. confusum adults were determined and the head transcriptome of T. confusum adults was sequenced. It is speculated that the differentially expressed genes may play an important role in T. confusum repelling the three plant-derived compounds.

Stridulatory organs and features of acoustic signals of Hylurgus ligniperda (Coleoptera: Curculionidae) adults and their behavioral response to vibroacoustic treatments in logs

LIAO Jun-Zhe, YAN Hong, LI Hong-Yun, WANG Chuan-Zhen, CHANG Zong-Tao, SHI Juan

2025, 68(7): 947-959. doi:10.16380/j.kcxb.2025.07.008

Abstract ( 32 )

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【Aim】 To define the stridulatory organs and the features of acoustic signals of Hylurgus ligniperda adults, and explore the vibroacoustic treatment modes that can inhibit the female entry into logs, tunneling and fecundity. 【Methods】The stridulatory organs of female and male adults of H. ligniperda were observed using a scanning electron microscope to measure their parameters. Stress chirps, courtship chirps and rivalry chirps from male adults of H. ligniperda were recorded and analyzed for time-domain and frequency-domain parameters. Based on above acoustic studies, different vibroacoustic treatments were designed, using exciters to transmit sounds to logs. Stress chirps, courtship chirps, rivalry chirps and colony chirps of male adults of H. ligniperda, white noise, 6 kHz sine wave, sine sweep signal and stress chirps of Arhopalus rusticus adults were played for 6 d. The adult entry rate, the length of parent gallery and the number of eggs laid per female adult of H. ligniperda were counted.【Results】The stridulatory organs of H. ligniperda adults consist of plectrum and file, with males having more developed stridulatory organs. The end of the 6th abdominal tergite in males is characterized by leaf-shaped plectrums, a specialized structure absent in females. The files are located at the end of the elytral underside, near the sutural margin and close to the wing coupling. The chirp rate, duration of a single chirp, number of tooth-strikes per chirp, tooth-strike rate, and peak frequency of male adults of H. ligniperda showed extremely significant differences under the contexts of stress, courtship and competition. Different vibroacoustic treatments had no significant effect on the female entry rate of H. ligniperda adults. In the colonization phase after entry, certain vibroacoustic treatments significantly affected the length of parent gallery and the number of eggs laid per female of adults. The length of parent gallery was shortened in the rivalry chirp group of H. ligniperda at 50 cm from the exciter, and the number of eggs laid per female was reduced in the stress chirp group at the same distance from the exciter. 【Conclusion】The stridulatory organs and the characteristics of the acoustic signals of H. ligniperda adults were clarified. The rivalry chirps of H. ligniperda have the potential to inhibit tunneling, and stress chirps have the potential to inhibit oviposition by H. ligniperda. These findings provide a preliminary basis for future ecological regulation of H. ligniperda using acoustic signals.

Effects of releasing high-dose synthesized sex pheromones at regular intervals on the calling, mating and oviposition of Helicoverpa armigera (Lepidoptera: Noctuidae)

QU Li-Li , LI Yan-Hui , GANG Shuang, HUANG Xin-Yang , CHEN Wei , MENG Wei , ZHANG Wan-Min, GUO Qian-Shuang, DU Yong-Jun

2025, 68(7): 960-972. doi:10.16380/j.kcxb.2025.07.009

Abstract ( 55 )

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【Aim】To develop an efficient mating disruption technique for Helicoverpa armigera and to explore the changes of the calling and mating behaviors, number of eggs laid and egg hatching rate of H. armigera under high-dose sex pheromone environment. 【Methods】 In the laboratory wind tunnel, an active aerosol dispenser was set up to release high-dose sex pheromones at regular intervals. Four treatments were provided, including the complete sex pheromone blend of H. armigera (Z11-16∶Ald∶Z9-16∶Ald=10∶1) and single sex pheromone components Z11-16∶Ald, Z11-16∶OH and Z9-16∶Ald. The complete sex pheromone blend of H. armigera was sprayed once at the intervals of 20, 10 and 5 min, and the spraying interval of the three single sex pheromone components was 5 min. The total duration of sex pheromone spraying treatment was 12 h (from 16:00 to 4:00 of the next day). The calling and mating behaviors of female H. armigera moths, the number of eggs laid and their hatching rates were observed and compared. 【Results】In the high-dose complete sex pheromone blend environment, the calling onset time of female H. armigera moths was delayed in both day-old age and circadian rhythm, and the proportion of female adults extending ovipositor also decreased, as compared with those in the control (in the environment without sex pheromone). The duration of ovipositor extrusion of female moths significantly differed only at the 5-day-old when the complete sex pheromone blend was sprayed at the intervals of 10 and 5 min, but the onset time of ovipositor extrusion of female moths significantly differed at the 1-day-old when the complete sex pheromone blend was sprayed at the intervals of 20, 10 and 5 min. The average mating rate in the control group without sex pheromones was 84.0%±2.1%, as compared with that (5.0%-17.5%) in the complete sex pheromone blend treatment group. The onset age of mating in the complete sex pheromone blend treatment group was also delayed by 1-5-2-day-old as compared with that in the control group. In the experiment of single-component sex pheromone tests, the mating rate of the control group was 88.0%±3.7%, while the single sex pheromone components Z11-16∶Ald and Z11-16∶OH had significant effects on the mating rates, which were suppressed to only 14.0%±4.0% and 14.0%±2.4%, respectively, while the inhibitory effect of Z9-16∶Ald on the mating rate was minor, with the mating rate of 73.3%±3.3%, and Z11-16∶Ald delayed the onset age of mating by 1.5-day-old, and the effect of Z11-16∶OH and Z9-16∶Ald on the onset age of mating was not obvious. Both the complete sex pheromone blend and single sex pheromone components significantly inhibited the number of matings of female moths (resulted in reduction by 1.3-1.5 times). In the high-dose sex pheromone environment, the egg-laying time of female moths was significantly delayed by 2 d and the average number of eggs laid by mated female moth decreased, but the egg hatching rate of the mated female moths showed no significant change as compared with those in the control. 【Conclusion】The high-dose sex pheromone environment significantly inhibited the calling and mating behaviors of female moths of H. armigera, which further confirmed the autodetection ability of female moths to sex pheromones. By inhibiting calling and mating, sex pheromones delay the mating and oviposition day-old age of female moths of H. armigera, resulting in decreases in the number of eggs laid and hatching rate. The synthetic sex pheromone released by the active aerosol not only prevents the behavioral orientation response of male moths of H. armigera to female moths, but also affects the calling of female moths, and inhibits and delays the mating with male moths, resulting in a decrease in the number of egg laid. Therefore, it may have the potential for higher control efficacy when used in the field.

Effects of indoor-rearing generations on the parasitization ability of Aphidius gifuensis (Hymenoptera: Braconidae) and its growth and development-related enzymes

LAI Yu-Fei, ZHOU Ting, HAN Meng, HE Jiao-Ping, GU Gang, LAI Rong-Quan

2025, 68(7): 973-982. doi:10.16380/j.kcxb.2025.07.010

Abstract ( 45 )

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【Aim】 In the biological control of Myzus persicae, Aphidius gifuensis is widely used in production practice due to its significant parasitic advantages. However, in the process of large-scale breeding of this parasitoid wasp species, after many generations of breeding, the parasitization ability is weakened and the body size becomes smaller. This study aims to clarify the physiological and biochemical degradation mechanism of the parasitization ability of A. gifuensis by measuring and analyzing the changes in parasitization ability on M. persicae and contents and activities of growth and development-related enzymes of A. gifuensis reared in laboratory for 12 generations. 【Methods】 A. gifuensis collected in the field was randomly selected, and reared for five generations (1st, 3rd, 6th, 9th and 12th generations) in groups indoors. The parasitization ability ［parasitism rate and body size (hind tibia length)］, and the contents and activities of growth and development-related enzymes including carboxylesterase (CarE), phenoloxidase (PO), superoxide dismutase (SOD) and trehalase in A. gifuensis adults of different generations were measured. 【Results】 The parasitism rate and hind tibia length of adult offspring of A. gifuensis were significantly affected by the indoor-rearing generations. The parasitism rate and hind tibia length of the F₁₂ generation of A. gifuensis adults were decreased by 36.70% and 38.54%, respectively, as compared to those in the F₁ generation. Indoor-rearing generations significantly affected the contents of growth and development-related enzymes in adults of A. gifuensis offspring. The contents of CarE, PO, SOD and trehalase in adults of the F₁₂ generation of A. gifuensis were decreased by 54.00%, 43.13%, 35.82% and 45.87%, respectively, meanwhile the activities of PO and SOD in adults of the F₁₂ generation of A. gifuensis showed no significant change, as compared to those in the F₁ generation. Additionally, the contents of CarE, PO, SOD and trehalase in adult offspring of A. gifuensis were significantly positively correlated with the parasitism rate, the CarE content and CarE activity in adult offspring of A. gifuensis were also significantly positively correlated with the hind tibia length of A. gifuensis. 【Conclusion】 With the increase of indoor-rearing generations, the parasitism rate and the body size of the adult offspring of A. gifuensis generally decline, and the contents of the growth and development-related enzymes and CarE activity in the adult offspring of A. gifuensis exhibit significant change.

Dynamics of ovarian development during parental caring in adult females of ectoparasitoid Sclerodermus guani (Hymenoptera: Bethylidae)

LI Guo-Hong, CHEN Yue-Nan, WU Sha-Sha, LI Li, WEI Yun, ZHANG Meng-Meng

2025, 68(7): 983-998. doi:10.16380/j.kcxb.2025.07.011

Abstract ( 32 )

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【Aim】 The subsocial parasitoid wasp Sclerodermus guani exhibits typical parental care behavior that extends throughout its offspring development. This prolonged parental investment, while potentially reducing the parental future reproductive capacity, can effectively enhance the survival rate of the current offspring, thereby promoting population development. The trade-off between parental care and reproduction entails a strategic decision for the parasitoid wasp, balancing the production of more offspring against the care of a limited number of offspring. The plasticity in parental ovarian development serves as a crucial adaptive mechanism to ensure the reproductive benefits at the population level. This plasticity not only regulates the utilization rate of limited host resources by parents but also promotes the survival and development of their offspring. This study aims to clarify the dynamics of ovarian development in S. guani before, during and after parental care, so as to provide a scientific basis for elucidating the physiological mechanisms underpinning parental care and reproductive trade-offs in this species. 【Methods】 In the 2-day-old S. guani adult females parasitizing Monochamus alternatus hosts and engaged in host for oviposition (within 12 d post inoculation), we conducted regular dissections to assess various quantitative traits associated with ovarian development (ovarian length and width, ovarian index, basal egg length and width, and number of eggs) and abdominal changes (abdominal length and width, and abdominal index) of the female adults. We evaluated the degree of ovarian development and investigated the relationship between abdominal physogastry stages and ovarian development in female adults. Additionally, we compared and analyzed the dynamic changes of ovarian development of S. guani female adults under different physiological states during the parental caring process. 【Results】 The progression of ovarian development of S. guani was classified into five periods (five levels) based on ovarian coloration, yolk deposition status and egg maturity: transparent period (level Ⅰ), vitellogenesis period (level Ⅱ), egg maturation period (level Ⅲ), egg-laying period (level Ⅳ) and late egg-laying period (level Ⅴ). Corresponding to this process, a typical abdominal physogastry of female adults was observed, and could be divided into 5 stages: non-physogastric stage, early physogastric stage, physogastric stage, last physogastric stage and physogastry termination stage. Both abdominal and ovarian quantitative traits of female adults exhibited a pattern of increase followed by decrease, with the exception of basal egg length and width. Prior to parental care, the newly emerged female adults ［(virgin female without feeding, VF) and (mated females without feeding (MF)］ were devoid of eggs. However, following mating and feeding, ovarian development in female adults (mated females with feeding, MFF) became progressively evident, the ovarian length ［(2 871.31±80.17) μm］, ovarian width ［(405.91±29.14) μm］, ovarian index ［(1.19±0.09) mm²］, and the number of eggs ［mature eggs: (7.94±1.49) grains; immature eggs: (9.76±1.70) grains］ of the mated females in the early oviposition stage (MFEO) all reached maximum values. The ovarian length and width and ovarian index of females caring for eggs (FCE) were notably greater during the egg-caring stage compared to other caring developmental stages. Eggs were observed within the ovaries of females in various parental caring states, including FCE, females caring for early instar larvae (FCEIL), females caring for mature larvae (FCML), and females caring for late pupal cocoons (FCLPC), while females in other states did not exhibit egg-carrying behavior. A significant positive association was identified between the abdominal index and ovarian index of female adults throughout ovarian development. 【Conclusion】 The ovarian development in adult female S. guani is closely linked to its feeding and parental care behaviors. When provided with additional nutrients, the ovaries of the female parents initiate development. However, during the period of caring offspring of S. guani, the ovarian development in the parent females is suppressed, despite of their reproductive potential. This mechanism ensures that parental care is prioritized to optimize the survival and development of the offspring S. guani.

Cropland landscape fragmentation may not necessarily promote crop pest occurrence: A case study of paddy landscape in Wenchang, Hainan, southern China

TANG Yan-Jie, YANG Quan-Feng, YANG Jue-Jie, ZHENG Hua

2025, 68(7): 999-1006. doi:10.16380/j.kcxb.2025.07.012

Abstract ( 34 )

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【Aim】 This study aims to explore the effects of compositional and configurational heterogeneity at the landscape scale on the occurrence of pests and natural enemy insects in paddy fields. 【Methods】Using landscape gradient design, remote sensing image interpretation, systematic insect surveys, and linear mixed-effects model analysis, we investigated the effects of landscape compositional and configurational heterogeneity at multiple spatial scales (0.10-2.00 km) on the abundance (individual number) of the main late rice pest Sogatella furcifera, and its dominant natural enemy Cyrtorhinus lividipennis in 15 landscape plots in paddy fields in Wenchang, Hainan, southern China. Additionally, we further analyzed the impacts of the configurational heterogeneity characteristics of different landscape habitats, including cropland, grassland and forest, on the abundance of S. furcifera and its dominant natural enemy C. lividipennis.【Results】At the 1.00 km scale, the abundance of S. furcifera in paddy fields was significantly positively correlated with the proportion of surrounding grassland area. At the 0.25 km scale, the greater the landscape patch diversity, the fewer the abundance of S. furcifera. Conversely, at the 0.25 km scale, the larger the average patch size, the larger the abundance of C. lividipennis. In terms of the effects of configurational heterogeneity of landscape habitat components, in cropland, at the 0.25 km scale, the abundance of C. lividipennis in paddy fields decreased with the edge density increasing of cropland, and at the 0.50-1.00 km scale, the higher the patch density, the fewer the abundance of both S. furcifera and C. lividipennis. In forest, an increase in edge density at the 0.25 km scale, and an increase in average patch size of forest at the 0.50 km scale and both led to a decrease in the abundance of C. lividipennis in paddy fields. 【Conclusion】 Thus, the fragmentation of cropland, which reduced the occurrence of S. furcifera, could also suppress the population of its natural enemy C. lividipennis, indicating that cropland fragmentation does not necessarily promote the occurrence of rice pests. Therefore, it is essential to further investigate the specific impacts of the configuration characteristics of various landscape habitat components on the populations of pests and their natural enemies in croplands. This research can provide a scientific basis for more effectively enhancing pest control services through landscape management approaches.

ROS-mediated immune defense mechanisms and the role of ROS in regulating lifespan in insects

MA Zhen-Gang, CHEN Sheng, ZHANG Jun, HUANG Ting-Yue, ZHOU Ze-Yang

2025, 68(7): 1007-1022. doi:10.16380/j.kcxb.2025.07.013

Abstract ( 45 )

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Reactive oxygen species (ROS) is a general term for a class of oxygen-containing free radicals formed due to incomplete oxidation of oxygen molecules, or peroxides that are easy to form oxygen free radicals. When insects are invaded by pathogens, the ROS defense system mediated by dual oxidase (DUOX) will respond quickly to produce a large amount of ROS to resist the invasion of pathogenic bacteria, and then play a role in regulating the immune defense process of insects. However, high level of ROS can damage the biological macromolecules such as proteins, DNA and lipids in cells, causing damage to insect cells and affecting the normal development of insects. In order to avoid damage from excessive oxidative stress, insects have formed a complete antioxidant defense system mainly composed of antioxidant enzymes and small molecule antioxidants to prevent excessive damage from occurring. It is interesting that changes in ROS levels in cells can play completely different roles in regulating insect lifespan: for certain insects the accumulation of a large amount of ROS could lead to a shortened lifespan, while for some other insects the presence of high physiological levels of ROS could also induce diapause and prolong their lifespan. Studies on the regulatory mechanisms of ROS in insect lifespan have achieved a lot of progress in recent years. Therefore, in this article, we comprehensively reviewed the sources and influencing factors of insect ROS, the defense mechanisms mediated by ROS, and for the first time made a summary and outlook on the specific roles of ROS in regulating insect lifespan, so as to provide a reference for subsequent research on ROS-related topics.

Cloning and in vivo induced expression of the antimicrobial peptide Drosomycin gene SlDros in Shelfordella lateralis (Blattodea: Blattidae)

LIU Lu-Yao, GUI Hang, REN Shu-Jin, YUSHAN Yi-Li-Mu-Nu-Er, ZHANG Bing-Chuan, LI Fei, HE Shu-Lin, ZHOU Cao

2025, 68(7): 1023-1030. doi:10.16380/j.kcxb.2025.07.014

Abstract ( 27 )

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【Aim】The aim of this study is to identify antimicrobial peptide Drosomycin gene in Shelfordella lateralis, and examine the developmental and tissue expression properties and the expression of antimicrobial peptide Drosomycin gene induced by bacteria and insecticide. 【Methods】Drosomycin gene of S. lateralis was identified based on the transcriptome data of S. lateralis and further validated through RT-PCR. The expression levels of the Drosomycin gene in S. lateralis at different developmental stages (1st instar nymph, 4th instar nymph, and the 6-day-old female and male adults), in different tissues (head, thorax, gut, leg, fat body, hemolymph and integument) of the 4th instar nymphs, and in the 4th instar nymphs after injection of Escherichia coli, Staphylococcus aureus, and deltamethrin (1×10^-5 mg/L) were assayed by using RT-qPCR. 【Results】The cDNA sequence of Drosomycin gene SlDros (GenBank accession no.: PQ464795) of S. lateralis was cloned. The open reading frame of SlDros was 201 bp in length encoding 66 amino acids. SlDros was highly expressed in the 6-day-old male adults. SlDros was mainly expressed in the head, integument, thorax and hemolymph of the 4th instar nymphs. The expression levels of SlDros in the 4th instar nymphs at 12, 24 and 48 h after injection of E. coli, and those at 6, 12, 24 and 72 h after injection of S. aureus were significantly increased as compared with those of the control group injected with distilled water. At 96 h post-injection of deltamethrin, the expression level of SlDros in the 4th instar nymphs was significantly higher than that of the control group injected with acetone. 【Conclusion】The antimicrobial peptide Drosomycin gene is present in S. lateralis, and stress of bacteria or insecticide can induce its expression. These results provide a foundation for studying the function of antimicrobial peptides in S. lateralis and the further development of new antimicrobial drugs.

Contents of Vol. 68 Issue 7

2025, 68(7): 1031-1031.

Abstract ( 19 )

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