【Aim】 To investigate the convenient method for functional study of non-coding RNAs (ncRNAs) in the silkworm Bombyx mori, via injection of the overexpression vector of ncRNAs into the coelom of B. mori larva and detection of the expression changes of ncRNAs in different tissues of the larvae after injection. 【Methods】 The overexpression vectors piggyBac［A3-EGFP-A3-Bm-15］ and piggyBac［A3-EGFP-A3-Bm-152］ of ncRNA Bm-15 and Bm-152, respectively, were injected into the junction of the 7th－8th abdominal segments of the day-3 5th instar larvae of B. mori by microinjector (glass microinjection needle). The total RNA was extracted from larval head, thorax, caudal end, abdominal tergum, abdominal sternum and silk gland after 48 h of injection, and the expression levels of Bm-15 and Bm-152 in different larval tissues were detected by qPCR. 【Results】 The wound surface caused by glass microinjection needle was small, and the infection and mortality rates of B. mori larvae were less than 10%. Bm-15 was significantly overexpressed in the larval head and caudal end after injection of the overexpression vector, with the expression level increased by 17-fold in the head as compared to that in the injection group of the blank vector piggyBac［A3-EGFP］. However, the expression levels of Bm-15 in the other four tissues of B. mori larvae after injection of overexpression vector showed little change as compared to those of the uninjected control group. Bm-152 was also significantly overexpressed in larval head and caudal end of the silkworm after injection of the overexpression vector, with the expression level being 6.6-fold higher than that in the injection group of the blank vector piggyBac ［A3-EGFP］ in larval head. Bm-152 also showed obvious overexpression in larval abdominal tergum and silk gland, with the expression level being 3.4 and 4.5 times as high as that in the injection group of the blank vector piggyBac ［A3-EGFP］, respectively. 【Conclusion】 By coelomic microinjection of overexpression vectors of ncRNAs, ncRNAs can be stably overexpressed in the larval head of B. mori. This study provides a good strategy and method for the subsequent functional study of neuro-related ncRNAs.

【Aim】 This study aims to clarify the molecular characteristics and expression patterns of juvenile hormone receptor genes (Met) and to analyze their functions in reproductive regulation in the diamondback moth, Plutella xylostella, so as to provide basis for screening new targets for effectively controlling the diamondback moth. 【Methods】 Based on the genome database of P. xylostella we obtained previously, the fulllength cDNAs of two Met genes were cloned using PCR, and their expression patterns in different developmental stages and adult tissues of P. xylostella were detected via qPCR. Moreover, the role of the two Met genes in the reproductive development of female adults of P. xylostella was analyzed by RNAi. 【Results】 The cDNA sequences of PxMet-1 (GenBank accession no. MK697672) and PxMet-2 (GenBank accession no. MK697673) were cloned from P. xylostella, and they contain ORFs of 1 575 bp encoding 524 aa and 2 100 bp encoding 699 aa, respectively. The predicted molecular mass of PxMet-1 and PxMet-2 are 60.5 and 70.7 kD, and the theoretical isoelectric points are 6.73 and 5.50, respectively. PxMet-1 and PxMet-2 both contain a basic helix-loop-helix (bHLH) domain, two PAS motifs and one PAC motif. The results of phylogenetic tree analysis showed that PxMet-1 and PxMet-2 were clustered into different branches, but clustered into the same branch with lepidopteran Mets. The expression profiles showed that PxMet-1 and PxMet-2 were both expressed in the pupal stage (1-3 d after pupation) and female adult (0-72 h after eclosion). The expression level of PxMet-1 in the pupal stage (1-3 d after pupation) showed no significant difference, but was significantly higher than that in female adult (0-48 h after eclosion), and its expression peaked at 72 h after eclosion. In the female adult (0-48 h after eclosion), the mRNA level of PxMet-2 firstly increased, reached a peak at 12 h after eclosion, and then decreased. Moreover, the expression level of PxMet-2 at 0-36 h after eclosion was significantly higher than that in the pupal stage. The expression levels of PxMet-1 and PxMet-2 in the fat body of adult were significantly higher than those in other tissues. Injection of dsPxMet-1 and dsPxMet-2 significantly inhibited the expression of PxMet-1 and PxMet-2 within 24 h. In the female adults of P. xylostella with both PxMet-1 and PxMet-2 silenced, oogenesis was significantly inhibited, and the number of eggs laid per female within 3 d after eclosion significantly reduced. 【Conclusion】 Inhibition of the expression of PxMet-1 and PxMet-2 can significantly reduce egg maturation and oviposition of female P. xylostella. This study establishes a theoretical foundation for reproductive regulation mechanisms by JH in P. xylostella and facilitates screening potential targets used for genetic manipulation of P. xylostella populations.

【Aim】 The dosage compensation mechanism of Helicoverpa armigera is still unclear. This study aims to clone male-specific lethal 1 gene Hamsl1 from H. armigera and to investigate whether it regulates dosage compensation of H. armigera by RNA interference technology. 【Methods】 The full-length cDNA of Hamsl1 sequence of H. armigera was cloned by RT-PCR based on homologous sequence alignment. The gene expression profiles of Hamsl1 in different developmental stages of H. armigera were detected by qPCR. After RNAi of Hamsl1 via microinjection of Hamsl1 siRNA into the 3rd instar larvae of H. armigera, the expression levels of 15 Z-linked genes were detected by qPCR to verify whether Hamsl1 regulates the dose of genes on Z chromosome. 【Results】 The full-length cDNA of Hamsl1 was successfully cloned from H. armigera, and its mRNA was identified to have two alternative splicing transcripts, which were designated as Hamsl1a (GenBank accession no.: MK564008) and Hamsl1b (GenBank accession no.: MK564009), respectively. Functional domain analysis showed that HaMSL1 contains a typical PEHE domain and a coiled-coil domain, which are the characteristics of MSL1 protein. The qPCR analysis demonstrated that Hamsl1 gene was located on the Z chromosome of H. armigera. The expression of both Hamsl1a and Hamsl1b showed the developmental stage specificity, peaking at the adult stage, and the sex specificity with significantly different expression level between female and male after pupation. Fifteen Z-linked genes were identified by homologous alignment and qPCR at the DNA level. Microinjecting Hamsl1 siRNA into the 3rd instar larvae of H. armigera for 72 h resulted in a RNA interference efficiency of 36.01%-64.27%, but no male specific lethal phenomenon was found in the tested insects. The 15 Z-linked genes in the Hamsl1 RNAi group showed significantly up-regulated expression in males as compared to those in the control group, but no significant expression change in females. 【Conclusion】 This study preliminarily proves that Hamsl1 gene is located on the Z chromosome of H. armigera and may regulate the dosage compensation by inhibiting the expression of Z-linked genes in male H. armigera. This study provides a theoretical foundation for further study of the molecular mechanism of dosage compensation and environmentally-friendly control of H. armigera.

 【Aim】 This study aims to identify the structure of active components of sex pheromone of female moths of Micromelalopha sieversi. 【Methods】 The sex pheromone was extracted from sex glands of virgin female moths of M. sieversi by n-hexane. The active ingredient was located by gas chromatography-electroantennographic detection (GC-EAD). The additive derivative was obtained by the reaction of the extract from sex glands of virgin female moths with 4-methyl-3H-1,2,4-triazole-3,5(4H)-dione (MTAD). The characteristic ions of the extract and additive derivative were analyzed by gas chromatography-mass spectrometry (GC-MS). 【Results】 The GC-EAD results indicated that the antenna of male moth of M. sieversi showed sensitive reaction to one component of the extract from sex glands of virgin female moths. Based on the GC-MS data of the extract and additive derivative, the active component of sex pheromone was identified as 13,15-octadecadienal. 【Conclusion】 The identified planar structure of the active component of sex pheromone of female moths of M. sieversi is 13,15-octadecadienal, but the stereoscopic configuration of conjugated double bonds needs to be further identified through synthesizing more standard compounds. This study provides the direction in screening synthetic pheromone candidates and establishes the foundation for determining the sex pheromone structure of female moth of M. sieversi.

【Aim】 In our previous work, the interaction between rice stripe virus (RSV) and Himetobi P virus (HiPV) of the small brown planthopper (SBPH), Laodelphax striatellus, was found. This study aims to prepare the polyclonal antibody (PAb) of the capsid protein VP1 of HiPV and to assess its application in the detection of HiPV, so as to provide a technical basis for further studying the interaction of HiPV-RSV and HiPV-SBPH. 【Methods】 VP1 gene of HiPV was amplified from SBPH adult via RT-PCR, and subcloned into the prokaryotic expression vector pET-32a to construct the vector pET-VP1. The recombinant plasmid was transformed into Escherichia coli BL21 (DE3), and the recombinant protein was obtained by IPTG induction and purified by Ni²⁺-NTA affinity chromatography. The antibody was prepared by immunizing New Zealand white rabbit with the purified recombinant protein. 【Results】 A 774 bp product of capsid protein gene VP1 of HiPV was amplified from SBPH, and a 47.5 kD VP1 fusion protein was obtained through prokaryotic expression and purification. The purified VP1 recombinant protein was used to immunize New Zealand white rabbit, and the PAb was prepared. The titer of PAb was 1∶819 200 in indirect ELISA, and the PAb could react specifically with HiPV VP1 but not with SBPH proteins. Using PAb against HiPV, methods of Western blot and immunocapture-RT-PCR (IC-RT-PCR) for the detection of HiPV in single adult of SBPH were established. The detection results showed that HiPV was prevalent in the RSV-infected and uninfected SBPH high-affinity populations. 【Conclusion】 HiPV can be detected specifically in SBPH using the prepared VP1 polyclonal antibody. This study provides a technical support for the rapid detection of HiPV and the study of HiPV-RSV and HiPV-SBPH interaction.

【Aim】 There are long-winged and short-winged morphs in populations of the small brown planthopper (SBPH), Laodelphax striatellus. The wing morphs of SBPHs are affected by the genetic and environmental factors. The aim of this study is to illustrate the adaptability of the long-winged and short-winged strains of SBPHs to high and low temperatures. 【Methods】 The selection of long-winged and short-winged strains in SBPHs was performed under a constant condition, and the strains with long and short wings were set up after 63 and 65 generations of selection, respectively. The fecundity, survival rates and developmental duration of populations of the long-winged and short-winged strains and a wild population collected from rice filed in Nanjing were measured at 25, 30 and 35℃. The survival rates of nymphs of these three populations were measured after exposure to 5℃ and -20℃. The supercooling points of nymphs and adults of these three populations were also measured. The adaptability of long-winged and short-winged strains to high and low temperatures was analyzed by comparing the survival rate, developmental duration, fecundity and supercooling point. 【Results】 The fecundity of the female adults of the long-winged and short-winged strains of SBPH was significantly lower than that of the wild population at 25, 30 and 35℃, and there was no significant difference in the fecundity between the short-winged and long-winged strains. The fecundity of the female adults of the short-winged or long-winged strain at 25℃ was not significantly different than that at 30℃, but the fecundity of the female adults of the wild population at 25℃ was significantly higher than that at 30℃. At 35℃, the short-winged and long-winged strains hardly produce nymphs. The nymphal survival rate at 25℃ was similar among the short-winged strain, long-winged strain and wild population. But at 30℃, the nymphal survival rate of the short-winged strain was significantly lower than that of the wild population, and there was no significant difference in the nymphal survival rate between the short-winged and long-winged strains. At 35℃, the nymphs of the short-winged and long-winged strains only survived to the 3rd instar, but the nymphs of the wild population could survive to the 5th instar. The nymphal duration of the short-winged strain at 25℃ was significantly shorter than that of the wild population, but did not differ from that of the long-winged strain. At 30℃, however, the nymphal duration of the short-winged strain was significantly longer than those of the long-winged strain and the wild population. The survival days of the 3rd-4th instar nymphs of the long-winged strain were not different from those of the short-winged strain and the wild population at 5℃. The mortality rates of nymphs of the long-winged strain and the short-winged strain after exposure to -20℃ for 10 min showed no significant difference, but were significantly higher than that of the wild population. The supercooling points of adults were not significantly different among the short-winged strain, long-winged strain and wild population. However, the supercooling point of the 5th instar nymphs of the short-winged strain was significantly higher than that of the wild population, but showed no significant difference from that of the long-winged strain. 【Conclusion】 The adaptability of the long-winged and short-winged strains of SBPH to high and low temperatures is similar but lower than that of the wild population. The nymphal development of the short-winged strain of SBPH is slower than that of the long-winged strain under conditions of high temperature.

【Aim】 Trapping by sex pheromone has been used as an effective tool to monitor and control the striped rice stem borer, Chilo suppressalis, an important rice pest. This study aims to clarify the mechanism of sex pheromone trapping and the mating status of trapped male moths of C. suppressalis. 【Methods】 The characteristics of internal genital organs of male adults of C. suppressalis at different age (day-old) and in different mating statuses were studied with behavioral bioassay and genital anatomy and compared with those of male adults captured with sex pheromone lure in the field. 【Results】 The primary segment of single ejaculatory duct of male moth of C. suppressalis could be divided into seven segments. The genital contents in the genital duct were mostly white and could be grouped into five grades (grade 0-4) according to the compactness, with two statuses of the genital duct fully and not fully filled with contents. With the increase of the age (day-old), the grades of genital contents in accessory glands and segments 3 and 4 of ejaculatory duct decreased. The proportion of unfulfilled duct in segments 5 and 7 and the grade of contents in segments 5 and 7 increased. The grades of contents in segments 5 and 7 and in the double ejaculatory duct were significantly lower in the newly mated male moths than those in the unmated individuals of the same age, while the grades of contents in segments 1-4 of the newly mated males were significantly higher than those of the unmated individuals within 1 h after mating. At 24 h after mating, there was no significant difference in the grade of contents between mated and unmated individuals. At 36 h after mating, the proportion of unfulfilled duct in segments 5 and 7 of the mated moths was higher than that of the unmated individuals. However, the response to sex pheromones did not significantly affect the contents in the genital duct. The grades of contents in the terminal half part of accessory gland of male moths trapped by sex pheromone from the field were significantly higher than those of the unmated moths of the 2-6-day-old, while these of segments 3 and 4 of male moths trapped by sex pheromone from the field significantly lower than those of the newly emerged (0-day-old) male moths. 【Conclusion】 The results show that the characteristics of genital contents can be used to distinguish the mated and unmated individuals of C. suppressalis within 12 h after mating. Sex pheromone trapping can attract a large number of 1-day-old unmated male moths and is an effective measure for the control of C. suppressalis. Our results lay a theoretical foundation for the determination of mating status of male moths of C. suppressalis and for pest monitoring and control by pheromone trapping.

【Aim】 To explore the relationship between the testicular volume and mating activity of male moths of the striped rice stem borer, Chilo suppressalis, and to evaluate the effectiveness of sex pheromone trapping in the pest management. 【Methods】 The testicular volume of different day-old male moths of C. suppressalis under different mating statuses and trapped by sex pheromone were measured and compared, and the relationship between the testicular volume and the developmental and mating statuses of male moths was established. 【Results】 The age (day-old) of male moths of C. suppressalis significantly affected their mating activity. The mating rate of the newly emerged (0-day-old) male moths was low, and the mating rate was the highest in the 1-day-old male moth and then decreased gradually as the age (day-old) of male moths increased. There was a significant negative correlation between the testicular volume and the age of male moths of C. suppressalis. The testicular volume of the mated male moths was significantly larger than that of the unmated male moths of the same age. The testicular volume of the male moths caught by pheromone traps was significantly larger than that of the untrapped male moths, but was as large as that of the mated male moths of the same age. The development of the testis in the mated moths was similar to that of the unmated individuals. The testicular volume of male moths caught by sex pheromone traps in the field was smaller than that of the unmated male moths of 0-1-day-old, but larger than that of the unmated male moths of 2-6-day-old. 【Conclusion】 The results indicate a positive correlation between the response of male moths of C. suppressalis to sex pheromone and their testicular volume. Male moths trapped by sex pheromone lures show stronger responding activity to sex pheromone, and most of individuals caught by sex pheromone traps are the unmated ones. Copulation does not affect the testicular volume and the development of the testis of male moths of C. suppressalis. The relationship between the mating ability and testicular volume of male moths of C. suppressalis explains the effectiveness of sex pheromone trapping in pest management, and provides a basis for the mating study of other moths.

【Aim】 To explore the ecological regulation effectiveness of habitat heterogeneity on predatory natural enemies and rice pests in rice paddies, and to determine whether this strategy would cause other herbivorous insects to become main rice insect pests. 【Methods】 Single-season rice was planted for two consecutive years (2017-2018). Peanuts and soybeans were planted at the edge of rice paddy to construct the rice paddy with high heterogeneous marginal habitats (HHR). The occurrence and correlation of predatory natural enemies and rice pest functional groups in both HHR paddy and rice paddy with low heterogeneous marginal habitats (LHR) were investigated, and the predator-to-pest ratio was calculated. 【Results】 In 2017, 1 667 predatory natural enemies belonging to 40 species were collected in HHR, and 991 predatory natural enemies belonging to 30 species were collected in LHR. In 2018, 1 384 predatory natural enemies belonging to 33 species were collected in HHR, and 1 031 predatory natural enemies belonging to 34 species were collected in LHR. The similarities of species of the predatory natural enemies with the community importance value P_i≥0.01 in HHR and LHR were high, and the dominant species in the two paddies were similar. In 2017, the species richness of predatory natural enemies in HHR was significantly higher than that in LHR, which was mainly caused by the species with the community importance value P_i<0.01. There was no difference in the species richness of predatory natural enemies between the two paddies in 2018. The number of predatory natural enemies in the quadrat area in HHR was higher than that in LHR, and this difference was significant in the tillering and maturity stages in 2017 (P<0.05), and extremely significant in the flowering stage in 2018 (P<0.01). In 2017, 637 rice pests belonging to 22 species were collected in HHR, and 743 rice pests belonging to 19 species were collected in LHR, with the similarity coefficient of community of 0.88 between the two paddies. In 2018, 1 011 rice pests belonging to 16 species were collected in HHR, and 2 014 rice pests belonging to 16 species were collected in LHR, with the similarity coefficient of community of 0.75 and the same compositions of main pest species between the two paddies. The temporal dynamic analysis of rice insect pest populations showed that the number of insect pests in HHR was significantly higher than that in LHR (P<0.05) in the tillering stage when the total number of insect pests was small and their damage to rice was light. In the booting stage, flowering stage and maturity stage, the numbers of rice pests in HHR were significantly lower than those in LHR, and this difference was extremely significant in the maturity stage in 2017 and the booting stage in 2018 (P<0.01), and significant in the maturity stage in 2018 (P<0.05). The N_pi (the individual number ratio of predatory natural enemies to insect pests) values in HHR and LHR were 2.62 and 1.33 in 2017, and 1.37 and 0.51 in 2018, respectively. 【Conclusion】 The rice paddy with high heterogeneous marginal habitats can improve the conservation potential of predatory natural enemies, and significantly increase the number of predatory natural enemies and the predator-to-pest ratio in rice paddy. This makes up a better material basis for controlling pests, can promote the ecological control efficacy of predatory natural enemies on rice pests, and has no risk of causing other herbivorous insects to evolve into main rice pests, providing strategies and methods for protecting the natural enemies in rice ecosystems.

【Aim】A large majority of the sap beetle fauna of India thrives on rotten fruits and vegetables and their populations show considerable seasonal fluctuations over the year. It has been hypothesized that the population of sap beetles are largely dependent on environmental variables like temperature, humidity and rainfall. 【Methods】 The species composition, seasonal incidence and population structure of sap beetles (Coleoptera: Nitidulidae) were investigated in Garia, a peri-urban area of Kolkata, India from 2013 to 2015. Period of their activity, seasonal abundance and factors influencing their occurrence were recorded. 【Results】Altogether six species were encountered in varying numbers in the peri-urban area of Kolkata, India during the study period. The most commonly collected sap beetle was Urophorus humeralis. This species was encountered for the largest number and during almost all months of the year. Other common species were Epuraea ocularis and E. luteola. Different species entered into the trap in successive stages of the fermenting food. Epuraea spp. were intercepted in the first 12 h while U. humeralis was mostly found in later successive stage when the food in the bait trap was severely rotten. The species richness was the highest in an optimum range of atmospheric temperature (22℃ to 29℃) and relative humidity (82.5% to 86%), demonstrating that these environmental variables have considerable influence over sap beetle population.【Conclusion】Major fruits and vegetables grow during the post-monsoon season in Kolkata. Sap beetles which feed on these crops show the highest incidence both in terms of species richness and abundance during the post-monsoon season. The study result may help in designing effective field management strategy for these beetles.

Symbionts universally exist in insects, not only providing host insects with nutrients such as amino acids and sterols that are necessary for their growth and development, but also improving the adaptability of insects to external adverse environmental factors such as high temperature, parasites and viruses. Insects provide a stable living environment and nutrients for symbionts. Symbionts and host insects are interdependent. In most cases, symbionts are vertically transmitted between generations of their host insects, from the mother to its offsprings. In this article, based on the relevant studies in recent years we reviewed the vertical transmission modes of different insect symbionts. Except for a small number of intestinal symbionts that can be transmitted vertically through contaminated egg shells and then eaten by host larvae, most of vertically-transmitted symbionts are transovarially transmitted. According to different infection periods, most of the transovarial transmission modes of symbionts can be divided into the following four types: infecting germline stem cells in host insect larvae, infecting germline stem cells in the young female adult of host insect, infecting mature oocytes in the female adult of host insect, and infecting blastocyst embryos of host insect. Among them, some symbionts enter the host ovary in the form of bacteriocyte. In addition, a few intestinal symbionts are also vertically transmitted through the ovary. Such symbionts firstly infect the lateral oviduct and accumulate in it, and then enter the oocyte when the oocyte is discharged into the lateral oviduct. We also explored the cellular and immune mechanisms of vertical transmission of insect symbionts, including the avoidance of host immune responses by symbionts, the entry of symbionts into ovaries by endocytosis, and the synergistic effects between different symbionts.

Begomoviruses (Geminiviridae) are a group of important plant viruses that affect the production of many crops such as tomato, tobacco and cotton, and they are transmitted by the whitefly Bemisia tabaci under natural conditions. The outbreak of begomoviruses in the field is shaped by many factors, among which their whitefly vectors are one of the most significant. Therefore, determining the role of whitefly in the transmission and spread of certain begomoviruses is the key to deciphering the nature of plant diseases caused by begomoviruses. In this article, we discussed the factors affecting the transmission of begomoviruses and the mechanisms underlying the adaptation of viruses to their insect vectors. Both begomoviruses and whiteflies are pests with a cosmopolitan distribution, and bioinformatics-based analysis indicates that both exhibit geography-related genetic variation. Transmission assays showed that begomoviruses tend to be transmitted with higher efficiency by the whitefly species sharing the same geographic origin than the ones whose origins are different from those of the viruses. Information provided here offers an important source of references for further research with regard to the transmission of begomoviruses by whiteflies.