【Aim】 Insects will express heat shock proteins (HSPs) efficiently to establish self-protection mechanism under high temperature and pesticide stress. This study aims to know the molecular mechanisms of hsp70 and hsc70 mRNA expression in Aphis glycines under thermal and imidacloprid stress at the transcriptome level and look for the vulnerable spot, so to provide some theoretical basis for biological control. 【Methods】 We adopted the homology-based cloning, RACE technique and real-time fluorescent quantitative PCR methods to research the expression of hsp70 and hsc70 in the 4th instar nymphs of A. glycines at different heat shock time or different recovery time after heat shock and after treatment with different concentrations of imidacloprid. 【Results】 The hsp70 transcription level in the 4th instar nymphs of A. glycines increased first after heat shock at 37℃, reaching 10.36-fold as high as that of the control (P<0.05) at 1 h after heat shock, and then declined little by little. The recovery time after heat shock significantly influenced the hsp70 expression quantity. The hsp70 of A. glycines was abundantly expressed immediately after heat shock, with the expression level of 8.78-fold as high as that of the control (P<0.05), and then decreased to the control level, while the hsc70 expression quantity did not change significantly (P>0.05). Treated with imidacloprid, the peak time of hsp70 and hsc70 expression quantity in the 4th instar nymphs of A. glycines varied with the concentration of imidacloprid and stress time, showing an obvious short-term effect with a downward trend after rising first. 【Conclusion】 The transcription level of hsp70 and hsc70 in A. glycines under imidacloprid stress increases. However, hsp70 and hsc70 in A. glycines subjected to heat shock have different transcription expression patterns: the high temperature induces the expression of hsp70, but has no obvious inductive effect on hsc70.

【Aim】 Phenacoccus solenopsis Tinsley is one of the most important quarantine pests in China. Simple sequence repeats (SSRs) are very useful molecular markers in genetic studies such as genetic mapping, physical mapping, marker-assisted breeding and species identification, gene location, genetic diversity, classification and evolution of plants and animals, etc. Screening SSR primers will provide an important resource for marker-assisted investigation in genetic diversity, phylogenetic analysis and biological invasion of P. solenopsis. 【Methods】 A high-throughput method was used to develop the SSR genetic markers from the 28 120 unigenes of the transcriptome in the mealybug P. solenopsis. 【Results】 In total, 1 781 SSR genetic markers were developed from the previously constructed transcriptome database. The majority of them contained mono- and trinucleotide motifs (89.44% and 7.52%, respectively), of which A/T was the most abundant mononucleotide motif (87.42%). Based on the identified SSRs, 1 228 pairs of primer sets were designed from 481 unigenes by the Primer 3 program. 【Conclusion】 Our study shows that it is feasible to develop SSR markers by using P. solenopsis transcriptome, and the primers developed in this study provide the foundation for the analysis of genetic diversity, evolutionary biology, and invasion biology of P. solenopsis.

【Aim】 To compare four different extraction methods of proteins from larvae of the black soldier fly, Hermetia illucens, choose the method with highest extraction rate, and obtain the optimum process parameters so as to provide reference to protein extraction and resource utilization of H. illucens. 【Methods】 The methods of extraction by lye, enzyme, salt and Tris-HCl buffer were used and comparatively analyzed in extracting proteins from larvae of the black soldier fly. Then, the optimum levels of NaOH mass concentration, liquid-to-solid ratio, extraction temperature and time were determined by means of single factor tests. The experiment and analysis of Box-Behnken response surface was conducted based on the results of univariate tests and the actual situation. 【Results】 Among the four extraction methods of proteins from black soldier fly larvae, lye extraction was optimal, with the optimum extraction conditions of NaOH mass concentration 2.44 g/100 mL, liquid-to-solid ratio 22 mL/g, extraction temperature 53℃ and extraction time 2 h. The corresponding extraction ratio of verification test was 88.49%, with the relative error of only 0.28% compared with predictive value. 【Conclusion】 The response surface model is good fit, and the optimum extraction process is feasible.

【Aim】 Insect mandibular glands are exocrine organs that produce chemical substances known as pheromones which play an important role in intraspecific communication of insects. Our study aimed to understand the anatomical organization and postembryonic development of the mandibular glands in the Chinese honeybee, Apis cerana cerana. 【Methods】 The structure and developmental process of the mandibular glands were comparatively studied by using histological, morphometrical and immunohistochemical (BrdU incorporation) methods. 【Results】 The results showed that the mandibular glands presented caste-specific polymorphism, the largest in queens , then in workers, and the smallest in drones. The mandibular glands appeared during metamorphosis from the last instar larva to prepupa, and extensive proliferation in the mandibular glands could be detected only on the 1st day of pupal development. Proliferative nuclei disappeared on the 6th day of pupal development. Intima was divided from the secretory cell during early development of the mandibular glands, and kept to adults. 【Conclusion】 This study provides an essential foundation for studying the development and function of insect mandibular glands.

【Aim】 The study aimed to screen a highly pathogenic Metarhizium anisopliae strain against Orthaga achatina larvae, to determine its virulence by feeding larvae with crude toxin and to assess the lymphocyte responses in the larvae. 【Methods】 The virulence of M. anisopliae strains and crude toxin to O. achatina larvae was assessed using mortality-time probability method and TDM model, respectively, and the changes of lymphocytes in treated larvae were observed through a microscope. 【Results】 When various strains are compared, Ma1291-2 strain exhibited the strongest virulence against O. achatina larvae, causing a corrected mortality of 99.8%±2.6%, the cadaver rate of 86.9%±1.3% and the half lethal time (LT₅₀) of 6.29 d after inoculation with (1.0±0.5)×108 spores/mL for 11 d. The crude toxin levels produced by different strains were significantly correlated with the corrected mortality and LT₅₀. A time-dose-mortality model was employed to estimate parameters of time and dose, showing that Ma1291-2 strain and its crude toxin had a strong lethal effect on O. achatina larvae during 6-7 and 3-4.5 d after treatment, respectively. The concentrations of total hemocytes, plasmatocytes, spherulocytes and oenocytoids reached the maximum at 2 d after the larvae were fed with the crude toxin of Ma1291-2 strain and then declined. The concentration of granulocytes rapidly increased at 2 d after the larvae were fed with the crude toxin of Ma1291-2 strain, and reached a peak at 3 d after treatment. However, the concentration of prohemocytes did not show any significant change during the first three days of treatment, but decreased significantly at 4 d after treatment. Rupture of plasmatocytes and granulocytes, and melanization of spherulocytes and oenocytoids were observed during 3-4 d after treatment with the crude toxin of Ma1291-2, but prohemocytes did not significantly change. 【Conclusion】 The results show that the immune response of larval lymphocytes to the crude toxin is the strongest during 2-3 d after treatment, and the crude toxin is toxic to lymphocytes. This study proves potential applicability of this pathogen in the development of biological control for O. achatina.

【Aim】 To reveal the effects of different photoperiods on the developmental duration, fecundity and dynamics for the laboratory population of the cotton mealybug, Phenacoccus solenopsis Tinsley, and provide the scientific basis for control measures of the mealybug. 【Methods】 The mealybug population was fed on Hibiscus rosa sinensis under the conditions of temperature 27±1℃, relative humidity 70%±5%, illumination intensity 4 000 lx. The developmental duration, survival rate, and fecundity of the mealybug were observed, and the life tables were constructed under different photoperiods (8L∶16D, 10L∶14D, 12L∶12D, 14L∶10D and 16L∶8D, respectively). 【Results】 The developmental durations of the 1st and 3rd instar nymphs and the fecundities of female adults varied significantly among different photoperiods, while the survival rates of all nymphal stages were not significantly different. The developmental rate of the 1st and 3rd instar nymph of P. solenopsis accelerated as the light period increased, which were 5.43 and 6.35 d under 8 h light period, and 4.16 and 4.75 d under 16 h light period, respectively. The whole nymphal durations under 8 h and 16 h light periods were 15.54 and 12.74 d, and the generation durations were 27.75 and 23.45 d, respectively. The female adults produced offsprings earlier and had higher fecundity under longer light period. The pre-ovipositional durations for the female under the light periods of 16, 10 and 8 h were 18, 22, and 22 d, respectively. The number of offsprings produced per female under 16 h light period was 417.06, which was significantly higher than those under the 12, 10, and 8 h light periods (353.59, 347.61, and 336.00, respectively). The population trend indices (I) and growth potential were bigger under the longer light periods. The I values under 16, 10 and 8 h light periods were 175.37, 133.94 and 141.99, respectively. The net reproductive rate (R₀), the intrinsic rate of increase (r_m) and the finite rate of increase (λ) showed a gradually increasing trend with light periods, which were 88.57, 86.85, 100.77, 124.16, and 126.86 under the light periods of 8, 10, 12, 14, and 16 h, respectively. The r_m values varied from 0.1616 to 0.2066, and the λ values varied form 1.1754 to 1.2294 when the light periods increased from 8 h to 16 h. Contrarily, the population doubling time (t) decreased from 4.29 d to 3.36 d as the light periods increased from 8 h to 16 h. 【Conclusion】 Longer photoperiods are favorable for the development and fecundity of the cotton mealybug population, and the generation duration decreases while the population growth pontential increases as the light period increases.

Aim】 The solenopsis mealybug, Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae), is an important alien invasive pest recorded in China in the past several years and has a potential threat to cotton. In this study, the effects of constant and fluctuating temperatures on the growth and development of P. solenopsis on cotton was studied. 【Methods】 Under laboratory conditions (photoperiod 12L∶12D, RH 70%±5%), the developmental duration, developmental rate, survival and fecundity were investigated under a series of temperatures, and the effective accumulated temperature, developmental threshold temperature and optimal development temperature were analyzed. 【Results】 The results showed that the temperature had significant effect on the development of P. solenopsis. Within the constant temperature ranging from 17 to 32℃, the developmental duration of each stage of P. solenopsis shortened as the temperature rose gradually, and the developmental rate showed a significant positive correlation with temperature. The mealybug had higher developmental rate, survival rate and fecundity during the constant temperatures of 22-32℃. However, under the constant temperature of 37℃, the development was suppressed obviously and the mealybug died before completing a whole life span. In the fluctuating circumstance (25-40℃), P. solenopsis showed a better acclimatization, and had shorter developmental duration, higher survival rate and faster developmental rate. The minimum temperature thresholds (T_min) of females and males were 9.0 and 8.1℃, respectively. The effective accumulated-temperatures (K) of females and males were 322.6 degreedays and 344.8 degree-days, respectively. By analyzing the nonlinear regression relationships of the developmental rate and temperature, we calculated the optimal temperatures (T_opt) of females and males (30.5 and 29.95℃, respectively), and the maximum temperature thresholds (T_max) of females and males (36.6 and 35.8℃, respectively). 【Conclusion】 P. solenopsis has a wide range of adaptive temperature and can adapt to high temperature threshold under the fluctuating temperatures. These results will be helpful for predicting the distribution of this pest in the cotton regions in China.

【Aim】 Salicylic and jasmonic acids play important roles in inducing resistance to insects. This study aims to explore the induced resistance to phylloxera by salicylic and jasmonic acids in Kyoho grapevine. 【Methods】 Potted Kyoho grapevines were inoculated with grape phylloxera (Daktulosphaira vitifoliae) and sprayed with salicylic and jasmonic acids at the same time. Thereafter, the impacts of the above two hormones were detected and evaluated in the phylloxerainoculated grapevines, including the development and fecundity of phylloxera, the activities of antioxidant enzymes ［peroxidase (POD) and catalase (CAT)］, the content of malondialdehyde (MDA) in grape roots, shoot growth and the net photosynthetic rate. 【Results】 On the salicylic and jasmonic acidtreated grapevines, the total number of eggs per plant decreased by 41.35% and 50.00%, respectively, and the number of the 1st and 2nd instar nymphs of the next generation decreased by 42.31% and 50.00%, respectively, at 35 d after inoculation. After phylloxera infection, POD and CAT activities in grape roots increased first and then decreased, and were higher in salicylic and jasmonic acid-treated roots. The MDA content, however, was lower in salicylic and jasmonic acid-treated roots. Salicylic and jamonic acid treatment alleviated the growth depression caused by phylloxera. The growth of grape shoot and the net photosynthetic rate were remarkably decreased by 48.11% and 58.77%, respectively, at 30 d after inoculation. By contrast, the growth of salicylic and jasmonic acidtreated grape shoots decreased by 31.57％ and 25.71％, respectively, and the net photosynthetic rate decreased by 32.89％ and 24.67％, respectively. 【Conclusion】 Salicylic or jasmonic acid treatment can decrease the phylloxera population density, improve scavenging capacity of active oxygen and activities of defense enzymes, and alleviate the growth depression caused by phylloxera.

【Aim】 In recent years Apolygus lucorum (Meyer-Dür) damage to cotton has become the hot topics and research focus. To more deeply understand the damage characteristics of this pest to different growth stages of cotton, quantify the damage, and provide the basis for early forecasting of damage, we examined the relationship of early damage characteristics at different cotton growth stages and late bolls. 【Methods】 The damage characteristics of A. lucorum to different growth stages of cotton were investigated with artificial pest infection method in the field. 【Results】 Piercingsucking damage for 24 h by A. lucorum at the cotton cotyledon stage and 2-leaf stage could cause headless plants, while no headless plants were observed after 2-leaf stage. Regression model of the rate of headless seedlings with the damage degree of cotton growing point (y=0.1906x-0.0439, 1≤x≤5), and regression models of the damaged leaf index with the damage degree of cotton growing point and the number of piercing points at 4-leaf stage (y=0.532+0.202x₁+0.005x₂, 0≤x₁≤5, 1≤x₂≤5), 6-leaf stage (y=-0.063+0.339x1+0.002x2, 0≤x₁≤5, 1≤x₂≤5) and 8-leaf stage (y=-0.150+0.087x₁+0.001x2, 0≤x₁≤5, 1≤x₂≤5) were built respectively. Damage of A. lucorum to cotton at the budding and flowering stages had no significant effects on the abscission rates and sizes of late bolls. Damage of A. lucorum to the young cotton bolls with diameter less than 10 mm and 15 mm caused the corrected abscission rates of 55.0% and 26.6%, respectively, while the abscission rates of bolls with more than 15 mm diameter were 0. Sizes of mature bolls were not significantly influenced by A. lucorum damage. Regression models of the abscission rates of cotton bolls with 10 mm diameter (y=0.1857x-0.081, 1≤x≤5) and 10-15 mm diameter (y=0.0522x-0.0068, 1≤x≤5) with piercing points were built respectively. 【Conclusion】 The results indicate that cotton at the cotyledon stage, 2-leaf stage and young boll stage are very sensitive to the damage of A. lucorum. The regression model of piercing-sucking damage could be used in short-term forecasting for damage loss of A. lucorum. Key periods of cotton plants sensitive to damage of A. lucorum should be selected to promote the control efficiency.

【Aim】 Herbivorous insects may have difficulty in decision-making relative to selection of hosts for food and oviposition sites in the presence of multiple suitable hosts. Such potential interference with host selection may affect population dynamics. The objective of this study was to test the hypothesis that mixed populations of similar hosts would suppress population densities of the diamondback moth (DBM), Plutella xylostella (L.). 【Methods】 A randomized complete block (RCB) experimental design with 3 treatments was established in a field naturally infested with DBM. Treatments included mixed cultivation of Brassica campestris L. and B. juncea Coss, both of which are favorable hosts for DBM, and monocultures of either host. Moreover, mixed cultivation with different ratios of B. campestris to B. juncea and different intervals between the two hosts were established in the field also naturally infested with DBM. 【Results】 The population densities of DBM in mixed cultivation were significantly lower than densities on monocultures of either host (F_2,7=14.409 and 6.400 in 2010 and 2012, respectively, P<0.05). A population life table in 2012 yielded the population trend indexes (I) for DBM on B. campestris (I = 6.549) or B. juncea (I = 6.858) that were greater than the values on mixtures of the two hosts (I = 4.797). With B. campestris density increasing, the population densities of DBM first decreased and then increased. No differences were observed among population densities on hosts in mixtures at different intervals within 2 m (F_3,8 = 0.204, P > 0.05). 【Conclusion】 Population densities of DBM are lower on mixtures of favorable hosts, which is consistent with the hypothesis that in such situations the ability of insects to select a host is diminished. This phenomenon may have application value for management of DBM.

【Aim】 Whiteflies belong to a species-rich family with small body size. Identification of whitefly species is commonly done with the aid of molecular methods.  This study aims to clarify the effectiveness of the 5′- and 3′-ends of the mitochondrial cytochrome c oxidase subunit I (COI) gene sequences in molecular identification of common whiteflies species. 【Methods】 The COI gene sequences in 16 whitefly species common in China were amplified using the 5′- and 3′-end universal primers. The obtained 5′-end (641 bp) and 3′-end (738 bp) fragments were sequenced. The intra- and inter-species genetic distances were calculated using the Kimura-2-Parameter model; the phylogenetic trees were established by a neighbor-joining (NJ) method of the MEGA (Version 5.10) software.【Results】 The identification based on the phylogenetic tree was consistent with those based on morphological characteristics for the 16 whitefly species when the 5′-end fragments were analyzed. However, when the 3′-end fragments were analyzed, the identification results based on the phylogenetic tree were not consistent with those based on morphological characteristics in the case of Pealius mori and Bemisia tabaci Asia II 1. The average inter-species genetic distance was 193.1 (0.2897 vs. 0.0015) and 402.4 (0.2817 vs. 0.0007) times higher than the corresponding intra-species genetic distance for the 5′- and 3′-end fragments, respectively. There was no overlap between inter- and intra-species genetic distances when the 5′-end fragments were analyzed, but overlap was observed between P. mori and B. tabaci Asia II 1 when the 3′-end fragments were analyzed. 【Conclusion】 The DNA barcoding based on the 5′-end fragment of the partial COI gene can provide a rapid and accurate identification of these whitefly species.

Although cytochrome P450s have been well known to play crucial roles in insecticide resistance in insects, the mechanisms of P450-based metabolic resistance have not been fully characterized at the molecular level. Thanks to the development of genomics and biochemical techniques, rapid advances in the studies on the mechanisms of P450-mediated insecticide resistance have been achieved in recent years. This review attempts to summarize the current understandings in this field. P450-mediated resistance is a very common mechanism for almost all types of insecticides, and a single P450 enzyme may confer cross-resistance to different classes of pesticides. Variable genetic basis of resistance has been documented between populations resistant to the same insecticide due to multiple P450 options for evolving resistance. P450-mediated resistance may be due to either increased enzyme production (via enhanced transcription and/or gene duplication and amplification), or a change in structural gene itself that may alter the catalytic properties of the enzyme (caused by point mutations), or gene recombination of two closely linked genes that creates a chimeric enzyme with a novel ability. Constitutive transcriptional overexpression of resistance-associated P450 can be caused by cis- or/and trans-acting factors that have not been well understood. These findings suggest that mechanisms underlying P450-mediated insecticide resistance are diverse and complicated, and resistance monitoring and management should be customized for specific populations in a dynamic context.

The superorder Psocodea has over 10 000 described species in two orders: Psocoptera (barklice and booklice) and Phthiraptera (chewing lice and sucking lice). Many psocodean insects are important storedproduct pests, and some are important vectors for human and animal diseases. Recent studies indicate that psocodean insects have the most dramatic variation of mitochondrial (mt) genomes observed in insects, including genome architecture, gene order, gene content and gene strand asymmetry. In this review, we summarized the evolutionary features of the multipartite mt genomes observed in species of the Psocodea and introduced a new concept “mitochondrial genome karyotypes” to describe the complexity of animal mt genome. Furthermore, in combination with fragmented mt genomes of other bilateral animals, we proposed the mechanism to explain how multipartite circular mt genomes are generated. We propose that the selection pressure for compact mt genomes in bilateral animals favors small mt chromosomes when small mt chromosomes co-exist with the typical large mt chromosomes. Thus, small mt chromosomes may have selective advantages over large ones in bilateral animals. Fragmentation of mt genome is likely an important strategy to streamline mt genome. Meanwhile, we also investigated the current controversial views on the phylogenetic relationships among major lineages of the Psocodea. This review will provide new insights into the evolutionary pattern of mt genome of psocodean insects and other bilateral animals, as well as the phylogeny of Psocodea.

【Aim】 To understand the molecular evolution characteristics and genetic diversity of VP1 protein of Chinese sacbrood virus (CSBV) in Apis cerana cerana. 【Methods】 Eight cDNA sequences encoding VP1 proteins were cloned by RTPCR from Beijing isolates of Chinese sacbrood virus. 【Results】 Sequence analysis results showed that the open reading frame (ORF) of VP1 gene is 945 bp in length, encoding 315 amino acids with the predicted molecular weight of 35.42 kDa and the theoretical isoelectric point of 9.23, and the encoded protein has hydrophilicity and immunogenicity characteristics. Multiple sequence alignment indicated that the VP1 proteins from these CSBV Beijing isolates in different years share high amino acid sequence identity with occasional changes. The VP1 genes from Beijing isolates have high nucleotide sequence identity with those of Liaoning (LN) and Vietnam isolates (93%), India and Korea isolates (92%), while have the lowest nucleotide sequence identity with that of UK isolate (88%). The sequence analysis results also showed that the VP1 gene from Beijing isolates, other than from some isolates in other areas, has a specific amino acid characteristic which includes amino acid insertion. The nucleotide substitution rate among all Asian isolates was less than that between Asian and European isolates. A recombinant plasmid pEASY-E1-VP1, containing the coding sequence of VP1 protein, was constructed using pEASY-E1 as a fused expression vector, and VP1 protein was expressed successfully after induced with isopropyl-beta-D-thiogalactopyranoside (IPTG) in BL21(DE3)pLysS strain of Escherichia coli. 【Conclusion】 The results provide the basis for further studying the molecular mechanisms of the pathogenicity evolution of CSBV by confirming the existence of mutants in CSBV of different isolates.

【Aim】 To study the feeding behavior of Phenacoccus solenopsis during host shift for evaluating its host adaptability. 【Methods】 Feeding behavior of the solenopsis mealybug was quantitatively analyzed by electronic penetration graph (EPG) technique to evaluate its resource utilization efficiency when transferred to a novel host. 【Results】 During host shift, feeding behavior were significantly affected, including more time needed to reach phloem, less total feeding time, and lower ingestion efficiency. The next generation adults on the transferred host, however, showed increased ingestion efficiency, together with similar feeding behavior as their mothers before host shift, including the total number and time of probes, time of feeding and the efficiency to reach phloem. 【Conclusion】 High plasticity of feeding behavior is advantageous for P. solenopsis to adapt the transferred host and should be beneficial to expand its host range, which is supposed to be one reason that P. solenopsis would be an important agricultural invasive pest.