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The band-winged grasshopper Oedaleus asiaticus (Orthoptera: Acridoidea) is an important insect pest in north China. Chemosensory membrane proteins are believed to be crucial factors in direct interactions with odorants in the chemosensory process. However, there is much limited information on the chemosensory system in this pest. In this study, a total of 69 candidate chemosensory membrane protein genes, including 60 olfactory receptors (ORs), 6 ionotropic receptors (IRs) and 3 sensory neuron membrane proteins (SNMPs), were identified for the first time from the antennal transcriptomes of O. asiaticus. Blastp match and phylogenetic analysis demonstrated that these chemosensory membrane proteins were the closest to their orthologous species, Locusta migratoria. The qRT-PCR analysis revealed that all tested 14 OR and two SNMP genes (OasiSNMP1 and OasiSNMP2a) were strongly expressed in adult antennae, and nearly all tested genes (15/16) displayed significant differences in the expression levels between both sexes. Moreover, two IR genes (OasiIR25a and OasiIR76b) had uniquely high expression levels in the antennae, labial palps and maxillary palps, while three IR genes (OasiIR1 , OasiIR2 and OasiIR3) were highly expressed in most tested tissues (heads without antennae and mouthparts, labial palps, maxillary palps, labia without labial palps, thoraxes, tarsi, and abdomens) except for antennae, labra, and wings but OasiIR5a was just faintly expressed in the antennae, labia without labial palps, labial palps, maxillary palps and abdomen. Our results provide important molecular information for further investigation on the chemoreception mechanisms in O. asiaticus. Unlabelled Image [ABSTRACT FROM AUTHOR]

Abstract Galeruca daurica is a new pest causing great losses in the Inner Mongolian grasslands of China. The adults enter obligatory diapause during summer. However, the molecular mechanism of summer diapause remains unknown. We used iTRAQ to conduct proteomic analysis of adult G. daurica at the pre-diapause (PD), diapause (D) and post-diapause (TD) stages during summer diapause. A total of 139 and 118 differentially expressed proteins (DEPs) were detected in D/PD and TD/D comparisons, respectively. Besides a large number of DEPs involved in metabolic process, stress response, cytoskeletal reorganization, and phagosome pathway, many new proteins related to diapause were found in this study, such as encapsulation-relating proteins, odorant binding proteins, chemosensory proteins and ribosomal proteins. KEGG analysis revealed that the phagosome pathway was the only common significantly enriched pathway in both D/PD and TD/D. In addition, juvenile hormone regulation and Ca2+ signaling may play an important role in the regulation of summer diapause in G. daurica. Our proteomic analysis provides a new insight into the mechanism of obligatory summer diapause, and lays a foundation for future molecular level studies. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

Abstract To investigate the olfactory mechanisms in Oedaleus infernalis , one of important pests of cereals and pasture in the northern China, the whole-body transcriptome was constructed by RNA-Seq in this study. By de novo assembly, a total of 92,476 unigenes were generated in the adult sample, and 32,693 unigenes (35.35%) were successfully annotated by Blastx. Eighteen putative odorant binding proteins (OBPs) were identified, and phylogenetic analysis indicated the closest genetic relationship of eight OBPs in O. infernalis with those in its sibling species, Oedaleus asaiticus , while five OBPs in O. infernalis with those in Locusta migratoria. qRT-PCR analysis of the expression patterns of all 18 OinfOBPs in different tissues indicated that most OinfOBP s, especially OinfOBP7 and OinfOBP12 , had higher expression levels in the antennae meanwhile no or faint expression in other body parts, including heads (without antennae), thoraxes, abdomens, legs, and wings, suggesting that these OBPs may play important roles in olfaction. OinfOBP2 was highly expressed only in male heads. Interestingly, only OinfOBP13 displayed high expressions in nearly all tested tissues. These two OBPs may have different physiological functions in O. infernalis. The remaining OBP s were not or weakly detected in all tested tissues. Our results provide important molecular information for further studies on chemosensory mechanisms in this pest. [ABSTRACT FROM AUTHOR]

Using the thermocouple method, the supercooling point (SCP) and cold hardiness of Pararcyplera microptera meridionalis eggs were measured in the laboratory. The soil water content significantly affected the water content of pre-diapause eggs, but had no significant effect on the SCP, and the water content of pre-diapause eggs rose with the increasing soil water content. There were highly significant differences among the SCPs, water contents or fat contents in the eggs at different developmental stages. With the egg-s development, the water content decreased from 51. 5% at oviposition to 46. 8% in 120 days after oviposition, the fat content increased from 10. 5% (fresh mass) /19. 0% (dry mass) to 14. 5% (fresh mass) /28. 9% (dry mass), and the SCP declined from -23. 5 °Cto -30. 0 °C. There was a significant correlation between the SCP and the water content or fat content. The SCPs of deep-diapause eggs were lower than those of pre-and earlydiapause eggs. The different low temperatures and treatment durations significantly affected the survival rate of diapause eggs. The lethal low temperature (Ltemp50 ) for 12 h exposure was -27. 3 and the lethal time (Ltime50) at -25 °C was 22. 73 days. As the mean SCPs of diapause eggs was much similar to their Ltemp50, the SCP could be considered as a good indicator of cold hardiness for P. m. meridionalis eggs and this species is a freeze-intolerant insect. [ABSTRACT FROM AUTHOR]

Both 20-hydroxyecdysone (20E) and miRNAs have multiple functions in the regulation of various physiological processes in insects. However, little is known about the interaction between 20E and miRNAs. In this study, six small RNA libraries were constructed from the adult Galeruca daurica treated with 20E and dimethyl sulfoxide (DMSO), respectively. Using small RNA sequencing, a total of 183 miRNAs, including 140 known and 43 novel miRNAs, were identified. Compared with the control (DMSO), 52 miRNAs (21 up-regulated and 31 down-regulated) were significantly differentially expressed after 20E treatment. The KEGG and GO analysis of the predicted genes targeted by 20E-responsive miRNAs indicate that 20E may influence the metabolic change during reproductive diapause in G. daurica via regulating miRNAs. [Display omitted] • The 140 known and 43 novel miRNAs were identified from the adult Galeruca daurica post-20E treatment. • The 52 miRNAs were significantly differentially expressed after 20E treatment. • These 20E-resonsive miRNAs may be contributory to metabolic change during adult diapause in G. daurica. [ABSTRACT FROM AUTHOR]

A comparative study was conducted on the life table parameters of Aphis gossypii reared on five host plant species at (25±1) ° in laboratory. There existed significant differences in the durations of various developmental stages, adult longevity, mean offspring number per day, net reproductive rate, intrinsic rate of increase, finite rate of increase, mean generation time, and population doubling time for the A. gossypii populations reared on the host plants. For the aphids on Lagenaria siceraria var. turbinate, they needed the longest time (5. 84 days) to complete one generation, but for those on the other four plants, no significant differences were observed, with the time needed ranged from 5. 24 to 5. 45 days. The adult longevity was the longest (20. 04 days) on Cucumis sativus, but had no significant differences on the other four host plants, being from 14. 76 to 16. 03 days. The populations' survival curves on all test host plants were of Deevey I, i. e. , the death mainly occurred during late period. The survival rate on C. sativus was higher than those on the other four host plants. Based on the intrinsic rates of increase of A. gossypii, its host suitability was in the order of Cucumis melo var. saccharinus > Lagenaria siceraria var. turbinate > Cucurbita moschata var. melonaeformis > Cucumis sativus > Cucurbita pepo var. medullosa. [ABSTRACT FROM AUTHOR]

MicroRNAs (miRNAs) regulate gene expression at the post-transcriptional level. Although the regulatory roles of miRNAs in various physiological processes throughout insect development have been investigated, it is almost unknown about the roles of miRNAs involved in regulation of diapause in insects. We constructed nine small RNA libraries from Galeruca daurica adults at different diapause stages: pre-diapause (PD), diapause (D), and post-diapause (TD). Using Illumina sequencing, a total of 95.06 million valid reads was obtained, and 222 miRNAs, including 135 conserved and 87 novel miRNAs, were identified from G. daurica. The expression profiles of these miRNAs were analyzed across different diapause stages. The 30 and 13 miRNAs were differentially expressed in the D/PD and TD/D comparisons, respectively. The KEGG and GO analysis of the predicted target genes suggested the essential roles of miRNAs in the regulation of summer diapause in G. daurica , especially via the juvenile hormone, ribosome, MAPK signaling, and Ca2+ signaling pathways. Our research results indicate that miRNAs may be involved in the regulation of summer diapause in G. daurica , and these results also provide an important new small RNA genomics resource for further studies on insect diapause. Unlabelled Image • The 135 conserved and 87 novel miRNAs were identified at different diapause stages of Galeruca daurica adults. • The 30 and 13 differentially expressed miRNAs (DEMs) were obtained in the D/PD and TD/D comparisons, respectively. • The predicted target genes of these DEMs suggested potential pathways regulating summer diapause in G. daurica. [ABSTRACT FROM AUTHOR]

The plant mirid bugs, Lygus pratensis Linnaeus and Polymerus cognatus Fieber, are key pests on economically important cotton crops and ecologically important grassland in northwestern China. Lambda-cyhalothrin is frequently used against mirid bugs in the regions. In this study, we examined the sublethal and transgenerational effects of short-term exposure to lambda-cyhalothrin on biological traits using a miminal dose, LD 5 [0.484 ng/ L. pratensis adult, and 0.171 ng/ P. cognatus adult], a low lethal dose, LD 25 [1.353 ng/ L. pratensis adult, and 0.781 ng/ P. cognatus adult] and a moderate lethal dose, LD 50 [2.766 ng/ L. pratensis adult, and 2.243 ng/ P. cognatus adult]. Direct exposure to LD 50 of lambda-cyhalothrin led to decreased adult longevity, shorter female oviposition period and lower fecundity of the parental generation for both species, whereas treatment with LD 5 lambda-cyhalothrin stimulated female fecundity on L. pratensis , but not on P. cognatus. The F1 generation underwent transgenerational effects, i.e. there was delayed egg-laying period and larval development and decreased hatchability for both species, decreased adult longevity and fecundity for L. pratensis , and shortened adult longevity for the LD 50 group of P. cognatus. Compared with the untreated control group, the net reproductive rate (R 0), the intrinsic rate of increase (r m), and finite rate of increase (λ) were significantly decreased for the groups treated with different doses of lambda-cyhalothrin, whereas the generation time (T) was increased. Our results demonstrate that sublethal effects of lambda-cyhalothrin can retard development and suppress population growth for both of these mirid species. Therefore, this insecticide can be used effectively against mirid bugs in northern China and its application strategy to control mirid bug is discussed. • Direct exposure to LD 50 of lambda-cyhalothrin decreased adult longevity, female oviposition for two mirid bugs. • The transgenerational effects can be observed and passed on to the F1 generation for both species. • The sublethal effects of lambda-cyhalothrin can retard development and suppress population growth for the two mirid species. • Lambda-cyhalothrin can be used as an alternative insecticide option against key mirid pests in the field in northern China. [ABSTRACT FROM AUTHOR]