High and Low Temperatures Differentially Affect Survival, Reproduction, and Gene Transcription in Male and Female Moths of Spodoptera frugiperda.

In this study, we found that both heat and cold stresses significantly affected the survival and reproduction of both sexes in Spodoptera frugiperda adults, with larvae showing relatively higher extreme temperature tolerance. Further transcriptomic analysis in adults found remarkable differences and similarities between sexes in terms of temperature stress responses. Metabolism-related processes were suppressed in heat stressed females, which did not occur to the same extend in males. Moreover, both heat and cold stress reduced immune activities in both sexes. Heat stress induced the upregulation of many heat shock proteins in both sexes, whereas the response to cold stress was insignificant. More cold tolerance-related genes, such as cuticle proteins, UDP-glucuronosyltransferase, and facilitated trehalose transporter Tret1, were found upregulated in males, whereas most of these genes were downregulated in females. Moreover, a large number of fatty acid-related genes, such as fatty acid synthases and desaturases, were differentially expressed under heat and cold stresses in both sexes. Heat stress in females induced the upregulation of a large number of zinc finger proteins and reproduction-related genes; whereas cold stress induced downregulation in genes linked to reproduction. In addition, TRPA1-like encoding genes (which have functions involved in detecting temperature changes) and sex peptide receptor-like genes were found to be differentially expressed in stressed moths. These results indicate sex-specific heat and cold stress responses and adaptive mechanisms and suggest sex-specific trade-offs between stress-resistant progresses and fundamental metabolic processes as well as between survival and reproduction.

Interference Efficiency and Effects of Bacterium-mediated RNAi in the Fall Armyworm (Lepidoptera: Noctuidae).

RNAi is an effective tool for gene function analysis and a promising strategy to provide environmentally friendly control approaches for pathogens and pests. Recent studies support the utility of bacterium-mediated RNAi as a cost-effective method for gene function study and a suitable externally applied delivery mechanism for pest control. Here, we developed a bacterium-mediated RNAi system in Spodoptera frugiperda based on four target genes, specifically, Chitinase (Sf-CHI), Chitin synthase B (Sf-CHSB), Sugar transporter SWEET1 (Sf-ST), and Hemolin (Sf-HEM). RNAi conducted by feeding larvae with bacteria expressing dsRNAs of target genes or injecting pupae and adults with bacterially synthesized dsRNA induced silencing of target genes and resulted in significant negative effects on growth and survival of S. frugiperda. However, RNAi efficiency and effects were variable among different target genes and dsRNA delivery methods. Injection of pupae with dsCHI and dsCHSB induced a significant increase in wing malformation in adults, suggesting that precise regulation of chitin digestion and synthesis is crucial during wing formation. Injection of female moths with dsHEM resulted in lower mating, fecundity, and egg hatching, signifying a critical role of Sf-HEM in the process of egg production and/or embryo development. Our collective results demonstrate that bacterium-mediated RNAi presents an alternative technique for gene function study in S. frugiperda and a potentially effective strategy for control of this pest, and that Sf-CHI, Sf-CHSB, Sf-ST, and Sf-HEM encoding genes can be potent targets.

Complete mitochondrial genome of the black-winged fly, Felderimyia fuscipennis (Diptera: Tephritidae) and its phylogenetic relationship within family Tephritidae.

The black-winged fly, Felderimyia fuscipennis (Diptera: Tephritidae), is an insect pest of bamboo shoot, mainly distributed in Thailand, Malaysia and Yunnan Province and Guangxi Autonomous Region, China. The complete sequence of the mitogenome of F. fuscipennis has been determined in this study. The whole mitogenome sequence is 16,536 bp in length, which totally contains 13 protein-coding genes (PCGs), 2 rRNA genes, 22 tRNA genes, and a non-coding region (putative control region, CR). The phylogeny indicates that F. fuscipennis of subfamily Trypetinae was monophyletic and clearly separated from both Dacinae and Tephritinae with high bootstrap value supported.

Complete mitochondrial genome of melon fly, Zeugodacus cucurbitae (Diptera:Tephritidae) from Kunming, Southwest China and the phylogeny within subfamily Dacinae.

The melon fly, Zeugodacus cucurbitae (Diptera:Tephritidae) is an important invasive pest and distributed throughout tropical, subtropical countries and areas. In this study, we report the complete mitochondrial genome of the fly with 15, 685 base pair in length, which includes 37 genes (the large and small ribosomal RNA subunits, 22 transfer RNA genes, 13 genes encoding mitochondrial proteins) and a non-coding A + T-rich control region. Molecular phylogeny indicated that there was a high bootstrap value supported among Z. cucurbitae and Z. tau belonging to the Z. tau complex.