BACKGROUND: The bean bug, Riptortus pedestris, has received intense attention in recent years because of its involvement in increasing outbreaks of staygreen syndrome in soybean (Glycine max (L.)), often causing almost 100% loss of soybean yield in China. However, for this pest of great economic importance, potential current and future distribution patterns and their underlying driving factors remain unclear.RESULTS: Maxent modelling under climate, elevation and land-use (including the distribution information of G. max) variables showed that the current potential distribution covered a vast geographic range, primarily including most parts of south, South East and east Asia. Under future environmental scenarios, suitable habitat expanded markedly. Areas that would become highly suitable for R. pedestris were primarily located in north-east China and west India. Five bioclimatic (BIO13, BIO08, BIO18, BIO02 and BIO07) and one land-use (C3 annual crops) predictors contributed approximately 95% to the modelling, and analyses of curve responses showed that to a certain extent, R. pedestris preferred relatively high temperature and precipitation. Our results indicate that a high risk of R. pedestris outbreaks is present in parts of Asia, especially in the soybeangrowing regions of China, and this risk will continue in the future.CONCLUSION: The predicted distribution pattern and key regulating factors identified herein could provide a vital reference for developing pest management policies and further alleviate the incidence of staygreen syndrome in soybean.

Background Mitochondrial genomes (mitogenomes) have greatly improved our understanding of the backbone phylogeny of Lepidoptera, but few studies on comparative mitogenomics below the family level have been conducted. Here, we generated 13 mitogenomes of eight tortricid species, reannotated 27 previously reported mitogenomes, and systematically performed a comparative analysis of nucleotide composition, gene variation and phylogenetic performance. Results The lengths of completely sequenced mitogenomes ranged from 15,440 bp to 15,778 bp, and the gene content and organization were conserved in Tortricidae and typical for Lepidoptera. Analyses of AT-skew and GC-skew, the effective number of codons and the codon bias index all show a base bias in Tortricidae, with little heterogeneity among the major tortricid groups. Variations in the divergence rates among 13 protein-coding genes of the same tortricid subgroup and of the same PCG among tortricid subgroups were detected. The secondary structures of 22 transfer RNA genes and two ribosomal RNA genes were predicted and comparatively illustrated, showing evolutionary heterogeneity among different RNAs or different regions of the same RNA. The phylogenetic uncertainty of Enarmoniini in Tortricidae was confirmed. The synonymy of Bactrini and Olethreutini was confirmed for the first time, with the representative Bactrini consistently nesting in the Olethreutini clade. Nad6 exhibits the highest phylogenetic informativeness from the root to the tip of the resulting tree, and the combination of the third coding positions of 13 protein-coding genes shows extremely high phylogenetic informativeness. Conclusions This study presents 13 mitogenomes of eight tortricid species and represents the first detailed comparative mitogenomics study of Tortricidae. The results further our understanding of the evolutionary architectures of tortricid mitogenomes and provide a basis for future studies of population genetics and phylogenetic investigations in this group.

The role of floral visual cues was studied in both sexes of three nocturnal scarab beetle species (Holotrichia oblita, Holotrichia parallela, and Anomala corpulenta). Flower patterns were designed using n-petal rose curve and radial gradient tools. Bioassay of plain colored patterns showed that both sexes of H. oblita and H. parallela preferred yellow and white. In contrast, A. corpulenta showed sexual differentiation in preferences. Comparison between given radial gradient patterns and their color components indicated that a radial gradient was necessary in both sexes of H. oblita rather than both sexes of H. parallela to elicit the highest response. Sexual differentiation was found in A. corpulenta. Among 4-, 8-, and 12-petaled patterns, the 4-petaled patterns were most preferred by all of the test insects, regardless of species and sex. Choice assays that provided both odor and visual cues suggest that olfaction may be the primary sensory modality in the three scarab species.

The soybean aphid Aphis glycines Matsumura is a predominant insect pest in Asia and North America and causes great losses to soybean. The release of genome data for A. glycines will facilitate gene function research in the future. However, suitable reference genes for A. glycines under various experimental conditions are scarce. To search for appropriate reference genes for A. glycines, nine candidate reference genes, including Act, α-Tub, β-Tub, RPS12, RPS18, RPL5, RPL27, EF1α, and Fer, were tested under six experimental conditions to evaluate their suitability for use in the normalization of qRT‒PCR data. Results showed that EF1α and RPS12 were optimal for the developmental stages of A. glycines, RPS18 and RPS12 were appropriate for wing dimorphism, β-Tub and RPS18 were suitable for different tissues and RPL5, and α-Tub could be used for normalization at different temperatures. β-Tub and EF1α could be proposed as reference genes for insecticide treatment, and RPL5 and RPS12 were found to be the most stable reference genes in different photoperiods. The results provide appropriate reference genes for analyzing gene expression in A. glycines and contribute to future research on the molecular physiology and biochemistry of A. glycines.