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Color polymorphism is an ecologically important trait, which is related to local adaptation and ecological speciation. The pea aphid Acyrthosiphon pisum shows color polymorphism: the red and green color morphs where differences in ecological adaptation have been observed. Here, we measured genome-wide gene expression profiles of two color morphs in natural populations of A. pisum to explore the genetic basis of differentiated ecological adaptation. The results showed that only 32 genes were significantly differentially expressed between the two morphs, of which 18 had functional annotations. Among them, 13 genes were up-regulated [e.g. genes encoding protoheme IX farnesyltransferase (LOC100570971), carotene dehydrogenase ( tor ) and V-type proton ATPase subunit B (LOC100169462)] and 5 genes were down-regulated in the red morph (e.g. genes encoding transcription factors and heat shock proteins). To assess the functional importance of these differentially expressed genes (DEGs), we selected three highly expressed DEGs (LOC100169462, LOC100570971 and tor ) with functional annotations and analyzed their expression levels in the red morph under three low temperatures (1 °C, 4 °C, and 8 °C) for 24 h. These three DEGs showed an interesting expression response to the cold acclimating conditions which resulted in an obvious phenotypic change of the red individuals to be greenish variants. This study suggests a link between gene expressions and body color polymorphisms in the pea aphid and provides important clues for further studying molecular mechanisms of ecological adaptation in aphids. [ABSTRACT FROM AUTHOR]

The Indian meal moth Plodia interpunctella (Lepidoptera: Pyralidae) is a worldwide pest that causes serious damage to stored foods. Although many efforts have been conducted on this species due to its economic importance, the study of genetic basis of development, behavior and insecticide resistance has been greatly hampered due to lack of genomic information. In this study, we used high throughput sequencing platform to perform a de novo transcriptome assembly and tag-based digital gene expression profiling (DGE) analyses across four different developmental stages of P. interpunctella (egg, third-instar larvae, pupae and adult). We obtained approximate 9 gigabyte (GB) of clean data and recovered 84,938 unigenes, including 37,602 clusters and 47,336 singletons. These unigenes were annotated using BLAST against the non-redundant protein databases and then functionally classified based on Gene Ontology (GO), Clusters of Orthologous Groups (COG), and Kyoto Encyclopedia of Genes and Genomes databases (KEGG). A large number of differentially expressed genes were identified by pairwise comparisons among different developmental stages. Gene expression profiles dramatically changed between developmental stage transitions. Some of these differentially expressed genes were related to digestion and cuticularization. Quantitative real-time PCR results of six randomly selected genes conformed the findings in the DGEs. Furthermore, we identified over 8000 microsatellite markers and 97,648 single nucleotide polymorphisms which will be useful for population genetics studies of P. interpunctella . This transcriptomic information provided insight into the developmental basis of P. interpunctella and will be helpful for establishing integrated management strategies and developing new targets of insecticides for this serious pest. [ABSTRACT FROM AUTHOR]

The adaptive evolution of animals to high-elevation environments has been extensively studied in vertebrates, while few studies have focused on insects. Gynaephora species (Lepidoptera: Lymantriinae) are endemic to the Qinghai-Tibetan Plateau (QTP) and represent an important insect pest of alpine meadows. Here, we present a detailed comparative analysis of the mitochondrial genomes (mitogenomes) of two Gynaephora species inhabiting different high-elevation environments: G. alpherakii and G. menyuanensis . The results indicated that the general mitogenomic features (genome size, nucleotide composition, codon usage and secondary structures of tRNAs) were well conserved between the two species. All of mitochondrial protein-coding genes were evolving under purifying selection, suggesting that selection constraints may play a role in ensuring adequate energy production. However, a number of substitutions and indels were identified that altered the protein conformations of ATP8 and NAD1, which may be the result of adaptive evolution of the two Gynaephora species to different high-elevation environments. Levels of gene expression for nine mitochondrial genes in nine different developmental stages were significantly suppressed in G. alpherakii , which lives at the higher elevation (~ 4800 m above sea level), suggesting that gene expression patterns could be modulated by atmospheric oxygen content and environmental temperature. These results enhance our understanding of the genetic bases for the adaptive evolution of insects endemic to the QTP. [ABSTRACT FROM AUTHOR]