Phylogenetic Relationships of Tribes Within Harpalinae (Coleoptera: Carabidae) as Inferred from 28S Ribosomal DNA and the Wingless Gene

Harpalinae is a large, monophyletic subfamily of carabid ground beetles containing more than 19,000 species in approximately 40 tribes. The higher level phylogenetic relationships within harpalines were investigated based on nucleotide data from two nuclear genes, wingless and 28S rDNA. Phylogenetic analyses of combined data indicate that many harpaline tribes are monophyletic, however the reconstructed trees showed little support for deeper nodes. In addition, our results suggest that the Lebiomorph Assemblage (tribes Lebiini, Cyclosomini, Graphipterini, Perigonini, Odacanthini, Lachnophorini, Pentagonicini, Catapiesini and Calophaenini), which is united by a morphological synapomorphy, is not monophyletic, and the tribe Lebiini is paraphyletic with respect to members of Cyclosomini. Two unexpected clades of tribes were supported: the Zuphiitae, comprised of Anthiini, Zuphiini, Helluonini, Dryptini, Galeritini, and Physocrotaphini; and a clade comprised of Orthogoniini, Pseudomorphini, and Graphipterini. The data presented in this study represent a dense sample of taxa to examine the molecular phylogeny of Harpalinae and provide a useful framework to examine the origin and evolution of morphological and ecological diversity in this group

Tissue-Specific Transcriptomics of the Exotic Invasive Insect Pest Emerald Ash Borer (Agrilus planipennis)

BACKGROUND: The insect midgut and fat body represent major tissue interfaces that deal with several important physiological functions including digestion, detoxification and immune response. The emerald ash borer (Agrilus planipennis), is an exotic invasive insect pest that has killed millions of ash trees (Fraxinus spp.) primarily in the Midwestern United States and Ontario, Canada. However, despite its high impact status little knowledge exists for A. planipennis at the molecular level. METHODOLOGY AND PRINCIPAL FINDINGS: Newer-generation Roche-454 pyrosequencing was used to obtain 126,185 reads for the midgut and 240,848 reads for the fat body, which were assembled into 25,173 and 37,661 high quality expressed sequence tags (ESTs) for the midgut and the fat body of A. planipennis larvae, respectively. Among these ESTs, 36% of the midgut and 38% of the fat body sequences showed similarity to proteins in the GenBank nr database. A high number of the midgut sequences contained chitin-binding peritrophin (248)and trypsin (98) domains; while the fat body sequences showed high occurrence of cytochrome P450s (85) and protein kinase (123) domains. Further, the midgut transcriptome of A. planipennis revealed putative microbial transcripts encoding for cell-wall degrading enzymes such as polygalacturonases and endoglucanases. A significant number of SNPs (137 in midgut and 347 in fat body) and microsatellite loci (317 in midgut and 571 in fat body) were predicted in the A. planipennis transcripts. An initial assessment of cytochrome P450s belonging to various CYP clades revealed distinct expression patterns at the tissue level. CONCLUSIONS AND SIGNIFICANCE: To our knowledge this study is one of the first to illuminate tissue-specific gene expression in an invasive insect of high ecological and economic consequence. These findings will lay the foundation for future gene expression and functional studies in A. planipennis

Ecotype Differentiation in the Face of Gene Flow within the Diving Beetle Agabus bipustulatus (Linnaeus, 1767) in Northern Scandinavia

The repeated occurrence of habitat-specific polyphyletic evolved ecotypes throughout the ranges of widely distributed species implies that multiple, independent and parallel selection events have taken place. Ecological transitions across altitudinal gradients over short geographical distances are often associated with variation in habitat-related fitness, these patterns suggest the action of strong selective forces. Genetic markers will therefore contribute differently to differences between ecotypes in local hybrid zones. Here we have studied the adaptive divergence between ecotypes of the water beetle Agabus bipustulatus along several parallel altitudinal gradients in northern Scandinavia. This water beetle is well known for its remarkable morphological variation associated with mountain regions throughout the western Palaearctic. Two morphological ecotypes are recognised: a montane type with reduced flight muscles and a lowland type with fully developed muscles. Using a multilocus survey of allozyme variation and a morphological analysis with landmark-based morphometrics, across thirty-three populations and seven altitudinal gradients, we studied the local adaptive process of gene flow and selection in detail. Populations were sampled at three different elevations: below, at and above the tree line. The results indicate that the levels of divergence observed between ecotypes in morphology and allele frequencies at alpha-Glycerophosphate dehydrogenase relative to those shown by neutral molecular markers reflects local diversifying selection in situ. Four main lines of evidence are shown here: (1) A repeated morphological pattern of differentiation is observed across all altitudinal transects, with high reclassification probabilities. (2) Allele and genotype frequencies at the alpha-Gpdh locus are strongly correlated with altitude, in sharp contrast to the presumable neutral markers. (3) Genetic differentiation is two to three times higher among populations across the tree line than among populations at or below. (4) Genetic differentiation between ecotypes within independent mountain areas is reflected by different sets of allozymes