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Introduction: DNA barcoding in insects has progressed rapidly, with the ultimate goal of a complete inventory of the world's species. However, the barcoding effort to date has been driven by a few national campaigns and leaves much of the world unsampled. This study investigates to what degree the current barcode data cover the species diversity across the globe, using the leaf beetle family Chrysomelidae as an example. Methods: A recent version (June 2023) of the Barcode-of-Life database was subjected to test of sampling completeness using the barcode-to-BIN ratio and sampling coverage (SC) metric. All barcodes were placed in a phylogenetic tree of ~600 mitochondrial genomes, applying phylogenetic diversity (PD) and metrics of community phylogenetics to national barcode sets to test for sampling completeness at clade level and reveal the global structure of species diversity. Results: The database included 73342 barcodes, grouped into 5310 BINs (species proxies) from 101 countries. Costa Rica contributed nearly half of all barcode sequences, while nearly 50 countries were represented by less than ten barcodes. Only five countries, Costa Rica, Canada, South Africa, Germany, and Spain, had a high sampling completeness, although collectively the barcode database covers most major taxonomic and biogeographically confined lineages. PD showed moderate saturation as more species diversity is added in a country, and community phylogenetics indicated clustering of national faunas. However, at the species level the inventory remained incomplete even in the most intensely sampled countries, and the sampling was insufficient for assessment of global species richness patterns. Discussion: The sequence-based inventory in Chrysomelidae needs to be greatly expanded to include more areas and deeper local sampling before reaching a knowledge base similar to the existing Linnaean taxonomy. However, placing the barcodes into a backbone phylogenetic tree from mitochondrial genomes, a taxonomically and biogeographically highly structured pattern of global diversity emerges into which all species can be integrated via their barcodes. [ABSTRACT FROM AUTHOR]

Previous studies on the phylogeography of the meadow spittlebug Philaenus spumarius (L.) (Hemiptera: Aphrophoridae) suggest the existence of a contact zone of its main phylogenetic lineages along mountain chains in Europe and western Asia. This study presents a detailed examination of the population genetics of P. spumarius within the Carpathian Mountains. The main objective was to determine whether the populations inhabiting that area consist of individuals belonging to different genetic units and whether the observed pattern could be an example of secondary contact zone which formed after incomplete allopatric speciation. Specimens from six transects across the Carpathian arc were examined. The mitochondrial phylogeography of the meadow spittlebug in the examined area clearly shows that individuals from both main clades meet and mix there. Representatives of all three main EF1-α clades were also found. The present distribution of the main clades with a zone of overlap along the mountain ranges may suggest that these phylogenetic lineages form a young hybrid zone. Moreover, a limited number of individuals were shown to possess heteroplasmic mitochondrial DNA, which gives additional support to intraspecific hybridization. P. spumarius could be used in future work as an excellent model species in investigating population genetics, intraspecific hybridization, and speciation in progress., (© The Author 2014. Published by Oxford University Press on behalf of the Entomological Society of America.)

Centricnemus leucogrammus is a weevil characteristic of European xerothermic habitats and steppes. The species was probably more widespread during the Pleistocene glaciations, while its current distribution is limited to "warm-stage refugia." It may be regarded as a typical representative of flightless xerothermophilous beetles. Previous studies concentrated on its genetic variation using mitochondrial genes. Here, we identified, tested and characterized 24 polymorphic microsatellite loci with the use of 454 sequencing of microsatellite enriched genomic libraries. The new set of loci will be used in studies on the population structure of this weevil and may provide valuable information for its conservation.