Search

The stingless bee Melipona (Michmelia) seminigra Friese is a polytypic species widely distributed in Brazilian Amazon and Bolivia. Seven subspecies are recognized, four are described, which inhabit mutually exclusive areas in the Amazon basin, although zones of hybridization are recorded. The three other subspecies, despite being recognized by taxonomists are undescribed. Melipona seminigra is a good honey-producer and an important pollinator of native flora and crops. Partial DNA sequence of cytochrome c oxidase subunit 1 (COI) mitochondrial gene (526 bp) was used to identify the four described subspecies of M. seminigra (M. s. abunensis, M. s. merrillae, M. s. pernigra, M. s. seminigra) and two other possible subspecies (M. s. ssp1 and M. s. ssp2). We added public data (sequences of ten other Melipona species) of the same subgenera and carried out phylogenetic analyses. The aim was to evaluate if subspecies in the M. seminigra complex could be delimited using COI and measure the genetic distances between them. Our results revealed that the genetic distances between subspecies of M. seminigra ranged from 0.4 to 2.7% (average 1.80 ± 0.47) and among Melipona species from 0.2 to 2.9% (average 2.13 ± 0.5). The average haplotype diversity was 0.8770 ± 0.0140 and average nucleotide diversity 0.0166 ± 0.0004. Phylogenetic and clustering analysis revealed well delimited clusters for subspecies of M. seminigra and that the inter subspecies divergences are similar to inter species divergence. Our findings indicate that the COI gene can be used for delimiting subspecies of M. seminigra.

Thrips tabaci Lindeman is one of the most important polyphagous horticulture crop pests in Lithuania. The aim of this work was to investigate new approach with the geographic distributions and host plant associations between different mtDNA COI haplotypes of T. tabaci. Specimens of T. tabaci were collected from different horticultural crops in the main horticulture regions across Lithuania, where sustainable plant protection practice is used. Four different haplotypes of T. tabaci were detected during investigation, and the greatest haplotype diversity was registered in the northern districts of Lithuania. The mean genetic distance between different haplotypes was 1.6%, and diversity was up to 2.9% comparing with sequences from other European countries (the Netherlands, UK and France) deposited in GenBank. Sequences obtained during this investigation differed by ≥10% comparing with sequences from other countries. Thrips tabaci COI gene differences partly reflect the geographic distribution, but results did not reveal the relationship between COI gene polymorphism of T. tabaci and different host plants.

Thrips tabaci Lindeman is one of the most important polyphagous horticulture crop pests in Lithuania. The aim of this work was to investigate new approach with the geographic distributions and host plant associations between different mtDNA COI haplotypes of T. tabaci. Specimens of T. tabaci were collected from different horticultural crops in the main horticulture regions across Lithuania, where sustainable plant protection practice is used. Four different haplotypes of T. tabaci were detected during investigation, and the greatest haplotype diversity was registered in the northern districts of Lithuania. The mean genetic distance between different haplotypes was 1.6%, and diversity was up to 2.9% comparing with sequences from other European countries (the Netherlands, UK and France) deposited in GenBank. Sequences obtained during this investigation differed by ≥10% comparing with sequences from other countries. Thrips tabaci COI gene differences partly reflect the geographic distribution, but results did not reveal the relationship between COI gene polymorphism of T. tabaci and different host plants. [ABSTRACT FROM AUTHOR]

Using mitochondrial COI sequencing, we explored the genetic diversity and population structuring of the common cockle Cerastoderma edule (Linnaeus, 1758) in the Norwegian and Barents Seas. Phylogeographic diversity and hence the evolutionary history of C. edule on the Scandinavian and Russian coastlines were found to be richer than expected for populations of temperate species in postglacially colonized seas. A major phylogeographic break at Lofoten Islands separated a group of subarctic populations dominated by a distinct star‐shaped clade of haplotypes from those to the south, extending to the North Sea and having highest gene diversities (h). At the northeastern edge of the range of C. edule, the Russian Murman coast, populations show a mosaic structure with considerable admixture of haplotypes from the south and high local‐scale variation in haplotype diversity (ranging between 0 and 0.8). To explain this mosaic we refer to the core‐satellite metapopulation model, with Norwegian populations as core, and Murman populations as satellites. Our results contradict the conventional biogeographic paradigm implying lack of metapopulation structuring in marine broadcast spawning invertebrates. Hypotheses considered to explain the origin of the unique variation in cockles from Northern Norway involve an early postglacial colonization and establishment of these populations (10–12 ka ago), a persistent oceanographic break at Lofoten, and a mitochondrial selective sweep associated with the postglacial recolonization of the subarctic seas by the boreal C. edule. Using mitochondrial COI sequencing, we revealed strong population structuring in the common cockle Cerastoderma edule (Linnaeus, 1758) populations from the Norwegian and Barents Seas. Low genetic diversity of the subarctic cockle populations predominantly consists of a distinct clade of haplotypes, which is much less common in populations located south of the Arctic Circle and completely lacking in the North Sea. The Barents Sea C. edule seems to be the first conclusive example of true metapopulation revealed in marine broadcast spawners. [ABSTRACT FROM AUTHOR]

Thaumastocoris peregrinus is a recently introduced invertebrate pest of non-native Eucalyptus plantations in the Southern Hemisphere. It was first reported from South Africa in 2003 and in Argentina in 2005. Since then, populations have grown explosively and it has attained an almost ubiquitous distribution over several regions in South Africa on 26 Eucalyptus species. Here we address three key questions regarding this invasion, namely whether only one species has been introduced, whether there were single or multiple introductions into South Africa and South America and what the source of the introduction might have been. To answer these questions, bar-coding using mitochondrial DNA (COI) sequence diversity was used to characterise the populations of this insect from Australia, Argentina, Brazil, South Africa and Uruguay. Analyses revealed three cryptic species in Australia, of which only T. peregrinus is represented in South Africa and South America. Thaumastocoris peregrinus populations contained eight haplotypes, with a pairwise nucleotide distance of 0.2–0.9% from seventeen locations in Australia. Three of these haplotypes are shared with populations in South America and South Africa, but the latter regions do not share haplotypes. These data, together with the current distribution of the haplotypes and the known direction of original spread in these regions, suggest that at least three distinct introductions of the insect occurred in South Africa and South America before 2005. The two most common haplotypes in Sydney, one of which was also found in Brisbane, are shared with the non-native regions. Sydney populations of T. peregrinus, which have regularly reached outbreak levels in recent years, might thus have served as source of these three distinct introductions into other regions of the Southern Hemisphere. [ABSTRACT FROM AUTHOR]

Pest species adaptation can cause genetic differentiation which leads to the pest adaptation to new host plants, new pest races or strains. Thrips tabaci Lindeman and Tetranychus urticae Koch are one of the most important polyphagous plant pests in Lithuania. The aim of this work was to study whether the genetic structure (COI sequences) of T. urticae and T. tabaci can be reflected to their host plants assortment and their geographical distribution. The material was collected in five localities in Lithuania. T. urticae were collected from cucumbers, apple-trees, currants and strawberries; T. tabaci \ from cabbages, apple-trees and onions. DNA extraction and PCR reactions were performed in the Nature Research Centre, sequencing was performed Macrogen Inc. Five different haplotypes of T. urticae were detected during the investigation. The highest haplotype diversity was registered in north-middle parts of Lithuania. Genetic distance between different haplotypes was on average 1.1%, and diversed up to 4.2% comparing with sequences from Genbank. Results did not reveal the relationship between COI gene polymorphism of T. urticae and different host plants. Four different haplotypes of T. tabaci were detected during the investigation. The highest haplotype diversity was registered in middle Lithuania. Genetic distance between different haplotypes was on average 1.4%, and diversed up to 2.9% comparing with sequences from Europe (the Netherlands, the UK, France) deposited in Genbank. Our sequences differed by more than 10% comparing with sequences from other countries. Some authors point out that differences between T. tabaci populations can reach up to 12.9% and genetic differences between species can be 16-27.5%. T. tabaci COI gene differences partly reflect the geographic distribution, but results did not reveal the relationship between COI gene polymorphism of T. tabaci and different host plants. [ABSTRACT FROM AUTHOR]