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Spiders (Araneae) of Churchill, Manitoba: DNA barcodes and morphology reveal high species diversity and new Canadian records.

Blagoev GA, Nikolova NI, Sobel CN, Hebert PD, Adamowicz SJ - BMC Ecol. (2013)

Bottom Line: As well, one probable new species of Alopecosa (Lycosidae) was recognized.This study provides the first comprehensive DNA barcode reference library for the spider fauna of any region.The capacity of DNA barcoding to enable the identification of otherwise taxonomically ambiguous specimens (juveniles, females) also represents a major advance for future monitoring efforts on this group.

View Article: PubMed Central - HTML - PubMed

Affiliation: Biodiversity Institute of Ontario, University of Guelph, Guelph, Ontario N1G 2W1, Canada. gblagoev@uoguelph.ca.

ABSTRACT

Background: Arctic ecosystems, especially those near transition zones, are expected to be strongly impacted by climate change. Because it is positioned on the ecotone between tundra and boreal forest, the Churchill area is a strategic locality for the analysis of shifts in faunal composition. This fact has motivated the effort to develop a comprehensive biodiversity inventory for the Churchill region by coupling DNA barcoding with morphological studies. The present study represents one element of this effort; it focuses on analysis of the spider fauna at Churchill.

Results: 198 species were detected among 2704 spiders analyzed, tripling the count for the Churchill region. Estimates of overall diversity suggest that another 10-20 species await detection. Most species displayed little intraspecific sequence variation (maximum <1%) in the barcode region of the cytochrome c oxidase subunit I (COI) gene, but four species showed considerably higher values (maximum = 4.1-6.2%), suggesting cryptic species. All recognized species possessed a distinct haplotype array at COI with nearest-neighbour interspecific distances averaging 8.57%. Three species new to Canada were detected: Robertus lyrifer (Theridiidae), Baryphyma trifrons (Linyphiidae), and Satilatlas monticola (Linyphiidae). The first two species may represent human-mediated introductions linked to the port in Churchill, but the other species represents a range extension from the USA. The first description of the female of S. monticola was also presented. As well, one probable new species of Alopecosa (Lycosidae) was recognized.

Conclusions: This study provides the first comprehensive DNA barcode reference library for the spider fauna of any region. Few cryptic species of spiders were detected, a result contrasting with the prevalence of undescribed species in several other terrestrial arthropod groups at Churchill. Because most (97.5%) sequence clusters at COI corresponded with a named taxon, DNA barcoding reliably identifies spiders in the Churchill fauna. The capacity of DNA barcoding to enable the identification of otherwise taxonomically ambiguous specimens (juveniles, females) also represents a major advance for future monitoring efforts on this group.

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Summary of sequence distances (K2P) at COI for spiders of Churchill. Each species is represented by a point, with its maximum intraspecific distance plotted against its nearest neighbour (minimum interspecific) distance.
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Figure 5: Summary of sequence distances (K2P) at COI for spiders of Churchill. Each species is represented by a point, with its maximum intraspecific distance plotted against its nearest neighbour (minimum interspecific) distance.

Mentions: There was strong correspondence between the boundaries of barcode clusters and species designations based on morphology. Nearly all species (97%, 159/164) represented by two or more individuals displayed a barcode gap (Figure 5), reflecting the fact that the maximum intraspecific divergence was less than the distance to the nearest neighbour. As well, most of these species (94%, 158/168) showed more than 2% divergence from their nearest neighbour. The other 34 species (those represented by a single specimen) all showed more than 2% divergence from their nearest neighbour, and most (31/34) had >4% divergence. Even prior to taxonomic reassessments motivated by the barcode results, it is clear that DNA barcoding is a very effective tool for identification of spiders. Moreover, the close correspondence between BINs and species (Figure 2) indicates the value of DNA barcoding as a quick tool for the determination of species richness in unstudied araneofaunas.


Spiders (Araneae) of Churchill, Manitoba: DNA barcodes and morphology reveal high species diversity and new Canadian records.

Blagoev GA, Nikolova NI, Sobel CN, Hebert PD, Adamowicz SJ - BMC Ecol. (2013)

Summary of sequence distances (K2P) at COI for spiders of Churchill. Each species is represented by a point, with its maximum intraspecific distance plotted against its nearest neighbour (minimum interspecific) distance.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4222278&req=5

Figure 5: Summary of sequence distances (K2P) at COI for spiders of Churchill. Each species is represented by a point, with its maximum intraspecific distance plotted against its nearest neighbour (minimum interspecific) distance.
Mentions: There was strong correspondence between the boundaries of barcode clusters and species designations based on morphology. Nearly all species (97%, 159/164) represented by two or more individuals displayed a barcode gap (Figure 5), reflecting the fact that the maximum intraspecific divergence was less than the distance to the nearest neighbour. As well, most of these species (94%, 158/168) showed more than 2% divergence from their nearest neighbour. The other 34 species (those represented by a single specimen) all showed more than 2% divergence from their nearest neighbour, and most (31/34) had >4% divergence. Even prior to taxonomic reassessments motivated by the barcode results, it is clear that DNA barcoding is a very effective tool for identification of spiders. Moreover, the close correspondence between BINs and species (Figure 2) indicates the value of DNA barcoding as a quick tool for the determination of species richness in unstudied araneofaunas.

Bottom Line: As well, one probable new species of Alopecosa (Lycosidae) was recognized.This study provides the first comprehensive DNA barcode reference library for the spider fauna of any region.The capacity of DNA barcoding to enable the identification of otherwise taxonomically ambiguous specimens (juveniles, females) also represents a major advance for future monitoring efforts on this group.

View Article: PubMed Central - HTML - PubMed

Affiliation: Biodiversity Institute of Ontario, University of Guelph, Guelph, Ontario N1G 2W1, Canada. gblagoev@uoguelph.ca.

ABSTRACT

Background: Arctic ecosystems, especially those near transition zones, are expected to be strongly impacted by climate change. Because it is positioned on the ecotone between tundra and boreal forest, the Churchill area is a strategic locality for the analysis of shifts in faunal composition. This fact has motivated the effort to develop a comprehensive biodiversity inventory for the Churchill region by coupling DNA barcoding with morphological studies. The present study represents one element of this effort; it focuses on analysis of the spider fauna at Churchill.

Results: 198 species were detected among 2704 spiders analyzed, tripling the count for the Churchill region. Estimates of overall diversity suggest that another 10-20 species await detection. Most species displayed little intraspecific sequence variation (maximum <1%) in the barcode region of the cytochrome c oxidase subunit I (COI) gene, but four species showed considerably higher values (maximum = 4.1-6.2%), suggesting cryptic species. All recognized species possessed a distinct haplotype array at COI with nearest-neighbour interspecific distances averaging 8.57%. Three species new to Canada were detected: Robertus lyrifer (Theridiidae), Baryphyma trifrons (Linyphiidae), and Satilatlas monticola (Linyphiidae). The first two species may represent human-mediated introductions linked to the port in Churchill, but the other species represents a range extension from the USA. The first description of the female of S. monticola was also presented. As well, one probable new species of Alopecosa (Lycosidae) was recognized.

Conclusions: This study provides the first comprehensive DNA barcode reference library for the spider fauna of any region. Few cryptic species of spiders were detected, a result contrasting with the prevalence of undescribed species in several other terrestrial arthropod groups at Churchill. Because most (97.5%) sequence clusters at COI corresponded with a named taxon, DNA barcoding reliably identifies spiders in the Churchill fauna. The capacity of DNA barcoding to enable the identification of otherwise taxonomically ambiguous specimens (juveniles, females) also represents a major advance for future monitoring efforts on this group.

Show MeSH
Related in: MedlinePlus