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The largest study done on the spiders that live in the Iberian Peninsula has revealed the existence of a great diversity of arachnids and has sequenced the genetics of 371 species, approximately a quarter of those registered in Spain, where there are more than 1,400 species.
The study, published in the journal ‘Insect Conservation and Diversity’ and directed by the professor of Biology Miquel Arnedo, of the Biodiversity Research Institute (IRBio) of the University of Barcelona (UB), is the most comprehensive on the biodiversity of spiders of the Iberian Peninsula made with the genetic barcode methodology (DNA barcoding), a comparative genetic technique to identify species.
The work has revealed, among other things, that the populations of peninsular spiders that weave webs from aerial capture and disperse through the air with the technique of arachnid flight present a more homogeneous genetic structure and are better connected to each other.
In contrast, nocturnal spider species, which hunt on the run and have little dispersal capacity, are found in genetically less connected populations and are more vulnerable to local extinction processes due to environmental factors.
Spain has a wide variety of spiders | Pexels
The study, in which IRBio biologists Marc Domènech, Alba Enguídanos and Cesc Múrria have also participated, and the researcher from the University of Azores (Portugal) Jagoba Malums-Olarte, has revealed the existence of a taxonomic diversity that, according to said Arnedo, “until now it had gone unnoticed & rdquor ;.
The team has contributed more than 3,200 new sequences of spiders, corresponding to 371 species, which inhabit oak groves in six national parks: Aigüestortes and Estany de Sant Maurici, Ordesa and Monte Perdido, Picos de Europa, Monfragüe, Cabañeros and Sierra Nevada.
“Iberian spider populations are characterized by exceptionally high biodiversity and a high degree of endemism that, together with a relatively reduced distribution, makes peninsular populations more vulnerable to possible local extinctions, a phenomenon that compromises the viability of the species & rdquor ;, Arnedo warned.
According to the professor, “in other populations on the European continent, the degree of endemism is lower; This implies a more extensive distribution that guarantees the permanence of the species, despite the possible extinction of some of the & rdquor; populations.
The study concludes that some peninsular species show remarkable genetic homogeneity throughout the territory, but others show great variability between populations.
Mediterranean brown recluse spider | EZSA
“In some cases, the delimitation of species based on genetic information has revealed the existence of well-differentiated lineages within the same species& rdquor ;, has specified Arnedo.
“These lineages – he clarified – could simply reflect that they are populations little connected to each other. In other cases they could indicate the possible existence of a hidden diversity that we had overlooked, if we exclusively rely on the morphological characters & rdquor ;.
“Thus, we have discovered that species such as Eratigena montigena or Nuctenea umbratica actually contain several lineages that had gone unnoticed due to their great morphological similarity. Future studies with these species could determine if these lineages correspond to different species& rdquor ;, the researcher concluded.
1,400 species in the Peninsula
In Spain, according to previous studies, there are more than 1,400 species of spiders and these are especially abundant in gall oak forests. “The results of the investigation reveal that the gall oak (Q. faginea) forests are the ones that show the highest number of spider species, probably due to the combined effects of the physical structure of the habitat and the climatic conditions”, detailed Miguel Arnedo , Professor of Evolutionary Biology, Ecology and Environmental Sciences at the UB.
Cobweb | Sepik
The study identified a pattern that relates the increase in the degree of endemism of the spider communities with the increase in temperature and the decrease in annual precipitation, which are typical characteristics of the Mediterranean climate.
“Spider communities in Mediterranean areas seem to be more endemic and contain a greater number of exclusively Iberian species & rdquor;”, explained Jagoba Malunos, another of the authors of this latest study.
Full report (in English): https://onlinelibrary.wiley.com/doi/10.1111/icad.12552