Evidence of venom variability associated with venom extraction interval in the monocled cobra (Naja kaouthia)

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  Evidence of venom variability associated with venom extraction interval in the monocled cobra (Naja kaouthia) Abstract Snake venom variability is a critical factor in antivenom production. Although several influencing factors have been studied, the impact of extraction interval on venom properties remains poorly understood. This study evaluated the effects of various extraction intervals on venom yield, the percentage of dry weight (%Dw), and composition in the monocled cobra ( Naja kaouthia ). Twenty-five captive snakes were randomly allocated to five groups, each undergoing a control extraction followed by a repeated extraction at 1, 4, 7, 10, or 14 days. Venom profiles were characterized using reversed-phase high-performance liquid chromatography (RP-HPLC) and Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS). Results indicated that while fresh venom yield remained stable across all intervals, %Dw significantly decreased in extractions performed between 1 and 10 days, ...

Across mountains and ocean: species delimitation and historical connectivity in Holarctic and Arctic-Alpine wolf spiders (Lycosidae, Pardosa)

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Across mountains and ocean: species delimitation and historical connectivity in Holarctic and Arctic-Alpine wolf spiders (Lycosidae, Pardosa)

Abstract

Holarctic species offer great opportunities to study biogeography, phylogenetics, taxonomy, and local adaptation. Species that are considered conspecific between the Palearctic and the Nearctic realms are often split into 2 or more species when denser sampling and molecular markers are applied. Similar in complexity but at a finer geographical scale are species groups having Arctic-Alpine distributions where lineages have complicated demographic histories due to glacial dynamics. In both cases, allopatric speciation might not result in fast differentiation of morphological characters if environmental conditions in isolated areas are similar and the main driver of variability is genetic drift. Here, we study the Holarctic Pardosa hyperborea (Thorell, 1872) and its closest European relatives to assess their taxonomic status and patterns of genetic variability. Based on DNA barcodes and genomic data from double-digest restriction site associated sequencing, we propose that the North American populations should be regarded as a distinct species (P. luteola Emerton,1894, stat. resurr.), possibly consisting of several independent lineages. With the help of D-statistics, population genetic simulations and phylogenetic networks analysis, we demonstrate historical introgression among European species of the group and a likely explanation for shared DNA barcodes among allopatric and fully differentiated species. Our study exposes a promising model for studying speciation processes and demographic history in parallel on both sides of the Atlantic Ocean and demonstrates the usefulness of genomic tools in elucidating the taxonomy and biogeography of taxa across broad geographic scales.


Vladislav Ivanov, Gergin Blagoev, Samuel Danflous, Peter Gajdoš, Toke Thomas Høye, Kyung Min Lee, Yuri Marusik, Cecilie Lohse Mielec, Christoph Muster, Julien Pétillon, Jörg Spelda, Marko Mutanen, Across mountains and ocean: species delimitation and historical connectivity in Holarctic and Arctic-Alpine wolf spiders (Lycosidae, Pardosa), Insect Systematics and Diversity, Volume 7, Issue 5, September 2023, 1, https://doi.org/10.1093/isd/ixad018