Relevance of ddRADseq method for species and population delimitation of closely related and widely distributed wolf spiders (Araneae, Lycosidae)

Abstract

Although species delimitation is often controversial, emerging DNA-based and classical morphology-based methods are rarely compared using large-scale samplings, even less in the case of widely distributed species that have distant, allopatric populations. In the current study, we examined species boundaries within two wolf spider species of the genus Pardosa (Araneae, Lycosidae), P. riparia and P. palustris. Wolf spiders constitute an excellent model for testing the relevance of traditional vs. modern methods in species and population delimitation because several closely related species are distributed over cross-continental geographic ranges. Allopatric populations of the two Pardosa species were sampled across Europe to Far East Russia (latitudinal range > 150°) and several dozen individuals were studied using morphological characters (morphometry of three measures for both sexes, plus five in males only and two in females only), DNA barcoding (COI sequencing) and double-digest restriction site associated DNA sequencing (ddRADseq). The results obtained allow for changing the taxonomic status of two Far East Russian populations to subspecies and ddRADseq proved to be a powerful tool for taxonomic research despite scarce sampling and inherent subjectivity of species delimitation in allopatry. Overall, this study pleads for both multi-criteria and more population-based studies in taxonomy.

Island hoppers: Integrative taxonomic revision of Hogna wolf spiders (Araneae, Lycosidae) endemic to the Madeira islands with description of a new species

“…The ability of Hogna endemic species in Madeira to disperse between islands, which could promote introgression, is evident by the surprising finding of immature specimens originally identified as H. insularum, but that both mitochondrial and nuclear DNA suggested they belong to H. ingens, supposedly endemic to Desertas. Similar conflicting signals between different sources of evidence, namely morphology and molecules, may also arise in recently diverged species or species with large ancestral population sizes, as exemplified by wolf spiders in the genus Pardosa (Ivanov et al 2021). Discerning alternative scenarios will require the future integration of large-scale population sampling with novel genome wide screening (e.g., ddRADSeq) methods.…”

“…The report of new endemic Hogna species had to wait for almost a century, until the description of H. biscoitoi Wunderlich, 1992, H. schmitzi Wunderlich, 1992, and H. nonannulata Wunderlich, 1995 Although no other taxonomic work on Madeiran Hogna has been published for more than 25 years, a number of taxonomic problems remained to be tackled, including nomenclatural issues and the interpretation of intraspecific variability in the context of intermediate forms (Wunderlich 1992(Wunderlich , 1995. In addition, recent studies suggest that species delimitation in wolf spiders may be hampered by either the recent origin of some species (Ivanov et al 2021) or introgression events among close relatives (De Busschere et al 2015). On the other hand, the genus Hogna is in much need of a thorough revision (Logunov 2020).…”

A shift in the host web occupancy of dew‐drop spiders associated with genetic divergence in the Southwest Pacific

“…These markers are the most common sources of genetic variation among members of the same species and currently are the focus of genome‐wide research (Uffelmann et al., 2021). Cross‐genome information represented in SNPs data is powerful for species delimitation (Arrigoni et al., 2020; Georges et al., 2018; Ivanov et al., 2021), distribution patterns (Colli et al., 2018), molecular ecology, and geographically explicit landscape characterizations of organismal dispersal conduits and corridors (Dömel et al., 2020)—especially for characterizing these patterns intraspecifically or among closely‐related species. However, RAD‐seq proves less efficient in evaluating hypotheses related to adaptation and selection, given its susceptibility to miss loci under selection in investigations of local adaptation (Lowry et al., 2017).…”

A shift in the host web occupancy of dew-drop spiders associated with genetic divergence in the Southwest Pacific

“…These markers are the most common sources of genetic variation among members of the same species and currently are the focus of genome-wide research (Uffelmann et al, 2021). Cross-genome information represented in SNPs data is powerful for species delimitation (Georges et al, 2018; Arrigoni et al, 2020; Ivanov, Marusik, Pétillon, & Mutanen, 2021), distribution patterns (Colli et al, 2018), molecular ecology, and geographically-explicit landscape characterizations of organismal dispersal conduits and corridors (Dömel et al, 2020)—especially for characterizing these patterns intraspecifically or among closely-related species. However, RAD-seq proves less efficient in evaluating hypotheses related to adaptation and selection, given its susceptibility to miss loci under selection in investigations of local adaptation (Lowry et al, 2017).…”