Caribbean golden orbweaving spiders maintain gene flow with North America

Abstract

The Caribbean archipelago offers one of the best natural arenas for testing biogeographic hypotheses. The intermediate dispersal model of biogeography (IDM) predicts variation in species richness among lineages on islands to relate to their dispersal potential. To test this model, one would need background knowledge of dispersal potential of lineages, which has been problematic as evidenced by our prior biogeographic work on the Caribbean tetragnathid spiders. In order to investigate the biogeographic imprint of an excellent disperser, we study the American Trichonephila, a nephilid genus that contains globally distributed species known to overcome long, overwater distances. Our results reveal that the American T. clavipes shows a phylogenetic and population genetic structure consistent with a single species over the Caribbean, but not over the entire Americas. Haplotype network suggests that populations maintain lively gene flow between the Caribbean and North America. Combined with prior evidence from spider genera of different dispersal ability, these patterns coming from an excellent disperser (Trichonephila) that is species poor and of a relatively homogenous genetic structure, support the IDM predictions.

Comparative phylogeography of mainland and insular species of Neotropical molossid bats (Molossus)

“…Populations on islands are more isolated, have a smaller meta‐population size, and are more vulnerable to habitat disturbance than mainland populations, which might alter insular population structure (Leisler & Winkler, ; Losos & Ricklefs, ; Spilani et al, ). Although alternative drivers of phylogeographic and population structure have been proposed for continental (Gray et al, ; Kalkvik, Stout, Hoffman, & Parkinson, ) and island populations (Čandek, Agnarsson, Binford, & Kuntner, ), few studies have explicitly compared the patterns between these two biogeographic systems (e.g., Pons et al, ). This comparison provides an opportunity to investigate the relative role of isolation, habitat selection, and demographic history in shaping phylogeographic patterns (Kalkvik et al, ; Sexton, Hangartner, & Hoffmann, ), especially using closely related species with similar life histories.…”

High genetic diversity of spider species in a mosaic montane grassland landscape

“…Another point of consideration regarding gene flow results of these spider species is the implication of uniparental inheritance and sex-biased dispersal. Due to only mtDNA being utilised in this study, there is the possibility that some of the haplotypes detected may have been from male lineages no longer existing, inflating the contemporary diversity seen in this study [132]. Mated adult female spiders are often responsible for gene flow, with little or no male gene flow among populations, resulting in highly inbred populations and large genetic differentiation between localities at both maternal and biparental inherited loci [133][134].…”

Physiological evaluation of newly invasive jorō spiders (Trichonephila clavata) in the southeastern USA compared to their naturalized cousin, Trichonephila clavipes

“…Interestingly, another spider species in the same genus has already become naturalized in the U.S. after 160+ years (Bakkegard & Davenport, 2012). The “golden silk spider,” Trichonephila clavipes , is endemic to Central and South America but is now found throughout much of the southeastern USA, including in Georgia (Candek et al, 2020). The overlapping ranges of each species can be readily seen from citizen science observations in iNaturalist (http://www.inaturalist.org; Figure 2).…”