Impacts on Natural Ecosystems

Ohsawa, Masahiko; Eguchi, Tomohiro; Tanaka, Nobuyuki; Ikeda, Hiroaki; Nemoto, Masami; Hada, Yoshio

doi:10.1007/978-4-431-68491-6_2

Cited by 5 publications

(1 citation statement)

References 60 publications

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“…While the separation between the Honshu and Hokkaido Islands, forming the Tsugaru Strait (Figure ), is dated to the Pliocene (2.6–5.3 Ma; Uozumi, ), tectonic shifts and volcanism in the Oshima Peninsula (Kuno, ) may have mediated successive events of separation and reconnection between Hokkaido and Tohoku (Sasa & Izaki, ; Uozumi, ). While the Tsugaru Strait forms a well‐known biogeographic boundary for vertebrates (the Blakiston Line; Ohsawa et al., ), it is possible that this split is less informative for arthropods like harvestmen.…”

Section: Discussionmentioning

confidence: 99%

Population genomics and geographical parthenogenesis in Japanese harvestmen (Opiliones, Sclerosomatidae, Leiobunum)

Burns

Hedin

Tsurusaki

2017

Ecology and Evolution

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Naturally occurring population variation in reproductive mode presents an opportunity for researchers to test hypotheses regarding the evolution of sex. Asexual reproduction frequently assumes a geographical pattern, in which parthenogenesis‐dominated populations are more broadly dispersed than their sexual conspecifics. We evaluate the geographical distribution of genomic signatures associated with parthenogenesis using nuclear and mitochondrial DNA sequence data from two Japanese harvestman sister taxa, Leiobunum manubriatum and Leiobunum globosum. Asexual reproduction is putatively facultative in these species, and female‐biased localities are common in habitat margins. Past karyotypic and current cytometric work indicates L. globosum is entirely tetraploid, while L. manubriatum may be either diploid or tetraploid. We estimated species phylogeny, genetic differentiation, diversity, and mitonuclear discordance in females collected across the species range in order to identify range expansion toward marginal habitat, potential for hybrid origin, and persistence of asexual lineages. Our results point to northward expansion of a tetraploid ancestor of L. manubriatum and L. globosum, coupled with support for greater male gene flow in southern L. manubriatum localities. Specimens from localities in the Tohoku and Hokkaido regions were indistinct, particularly those of L. globosum, potentially due to little mitochondrial differentiation or haplotypic variation. Although L. manubriatum overlaps with L. globosum across its entire range, L. globosum was reconstructed as monophyletic with strong support using mtDNA, and marginal support with nuclear loci. Ultimately, we find evidence for continued sexual reproduction in both species and describe opportunities to clarify the rate and mechanism of parthenogenesis.

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Section: Discussionmentioning

confidence: 99%