Time filter

Source Type

Tabata J.,Japan National Institute for Agro - Environmental Sciences | Ichiki R.T.,Japan International Research Center for Agricultural science | Tanaka H.,Tottori Prefectural Museum | Kageyama D.,Japan National Institute of Agrobiological Science
PLoS ONE | Year: 2016

Asexual reproduction, including parthenogenesis in which embryos develop within a female without fertilization, is assumed to confer advantages over sexual reproduction, which includes a "cost of males." Sexual reproduction largely predominates in animals, however, indicating that this cost is outweighed by the genetic and/or ecological benefits of sexuality, including the acquisition of advantageous mutations occurring in different individuals and the elimination of deleterious mutations. But the evolution of sexual reproduction remains unclear, because we have limited examples that demonstrate the relative success of sexual lineages in the face of competition from asexual lineages in the same environment. Here we investigated a sympatric occurrence of sexual and asexual reproduction in the pineapple mealybug, Dysmicoccus brevipes. This pest invaded southwestern Japan, including Okinawa and Ishigaki Islands, in the 1930s in association with imported pineapple plants. Our recent censuses demonstrated that on Okinawa sexually reproducing individuals can coexist with and even dominate asexual individuals in the presence of habitat and resource competition, which is considered to be severe for this nearly immobile insect. Molecular phylogeny based on partial DNA sequences in the mitochondrial and nuclear genomes, as well as the endosymbiotic bacterial genome, revealed that the asexual lineage diverged from a common sexual ancestor in the relatively recent past. In contrast, only the asexual lineage exhibiting obligate apomictic thelytoky was discovered on Ishigaki. Co-existence of the two lineages cannot be explained by the results of laboratory experiments, which showed that the intrinsic rate of increase in the sexual lineage was not obviously superior to that of the asexual lineage. Differences in biotic and/or abiotic selective forces operating on the two islands might be the cause of this discrepancy. This biological system offers a unique opportunity to assess the relative success of sexual versus asexual lineages with an unusual morphology and life cycle. © 2016 Tabata et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Source

Kato K.,Graduate University for Advanced Studies | Arikawa T.,Tottori Prefectural Museum | Imura S.,Graduate University for Advanced Studies | Imura S.,Japan National Institute of Polar Research | And 2 more authors.
Polar Biology | Year: 2013

Due to the morphological variability, the identification of moss species can be difficult when the plant grows in submerged environments. The taxonomic status of an aquatic moss found in lakes of the Sôya Coast region, East Antarctica, had been controversial, and then, it was investigated by molecular phylogenetic and haplotype network analysis of two chloroplast regions (rps4 and trnL-F) and/or the nuclear ribosomal ITS region. Based on the results of the analyses, the moss was assigned to the genus Leptobryum and determined to be conspecific with Leptobryum wilsonii (Mitt.) Broth. described from South America. Almost no genetic variation was observed between all samples from Antarctic lakes and some samples of L. wilsonii from Chile. Molecular and geohistorical evidence suggests that immigration of L. wilsonii into Antarctic lakes took place during the Holocene via long-distance dispersal from South America. This study gives a clear example of the widespread assumption that most of the Antarctic moss species are post-glacial immigrants. © 2013 Springer-Verlag Berlin Heidelberg. Source

Shaw A.J.,Duke University | Shaw B.,Duke University | Higuchi M.,National Museum of Nature and Science | Arikawa T.,Tottori Prefectural Museum | And 2 more authors.
Bryologist | Year: 2012

Climacium is a small but morphologically distinctive genus ("tree mosses") with four species distributed primarily in the Northern Hemisphere. Climacium dendroides occurs around the globe at northern latitudes with disjunct populations in Mexico and New Zealand, whereas C. americanum and C. kindbergii are endemic to eastern North America and C. japonicum is limited to eastern Asia. Using nucleotide sequence data from five plastid loci plus the nuclear ribosomal ITS region we assessed evidence for monophyly of taxonomic species and tested the hypothesis that C. americanum and C. kindbergii from eastern North America have a sister group relationship with C. japonicum from eastern Asia. Climacium japonicum is resolved as sister to a clade containing the circumboreal C. dendroides, C. americanum, and C. kindbergii. Climacium americanum and C. kindbergii were not resolved as monophyletic based on sequence data but together they composed the sister lineage to C. dendroides. Geographically disjunct populations of C. dendroides in Asia, Mexico, the United States, and Canada vary at only a few polymorphic nucleotide sites across the three loci. The disjunctive New Zealand plants of C. dendroides are related to Asian accessions. © 2012 by The American Bryological and Lichenological Society, Inc. Source

The Japanese soft scale Takahashia citricola Kuwana, 1909 is redescribed and transferred to the genus Pulvinaria Targioni Tozzetti as Pulvinaria citricola (Kuwana, 1909), comb. n. (Coccoidea: Coccidae). Pulvinaria gamazumii Kanda, 1960 is synonymized with P. citricola comb. n. and Pulvinaria nipponica Lindinger, 1933, is resurrected as the replacement name for Pulvinaria citricola Kuwana, 1914 (nee Kuwana, 1909). The adult female of P. citricola (Kuwana, 1909) is redescribed and illustrated. © Hirotaka Tanaka. Source

Tanaka H.,Tottori Prefectural Museum | Kondo T.,Research Center Palmira
ZooKeys | Year: 2015

A new soft scale (Hemiptera: Coccoidea: Coccidae) species, Pulvinaria caballeroramosae Tanaka & Kondo, sp. n., is described from specimens collected on twigs of Ficus soatensis Dugand (Moraceae) in Bogota, Colombia. The new species resembles P. drymiswinteri Kondo & Gullan, described from Chile on Drimys winteri J.R. Forst. & G. Forst. (Winteraceae), but differs in the distribution of preopercular pores on the dorsum, the presence of dorsal tubular ducts, dorsal microducts, and reticulation on the anal plates; and in its feeding habits, i.e., P. caballeroramosae feeds on the twigs whereas P. drymiswinteri feeds on the leaves of its host. A key to the Colombian species of Pulvinaria Targioni Tozzetti is provided. © Hirotaka Tanaka, Takumasa Kondo. Source

Discover hidden collaborations