ABSTRACT
The alfalfa weevil Hypera postica, native to the Western Palearctic, is an invasive legume pest with two divergent mitochondrial clades in its invading regions, the Western clade and the Eastern/Egyptian clade. However, knowledge regarding the native populations is limited. The Western clade is infected with the endosymbiotic bacteria Wolbachia that cause cytoplasmic incompatibility in host weevils. Our aim was to elucidate the spatial genetic structure of this insect and the effect of Wolbachia on its population diversity. We analyzed two mitochondrial and two nuclear genes of the weevil from its native ranges. The Western clade was distributed in western/central Europe, whereas the Eastern/Egyptian clade was distributed from the Mediterranean basin to central Asia. Intermediate mitotypes were found from the Balkans to central Asia. Most Western clade individuals in western Europe were infected with an identical Wolbachia strain. Mitochondrial genetic diversity of the infected individuals was minimal. The infected clades demonstrated a higher nonsynonymous/synonymous substitution rate ratio than the uninfected clades, suggesting a higher fixation of nonsynonymous mutations due to a selective sweep by Wolbachia. Trans-Mediterranean and within-European dispersal routes were supported. We suggest that the ancestral populations diversified by geographic isolation due to glaciations and that the diversity was reduced in the west by a recent Wolbachia-driven sweep(s). The intermediate clade exhibited a body size and host plant that differed from the other clades. Pros and cons of the possible use of infected-clade males to control uninfected populations are discussed.
Subject(s)
Weevils/microbiology , Wolbachia , Animals , Asia , Body Size , Europe , Female , Genetic Variation/genetics , Haplotypes/genetics , Introduced Species , Male , Mitochondria/genetics , Phylogeny , Phylogeography , Weevils/geneticsABSTRACT
The herein reported beetles (Figs 1, 2) were repeatedly sampled by the first author since 2008 by sifting leaf litter in two forested localities in Southwest China: Cang Shan Mountain Range in Yunnan and Mount Emei in Sichuan (Fig. 3). The specimens' characteristic appearance and edaphic way of life were consistent with those of various members of the subfamily Cossoninae (Morimoto 1973, 1993, 1995), although a more precise taxonomic assignment remained elusive. In 2015 the second author saw images of these beetles and suggested their affinities to the genus Cotasterosoma Konishi, 1962. This taxon until present was known from a single specimen collected in 1954 in Shikoku, Japan, and illustrated in Morimoto (1993), although additional congeneric specimens are known to the second author. The purpose of this paper is to document our discovery of the genus in Southwest China by describing a new species, illustrating its external and genital morphological characters, releasing DNA barcode data and providing phylogeographic interpretations of our findings.
Subject(s)
Weevils/anatomy & histology , Weevils/classification , Animals , China , DNA Barcoding, Taxonomic , DNA, Mitochondrial/genetics , Female , Male , Phylogeny , Species Specificity , Weevils/geneticsABSTRACT
A new species Megabruchidiussophorae (Insecta, Coleoptera) is described from Japan (Honshu). The larval host of this bruchid is the seeds of the tree legume 'enju', or chinese scholar tree, Styphnolobium japonicum (a senior synonym of Sophora japonica), which is a new host genus to Bruchidae. Styphnolobium is positioned basally in molecular phylogeny of the leguminous subfamily Papilionoideae. Other members of Megabruchidius are known to feed on Gleditsia, the tree legumes that belong to the most ancestral subfamily Caesalpinioideae. Therefore, Megabruchidius utilizes ancestral groups of legumes as its host plants. Megabruchidius has been inferred to be ancestral, based on its behavior. The character state of the host for this third Megabruchidius species supports that the genus is ancestral, at least in the subfamily Bruchinae. We also reviewed the genera closely related to Megabruchidius, i.e., Bruchidius and Sulcobruchus in Bruchidini, and wrote a key to the species in the genus Megabruchidius.
Subject(s)
Animal Structures/anatomy & histology , Classification , Coleoptera/anatomy & histology , Ecosystem , Feeding Behavior/physiology , Animals , Fabaceae , Japan , Species SpecificityABSTRACT
Publication data relating to a rare and obscure Japanese journal "Lansania Journal of Arachnology and Zoology" (1929-1941) are examined. Available facts, together with a substantial body of circumstantial and anecdotal evidence suggest that many planned issues, including several cited by independent sources as having been published, were not published. Some biographical data relating to the editor, Kyukichi Kishida (1888-1968), are provided. Titles of all papers known to have been published in "Lansania," with page numbers and claimed publication dates are presented, together with a list of 113 new zoological names proposed in the journal. Known library holdings of the journal worldwide are indicated. Details are provided of unpublished manuscripts in proof obtained from Kishida in the 1960s. The strong probability that some printed publication dates are inaccurate is discussed in detail.