Mitochondrial genomes reveal the global phylogeography and dispersal routes of the migratory locust

The migratory locust, Locusta migratoria, is the most widely distributed grasshopper species in the world. However, its global genetic structure and phylogeographic relationships have not been investigated. In this study, we explored the worldwide genetic structure and phylogeography of the locust populations based on the sequence information of 65 complete mitochondrial genomes and three mitochondrial genes of 263 individuals from 53 sampling sites. Although this locust can migrate over long distances, our results revealed high genetic differentiation among the geographic populations. The populations can be divided into two different lineages: the Northern lineage, which includes individuals from the temperate regions of the Eurasian continent, and the Southern lineage, which includes individuals from Africa, southern Europe, the Arabian region, India, southern China, South‐east Asia and Australia. An analysis of population genetic diversity indicated that the locust species originated from Africa. Ancestral populations likely separated into Northern and Southern lineages 895 000 years ago by vicariance events associated with Pleistocene glaciations. These two lineages evolved in allopatry and occupied their current distributions in the world via distinct southern and northern dispersal routes. Genetic differences, caused by the long‐term independent diversification of the two lineages, along with other factors, such as geographic barriers and temperature limitations, may play important roles in maintaining the present phylogeographic patterns. Our phylogeographic evidence challenged the long‐held view of multiple subspecies in the locust species and tentatively divided it into two subspecies, L. m. migratoria and L. m. migratorioides.     

Phylogeography of the Japanese pipistrelle bat,Pipistrellus abramus,in China: the impact of ancient and recent events on population genetic structure

The influence of Pleistocene climatic oscillations on shaping the genetic structure of Asian biota is poorly known. The Japanese pipistrelle bat occurs over a wide range in eastern Asia, from Siberia to Japan. To test the relative impact of ancient and more recent events on genetic structure in this species, we combined mitochondrial (cytochrome b) and microsatellite markers to reconstruct its phylogeographic and demographic history on continental China and its offshore islands, Hainan Island and the Zhoushan Archipelago. Our mitochondrial DNA tree recovered two divergent geographical clades, indicating multiple glacial refugia in the region. The first clade was mainly confined to Hainan Island, indicating that gene flow between this population and the continent has been restricted, despite being repeatedly connected to the mainland during repeated glacial episodes. By contrast, haplotypes sampled on the Zhoushan Archipelago were mixed with those from the mainland, suggesting a recent shared history of expansion. Although microsatellite allele frequencies showed clear discontinuities across the sampling range, supporting the current isolation of both Hainan Island and the Zhoushan Archipelago, we also found clear evidence of more recent back colonization, probably via post‐glacial expansion or, in the latter case, occasional long distance dispersal. The results obtained highlight the importance of using multiple sets of markers for teasing apart the roles of ancient and more recent events on population genetic structure. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99 , 582–594.     

Phylogeography of the Japanese giant flying squirrel, Petaurista leucogenys (Rodentia: Sciuridae): implication of glacial refugia in an arboreal small mammal in the Japanese Islands

To test the association between temperate forest dynamics and glacial refugia for arboreal small mammals, we studied the phylogeography of the Japanese giant flying squirrel ( Petaurista leucogenys ) using complete mitochondrial cytochrome b gene sequences (1140 bp). This squirrel is endemic to three of Japan's main islands: Honshu, Shikoku, and Kyushu. We examined 58 specimens of P. leucogenys collected from 40 localities in Japan. Additionally, two individuals with unknown sampling localities were included in phylogenetic analyses. There were 54 haplotypes of P. leucogenys. We found five major phylogroups (Northern, Central, South-eastern, South-western, and Southern). These phylogroups may have originated from glacial refugia during the Late Pleistocene. After the last glaciation, the Northern phylogroup, widely distributed in eastern Japan, could have extensively expanded northward from its refugia. By contrast, in western Japan, population expansion was restricted to western Japan. All members of four phylogroups existed in western Japan during glaciations. The complicated phylogeographical pattern of P. leucogenys populations originating from western Japan may have resulted from the long history.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 98 , 47–60.     

Further Analysis of Intraspecific Sequence Variation of Chloroplast DNA in Primula cuneifolia Ledeb. (Primulaceae): Implications for Biogeography of the Japanese Alpine Flora

Primula cuneifolia Ledeb. (Primulaceae), we analyzed intraspecific variation of the nucleotide sequences of non-coding regions of chloroplast DNA: the intergenic spacers between trnT (UGU) and the trnL (UAA) 5′exon, the trnL (UAA) 3′exon and trnF (GAA), and atpB and rbcL. In 20 populations of P. cuneifolia, 22 nucleotide substitutions and five insertions/deletions were inferred, and their genetic distances ranged from 0.001 to 0.008. Eight distinct haplotypes could be recognized and each haplotype was found to be geographically structured. Three major clades (the Northern, Hokkaido and Southern clades) were revealed in phylogenetic analyses of the haplotypes. The haplotypes of the Northern clade had a wider distribution area in the populations of Mt. Rausu and Rishiri Island of eastern and northern Hokkaido in Japan, northward to Unalaska Island in the Aleutians, and those of the Hokkaido clade were distributed in the populations of central Hokkaido and Mt. Iwaki of the northern Honshu in Japan; in addition, those of the Southern clade were observed only in the populations of the central Honshu. It was shown that the genetic diversifications of the Southern clade were higher than those of the Northern and Hokkaido clades. Furthermore, it was shown that the topology within the Southern clade was hierarchical, and the haplotypes of the Southern populations in the clade were derivative. From these results, we concluded that the cpDNA haplotypes of the three clades in P. cuneifolia arose and assumed the present distribution areas through several cycles of glacial advance and retreat in the Pleistocene. Received 24 June 1998/ Accepted in revised form 28 December 1998     

Northern richness and southern poverty: contrasting genetic footprints of glacial refugia in the relictual tree Sciadopitys verticillata (Coniferales: Sciadopityaceae)

Sciadopitys verticillata is amongst the most relictual of all plants, being the last living member of an ancient conifer lineage, the Sciadopityaceae, and is distributed in small and disjunct populations in high rainfall regions of Japan. Although mega‐fossils indicate the persistence of the species within Japan through the Pleistocene glacial–interglacial cycles, how the species withstood the colder and drier climates of the glacials is not well known. The present study utilized phylogeography and palaeodistribution modelling to test whether the species survived within pollen‐based coastal temperate forest glacial refugia or within previously unidentified refugia close to its current range. Sixteen chloroplast haplotypes were found that displayed significant geographical structuring. Unexpectedly, northern populations in central Honshu most distant from coastal refugia had the highest chloroplast diversity and were differentiated from the south, a legacy of glacial populations possibly in inland river valleys close to its current northern range. By contrast, populations near putative coastal refugia in southern Japan, harboured the lower chloroplast diversity and were dominated by a single haplotype. Fragment size polymorphism at a highly variable and homoplasious mononucleotide repeat region in the trnT‐trnL intergenic spacer reinforced the contrasting patterns of diversity observed between northern and southern populations. The divergent histories of northern and southern populations revealed in the present study will inform the management of this globally significant conifer. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 108 , 263–277.     

Different phylogeographic patterns in two Japanese Silpha species (Coleoptera: Silphidae) affected by climatic gradients and topography

To reveal differences in phylogeographic patterns of flightless insect species occurring in different regions of Japan, we studied the phylogeography and demographic history of Silpha beetles occurring in cool-temperate habitats of two major islands, Honshu and Hokkaido, using sequences of the mitochondrial cytochrome oxidase subunit I (COI) gene. Honshu has a more mountainous topography, and cool-temperate habitats occur discontinuously, whereas Hokkaido, located to the north of Honshu, has more continuous cool-temperate habitats. A species endemic to Honshu, S. longicornis occurs on Honshu, whereas S. perforata occurs on Hokkaido and the East Asian continent. Our results indicate that the ancestors of S. longicornis colonized Honshu via a south-west route c . 0.7 Mya and the species has highly divergent populations in isolated mountainous areas of Honshu, whereas S. perforata colonized Hokkaido via a northern route less than 90 000 years ago and has less divergent geographic populations. During the last glacial period, S. perforata was probably restricted to refugia in southern Hokkaido and later expanded into northern Hokkaido, whereas S. longicornis populations existed in many isolated refugia, probably because of the complex topography of Honshu. Thus, our study demonstrates that, even between closely related species, interactions among biology, latitudinal climatic gradients and topography can produce different phylogeographic patterns.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 98 , 452–467.     

Phylogeography of the leaf beetle Chrysolina virgata in wetlands of Japan inferred from the distribution of mitochondrial haplotypes

The genetic differentiation among populations of the leaf beetle Chrysolina virgata living in wetlands of Japan was studied based on the sequence data of the mitochondrial cytochrome oxidase subunit I gene region (750 bp). Two distinct lineages of mitochondrial haplotypes were found: one (clade A) consisted of 26 haplotypes distributed over the distribution range of C. virgata between north‐east Honshu and Kyushu, whereas the other (clade B) was monotypic and confined to a small region in north‐east Honshu where it coexisted with clade A. Nested clade analysis for these haplotypes suggested that range expansion and following differentiation due to isolation by distance might have resulted in the present distribution pattern of the haplotypes in clade A. We discuss the evolutionary process leading to the occurrence of two distinct haplotype clades in Japan in terms of repeated colonization from the continent and range expansion and contraction during climatic changes.     

Occurrence and genetics of black‐eyed migratory locusts,Locusta migratoria (Orthoptera: Acrididae)

Black‐eyed Locusta migratoria appeared in albino locusts as a result of crossing between a short‐winged strain originating from Tsushima Island, Japan, and an albino strain originating from Okinawa Island. The black eye trait was recessive to the white eye trait because the crosses between black‐ and white‐eyed albino locusts produced only individuals with white eyes in the F₁ generation. In the F₂ generation, black‐ and white‐eyed individuals appeared in a ratio of 1:3, indicating that the black eye trait was controlled by a simple Mendelian unit. The black eye trait showed no genetic association with other traits including wing morph, adult body dimensions and classical morphometric ratios such as hind femur length / head width and forewing length / hind femur length.     

Extensive genetic divergence in the East Asian natricine snake,Rhabdophis tigrinus (Serpentes: Colubridae), with special reference to prominent geographical differentiation of the mitochondrial cytochrome b gene in Japanese populations

We investigated intraspecific phylogenetic relationships in the natricine snake, Rhabdophis tigrinus. A partial sequence of mitochondrial cytochrome b gene (990 bp) was sequenced for 220 individuals from 112 populations. The phylogeny indicated monophyly of the Japanese populations against the continental and Taiwanese populations, sister relationships of the Japanese and continental populations, and monophyly of the whole species. The results strongly suggested substantial genetic divergences among population assemblages from those three regions. We thus consider both lateralis from the continent, which is often synonymized to R. tigrinus, and formosanus from Taiwan, which is usually regarded as a subspecies of the latter, as distinct full species based on the evolutionary species concept. In the Japanese populations, haplotypes were classified to in two major clades (I and II) that were parapatric to each other. Clade I consisted of three distinct subclades (I‐A, I‐B, and I‐C), of which the former two were parapatric with each other, whereas the latter was sympatric with each of the former two subclades. The geographical haplotype structure exhibited by the Japanese populations is likely to have resulted from a series of allopatric differentiations with rapid range extensions of resultant lineages, leading to secondary contact or further admixture of mitochondrial haplotype clades and subclades. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 105 , 395–408.     

Phylogeography of a northeast Asian spruce, Picea jezoensis, inferred from genetic variation observed in organelle DNA markers

Range-wide genetic variation of the widespread cold-temperate spruce Picea jezoensis was studied throughout northeast Asia using maternally inherited mitochondrial DNA and paternally inherited chloroplast DNA markers. This study assessed 33 natural populations including three varieties of the species in Japan, Russia, China, and South Korea. We depicted sharp suture zones in straits around Japan in the geographical distribution pattern of mitochondrial haplotypes (GST=0.901; NST=0.934). In contrast, we detected possible extensive pollen flow without seed flow across the straits around Japan during the past population history in the distribution pattern of chloroplast haplotypes (GST=0.233; NST=0.333). The analysis of isolation by distance of the species implied that by acting as a barrier for the movement of seeds and pollen, the sharp suture zones contributed considerably to the level of genetic differentiation between populations. Constructed networks of mitochondrial haplotypes allowed inference of the phylogeographical history of the species. We deduced that the disjunction with Kamchatka populations reflects range expansion and contraction to the north of the current distribution. Within Japan, we detected phylogeographically different types of P. jezoensis between Hokkaido and Honshu islands; P. jezoensis in Honshu Island may have colonized this region from the Asian continent via the Korean peninsula and the species in Hokkaido Island is likely to have spread from the Asian continent via Sakhalin through land bridges. Japanese endemism of mitochondrial haplotypes in Hokkaido and Honshu islands might have been promoted by separation of these islands from each other and from the Asian continent by the straits during the late Quaternary.     

The second phantom aquatic leaf beetle in Japan: Macroplea mutica rediscovery in the wetlands (Coleoptera: Chrysomelidae)

Wetland biodiversity is currently declining on a global scale. Wetland biodiversity understanding is critical for determining the wetlands' conservation value. In this study, Macroplea Samouelle, 1819 (Coleoptera: Chrysomelidae) was discovered in Aomori Prefecture, Honshu Island, Japan. Only two Macroplea species have been recorded in Japan, M. japana (Jacoby, 1885) and M. mutica (Fabricius, 1792). Macroplea japana had been unrecorded for 60 years before being rediscovered in Honshu Island in 2022, and a single adult M. mutica female was discovered in Hokkaido Prefecture in 2003. The discovered individuals were concluded to be M. mutica based on morphological and molecular analyses. Although morphological differences were observed with the Eurasian M. mutica individuals, the male genitalia was nearly identical to M. mutica. For the molecular phylogenetic analysis based on COI and 28S sequences, Macroplea individuals in Japan were clustered with M. mutica on the Eurasian Continent. This is the first record of this species on Honshu Island (and the second in Japan), as well as the first record of adult males. This species would require conservation policies and additional distributional surveys.     

Contrasting patterns of nuclear microsatellite genetic structure of Fraxinus mandshurica var. japonica between northern and southern populations in Japan

Aim The aim of this study is to detect extant patterns of population genetic structure of Fraxinus mandshurica var. japonica in Japan, and to provide insights into the post‐glacial history of this species during the Holocene. Location Hokkaido and Honshu islands, Japan (including the Oshima and Shimokita peninsulas). Methods We examined nine polymorphic nuclear microsatellite loci to assess genetic variation within and among 15 populations across almost the entire range of the species in Japan. Extant patterns of geographical structure were analysed using Bayesian clustering, Monmonier’s algorithm, analysis of molecular variance, Mantel tests and principal coordinates analysis. Recent bottlenecks within populations and regional genetic variation were also assessed. Results Northern populations (Hokkaido Island and the Shimokita Peninsula) formed a single homogeneous deme, maintaining the highest level of allelic diversity on the Oshima Peninsula. By contrast, southern populations (Honshu Island) demonstrated strong substructure on both coasts. Specifically, populations on the Pacific side of Honshu exhibited significant bottlenecks and erosion of allelic diversity but preserved distinct subclusters diverging from widespread subclusters on the Japan Sea side of this island. Main conclusions Genetic evidence and life history traits suggest that F. mandshurica occupied cryptic northern refugia on the Oshima Peninsula during the Last Glacial Maximum, which is reflected in the species’ extant northern distribution. Strong geographical structure in southern populations, in agreement with fossil pollen records, suggests geographical isolation by mountain ranges running north–south along Honshu. Given that this tree species is cold‐adapted and found in riparian habitats, populations on the Pacific side of Honshu probably contracted into higher‐elevation swamps during warm post‐glacial periods, leading to a reduction of effective population sizes and rare allelic richness.     

Mitochondrial DNA Sequence-Based Population Genetic Structure of the Firefly, Pyrocoelia rufa (Coleoptera: Lampyridae)

The genetic divergence, population genetic structure, and possible speciation of the Korean firefly, Pyrocoelia rufa, were investigated on the midsouthern Korean mainland, coastal islets, a remote offshore island, Jedu-do, and Tsushima Island in Japan. Analysis of DNA sequences from the mitochondrial COI protein-coding gene revealed 20 mtDNA-sequence-based haplotypes with a maximum divergence of 5.5%. Phylogenetic analyses using PAUP, PHYLIP, and networks subdivided the P. rufa into two clades (termed clade A and B) and the minimum nucleotide divergence between them was 3.7%. Clade A occurred throughout the Korean mainland and the coastal islets and Tsushima Island in Japan, whereas clade B was exclusively found on Jeju-do Island. In the analysis of the population genetic structure, clade B formed an independent phylogeographic group, but clade A was further subdivided into three groups: two covering western and eastern parts of the Korean peninsula, respectively, and the other occupying one eastern coastal islet and Japanese Tsushima Island. Considering both phylogeny and population structure of P. rufa, the Jeju-do Island population is obviously differentiated from other P. rufa populations, but the Tsushima Island population was a subset of the Korean coastal islet, Geoje. We interpreted the isolation of the Jeju-do population and the grouping of Tsushima Island with Korean coastal islets in terms of Late Pleistocene-Holocene events. The eastern-western subdivision on the Korean mainland was interpreted partially by the presence of a large major mountain range, which bisects the midpart of the Korean peninsula into western and eastern parts.     

Genetic and morphological differentiation of the mangrove crab Perisesarma guttatum (Brachyura: Sesarmidae) along an East African latitudinal gradient

The genetic structure and morphometric differentiation of mangrove crab Perisesarma guttatum populations were examined among shelf connected locations along a latitudinal gradient on the East African coast. Over 2200 specimens were sampled from 23 mangrove sites for geometric morphometrics analysis. Population genetic analyses of mitochondrial cytochrome c oxidase subunit I (COI) DNA sequences were used to evaluate connectivity among populations. A total of 73 haplotypes were detected, and almost no haplotypes were found in common between two highly supported phylogeographic clades: southern Mozambique (Inhaca Island and Maputo Bay) and a northern clade that included north Mozambique, Tanzania and Kenya. These two clades were identified based on the species' populations pairwise genetic differentiation and geographical location. Φ_ST values were considerably high between the two clades, indicating the presence of significant population genetic structure between Kenya and South Mozambique. However, each clade was composed of genetically similar populations along the latitudinal gradient, and no significant population structure was found within each clade because the Φ_st values were not significant. The morphometric analysis corroborated the division into two clades (i.e. Inhaca Island/Maputo Bay and northern populations) and also detected less shape variation among populations that were few kilometres apart. The significant spatial genetic structuring between the southern and the northern populations of P. guttatum along the geographic gradient under study, combined with morphological differences, suggests that these populations may be considered as cryptic species. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99 , 28–46.     

Geographic allozyme variation in the Japanese clouded salamander, Hynobius nebulosus (Amphibia: Urodela)

Using starch gel electrophoresis, geographical enzyme variation was surveyed in 46 populations of the Japanese salamander Hynobius nebulosus , which occurs widely in western Japan. This species exhibits substantial local genetic differentiation and is more diverse in inland regions than on small islands. In several different analyses, two groups of populations, one from Kyushu Island to the westernmost part of Chugoku district, Honshu (western group), and another from Shikoku through Kinki to Chubu district, Honshu (eastern group), were consistently recognized. Most of the remaining populations were placed in two less clearly-defined groups: the montane group from the Chugoku Mountains and the Chugoku group from the coastal regions of Chugoku district. The divergence patterns of H. nebulosus are thought to be related to the geological history of its range. The populations near the boundary of the western group were found to share several alleles that were predominant on both sides of the boundary, indicating past secondary contact. Differentiation in the montane group did not follow the isolation by distance model, probably because several populations included were genetically mixed with lowland populations of the Chugoku group.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 89 , 311–330.     

Origins of recently re‐established and newly discovered populations of the endangered butterfly Shijimiaeoides divinus (Lepidoptera: Lycaenidae) in Oita Prefecture,Japan

The endangered butterfly Shijimiaeoides divinus was believed to have been extirpated from Oita Prefecture, Kyushu, Japan, but was rediscovered in Taketa in recent years. This population is considered to have re‐established as a result of natural dispersal from Kumamoto, a neighboring prefecture located to the west of Oita. Furthermore, another population was recently found in Yufu, Oita Prefecture, which is an area where the species had never been recorded. To elucidate the origins of these two populations newly found from Oita Prefecture, their DNA sequences of the mitochondrial cytochrome c oxidase subunit I (COI) gene were compared with those of other S. divinus populations from Kumamoto Prefecture, Honshu and Korea. The results supported the hypothesis that the Taketa population originated from Kumamoto Prefecture. However, it was not clear whether this population originated from the natural dispersal or deliberate release of individuals. It was also found that the Yufu population was not established by the deliberate release of individuals from Honshu or Korea; however, it remained unclear whether the population of S. divinus was native to Yufu, or originated from other localities in Kyushu.     

Intraspecific sequence variation of chloroplast DNA inPedicularis chamissonis Steven (Scrophulariaceae) and geographic structuring of the Japanese “Alpine” plants

In order to clarify evolutionary patterns and processes of intraspecific diversification ofPedicularis chamissonis Steven, we analyzed intraspecific variation of the nucleotide sequences of non-coding regions of chloroplast DNA: the intergenic spacers betweentrnT (UGU) andtrnL (UAA) 5′exon,trnL (UAA) 3′exon andtrnF (GAA), andatpB andrbcL. In 24 populations ofP. chamissonis, 33 nucleotide substitutions and 12 insertions/deletions were inferred, and their genetic distances ranged from 0.001 to 0.014. Seventeen distinct cpDNA haplotypes could be recognized and each haplotype was found to be geographically structured. Two major clades (the Northern and Southern clades) were revealed in phylogenetic analyses of cpDNA haplotypes. The haplotypes of the Northern clade had a wider distribution area in the populations of Mts. lide of central Honshu in Japan, northward to Unalaska Island in the Aleutians. Relationships among most haplotypes were unresolved polytomies. On the other hand, the haplotypes of the Southern clade occurred from the populations of Mt. Gassan southwards to Mt. Arakawa of central Honshu. Within this clade, three subclades were clearly recognized. From these results, we concluded that the haplotypes of the Northern and Southern clades inP. chamissonis might have traveled down to Japanese Archipelago from the north in not a single glacial period.     

Surviving glacial ages within the Biotic Gap: phylogeography of the New Zealand cicada Maoricicada campbelli

Aim New Zealand is an ideal location in which to investigate the roles of landscape and climate change on speciation and biogeography. An earlier study of the widespread endemic cicada Maoricicada campbelli (Myers) found two phylogeographically distinguishable major clades – northern South Island plus North Island (northern‐SI + NI) and Otago. These two clades appeared to have diverged on either side of an area of the South Island known as the Biotic Gap. We sampled more intensively to test competing theories for this divergence. We aimed to discover if M. campbelli had survived within the Biotic Gap during recent glacial maxima, and if predicted areas of secondary contact between the two major clades existed. Location New Zealand. Methods We analysed mitochondrial DNA sequences (1520 bp; 212 individuals; 91 populations) using phylogenetic (maximum likelihood, Bayesian), population genetic (analysis of molecular variance) and molecular dating methods (Bayesian relaxed clock with improved priors). Results We found strong geographical structuring of genetic variation. Our dating analyses suggest that M. campbelli originated 1.83–2.58 Ma, and split into the two major clades 1.45–2.09 Ma. The main subclades in the northern‐SI + NI clade arose almost simultaneously at 0.69–1.03 Ma. Most subclades are supported by long internal branches and began to diversify 0.40–0.78 Ma. We found four narrow areas of secondary contact between the two major clades. We also found a difference between calling songs of the Otago vs. northern‐SI + NI clades. Main conclusions Phylogeographical patterns within M. campbelli indicate an early Pleistocene split into two major clades, followed by late Pleistocene range expansion and in situ population differentiation of subclades. The northern‐SI + NI clade diversified so rapidly that the main subclade relationships cannot be resolved, and we now have little evidence for a disjunction across the Biotic Gap. Structure within the main subclades indicates rapid divergence after a common bottlenecking event, perhaps attributable to an extremely cold glacial maximum at c. 0.43 Ma. Clade structure and dating analyses indicate that M. campbelli survived in many refugia during recent glacial maxima, including within the Biotic Gap. The narrow overlap between the two major clades is attributed to recent contact during the current interglacial and slow gene diffusion. The two major clades appear to be in the early stages of speciation based on genetic and behavioural differences.     

Development of microsatellite markers for an extremely limited distributed rare diving beetle species,Acilius kishii,and a widely distributed species,Acilius japonicus (Coleoptera: Dytiscidae)

Acilius kishii Nakane, 1963 (Coleoptera: Dytiscidae) is an endangered diving beetle species distributed in only one location, Lake Yashaga‐Ike, Honshu Island, Japan. Acilius japonicus, which is related to A. kishii, is distributed widely in northern Honshu Island and Hokkaido Island in Japan. In this study, we identified 14 microsatellite loci for A. kishii and A. japonicus, including both polymorphic and monomorphic loci, using the next‐generation sequencing method. We observed that 5 and 10 loci showed polymorphisms in 31 and 32 individuals of A. kishii and A. japonicus, respectively. The observed and expected heterozygosities were 0.00–1.00 and 0.00–0.74, respectively. These microsatellite loci could be useful for future conservation genetic studies, including monitoring of genetic diversity and extinction risk of A. kishii.     

Genetic structure of <Emphasis Type="Italic">Cerasus jamasakura</Emphasis>, a Japanese flowering cherry,revealed by nuclear SSRs: implications for conservation

The genetic resources of a particular species of flowering cherry, Cerasus jamasakura, have high conservation priority because of its cultural, ecological and economic value in Japan. Therefore, the genetic structures of 12 natural populations of C. jamasakura were assessed using ten nuclear SSR loci. The population differentiation was relatively low (F _ST, 0.043), reflecting long-distance dispersal of seeds by animals and historical human activities. However, a neighbor-joining tree derived from the acquired data, spatial analysis of molecular variance and STRUCTURE analysis revealed that the populations could be divided into two groups: one located on Kyusyu Island and one on Honshu Island. Genetic diversity parameters such as allelic richness and gene diversity were significantly lower in the Kyushu group than the Honshu group. Furthermore, STRUCTURE analysis revealed that the two lineages were admixed in the western part of Honshu Island. Thus, although the phylogeographical structure of the species and hybridization dynamics among related species need to be evaluated in detail using several marker systems, the Kyusyu Island and Honshu Island populations should be considered as different conservation units, and the islands should be regarded as distinct seed transfer zones for C. jamasakura, especially when rapid assessments are required.