Closing the ring: historical biogeography of the salamander ring species Ensatina eschscholtzii

Aim The salamander Ensatina eschscholtzii Gray is a classic example of a ring species, or a species that has expanded around a central barrier to form a secondary contact characterized by species‐level divergence. In the original formulation of the ring species scenario, an explicit biogeographical model was proposed to account for the occurrence of intraspecific sympatry between two subspecies in southern California (the ‘southern closure’ model). Here we develop an alternative ring species model that is informed by the geomorphological development of the California Coast Ranges, and which situates the point of ring closure in the Monterey Bay region of central coastal California (the ‘Monterey closure’ model). Our study has two aims. The first is to use phylogenetic methods to evaluate the two competing biogeographical models. The second is to describe patterns of phylogeographical diversity throughout the range of the Ensatina complex, and to compare these patterns with previously published molecular systematic data. Location Western North America, with a focus on the state of California, USA. Methods We obtained mitochondrial DNA sequence data from 385 individuals from 224 populations. A phylogeny was inferred using Bayesian techniques, and the geographical distributions of haplotypes and clades were mapped. The two biogeographical ring species models were tested against our Bayesian topology, including the associated Bayesian 95% credible set of trees. Results High levels of phylogeographical diversity were revealed, especially in central coastal and northern California. Our Bayesian topology contradicts the Monterey closure model; however, 0.08% of the trees in our Bayesian 95% credible set are consistent with this model. In contrast, the classic ring species biogeographical model (the southern closure model) is consistent with our Bayesian topology, as were 99.92% of the trees in our 95% credible set. Main conclusions Our Bayesian phylogenetic analysis most strongly supports the classic ring species model, modified to accommodate an improved understanding of the complex geomorphological evolution of the California Coast Ranges. In addition, high levels of phylogeographical diversity in central and northern California were identified, which is consistent with the striking levels of allozymic differentiation reported previously from those regions.     

GEOGRAPHIC VARIATION IN ALLOZYMES IN A “RING SPECIES,” THE PLETHODONTID SALAMANDER ENSATINA ESCHSCHOLTZII OF WESTERN NORTH AMERICA

The ring species Ensatina eschscholtzii (a plethodontid salamander) of western North America has a circle of subspecies surrounding the Central Valley of California which come into contact and are sympatric in southern California. We examined 26 proteins in 19 populations (maximum of 10 specimens per population) collected throughout the range in order to gain an understanding of the degree of differentiation in the group. Allozymic differentiation is profound, with genetic distances in excess of 0.5 (Rogers or Nei) between populations. Naturally hybridizing populations differ by genetic distances greater than 0.4. Two general classes of color morphs, blotched and unblotched, are segregated geographically, but they do not form discrete genetic units. Both are deeply differentiated, and genetic distances among populations of either class exceed those measured between the classes where they are sympatric in southern California. This study disclosed little evidence of gene exchange around the ring of populations and sampling of many additional populations in regions between populations sampled thus far will be required to determine whether smooth intergradation occurs. Although genetic distances measured exceed those between some co-occurring species of plethodontid salamanders, we find no evidence of borders between cryptic species.     

Distribution of mitochondrial haplotypes (cytb) in Polish populations of Emys orbicularis (L., 1758)

The European pond turtle, Emys orbicularis, inhabits a wide distribution area in the western Palaearctic. Polish populations of pond turtle represent the nominotypical subspecies Emys orbicularis orbicularis. The mitochondrial DNA haplotype (cytb gene) variation among 131 turtles from 26 locations in five regions of Poland was investigated. Five haplotypes belonging to three distinct lineages were identified. Two clades (I and II) were represented by two haplotypes each, while the other clade (IV) was represented by one haplotype. Three haplotypes were reported for the first time in E. orbicularis. The eastern part of Poland is inhabited exclusively by turtles bearing haplotype Ia. The remaining four sequence variants were recorded in western Poland where only the IIb haplotype is considered endemic. The distribution of the other haplotypes in western Poland could thus reflect past introductions or accidental releases. The authors regarded the two locations (Drzeczkowo and Karpicko) that were first included in the western Poland populations as autochthonous catchment areas of haplotype Ia.     

Characterizing the molecular variation among American marten (Martes americana) subspecies from Oregon and California

We investigated the subspecific identity of a rediscovered population of American martens within the range of a presumed extinct subspecies (Martes americana humboldtensis) by comparing mitochondrial DNA sequence diversity from contemporary individuals within the described ranges of M. a. humboldtensis, nearby ranges of M. a. caurina and M. a. sierrae, and a museum specimen of M. a. humboldtensis. Martens from the rediscovered population shared a haplotype (#2) with the museum specimen. This haplotype was found only in the coastal regions of Oregon and California, suggesting that the rediscovered population represents descendants of a relictual population that previously existed in coastal California. The subspecific boundary between M. a. humboldtensis and M. a. caurina may not be valid, because haplotype #2 was shared between coastal Oregon and coastal California populations and no known contemporary or historical biogeographic barriers prevent north–south movement. Thus, marten populations currently located in coastal forests of California and Oregon should be managed collectively to preserve the connectivity that our data suggest occurred historically. M. a. sierrae differed substantially from both M. a. humboldtensis and M. a. caurina, suggesting marten populations were not a historically genetically homogeneous population and divergence may have occurred in separate glacial refugia.     

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.     

Mitochondrial DNA evolution in the Anaxyrus boreas species group

The Anaxyrus boreas species group currently comprises four species in western North America including the broadly distributed A. boreas, and three localized species, Anaxyrus nelsoni, Anaxyrusexsul and Anaxyrus canorus. Phylogenetic analyses of the mtDNA 12S rDNA, cytochrome oxidase I, control region, and restriction sites data, identified three major haplotype clades. The Northwest clade (NW) includes both subspecies of A. boreas and divergent minor clades in the middle Rocky Mountains, coastal, and central regions of the west and Pacific Northwest. The Southwest (SW) clade includes A. exsul, A. nelsoni, and minor clades in southern California. Anaxyrus canorus, previously identified as paraphyletic, has populations in both the NW and SW major clades. The Eastern major clade (E) includes three divergent lineages from southern Utah, the southern Rocky Mountains, and north of the Great Basin at the border of Utah and Nevada. These results identify new genetic variation in the eastern portion of the toad's range and are consistent with previous regional studies from the west coast. Low levels of control region sequence divergence between major clades (2.2-4.7% uncorrected pair-wise distances) are consistent with Pleistocene divergence and suggest that the phylogeographic history of the group was heavily influenced by dynamic Pleistocene glacial and climatic changes, and especially pluvial changes, in western North America. Results reported here may impact conservation plans in that the current taxonomy does not reflect the diversity in the group.     

The hidden diversity of Coleodactylus amazonicus (Sphaerodactylinae,Gekkota) revealed by molecular data

Coleodactylus amazonicus, a small leaf-litter diurnal gecko widely distributed in Amazon Basin, has been considered a single species with no significant morphological differences between populations along its range. A recent molecular study, however, detected large genetic differences between populations of central Amazonia and those in the easternmost part of the Amazon Basin, suggesting the presence of taxonomically unrecognised diversity. In this study, DNA sequences of three mitochondrial (16S, cytb, and ND4) and two nuclear genes (RAG-1, c-mos) were used to investigate whether the species currently identified as C.amazonicus contains morphologically cryptic species lineages. The present phylogenetic analysis reveals further genetic subdivision including at least five potential species lineages, restricted to northeastern (lineage A), southeastern (lineage B), central-northern (lineage E) and central-southern (lineages C and D) parts of Amazon Basin. All clades are characterized by exclusive groups of alleles for both nuclear genes and highly divergent mitochondrial haplotype clades, with corrected pairwise net sequence divergence between sister lineages ranging from 9.1% to 20.7% for the entire mtDNA dataset. Results of this study suggest that the real diversity of “C. amazonicus” has been underestimated due to its apparent cryptic diversification.     

Phylogeny and genetic structure of the goitered gazelle (Artiodactyla,Bovidae) in north-western China indicated by the hypervariable mitochondrial control region

The goitered gazelle, Gazella subgutturosa, is a medium-sized ungulate inhabiting arid and semi-arid regions in the Middle East and central Asia. The intraspecific classification of the species remains unclear. We analysed the genetic diversity in mitochondrial DNA control region (CR) sequences (976?bp) from 104 wild samples from the Xinjiang Uyghur Autonomous Region (XUAR) in north-west China, and reconstructed phylogeny with additional sequences from across the species’ range. We detected 58 haplotypes in XUAR populations, all but three of which were specific to single sampling sites. The phylogenetic analysis displayed two obvious clades of mtDNA haplotypes and the other haplotypes differed from the two clades. A median-joining network showed three groups of haplotypes were to a high extent concordant with the phylogenetic tree. The haplotype clustering was consistent with their geographic distribution. Nei’s net sequence divergences amongst the three groups ranged from 0.010 to 0.018 and indicated three subspecies, two of which inhabit XUAR. We detected strong differentiation between northern (NX) and southern (SX) XUAR populations overall (F_ST?=?0.4448, P?相似文献   

Population structure and genetic analysis of narrow-clawed crayfish (Astacus leptodactylus) populations in Turkey

The genetic differentiation among Turkish populations of the narrow-clawed crayfish was investigated using a partial sequence of cytochrome oxidase subunit I gene (585 bp) of 183 specimens from 17 different crayfish populations. Median joining network and all phylogenetic analyses disclosed a strong haplotype structure with three prominent clades diverged by a range between 20 and 50 mutations and substantial inter-group pairwise sequence divergence (5.19–6.95 %), suggesting the presence of three distinct clades within the Anatolian populations of Astacus leptodactylus. The divergence times among the three clades of Turkish A. leptodactylus are estimated to be 4.96–3.70 Mya using a molecular clock of 1.4 % sequence divergence per million years, pointing to a lower Pliocene separation. The high level of genetic variability (H _d  = 95.8 %, π = 4.17 %) and numerous private haplotypes suggest the presence of refugial populations in Anatolia unaffected by Pleistocene habitat restrictions. The pattern of genetic variation among Turkish A. leptodactylus populations, therefore, suggests that the unrevealed intraspecific genetic structure is independent of geographic tendency and congruent with the previously reported geographic distribution and number of subspecies (A. l. leptodactylus and A. l. salinus) of A. leptodactylus.     

The Genetic Legacy of Multiple Beaver Reintroductions in Central Europe

The comeback of the Eurasian beaver (Castor fiber) throughout western and central Europe is considered a major conservation success. Traditionally, several subspecies are recognised by morphology and mitochondrial haplotype, each linked to a relict population. During various reintroduction programs in the 20th century, beavers from multiple source localities were released and now form viable populations. These programs differed in their reintroduction strategies, i.e., using pure subspecies vs. mixed source populations. This inhomogeneity in management actions generated ongoing debates regarding the origin of present beaver populations and appropriate management plans for the future. By sequencing of the mitochondrial control region and microsatellite genotyping of 235 beaver individuals from five selected regions in Germany, Switzerland, Luxembourg, and Belgium we show that beavers from at least four source origins currently form admixed, genetically diverse populations that spread across the study region. While regional occurrences of invasive North American beavers (n = 20) were found, all but one C. fiber bore the mitochondrial haplotype of the autochthonous western Evolutionary Significant Unit (ESU). Considering this, as well as the viability of admixed populations and the fact that the fusion of different lineages is already progressing in all studied regions, we argue that admixture between different beaver source populations should be generally accepted.     

PHYLOGEOGRAPHIC PATTERNS IN COASTAL NORTH AMERICAN TIGER BEETLES (CICINDELA DORSALIS SAY) INFERRED FROM MITOCHONDRIAL DNA SEQUENCES

Genetic variation was assessed in the tiger beetle, Cicindela dorsalis, by sequencing of three regions of the mtDNA genome. Populations of four morphologically distinguishable subspecies were sampled from 28 representative locations covering almost the entire geographic range of the species in coastal North America. In 78 individuals analyzed for 656 base pairs from four different genes, 17 different haplotypes could be distinguished. A cladistic analysis grouped the haplotype sequences into two main lineages, one from the Atlantic Ocean and one from the Gulf of Mexico. Haplotypes within the two clades were very similar to each other. Most of the characters that distinguished these closely related haplotypes were homoplastic. The geographic distribution of haplotypes did not coincide with the distribution of morphological subspecies, but no evidence for hybridization between two subspecies could be inferred from this observation. The implications of these findings for the evolution of gene sequences at and below the species level are discussed.     

Colonization and divergence: phylogeography and population genetics of the Atlantic coast beach mice

Barrier island taxa provide an opportunity to investigate recent evolutionary processes, such as colonization and isolation of recently diverged taxa, and provide important insights into understanding contemporary diversity and the assessment of conservation units. Using rapidly evolving genetic markers (mitochondrial DNA and microsatellites), we studied the Atlantic coast beach mouse subspecies (Peromyscus polionotus decoloratus, P. p. niveiventris, and P. p. phasma). Our data indicate that each of the extant coastal subspecies (P. p. niveiventris and P. p. phasma) is comprised of unique haplotypes indicative of their isolation, while the extinct subspecies, P. p. decoloratus, contain a single haplotype, which was shared with P. p. phasma. Moreover, all the coastal haplotypes originate from a single mainland haplotype found in central Florida, USA. The microsatellite data indicated high levels of genetic structure among our sampled populations. Additionally, these data group the populations into three distinct genetic clusters, with each of the extant coastal subspecies belonging to their own cluster and the mainland individuals forming a separate cluster. The extant Atlantic coast beach mice are on separate evolutionary trajectories, thus representative of separate taxonomic units. Therefore, the data support that two extant subspecies on the Florida Atlantic coast fit the Distinct Population Segment designation and should be managed and conserved as two separate independent units.     

Human introductions create opportunities for intra-specific hybridization in an alien lizard

Introduction of individuals from multiple sources could create opportunities for hybridization between previously isolated lineages, which may impact on the invasion process. Identifying the phylogeographic origin of introduced populations is therefore an important task to further test the causes and consequences of human-mediated translocations. The common wall lizard (Podarcis muralis) shows a strong phylogeographic structure as a result of past isolation in glacial refugia, but it has also been commonly introduced outside of its native range. Here we analysed 655 base pairs (bp) of the cytochrome b sequence from 507 individuals from 23 introduced populations of P. muralis in England. We identified 12 unique haplotypes in the introduced populations that were nested into five native geographically distinct clades with genetic divergences ranging from 2.1 to 5.7 %. Multiple clade origin was common within populations, with a maximum of three different haplotype clades being represented within a single population. The genetic data are consistent with a scenario whereby initial establishment was a result of translocation of animals from their native range, whereas more recent establishment (i.e. since the mid-1980s) is the result of translocations of animals from previously established non-native populations. However, this requires further study. Overall, our results show that human introductions have created substantial opportunities for hybridization between genetically and phenotypically distinct lineages, which may have important consequences for the establishment success and long-term viability of introduced wall lizard populations.     

Genetic distinctiveness of brown pelicans (<Emphasis Type="Italic">Pelecanus occidentalis</Emphasis>) from the Galápagos Islands compared to continental North America

We examined population differentiation across a substantial portion of the range of the brown pelican (Pelecanus occidentalis) to assess (1) the genetic distinctness of the Galápagos subspecies (P. o. urinator) and (2) genetic differentiation between subspecies that inhabit the coasts of North and Central America (P. o. californicus and P. o. carolinensis). Birds were sampled from coastal California, coastal Florida, and the Galápagos Islands. Using a 957 bp (bp) fragment of the NADH dehydrogenase subunit 2 (ND2) gene, 661 bp of the mitochondrial control region, and eleven microsatellite loci we characterize population genetic differentiation among 158 brown pelicans. The Galápagos subspecies is genetically distinct from the sampled continental subspecies, possessing a unique ND2 haplotype and unique mitochondrial control region haplotypes. Samples from the two continental subspecies all possessed the same ND2 haplotype and shared four mitochondrial control region haplotypes. Bayesian clustering in STRUCTURE placed the Galápagos subspecies in a distinct genetic group with high probability, but could not differentiate the continental subspecies from one another. Estimates of migration rates from BayesAss indicated substantial migration between continental subspecies, but no migration between the Galápagos subspecies and either continental subspecies. There are clearly two Evolutionarily Significant Units within the range of the brown pelican, which warrants conservation attention. Further investigation should determine how the un-sampled subspecies (P. o. murphyi and P. o. occidentalis) fit into the broader picture.     

Mitochondrial DNA and plumage evolution in the white wagtail Motacilla alba

We analyzed sequences of two mitochondrial DNA (mtDNA) gene regions (control region and ND2) totaling 1477 base‐pairs from 232 specimens of the white wagtail Motacilla alba obtained from 27 localities throughout Eurasia. Although overall haplotype diversity was relatively low (0.79) and the most common haplotype was shared by 45% of individuals, belonging to six subspecies, a high level of population differentiation was detected. The mtDNA tree revealed three clades: (1) most individuals from Krasnodar (belonging to M. a. alba subspecies), (2) all individuals from Almaty and some from Primor'e (belonging to M. a. personata, M. a. lugens and M. a. leucopsis subspecies), and (3) the remaining individuals (representing all subspecies and all localities except Almaty). We suggest that these three clades represent historically isolated populations that relatively recently came into secondary contact in Krasnodar and Primor'e. None of the six subspecies were reciprocally monophyletic in the mtDNA tree. The Krasnodar population appeared to receive immigrants from other localities, but distinctive haplotypes from this locality did not appear elsewhere, suggesting asymmetric gene flow. Signatures of recent gene flow between northern populations were detected, and there was no evidence of isolation by distance within the northern group of populations. Mismatch distributions for most localities were consistent with population expansions. We also analyzed 12 male plumage characters from 93 study skins sampled from 24 populations. Phylogenetic trees resulting from separate genetic and morphological analyses were incongruent. Plumage evolution seems to be under strong sexual or natural selection, which favors particular phenotypes in various areas irrespective of the mitochondrial background. Dispersal events at different evolutionary times could have obscured the effects of earlier isolation events. The mtDNA data does not support species status for M. a. lugens and M. a. personata, which shared haplotypes with other subspecies of M. alba. We recommend that M. lugens and M. personata are placed as junior synonyms of M. alba.     

Genetic structure analysis of mantis shrimp <Emphasis Type="Italic">Oratosquilla oratoria</Emphasis> based on mitochondrial DNA control region sequence

The genetic relationships of mantis shrimp Oratosquilla oratoria between the coastal waters of China and Japan were not well studied. To reveal the genetic differentiation and genetic structure among populations, we collected populations of mantis shrimp O. oratoria from the coastal waters of China and Japan to analyze the mtDNA control region variation. A total of 309 individuals of O. oratoria were collected from 13 localities (11 from China and 2 from Japan) and a segment of mitochondrial DNA control region was sequenced. Three hundred nine haplotypes were defined, yielding a very high haplotype diversity and nucleotide diversity. Two lineages of O. oratoria were revealed and displayed strong differences in the geographical distribution. In the coastal waters of China, the geographic distribution of the two lineages was completely separated by the Yangtze River estuary; however, the lineages showed geographic sympatry in two populations from Japan. Based on the lineage distribution, three groups were defined. There was no significant genetic differentiation among the populations within the three groups, indicating high gene flow within each group. Significant and negative values for Tajima D and Fu’s Fs tests, and mismatch distributions for two lineages indicated population expansion. The present result confirmed that the freshwater outflow from the Yangtze River formed a physical barrier and affected gene exchange. The different distribution patterns of the two lineages in coastal waters of China and Japan indicated that the larvae of O. oratoria were transferred from China to the coastal waters of Japan with a one-way gene flow.     

Genetic diversity,genetic structure and phylogeography of the Iberian endemic Gypsophila struthium (Caryophyllaceae) as revealed by AFLP and plastid DNA sequences: connecting habitat fragmentation and diversification

Iberian gypsum outcrops are highly fragmented and ecologically challenging environments for plant colonization. As gypsophytes occur exclusively in such habitats, they are ideal models for the study of both the effects of habitat fragmentation and selection on population genetic diversity and structure. In this study, we used amplified fragment length polymorphism (AFLP) and plastid DNA sequences to investigate the phylogeographical history of the Iberian plant Gypsophila struthium (Caryophyllaceae), a widespread endemic restricted to Iberian gypsum outcrops. Gypsophila struthium consists of two subspecies that differ in the architecture of their inflorescence and have mostly allopatric ranges. Gypsophila struthium subsp. struthium occurs in central, eastern and south‐eastern Iberia, whereas G. struthium subsp. hispanica occurs in northern and eastern areas. AFLPs revealed low but significant genetic differentiation between the subspecies, probably as a result of a recent diversification during the Pliocene–Pleistocene. In the geographical contact zone between the taxa, the Bayesian analyses revealed populations with mixed ancestries and genetic clusters predominantly of one or the other subspecies, indicating incomplete reproductive barriers between them. Plastid DNA haplotypes revealed strong geographical structure and testified to processes of isolation by distance and continuous range expansion for some haplotype clades. The Bayesian analyses of the population structure of AFLP data and nested clade phylogeographical analysis (NCPA) of plastid haplotypes revealed that the putative ancestral range corresponded to central and eastern populations of G. struthium subsp. struthium, with those lineages contributing through more recent expansion to increased genetic diversity and structure of the south‐eastern and eastern ranges of this subspecies and to the diversification of G. struthium subsp. hispanica in northern and eastern gypsum outcrops. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 173 , 654–675.     

Phylogeography of Supralittoral Rocky Intertidal Ligia Isopods in the Pacific Region from Central California to Central Mexico

Background

Ligia isopods are widely distributed in the Pacific rocky intertidal shores from central California to central Mexico, including the Gulf of California. Yet, their biological characteristics restrict them to complete their life cycles in a very narrow range of the rocky intertidal supralittoral. Herein, we examine phylogeographic patterns of Ligia isopods from 122 localities between central California and central Mexico. We expect to find high levels of allopatric diversity. In addition, we expect the phylogeographic patterns to show signatures of past vicariant events that occurred in this geologically dynamic region.

Methodology/Principal Findings

We sequenced two mitochondrial genes (Cytochrome Oxidase I and 16S ribosomal DNA). We conducted Maximum Likelihood and Bayesian phylogenetic analyses. We found many divergent clades that, in general, group according to geography. Some of the most striking features of the Ligia phylogeographic pattern include: (1) deep mid-peninsular phylogeographic breaks on the Pacific and Gulf sides of Baja peninsula; (2) within the Gulf lineages, the northern peninsula is most closely related to the northern mainland, while the southern peninsula is most closely related to the central-southern mainland; and, (3) the southernmost portion of the peninsula (Cape Region) is most closely related to the southernmost portion of mainland.

Conclusions/Significance

Our results shed light on the phylogenetic relationships of Ligia populations in the study area. This study probably represents the finest-scale phylogeographic examination for any organism to date in this region. Presence of highly divergent lineages suggests multiple Ligia species exist in this region. The phylogeographic patterns of Ligia in the Gulf of California and Baja peninsula are incongruent with a widely accepted vicariant scenario among phylogeographers, but consistent with aspects of alternative geological hypotheses and phylo- and biogeographic patterns of several other taxa. Our findings contribute to the ongoing debate regarding the geological origin of this important biogeographic region.     

Biogeography of <Emphasis Type="Italic">Phragmites</Emphasis><Emphasis Type="Italic">australis</Emphasis> lineages in the southwestern United States

The environmental and social impacts of Phragmites australis invasion have been extensively studied in the eastern United States. In the West where the invasion is relatively recent, a lack of information on distributions and spread has limited our ability to manage invasive populations or assess whether native populations will experience a decline similar to that in the East. Between 2006 and 2015, we evaluated the genetic status, distribution, and soil properties (pH, electrical conductivity, and soil texture) of Phragmites stands in wetlands and riparian systems throughout the Southwest. Native (subspecies americanus), Introduced (haplotype M), and Gulf Coast (subspecies berlandieri) Phragmites lineages were identified in the survey region, as well as watershed-scale hybridization between the Native and Introduced lineages in southern Nevada. Two Asian haplotypes (P and Q) that were previously not known to occur in North America were found in California. The Native lineage was the most frequent and widespread across the region, with four cpDNA haplotypes (A, B, H, and AR) occurring at low densities in all wetland types. Most Introduced Phragmites stands were in or near major urban centers and associated with anthropogenic disturbance in wetlands and rivers, and we document their spread in the region, which is likely facilitated by transportation and urban development. Soil pH of Native and hybrid stands was higher (averaging 8.3 and 8.6, respectively) than Introduced stands (pH of 7.5) and was the only soil property that differed among lineages. Continued monitoring of all Phragmites lineages in the Southwest will aid in assessing the conservation status of Native populations and developing management priorities for non-native stands.     

Geographic distribution of phylogenetically-distinct legume pod borer, Maruca vitrata (Lepidoptera: Pyraloidea: Crambidae)

Maruca vitrata Fabricius is a pantropical lepidopteran pest of legumes. Phylogenetic analysis of a mitochondrial cytochrome c oxidase-I gene (cox1) fragment indicates that three Maruca sp. mitochondrial lineages have unique geographic distributions [lineages 1 and 2: Australia, Taiwan, and West Africa (Niger, Nigeria, and Burkina Faso), and lineage 3: Puerto Rico]. The haplotype (T30, T114) is specific to lineages 1&2 and was assayed by NsiI and SacI polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) within population samples; it was not observed in the Puerto Rican samples, but was nearly fixed among samples from West Africa, Australia and Taiwan (85.5?C100%). Re-sequencing and phylogenetic analyses of PCR-RFLP defined cox1 haplotypes indicate that nucleotide diversity is highest among samples from West Africa. Phylogenetic reconstruction based upon ribosomal DNA (rDNA) internal transcribed spacer-2 (ITS-2) sequences provided additional evidence for three Maruca sp. clades. These data suggest that multiple unique Maruca species or subspecies are present worldwide, which has implications for the management of this pest species-complex.