Recent Range Expansion Research Articles

Genetic implications of phylogeographical patterns in the conservation of the boreal wetland butterflyColias palaeno(Pieridae)

The boreo-montane wetland butterfly species Colias palaeno has a European distribution from the Alps to northern Fennoscandia. Within its European range, the species’ populations have shrunk dramatically in recent historical times. Therefore, detailed baseline knowledge of the genetic makeup of the species is pivotal in planning potential conservation strategies. We collected 523 individuals from 21 populations across the entire European range and analyzed nuclear (20 allozyme loci) and mitochondrial (600 bp of the cytochrome c oxidase subunit I gene) genetic markers. The markers revealed contrasting levels of genetic diversity and divergence: higher in allozymes and lower in mitochondrial sequences. Five main groups were identified by allozymes: Alps, two Czech groups, Baltic countries, Fennoscandia, and Poland. The haplotype mitochondrial network indicates a recent range expansion. The most parsimonious interpretation for our results is the existence of a continuous Wurm glacial distribution in Central Europe, with secondary disjunction during the Last Glacial Maximum into a south-western and a north-eastern fragment and subsequent moderate differentiation. Both groups present signs of postglacial intermixing in the Czech Republic. However, even a complete extinction in this region would not considerably affect the species’ genetic basis, as long as the source populations in the Alps and in northern Europe, comprising the most relevant evolutionary units for conservation, are surviving.

Vivid molecular divergence over volcanic remnants: the phylogeography of Megadromus guerinii on Banks Peninsula, New Zealand

ABSTRACTMegadromus guerinii, an endemic carabid beetle (Carabidae), is the most common carabid throughout its restricted range on Banks Peninsula, a formation of extinct volcanoes in Canterbury, New Zealand. This study characterises the small-scale phylogeographic patterns of M. guerinii across the formerly volcanically active Banks Peninsula using mitochondrial and ribosomal genes. Between the eastern and western areas of the peninsula, the mitochondrial, but not nuclear, DNA has a well-defined geographic distribution. Specifically, mitochondrial cytochrome c oxidase subunit I (CO1) identifies two distinct groups (> 6% divergence between eastern and western beetles) while ribosomal genes show no discernible pattern. Whether such a pattern represents male-biased dispersal, Wolbachia infection, a recent range expansion of a divergent lineage, or a deeper historic separation is explored. There is potential that male-biased dispersal could have occurred. Wolbachia infection was not detected. We conclude that historical processes have likely separated taxa in the eastern and western peninsula.

Species range expansion constrains the ecological niches of resident butterflies

AbstractAimChanges in community composition resulting from environmental changes modify biotic interactions and affect the distribution and density of local populations. Such changes are currently occurring in nettle‐feeding butterflies in Sweden where Araschnia levana has recently expanded its range northward and is now likely to interact with resident species (Aglais urticae and Aglais io). Butterfly occurrence data collected over years and across regions enabled us to investigate how a recent range expansion of A. levana may have affected the environmental niche of resident species.LocationWe focused on two regions of Sweden (Skåne and Norrström) where A. levana has and has not established and two time periods (2001–2006 and 2009–2012) during its establishment in Skåne.MethodsWe performed two distinct analyses in each region using the PCA‐env and the framework described in Broennimann et al. (2012). First, we described the main sources of variation in the environment. Second, in each time period and region, we characterized the realized niches of our focal species across topographic and land use gradients. Third, we quantified overlaps and differences in realized niches between and within species over time.ResultsIn Skåne, A. levana has stabilized its distribution over time, while the distribution of the native species has shifted. These shifts depicted a consistent pattern of avoiding overlap between the native species and the environmental space occupied by A. levana, and it was stronger for A. urticae than for A. io. In both regions, we also found evidence of niche partitioning between native species.Main conclusionsInterspecific interactions are likely to affect local species distributions. It appears that the ongoing establishment of A. levana has modified local biotic interactions and induced shifts in resident species distributions. Among the mechanisms that can explain such patterns of niche partitioning, parasitoid‐driven apparent competition may play an important role in this community.

Genetic surfing, not allopatric divergence, explains spatial sorting of mitochondrial haplotypes in venomous coralsnakes.

Strong spatial sorting of genetic variation in contiguous populations is often explained by local adaptation or secondary contact following allopatric divergence. A third explanation, spatial sorting by stochastic effects of range expansion, has been considered less often though theoretical models suggest it should be widespread, if ephemeral. In a study designed to delimit species within a clade of venomous coralsnakes, we identified an unusual pattern within the Texas coral snake (Micrurus tener): strong spatial sorting of divergent mitochondrial (mtDNA) lineages over a portion of its range, but weak sorting of these lineages elsewhere. We tested three alternative hypotheses to explain this pattern-local adaptation, secondary contact following allopatric divergence, and range expansion. Collectively, near panmixia of nuclear DNA, the signal of range expansion associated sampling drift, expansion origins in the Gulf Coast of Mexico, and species distribution modeling suggest that the spatial sorting of divergent mtDNA lineages within M. tener has resulted from genetic surfing of standing mtDNA variation-not local adaptation or allopatric divergence. Our findings highlight the potential for the stochastic effects of recent range expansion to mislead estimations of population divergence made from mtDNA, which may be exacerbated in systems with low vagility, ancestral mtDNA polymorphism, and male-biased dispersal.

Recent Dispersal Events among Solomon Islands Bird Species Reveal Differing Potential Routes of Island Colonization

Abstract: Species assemblages on islands are products of colonization and extinction events, with traditional models of island biogeography emphasizing build-up of biodiversity on small islands via colonizations from continents or other large landmasses. However, recent phylogenetic studies suggest that islands can also act as sources of biodiversity, but few such “upstream” colonizations have been directly observed. I report four putative examples of recent range expansions among the avifauna of Makira and its satellite islands in the Solomon Islands, a region that has recently been subject to extensive anthropogenic habitat disturbance. They include three separate examples of inter island dispersal, involving Geoffroyus heteroclitus, Cinnyris jugularis, and Rhipidura rufifrons, which together represent three distinct possible patterns of colonization, and one example of probable downslope altitudinal range expansion in Petroica multicolor. Because each of these species is easily detected when present, a...

A review of Ruffe (Gymnocephalus cernua) life history in its native versus non-native range

Invasive Ruffe (Gymnocephalus cernua) has caused substantial ecological damage in North America, parts of Western Europe, Scandinavian countries, and the United Kingdom. The objectives of this review are to define Ruffe’s native and non-native range, examine life history requirements, explore the life cycle, and differentiate between life stages. We compare data from its native and non-native ranges to determine if there are any differences in habitat, size, age, genotype, or seasonal migration. Literature from both the native and non-native ranges of Ruffe, with some rare, translated literature, is used. In each life stage, Ruffe exhibit plasticity with regard to chemical, physical, biological, and habitat requirements. Adult Ruffe has characteristics that allow them to adapt to a range of environments, including rapid maturation, relatively long life and large size (allowing them to reproduce many times in large batches), batch spawning, genotype and phenotype (having plasticity in their genetic expression), tolerance to a wide range of water quality, broad diet, and multiple dispersal periods. There is, however, variability among these characteristics between the native, non-native North American, and European non-native populations, which presents a challenge to managing populations based on life history characteristics. Monitoring and preventative strategies are important because, based on Ruffe’s variable life history strategies and its recent range expansion, all of the Laurentian Great Lakes and many other water bodies in the UK, Europe, and Norway are vulnerable to Ruffe establishment.

Acoustic Detection Reveals Fine-Scale Distributions ofMyotis lucifugus, Myotis septentrionalis, andPerimyotis subflavusin Eastern Nebraska

Before white-nose syndrome arrives in Nebraska, it is important to document the preexposure distributions of cave bats in the state. We examined the distributions of Myotis lucifugus (little brown myotis), Myotis septentrionalis (northern long-eared myotis), and Perimyotis subflavus (tri-colored bat) in eastern Nebraska by setting acoustic detectors for a single night at 105 sites in wooded habitats during summers of 2012 and 2014. We compared 2 methods of determining presence at each site. Results of our analyses are fine-scale distributional maps for these bats and some range extensions from published records. Results for M. septentrionalis and P. subflavus are largely consistent with previous reports. Results for M. lucifugus vary depending on the method of determining presence; however, our preferred method creates a pattern consistent with the known vouchered distribution of this species. The differences between published distributions of these species and distributions based on acoustic detection from our study might result from a lack of extensive netting in many areas of eastern Nebraska, underrepresentation of P. subflavus from mist net surveys in Nebraska, and a recent westward range expansion of P. subflavus and M. septentrionalis in southern Nebraska.

Recent range expansion of a terrestrial orchid corresponds with climate-driven variation in its population dynamics.

The population dynamics and distribution limits of plant species are predicted to change as the climate changes. However, it remains unclear to what extent climate variables affect population dynamics, which vital rates are most sensitive to climate change, and whether the same vital rates drive population dynamics in different populations. In this study, we used long-term demographic data from two populations of the terrestrial orchid Himantoglossum hircinum growing at the northern edge of their geographic range to quantify the influence of climate change on demographic vital rates. Integral projection models were constructed to study how climate conditions between 1991 and 2006 affected population dynamics and to assess how projected future climate change will affect the long-term viability of this species. Based on the parameterised vital rate functions and the observed climatic conditions, one of the studied populations had an average population growth rate above 1 (λ=1.04), while the other was declining at ca. 3% year(-1) (λ=0.97). Variation in temperature and precipitation mainly affected population growth through their effect on survival and fecundity. Based on UK Climate Projection 2009 estimates of future climate conditions for three greenhouse gas emission scenarios, population growth rates are expected to increase in one of the studied populations. Overall, our results indicate that the observed changes in climatic conditions appeared to be beneficial to the long-term survival of the species in the UK and suggest that they may have been the driving force behind the current range expansion of H. hircinum in England.

Cranial variability of the Serbian golden jackal: Geographic variation, sexual dimorphism and allometry

Geometric morphometric approaches were employed for the first time to explore skull size and shape changes in golden jackal (Canis aureus) from Serbia. We examined three different, but connected aspects of its cranial variability: geographic variation, sexual dimorphism and allometry. To elucidate the pattern of cranial size and shape variation, we analyzed ventral crania of subadults and adults from two geographic regions of Serbia. For both age groups there were no significant size, but significant shape differences between golden jackals from northeastern and central Serbia. The observed shape differences were subtle, probably due to recent range expansion of this species in the Balkans and a strong founder effect in the newly established populations. The detected significant sexual size and shape dimorphisms (SSD and SShD) were slight and more evident in adult crania. Although the SShD observed in adult crania is influenced by SSD, factors responsible for the non-allometric component of shape variation, and not pure size differences between sexes, are those that are most important for generation of SShD in this species. A monogamous reproductive system, male parental care, omnivorous and opportunistic feeding behavior and the absence of division of labor between males and females in activities other than parental care, could all be related to the driving of morphological similarity between the sexes.

Widespread range expansions shape latitudinal variation in insect thermal limits

Research now shows that broad thermal niches observed in high-latitude ectotherms apply only to species undergoing range expansion or invasion. Non-range-expanding species are therefore unlikely to tolerate climatic warming at high latitudes. Current anthropogenic impacts, including habitat modification and climate change, may contribute to a sixth mass extinction1. To mitigate these impacts and slow further losses of biodiversity, we need to understand which species are most at risk and identify the factors contributing to current and future declines. Such information is often obtained through large-scale, comparative and biogeographic analysis of lineages or traits that are potentially sensitive to ongoing anthropogenic change—for instance to predict which regions are most susceptible to climate change-induced biodiversity loss2,3,4. However, for this approach to be generally successful, the underlying causes of identified geographical trends need to be carefully considered5. Here, I augment and reanalyse a global data set of insect thermal tolerances, evaluating the contribution of recent and contemporary range expansions to latitudinal variation in thermal niche breadth. Previous indications that high-latitude ectotherms exhibit broad thermal niches and high warming tolerances held only for species undergoing range expansions or invasions. In contrast, species with stable or declining geographic ranges exhibit latitudinally decreasing absolute thermal tolerances and no latitudinal variation in tolerance breadths. Thus, non-range-expanding species, particularly insular or endemic species, which are often of highest conservation priority, are unlikely to tolerate future climatic warming at high latitudes.

Connectivity in the cold: the comparative population genetics of vent-endemic fauna in the Scotia Sea, Southern Ocean.

We report the first comparative population genetics study for vent fauna in the Southern Ocean using cytochrome C oxidase I and microsatellite markers. Three species are examined: the kiwaid squat lobster, Kiwa tyleri, the peltospirid gastropod, Gigantopelta chessoia, and a lepetodrilid limpet, Lepetodrilus sp., collected from vent fields 440km apart on the East Scotia Ridge (ESR) and from the Kemp Caldera on the South Sandwich Island Arc, ~95km eastwards. We report no differentiation for all species across the ESR, consistent with panmixia or recent range expansions. A lack of differentiation is notable for Kiwa tyleri, which exhibits extremely abbreviated lecithotrophic larval development, suggestive of a very limited dispersal range. Larval lifespans may, however, be extended by low temperature-induced metabolic rate reduction in the Southern Ocean, muting the impact of dispersal strategy on patterns of population structure. COI diversity patterns suggest all species experienced demographic bottlenecks or selective sweeps in the past million years and possibly at different times. ESR and Kemp limpets are divergent, although with evidence of very recent ESR-Kemp immigration. Their divergence, possibility indicative of incipient speciation, along with the absence of the other two species at Kemp, may be the consequence of differing dispersal capabilities across a ~1000m depth range and/or different selective regimes between the two areas. Estimates of historic and recent limpet gene flow between the ESR and Kemp are consistent with predominantly easterly currents and potentially therefore, cross-axis currents on the ESR, with biogeographic implications for the region.

Genetic Population Structure of the Japanese Grass Lizard, Takydromus tachydromoides (Reptilia: Squamata), Inferred from Mitochondrial Cytochrome b Variations

Abstract We investigated the genetic population structure of the Japanese grass lizard, Takydromus tachydromoides, based on polymerase chain reaction—restriction fragment length polymorphisms (PCR-RFLPs) and DNA sequence analyses of the mitochondrial cytochrome b gene. The PCR-RFLP analysis of 163 specimens collected from the main islands of Japan and the adjacent islands identified a total of 25 mitochondrial haplotypes (mitotypes). The phylogeny of the mitotypes revealed that Osumi and Tokara Island populations were remarkably diverged from all other populations on the main islands of Japan. Furthermore, several regional groups were also recognized at the western part of Japan, namely mitotype groups in Kyushu, those in the western Honshu, and those in the central Honshu and Shikoku. In contrast, little genetic diversity was observed throughout eastern Japan. The regional genetic differentiation and recent range expansion of this species are considered to be associated with past geological events and cl...

Rangewide genetic analysis of Lesser Prairie-Chicken reveals population structure, range expansion, and possible introgression

The distribution of the Lesser Prairie-Chicken (Tympanuchus pallidicinctus) has been markedly reduced due to loss and fragmentation of habitat. Portions of the historical range, however, have been recolonized and even expanded due to planting of conservation reserve program (CRP) fields that provide favorable vegetation structure for Lesser Prairie-Chickens. The source population(s) feeding the range expansion is unknown, yet has resulted in overlap between Lesser and Greater Prairie-Chickens (T. cupido) increasing the potential for hybridization. Our objectives were to characterize connectivity and genetic diversity among populations, identify source population(s) of recent range expansion, and examine hybridization with the Greater Prairie-Chicken. We analyzed 640 samples from across the range using 13 microsatellites. We identified three to four populations corresponding largely to ecoregions. The Shinnery Oak Prairie and Sand Sagebrush Prairie represented genetically distinct populations (F ST > 0.034 and F ST > 0.023 respectively). The Shortgrass/CRP Mosaic and Mixed Grass ecoregions appeared admixed (F ST = 0.009). Genetic diversity was similar among ecoregions and N e ranged from 142 (95 % CI 99–236) for the Shortgrass/CRP Mosaic to 296 (95 % CI 233–396) in the Mixed Grass Prairie. No recent migration was detected among ecoregions, except asymmetric dispersal from both the Mixed Grass Prairie and to a lesser extent the Sand Sagebrush Prairie north into adjacent Shortgrass/CRP Mosaic (m = 0.207, 95 % CI 0.116–0.298, m = 0.097, 95 % CI 0.010–0.183, respectively). Indices investigating potential hybridization in the Shortgrass/CRP Mosaic revealed that six of the 13 individuals with hybrid phenotypes were significantly admixed suggesting hybridization. Continued monitoring of diversity within and among ecoregions is warranted as are actions promoting genetic connectivity and range expansion.

Beyond Serial Founder Effects: The Impact of Admixture and Localized Gene Flow on Patterns of Regional Genetic Diversity.

Geneticists have argued that the linear decay in within-population genetic diversity with increasing geographic distance from East Africa is best explained by a phylogenetic process of repeated founder effects, growth, and isolation. However, this serial founder effect (SFE) process has not yet been adequately vetted against other evolutionary processes that may also affect geospatial patterns of diversity. Additionally, studies of the SFE process have been largely based on a limited 52-population sample. Here, we assess the effects of founder effect, admixture, and localized gene flow processes on patterns of global and regional diversity using a published data set of 645 autosomal microsatellite genotypes from 5,415 individuals in 248 widespread populations. We used a formal tree-fitting approach to explore the role of founder effects. The approach involved fitting global and regional population trees to extant patterns of gene diversity and then systematically examining the deviations in fit. We also informally tested the SFE process using linear models of gene diversity versus waypoint geographic distances from Africa. We tested the role of localized gene flow using partial Mantel correlograms of gene diversity versus geographic distance controlling for the confounding effects of treelike genetic structure. We corroborate previous findings that global patterns of diversity, both within and between populations, are the product of an out-of-Africa SFE process. Within regions, however, diversity within populations is uncorrelated with geographic distance from Africa. Here, patterns of diversity have been largely shaped by recent interregional admixture and secondary range expansions. Our detailed analyses of the pattern of diversity within and between populations reveal that the signatures of different evolutionary processes dominate at different geographic scales. These findings have important implications for recent publications on the biology of race.

Phylogeography of the bobwhite (Colinus) quails

ABSTRACTThe bobwhites (Colinus) consist of 3 grassland‐associated, allopatric species of New World quails (family Odontophoridae): the northern bobwhite (C. virginianus), distributed from the eastern United States to Guatemala; the black‐throated bobwhite (C. nigrogularis), which occurs in scattered localities in the Yucatán Peninsula, Nicaragua, and Honduras; and the crested bobwhite (C. cristatus), whose range stretches from Guatemala to northern Brazil. We used mitochondrial DNA (mtDNA) sequences from both the control region and the ND2 gene to study the phylogenetic relationships and phylogeography of the 3 bobwhite species. We developed ecological niche models to evaluate conclusions inferred from genetic data. Colinus was composed of 2 deeply divergent lineages, 1 represented by the crested bobwhite and the other by northern and black‐throated bobwhites, both of which were genetically distinct from each other. Although the northern bobwhite had high haplotype diversity, this species exhibited evidence of past demographic and geographic expansion, no phylogeographic structure, and no congruence between genetic variation and subspecies taxonomy. Ecological niche modeling was congruent with a recent range expansion for the northern bobwhite from Late Pleistocene refugia in México and the southern United States. The black‐throated bobwhites from the Yucatán Peninsula were distinct from those in Nicaragua, and as a whole this species displayed little evidence of recent expansion. Ecological niche modeling suggested that the current, fragmented distribution of the black‐throated bobwhite has existed for the past 130,000 years. Although the crested bobwhite displayed little evidence of population expansion, the mtDNA data revealed 3–4 geographically and genetically distinct lineages. Results of niche modeling suggest that the crested bobwhite had a much wider distribution in Central and South America during the Last Glacial Maximum. Given the sensitivity of all 3 bobwhite species to climatic cycles, managers should consider impacts of climate change in addition to the loss of habitat when crafting conservation plans. © 2015 The Wildlife Society.

Nucleotide polymorphism and phylogeographic history of an endangered conifer species Pinus bungeana

Pinus bungeana Zucc. ex Endl. (Pinaceae), is an endangered conifer tree species and is endemic to western central China. In this study, we detected the nucleotide polymorphism and phylogeographic history of P. bungeana based on three nuclear genes. We collected 16 natural populations and covered the entire distributional ranges of P. bungeana. We found that this endangered species have extremely low level of nucleotide diversity (πt = 0.00098, πsil = 0.00229) compared with that of other conifers. Meanwhile, hierarchical AMOVA revealed that genetic variations of two nuclear loci (010054_01 and 0_12329_02) mainly occurred among populations (54% and 55%), and another locus (0_14221_01) existed within populations (64%). This finding may be caused by random fixation of nuclear genes. Neutrality tests and mismatch analysis suggested that P. bungeana may have experienced the recent range expansion. In addition, high genetic diversity and unique haplotypes were identified in the west areas of Qinling-Daba and Lvliang Mountains, and these areas may be the glacial refuges of P. bungeana. After the glaciation, the species expanded or migrated outward from these refuges, and the founder effect or bottleneck effect in this process may have resulted in the low level of nucleotide polymorphism of P. bungeana.

Prolonged pupal diapause drives population dynamics of the pine processionary moth (Thaumetopoea pityocampa) in an outbreak expansion area

Due to its negative impact on tree growth and human health, pine processionary moth is a major concern for forest managers, especially in recent outbreak expansion areas. As some individuals have prolonged diapause for more than a single year, population dynamics of this species is hard to understand. To decipher the mechanism of prolonged diapause and its role in population dynamics, we started a pest surveillance program in 1999 in a pine processionary population in the southern-central Alps of northern Italy, a recent range expansion zone for the species. The 16-year study used a pheromone trap network and four large rearing cages. We found some individuals could diapause for up to a maximum of seven years. With few exceptions, prolonged pupal diapause increased and retrieval rate of moth in cages decreased with increasing elevation. Moreover, we found prolonged diapausing individuals to emerge in advance of non-diapausing individuals. This trait allowed us to infer the proportion of prolonged diapausing individuals caught in the pheromone traps. Prolonged diapause was responsible for maintaining high population density for eight years in spite of annual applications of the biocontrol agent Bacillus thuringiensis kurstaki. This sustained density relied on individuals from cohorts before the application of insecticide started, and from cohorts not completely suppressed by the insecticide applications.

Mitochondrial DNA panmixia in the little brown seastar Echinaster spinulosus suggests a recent population expansion

In North America, the Atlantic-Gulf discontinuity depicts genetic breaks between populations distributed along the Florida peninsula. This study examines 83 specimens of E. spinulosus obtained from seven locations along the Florida coast to examine phylogeographic patterns, population structure and examine historical demographic patterns. Analyses of 511 bp from the cytochrome oxidase 1 (COI) mitochondrial gene inferred no significant genetic structure for E. spinulosus along either side of the Florida coast nor was there a genetic discontinuity associated with a “Gulf-Atlantic” split. Population-based statistical analyses revealed no significant degree of genetic differentiation (Fst, p < 0.05) among populations, thus indicating substantial gene flow. Similarly, summary statistics (Fu’s Fs, mismatch distributions) were significant indicating that there has been a population increase in the recent past. Recent range expansion, possibly due to a leading edge effect, combined with some level of contemporary larval mixing seems to be the main source of panmixia in this species.

Testing the enemy release hypothesis in a native insect species with an expanding range.

The enemy release hypothesis (ERH) predicts that the spread of (invasive) species will be facilitated by release from their enemies as they occupy new areas. However, the ERH is rarely tested on native (non-invasive, long established) species with expanding or shifting ranges. I tested the ERH for a native damselfly (Enallagma clausum) whose range has recently expanded in western Canada, with respect to its water mite and gregarine parasites. Parasitism levels (prevalence and intensity) were also compared between E. clausum and a closely related species, Enallagma boreale, which has long been established in the study region and whose range is not shifting. A total of 1,150 damselflies were collected at three ‘old’ sites for E. clausum in Saskatchewan, and three ‘new’ sites in Alberta. A little more than a quarter of the damselflies collected were parasitized with, on average, 18 water mite individuals, and 20% were parasitized by, on average, 10 gregarine individuals. I assessed whether the differences between levels of infection (prevalence and intensity) were due to site type or host species. The ERH was not supported: Enallagma clausum has higher or the same levels of parasitism in new sites than old sites. However, E. boreale seems to be benefitting from the recent range expansion of a native, closely related species through ecological release from its parasites because the parasites may be choosing to infest the novel, potentially naïve, host instead of the well-established host.

Population genetic structure of Indian oil sardine, Sardinella longiceps along Indian coast

Genetic stock structure and historical demography of Indian oil sardine, a commercially and ecologically important small pelagic fish, was studied using mitochondrial control region and Cytochrome C Oxidase I (COI) sequences. A 758bp portion of the control region in 287 individuals and a 576bp portion of the COI gene in 291individuals from 10 locations along the distribution range were amplified resulting in 236 and 84 haplotypes, respectively. The high haplotype and low nucleotide diversity values (0.99 and 0.19 for control region and 0.85 and 0.004 for COI, respectively) are characteristic of populations having undergone a demographic expansion. Genetic differentiation, ΦST, was low and insignificant between populations using both control region and COI gene markers. Mismatch analysis showed a recent demographic and spatial expansion coinciding with the late Pleistocene epoch. Mantel tests revealed the lack of isolation by distance which is attributable either to high levels of migration overriding the effect of genetic drift or to insufficient time for accomplishing a balance between migration and drift after a recent range expansion.