Novel polymorphic microsatellite loci for distinguishing rock bass (<Emphasis Type="Italic">Ambloplites rupestris</Emphasis>), Roanoke bass (<Emphasis Type="Italic">Ambloplites cavifrons</Emphasis>), and their hybrids

The rock bass (Ambloplites rupestris) is a popular sport-fish native to the Mississippi and Great Lakes basins of North America. The species has been widely introduced outside its native range, including into Atlantic-slope streams of Virginia where it may hybridize with an imperiled, similar-looking congener, the Roanoke bass (Ambloplites cavifrons). In this study, we identified and evaluated novel molecular markers to facilitate identification of these species and study the extent of hybridization. Using molecular libraries developed from A. rupestris, we identified a suite of candidate nuclear microsatellite loci, synthesized primer sets, and tested these markers for amplification and polymorphism in populations of both species. We then calculated standard diversity statistics within and differentiation statistics between species, the latter providing an indication of marker power for distinguishing the species and their hybrids. Additionally, we evaluated our efficiency for identifying hybrids by classifying simulated genotypes of known ancestry. Eleven loci were polymorphic (2–22 alleles per locus) and reliably amplified in both species. Multilocus genetic differentiation between A. cavifrons and A. rupestris was quite high (F _ST  = 0.66; D _LR  = 19.3), indicating the high statistical power of this marker set for species and hybrid identification. Analyses of simulated data suggested these markers reliably distinguish between hybrids and non-hybrids, as well as between F1 hybrids and backcrossed individuals. This panel of 11 loci should prove useful for understanding patterns of hybridization between A. rupestris and A. cavifrons. As the first microsatellite markers developed for Ambloplites, these markers also should prove broadly useful for population genetic studies of this genus.     

Contribution to the biology of germination of four species ofChenopodium album agg. under different condition

The study investigated various factors stimulating germination of seeds of four species ofChenopodium album agg.—C. album L. s. str.,C. ficifolium Sm.,C. strictum Roth,C. suecicum J. Murr. These factors were: storage in wet and cold, alternating temperature, nitrates mainly in combination with light and, to a lesser degree, the duration of chilling. Germination was inhibited by darkness, which was most marked with seeds ofC. strictum. The effect of alternating temperature was better on the germination ofC. ficifolium andC. suecicum than on that ofC. album andC. strictum. We also discussed several differences in specific reactions of the individual species to the factors under consideration.     

Molecular analyses of <Emphasis Type="Italic">Ficus erecta</Emphasis> and its allies within the subsection <Emphasis Type="Italic">Frutescentiae</Emphasis> (Moraceae)

Ficus (Moraceae) is a keystone group in tropical and subtropical forests with remarkable diversity of species and taxonomical challenges as a consequence of fig–pollinator coevolution. Ficus subsect. Frutescentiae includes about 30 species that are predominantly shrubs or small trees with Terminalia branching. Many of these species are difficult to delimit morphologically, and the group includes a tangle of uncertain taxa and incorrectly applied names. We conducted a phylogenetic analysis with internal and external transcribed spacer data (ITS and ETS) and data from 18 polymorphic microsatellite loci to evaluate the species status of the most perplexing members of this subsection. The results confirm the monophyly of subsect. Frutescentiae, with F. pedunculosa as sister to the rest. The F. erecta complex comprises approximately 17 taxa: F. erecta, F. abelii, F. boninsimae, F. nishimurae, F. iidaiana, F. gasparriniana var. laceratifolia, F. gasparriniana var. viridescens, F. pyriformis, F. stenophylla, F. fusuiensis, F. fengkaiensis, F. sinociliata, F. tannoensis, F. vaccinioides, F. formosana, F. pandurata, and F. periptera. The last five of these were supported as good species, while the others were not well supported by the present evidence. Evidence also supported the status of the non-F. erecta complex species including. F. pedunculosa, F. ischnopoda, F. heteromorpha, and F. variolosa. Ficus filicauda and F. neriifolia are possibly conspecific. The species status of F. potingensis should be restored and it should be treated as a member of section Eriosycea. Identification of the remaining taxa (F. gasparriniana var. esquirolii, F. ruyuanensis, F. daimingshanensis, F. chapaensis, F. changii, F. trivia, and F. tuphapensis) and their relationships to the F. erecta complex were not clarified. As a whole, only ten species in this subsection are confirmed, one is excluded, one is synonymous, and the others are either unresolved or short of samples. There appears to be a consistent genetic background among these unresolved groups, which suggests that repeated hybridization (as a result of pollinator host shifts) has filled up the interspecific gaps during the fig–pollinator coevolution process.     

Phenotypic,Genetic, and Cytogenetic Evidence of Hybridization Between Species of Trans-Andean Tamarins (Genus <Emphasis Type="Italic">Saguinus</Emphasis>)

Incomplete reproductive isolation and hybridization is relatively frequent in primates. However, no cases of hybridization between formally recognized species have been reported in tamarins (genus Saguinus), a highly specious group of Neotropical primates. Here, we provide evidence from different sources to demonstrate three cases of hybridization in captivity between species of Saguinus distributed west of the Andes (trans-Andean). To do this, we described fur color patterns, genotyped 12 microsatellite loci, sequenced the mitochondrial hypervariable region I, and generated chromosomal R bands for the three formally recognized species and the new hybrids of trans-Andean tamarins. We identified one case of interbreeding between the white-footed tamarin (Saguinus leucopus) and the cotton-top tamarin (S. ?dipus) and two independent reciprocal crosses of S. leucopus and the Geoffroy’s tamarin (S. geoffroyi). All these hybrids exhibit intermediate phenotypes between parental species, and genetic data are consistent with first-generation hybridization. Cytogenetic data suggest that the S. leucopus × S. ?dipus hybrid is sterile, as it is a female with XY karyotype apparently affected by a condition known as gonadal dysgenesis. Trans-Andean tamarin species occur in northwest Colombia with parapatric distributions bounded by major rivers. Potential contact zones, either natural or anthropogenic, might facilitate hybridization in the wild, but this scenario remains to be assessed. Our findings warrant future studies focused on the evolutionary mechanisms of reproductive isolation in tamarins. Given the risk of hybridization, caution should be taken in management and conservation of tamarins.     

Genomic clues to the parental origin of the wild flowering cherry <Emphasis Type="Italic">Prunus yedoensis</Emphasis> var. <Emphasis Type="Italic">nudiflora</Emphasis> (Rosaceae)

Prunus yedoensis Matsumura is one of the popular ornamental flowering cherry trees native to northeastern Asia, and its wild populations have only been found on Jeju Island, Korea. Previous studies suggested that wild P. yedoensis (P. yedoensis var. nudiflora) is a hybrid species; however, there is no solid evidence on its exact parental origin and genomic organization. In this study, we developed a total of 38 nuclear gene-based DNA markers that can be universally amplifiable in the Prunus species using 586 Prunus Conserved Orthologous Gene Set (Prunus COS). Using the Prunus COS markers, we investigated the genetic structure of wild P. yedoensis populations and evaluated the putative parental species of wild P. yedoensis. Population structure and phylogenetic analysis of 73 wild P. yedoensis accessions and 54 accessions of other Prunus species revealed that the wild P. yedoensis on Jeju Island is a natural homoploid hybrid. Sequence-level comparison of Prunus COS markers between species suggested that wild P. yedoensis might originate from a cross between maternal P. pendula f. ascendens and paternal P. jamasakura. Moreover, approximately 81% of the wild P. yedoensis accessions examined were likely F1 hybrids, whereas the remaining 19% were backcross hybrids resulting from additional asymmetric introgression of parental genotypes. These findings suggest that complex hybridization of the Prunus species on Jeju Island can produce a range of variable hybrid offspring. Overall, this study makes a significant contribution to address issues of the origin, nomenclature, and genetic relationship of ornamental P. yedoensis.     

Speciation of Eversmann and Mongolian hamsters (<Emphasis Type="Italic">Allocricetulus</Emphasis>, Cricetinae): Experimental hybridization

Contrary to the pre-existing concepts based on morphological and karyological data on the impossibility of hybridization between hamster species of the genus Allocricetulus (A. curtatus and A. eversmanni), F1 hybrids in both combinations, and backcrosses, were obtained for the first time. Some restrictions of hybridization between females of A. eversmanni and males of A. curtatus were detected. Analysis of the synaptonemal complex in the hybrids produced by crossing a female of A. curtatus with a male of A. eversmanni demonstarted that a significant portion of the cells was subject to arrest and selection at the stage of meiosis prophase I. Nevertheless, some spermatocytes still generate viable spermatozoa. Thus, the possibility of hybridization in the laboratory between two Allocricetulus species with different numbers of chromosomes may testify to a relatively low divergence between them.     

<Emphasis Type="Italic">Bruguiera hainesii</Emphasis>, a critically endangered mangrove species,is a hybrid between <Emphasis Type="Italic">B. cylindrica</Emphasis> and <Emphasis Type="Italic">B. gymnorhiza</Emphasis> (Rhizophoraceae)

Bruguiera hainesii (Rhizophoraceae) is one of the two Critically Endangered mangrove species listed in the IUCN Red List of Threatened Species. Although the species is vulnerable to extinction, its genetic diversity and the evolutionary relationships with other Bruguiera species are not well understood. Also, intermediate morphological characters imply that the species might be of hybrid origin. To clarify the genetic relationship between B. hainesii and other Bruguiera species, we conducted molecular analyses including all six Bruguiera species using DNA sequences of two nuclear genes (CesA and UNK) and three chloroplast regions (intergenic spacer regions of trnL-trnF, trnS-trnG and atpB-rbcL). For nuclear DNA markers, all nine B. hainesii samples from five populations were heterozygous at both loci, with one allele was shared with B. cylindrica, and the other with B. gymnorhiza. For chloroplast DNA markers, the two haplotypes found in B. hainesii were shared only by B. cylindrica. These results suggested that B. hainesii is a hybrid between B. cylindrica as the maternal parent and B. gymnorhiza as the paternal one. Furthermore, chloroplast DNA haplotypes found in B. hainesii suggest that hybridization has occurred independently in regions where the distribution ranges of the parental species meet. As the IUCN Red List of Threatened Species currently excludes hybrids (except for apomictic plant hybrids), the conservation status of B. hainesii should be reconsidered.     

Molecular and cytological analyses of A and C genomes at meiosis in synthetic allotriploid <Emphasis Type="Italic">Brassica</Emphasis> hybrids (ACC) between <Emphasis Type="Italic">B.napus</Emphasis> (AACC) and <Emphasis Type="Italic">B.oleracea</Emphasis> (CC)

Success of interspecific hybridization relies mostly on the adequate similarity between the implicated genomes to ensure synapsis, pairing and recombination between appropriate chromosomes during meiosis in allopolyploid species. Allotetraploid Brassica napus (AACC) is a model of natural hybridization between Brassica rapa (AA) and Brassica oleracea (CC), which are originally derived from a common ancestor, but genomic constitution of the same chromosomes probably varied among these species through time after establishment, giving rise to cytogenetic difference in the synthetic hybrids. Herein we investigated meiotic behaviors of A and C chromosomes of synthetic allotriploid Brassica hybrids (ACC) at molecular and cytological levels, which result from the interspecific cross between natural B. napus (AACC) and B.oleracea (CC), and the results showed that meiosis course was significantly aberrant in allotriploid Brassica hybrids, and chromosomes aligned chaotically at metaphase I, chromosome bridges and lags were frequently observed from later metaphase I to anaphase II during meiosis. Simultaneously, we also noticed that meiosis-related genes were abruptly down-regulated in allotriploid Brassica hybrids, which likely accounted for irregular scenario of meiosis observed in these synthetic hybrids. Therefore, these results indicated that inter-genomic exchanges of A and C chromosomes could occur frequently in synthetic Brassica hybrids, and provided an efficient approach for genetic changes of homeologous chromosomes during meiosis in polyploid B.napus breeding program.     

Microsatellite analysis supports the existence of three cryptic species within the bumble bee <Emphasis Type="Italic">Bombus lucorum sensu lato</Emphasis>

Mitochondrial cytochrome oxidase I (COI) partial sequences are widely used in taxonomy for species identification. Increasingly, these sequence identities are combined with modelling approaches to delineate species. Yet the validity of species delineation based on such DNA ‘barcodes’ is rarely tested and may be called into question by phenomena such as ancestral polymorphisms in DNA sequences, phylogeographic divergence, mitochondrial introgression and hybridization, or distortion of mitochondrial inheritance through such factors as Wolbachia infection. The common and widespread European bumble bee Bombus lucorum s. lato contains three distinct mitochondrial DNA lineages that are assumed to represent three cryptic species, namely Bombus cryptarum, B. lucorum s. str. and B. magnus. To test whether nuclear gene pools of the three putative species were differentiated, we genotyped 304 sympatric members of the lucorum complex (54 B. cryptarum females, 168 B. lucorum s. str. females and 82 B. magnus females, as defined using mtDNA COI haplotypes) from 11 localities spread across the island of Ireland at seven nuclear microsatellite loci. Multilocus genotypes clustered into three discrete groups that largely corresponded to the three mtDNA lineages: B. cryptarum, B. lucorum s. str. and B. magnus. The good fit of mitochondrial haplotype to nuclear (microsatellite) genotypic data supports the view that these three bumble bee taxa are reproductively isolated species, as well as providing a vindication of species identity using so-called DNA barcodes.     

Displacement of native Patagonian freshwater silverside populations (<Emphasis Type="Italic">Odontesthes hatcheri</Emphasis>, Atherinopsidae) by introgressive hybridization with introduced <Emphasis Type="Italic">O. bonariensis</Emphasis>

The Patagonian silverside Odontesthes hatcheri is a native fish restricted to streams and lakes of Patagonia (Argentina and Chile). Stocking programs to enhance recreational fisheries in man-made reservoirs have introduced a nonnative, closely-related species (the pejerrey O. bonariensis) in Patagonia almost a century ago, and yet little is known about the invasiveness of this species. To evaluate the impact of these introductions we analyze genetic data (microsatellite markers and mitochondrial DNA) to quantify the incidence of hybridization between these two species and assess potential effects on native population structure. Phylogeographic analyses reveal weak geographic differentiation among populations of O. hatcheri, in agreement with previous studies for other freshwater fishes in Patagonia strongly influenced by Quaternary glaciations and hydrographic basin changes since the last glaciation. However, many populations have unique genetic pools. In several areas, introductions resulted in extensive hybridization, with high frequencies of F2 and backcrossed hybrids in natural populations, and in some cases O. bonariensis has completely displaced the native populations. The negative impact of these introductions on native populations is correlated to temperature, a critical parameter in the face of global warming, suggesting that invasiveness of O. bonariensis may increase in the future. Our results advise against continuing stocking programs to preserve the integrity of natural populations of the Patagonian silverside.     

Hybridization rate and genotypic diversity of apomictic hybrids between native (<Emphasis Type="Italic">Taraxacum japonicum</Emphasis>) and introduced (<Emphasis Type="Italic">T. officinale</Emphasis>) dandelions in western Japan

Hybridization between the introduced and native plants may enhance invasiveness, especially in asexually reproducing species. Hybrid apomictic dandelions between native (Taraxacum platycarpum and T. japonicum) and exotic (T. officinale) species are distributed widely throughout Japan. To estimate the origin(s) and dispersal of the hybrids, we investigated the hybridization rate and genotypic diversity in mixed populations of T. japonicum, T. officinale and their hybrids at two green parks in western Japan. Among the plants identified as exotics from flower morphology, 86–96% were hybrids by genetic analysis. Genetic data with simple sequence repeat markers revealed a high clonal diversity of the hybrid both within and between populations, indicating multiple origins. A hybrid seed was found from among the 1891 seeds collected from T. japonicum in the parks, indicating ongoing hybridization in the field. T. officinale and hybrids were genetically differentiated between the two parks independent of the ploidy level; the allele frequency of T. officinale and tri- and tetraploid hybrids were similar within each park but different between the two parks. This suggests that the origins of hybrids were similar within the park but different between the parks. Overall, our results suggest that hybridization, including backcross, is an ongoing process, and that genetically diverse hybrids with various origins have been spreading in western Japan, probably because hybridization enhanced invasiveness at native habitat.     

Chemical and molecular identification of the invasive termite <Emphasis Type="Italic">Zootermopsis nevadensis</Emphasis> (Isoptera: Archotermopsidae) in Japan

Numerous termite species have been introduced outside their native ranges by human transport, and some have become invasive. The dampwood termite Zootermopsis nevadensis (Hagen), which is native to western North America, has been introduced to and become established in Kawanishi City, Hyogo Prefecture, Japan. Zootermopsis nevadensis is subdivided into two subspecies based on cuticular hydrocarbon (CHC) phenotypes: Z. nevadensis nevadensis and Z. nevadensis nuttingi (Haverty and Thorne). Here, we identified Z. nevadensis in Japan as hybrids between the two subspecies. Chemical analysis showed the presence of 7,15-dimethylhenicosane and 5,17-dimethylhenicosane in the CHCs of Z. nevadensis in Japan, corresponding to the CHC phenotype of Z. n. nevadensis. Conversely, all mitochondrial cytochrome c oxidase subunit I sequences of Z. nevadensis in Japan were identical to sequences from Z. n. nuttingi and hybrids between the two subspecies from a native hybrid zone in California, USA. In addition, phylogenetic analysis showed that Z. nevadensis in Japan formed a clade with Z. n. nuttingi and hybrids between the two subspecies. Our results show discordance between the chemical and genetic features of Z. nevadensis in Japan, indicating that individuals of Z. nevadensis in Japan are hybrids between the two subspecies.     

<Emphasis Type="Italic">Tamarix</Emphasis> (Tamaricaceae) hybrids: the dominant invasive genotype in southern Africa

Hybridization is regarded as a rapid mechanism for increasing genetic variation that can potentially enhance invasiveness. Tamarix hybrids appear to be the dominant genotypes in their invasions. Exotic Tamarix are declared invasive in South Africa and the exotic T. chinensis and T. ramosissima are known to hybridize between themselves, and with the indigenous T. usneoides. However, until now, it was not known which species or hybrid is the most prevalent in the invasion. With a biocontrol programme being considered as a way of suppressing the alien Tamarix populations, it is important to document the population genetic dynamics of all species in the region. This investigation sought to identify Tamarix species in southern Africa and their hybrids, describe their population structure, and reveal the geographic origin of the invasive species. To achieve this, nuclear Internal Transcribed Spacer (ITS) sequence data and the multilocus Amplified Fragment Length Polymorphisms (AFLPs) markers were used. Phylogenetic analysis and population genetic structure confirmed the presence of three species in South Africa (T. chinensis, T. ramosissima and T. usneoides) with their hybrids. The indigenous T. usneoides is clearly genetically distant from the alien species T. chinensis and T. ramosissima. Interestingly, the Tamarix infestation in South Africa is dominated (64.7 %) by hybrids between T. chinensis and T. ramosissima. The exotic species match their counterparts from their places of origin in Eurasia, as well as those forming part of the invasion in the US.     

Taxonomic revisions in the Microstromatales: two new yeast species,two new genera,and validation of <Emphasis Type="Italic">Jaminaea</Emphasis> and two <Emphasis Type="Italic">Sympodiomycopsis</Emphasis> species

Environmental sampling yielded two yeast species belonging to Microstromatales (Exobasidiomycetes, Ustilaginomycotina). The first species was collected from a leaf phylloplane infected by the rust fungus Coleosporium plumeriae, and represents a new species in the genus Jaminaea, for which the name Jaminaea rosea sp. nov. is proposed. The second species was isolated from air on 50% glucose media and is most similar to Microstroma phylloplanum. However, our phylogenetic analyses reveal that species currently placed in Microstroma are not monophyletic, and M. phylloplanum, M. juglandis and M. albiziae are not related to the type species of this genus, M. album. Thus, Pseudomicrostroma gen. nov. is proposed to accommodate the following species: P. glucosiphilum sp. nov., P. phylloplanum comb. nov. and P. juglandis comb. nov. We also propose Parajaminaea gen. nov. to accommodate P. albizii comb. nov. and P. phylloscopi sp. nov. based on phylogenetic analyses that show these are not congeneric with Jaminaea or Microstroma. In addition, we validate the genus Jaminaea, its respective species and two species of Sympodiomycopsis and provide a new combination, Microstroma bacarum comb. nov., for the anamorphic yeast Rhodotorula bacarum. Our results illustrate non-monophyly of Quambalariaceae and Microstromataceae as currently circumscribed. Taxonomy of Microstroma and the Microstromataceae is reviewed and discussed. Finally, analyses of all available small subunit rDNA sequences for Jaminaea species show that J. angkorensis is the only known species that possess a group I intron in this locus, once considered a potential feature indicating the basal placement of this genus in Microstromatales.     

Pattern of natural introgression in a <Emphasis Type="Italic">Nothofagus</Emphasis> hybrid zone from South American temperate forests

Interspecific gene flow is a common phenomenon in Nothofagaceae species; however, the dynamics of introgression in hybrid zones remains largely unknown. We focused on two ecologically and morphologically different Nothofagus species from Patagonia, Nothofagus nervosa and Nothofagus obliqua. In a natural hybrid zone, we established two plots 280 m apart in altitude (ca. 1.9 °C difference in mean temperature), and two subplots which captured microsite variation (abundance and spatial distribution of species and predominance of wind direction). We used intensive sampling of individuals (2055, including adults and regeneration) and molecular genotyping of 6 highly species-specific nuclear microsatellites for the identification and classification of hybrids, based on estimates of ancestry and interclass heterozygosity. We evaluated the relative contribution of our sampling effects to variation in hybrid incidence and direction of introgression using generalized linear mixed effects models. We determined that introgressive hybridization occurs at a global rate of 7.8% and that variation was mostly explained by plots (frequency at low altitude was approximately twice that found at high altitude), while it was less influenced by subplots. The high altitude plot was dominated by late-generation backcrosses to N. obliqua (asymmetric bimodality), whereas the low altitude plot consisted of intermediate hybrids (unimodality) and showed asymmetry for introgression between subplots. Differences were not detected between adults and regeneration, suggesting early-acting reproductive isolating barriers. F1 hybrids occur at a global frequency of 3.8%, and are fertile, as the detection of first- and late-generation hybrids indicates.     

Introgression from non-native species unveils a hidden threat to the migratory Neotropical fish <Emphasis Type="Italic">Prochilodus hartii</Emphasis>

Invasive species are one of the greatest threats to biodiversity, due to competition, predation, pathogen spread, and hybridization. The latter may remain undetected and impair the survival of species, due to genetic admixture and hybrid swarming (i.e., interbreeding between hybrid individuals and backcrossing with parental species). The impact of invasive species remains poorly studied in the Neotropical ichthyofauna, particularly when considering the potential for hybridization between native and introduced species. Due to fisheries importance and its commercial value, species of the Prochilodus genus have been introduced to other catchments in Brazil. Here, we evaluate the introduction of non-native Prochilodus species and the potential effect of hybridization with the native migratory fish P. hartii. To evaluate possible introgression of Prochilodus spp. to P. hartii in the Jequitinhonha river basin (JRB), we employed a morphogenetic approach, analysing 219 specimens sampled from a broad extent of the river basin. Morphological analyses using meristic characters were incongruent with molecular identification by DNA barcoding (COI) in 22.83% of the analysed specimens. Haplotypes from three non-native species (P. argenteus, P. costatus, and P. lineatus) were recovered from specimens morphologically identified as P. hartii. Hybridization between P. hartii and introduced species was confirmed using co-dominant nuclear microsatellite markers. We observed a pronounced introgression pattern in this Neotropical basin, and paradoxically, despite being one of the most abundant migratory species native to the JRB, due to ongoing levels of introgression, P. hartii’s genetic integrity and conservation might be affected.     

Chromosome number variability in central european members of the<Emphasis Type="Italic">Festuca ovina</Emphasis> and<Emphasis Type="Italic">F. pallens</Emphasis> groups (sect.<Emphasis Type="Italic">Festuca</Emphasis>)

Chromosome numbers for 98 plants ofF. pallens, 19 ofF. psammophila, F. belensis andF. vaginata, and 44 ofF. ovina (originating from Austria, the Czech Republic, Germany, Slovakia and Latvia) are given. In addition to theF. ovina andF. pallens groups, chromosome counts for the following taxa are also reported:F. alpestris (2n=14) reported for the first time in this work,F. amethystina subsp.amethystina (2n=28),F. brevipila (2n=42),F. cinerea (2n=28),F. rupicola subsp.rupicola (2n=42) andF. versicolor subsp.versicolor (2n=14).InF. pallens, two ploidy levels (2n=2x=14+0-1B, 2n=4x=28+0-1B) as well as two natural triploid plants (2n=21+0-1B), were found. In addition to the fourF. pallens types that have been distinguished in Austria, one new tetraploid type (F. pallens “scabrifolia”) from the Czech Republic and Germany is reported and its taxonomy is discussed. The distributions of the Oberösterreich-Niederösterreich and Pannonisches-HügellandF. pallens types outside of Austria are documented.Only the diploid chromosome number (2n=14) was found inF. psammophila andF. vaginata. Chromosome numbers forF. psammophila subsp.muellerstollii andF. belensis (both 2n=14) were determined here for the first time. Two ploidy levels, 2n=14+0-5B corresponding toF. ovina subsp.ovina and 2n=28 corresponding toF. ovina subsp.guestphalica andF. cf.duernsteinensis were confirmed inF. ovina. Differences in chromosome structure (simple and multiple secondary constrictions) betweenF. pallens as opposed toF. psammophila andF. vaginata are discussed. A complete survey of published chromosome counts for Central European species from theF. ovina andF. pallens groups is included.     

Sleeping with the ‘enemy’: hybridization of an endangered tree weta

While hybridization is an important part of the evolutionary process, for rare species mating with more common species hybridization can increase the risks of extinction. By mating with heterospecifics rare species waste valuable reproductive resources and as a result population sizes may decline. If introgression occurs, the rare species can become genetically swamped by alleles from the more common species, rendering it effectively extinct. As a consequence of these risks, hybridization with the more common species Hemideina femorata (Canterbury tree weta) may lead to the extinction of the range restricted species H. ricta (Banks Peninsula tree weta) on Banks Peninsula. The current study uses spatial interpolation to model the distribution of each species and the potential sympatric zone to guide sampling efforts. Polymorphic microsatellite markers and mitochondrial sequence data were used to determine the extent of hybridization between H. ricta and H. femorata. The results confirm that hybridization is possible between these species. However, hybrids and introgression appear to be very rare, suggesting that reproductive isolating barriers are present but incomplete. The threat of extinction to H. ricta via hybridization with H. femorata is low but extreme loss of habitat may cause changes to population densities that could increase the risks of hybridization. Therefore, landowners should be encouraged to conserve native bush.     

Conspecific tolerance and heterospecific competition as mechanisms for overcoming resistance to invasion by an intertidal crab

The success of the invasive Asian shore crab, Hemigrapsus sanguineus, stems partly from its ability to exclude established crab species from preferred rocky and cobble intertidal habitat. Here, we assessed preference and competition for habitat types (cobble vs. sand) for H. sanguineus and two competitor species; the previous invasive green crab, Carcinus maenas, and the native rock crab, Cancer irroratus, in New England. In simple laboratory experiments, we paired similarly sized heterospecifics and conspecifics from each species, and also grouped combinations of C. maenas and H. sanguineus in a series of four-individual sets in order to dissect the outcome of intra- and inter-specific competition at different densities. Individually, all three species preferred cobble substrate. With paired conspecifics, H. sanguineus individuals would cohabitate in cobble, whereas C. maenas and C. irroratus individuals each excluded conspecifics from cobble. In heterospecific pairs, H. sanguineus excluded both C. maenas and C. irroratus from cobble. C. maenas and C. irroratus, were equally likely to exclude the other species, but rarely excluded H. sanguineus. In larger assemblages, H. sanguineus preferentially grouped under cobble, whereas C. maenas were more evenly distributed among habitat types. These observations demonstrate that conspecific tolerance and heterospecific competition can be effective, complementary mechanisms for overcoming invasion resistance. Such mechanisms help explain the well-studied success of H. sanguineus following its introduction into New England coastal habitats, and the resulting exclusion of preexisting crab species.     

Two new species of <Emphasis Type="Italic">Conidiobolus</Emphasis> occurring in Anhui,China

Two new species of Conidiobolus were isolated from Anhui Province, China. A polyphasic taxonomic approach comprising morphological characteristics and molecular data (the nuclear large subunit of ribosomal DNA and the translation elongation factor 1 alpha gene sequences) was applied to determine their novel taxonomic status in the genus Conidiobolus. The new species C. mirabilis is a sister group to C. thromoides, but morphologically differs by smaller primary conidia and a unique formation of zygospores among two to four adjacent hyphal segments. The other new species C. pachyzygosporus characterized with thick-walled zygospores is phylogenetically closely related to C. antarcticus, C. couchii, and C. osmodes.