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1.
Alain Migeon Francisco Ferragut Lucía Adriana Escudero-Colomar Komi Fiaboe Markus Knapp Gilberto J. de Moraes Eddie Ueckermann Maria Navajas 《Experimental & applied acarology》2009,48(3):199-212
Predicting the potential geographical distribution of a species is particularly important for pests with strong invasive abilities.
Tetranychus evansi Baker & Pritchard, possibly native to South America, is a spider mite pest of solanaceous crops. This mite is considered
an invasive species in Africa and Europe. A CLIMEX model was developed to predict its global distribution. The model results
fitted the known records of T. evansi except for some records in dry locations. Dryness as well as excess moisture stresses play important roles in limiting the
spread of the mite in the tropics. In North America and Eurasia its potential distribution appears to be essentially limited
by cold stress. Detailed potential distribution maps are provided for T. evansi in the Mediterranean Basin and in Japan. These two regions correspond to climatic borders for the species. Mite establishment
in these areas can be explained by their relatively mild winters. The Mediterranean region is also the main area where tomato
is grown in open fields in Europe and where the pest represents a threat. According to the model, the whole Mediterranean
region has the potential to be extensively colonized by the mite. Wide expansion of the mite to new areas in Africa is also
predicted. Agricultural issues highlighted by the modelled distribution of the pest are discussed.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
2.
R. L. Nadel B. Slippers M. C. Scholes S. A. Lawson A. E. Noack C. F. Wilcken J. P. Bouvet M. J. Wingfield 《Biological invasions》2010,12(5):1067-1077
Thaumastocoris peregrinus is a recently introduced invertebrate pest of non-native Eucalyptus plantations in the Southern Hemisphere. It was first reported from South Africa in 2003 and in Argentina in 2005. Since then,
populations have grown explosively and it has attained an almost ubiquitous distribution over several regions in South Africa
on 26 Eucalyptus species. Here we address three key questions regarding this invasion, namely whether only one species has been introduced,
whether there were single or multiple introductions into South Africa and South America and what the source of the introduction
might have been. To answer these questions, bar-coding using mitochondrial DNA (COI) sequence diversity was used to characterise
the populations of this insect from Australia, Argentina, Brazil, South Africa and Uruguay. Analyses revealed three cryptic
species in Australia, of which only T. peregrinus is represented in South Africa and South America. Thaumastocoris peregrinus populations contained eight haplotypes, with a pairwise nucleotide distance of 0.2–0.9% from seventeen locations in Australia.
Three of these haplotypes are shared with populations in South America and South Africa, but the latter regions do not share
haplotypes. These data, together with the current distribution of the haplotypes and the known direction of original spread
in these regions, suggest that at least three distinct introductions of the insect occurred in South Africa and South America
before 2005. The two most common haplotypes in Sydney, one of which was also found in Brisbane, are shared with the non-native
regions. Sydney populations of T. peregrinus, which have regularly reached outbreak levels in recent years, might thus have served as source of these three distinct introductions
into other regions of the Southern Hemisphere. 相似文献
3.
Adriana Silva-Iturriza Jafet M. Nassar Ariany M. García-Rawlins Romel Rosales Alfredo Mijares 《Parasitology international》2013,62(2):95-99
Trypanosoma evansi is a mammal generalist protozoon which causes negative effects on health and productivity in bovine and equine herds in South America, Europe, Asia and Africa. By molecular methods, we screened the presence of that parasite together with other trypanosome species in 105 bats of 10 species collected in arid zones of northern Venezuela. The first molecular approach was fluorescent fragment length barcoding (FFLB), which relies on amplification of relative small regions of rRNA genes (four loci) and fluorescence detection. By FFLB, 17 samples showed patterns of possible trypanosomatid infections. These samples were used to test presence of trypanosomes by PCR using the following DNA markers: V7–V8 SSU rRNA, gGAPDH and kDNA minicircle regions. Only in one individual of the nectar-feeding bat, Leptonycteris curasoae, we were able to amplify 1000 bp of the trypanosome kDNA minicircle. That PCR product was sequenced and the parasite species was determined by NCBI-BLAST and phylogenetic analysis. Both analyses showed that the minicircle sequence corresponds to Trypanosoma evansi. The phylogenetic analysis of the sequence obtained in this study clustered with a T. evansi sequence obtained in a Venezuelan capybara, Hydrochoerus hydrochaeris, and distant of others two T. evansi sequences obtained in a Colombian capybara and horse. This result supports the hypothesis of multiple origins of T. evansi in South America. 相似文献
4.
Genetic differentiation can be promoted allopatrically by geographic isolation of populations due to limited dispersal ability and diversification over time or sympatrically through, for example, host-race formation. In crop pests, the trading of crops across the world can lead to intermixing of genetically distinct pest populations. However, our understanding of the importance of allopatric and sympatric genetic differentiation in the face of anthropogenic genetic intermixing is limited. Here, we examined global sequence variation in two mitochondrial and one nuclear genes in the seed beetle Callosobruchus maculatus that uses different legumes as hosts. We analyzed 180 samples from 42 populations of this stored bean pest from tropical and subtropical continents and archipelagos: Africa, the Middle East, South and Southeast Asia, Oceania and South America. For the mitochondrial genes, there was weak but significant genetic differentiation across continents/archipelagos. Further, we found pronounced differentiation among subregions within continents/archipelagos both globally and within Africa but not within Asia. We suggest that multiple introductions into Asia and subsequent intermixing within Asia have generated this pattern. The isolation by distance hypothesis was supported globally (with or without continents controlled) but not when host species was restricted to cowpeas Vigna unguiculata, the ancestral host of C. maculatus. We also document significant among-host differentiation both globally and within Asia, but not within Africa. We failed to reject a scenario of a constant population size in the recent past combined with selective neutrality for the mitochondrial genes. We conclude that mitochondrial DNA differentiation is primarily due to geographic isolation within Africa and to multiple invasions by different alleles, followed by host shifts, within Asia. The weak inter-continental differentiation is most likely due to frequent inter-continental gene flow mediated by human crop trade. 相似文献
5.
Many species are shifting their distributions due to climate change and to increasing international trade that allows dispersal of individuals across the globe. In the case of agricultural pests, such range shifts may heavily impact agriculture. Species distribution modelling may help to predict potential changes in pest distributions. However, these modelling strategies are subject to large uncertainties coming from different sources. Here we used the case of the tomato red spider mite (Tetranychus evansi), an invasive pest that affects some of the most important agricultural crops worldwide, to show how uncertainty may affect forecasts of the potential range of the species. We explored three aspects of uncertainty: (1) species prevalence; (2) modelling method; and (3) variability in environmental responses between mites belonging to two invasive clades of T. evansi. Consensus techniques were used to forecast the potential range of the species under current and two different climate change scenarios for 2080, and variance between model projections were mapped to identify regions of high uncertainty. We revealed large predictive variations linked to all factors, although prevalence had a greater influence than the statistical model once the best modelling strategies were selected. The major areas threatened under current conditions include tropical countries in South America and Africa, and temperate regions in North America, the Mediterranean basin and Australia. Under future scenarios, the threat shifts towards northern Europe and some other temperate regions in the Americas, whereas tropical regions in Africa present a reduced risk. Analysis of niche overlap suggests that the current differential distribution of mites of the two clades of T. evansi can be partially attributed to environmental niche differentiation. Overall this study shows how consensus strategies and analysis of niche overlap can be used jointly to draw conclusions on invasive threat considering different sources of uncertainty in species distribution modelling. 相似文献
6.
Unexpected mosaic distribution of two hybridizing sibling lineages in the teleplanically dispersing snail Stramonita haemastoma suggests unusual postglacial redistribution or cryptic invasion
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Tahani El Ayari Najoua Trigui El Menif Carlos Saavedra David Cordero Frédérique Viard Nicolas Bierne 《Ecology and evolution》2017,7(21):9016-9026
Molecular approaches have proven efficient to identify cryptic lineages within single taxonomic entities. Sometimes these cryptic lineages maybe previously unreported or unknown invasive taxa. The genetic structure of the marine gastropod Stramonita haemastoma has been examined in the Western Mediterranean and North‐Eastern Atlantic populations with mtDNA COI sequences and three newly developed microsatellite markers. We identified two cryptic lineages, differentially fixed for alternative mtDNA COI haplogroups and significantly differentiated at microsatellite loci. The mosaic distribution of the two lineages is unusual for a warm‐temperate marine invertebrate with a teleplanic larval stage. The Atlantic lineage was unexpectedly observed as a patch enclosed in the north of the Western Mediterranean Sea between eastern Spain and the French Riviera, and the Mediterranean lineage was found in Macronesian Islands. Although cyto‐nuclear disequilibrium is globally maintained, asymmetric introgression occurs in the Spanish region where the two lineages co‐occur in a hybrid zone. A first interpretation of our results is mito‐nuclear discordance in a stable postglacial hybrid zone. Under this hypothesis, though, the location of genetic discontinuities would be unusual among planktonic dispersers. An alternative interpretation is that the Atlantic lineage, also found in Senegal and Venezuela, has been introduced by human activities in the Mediterranean area and is introgressing Mediterranean genes during its propagation, as theoretically expected. This second hypothesis would add an additional example to the growing list of cryptic marine invasions revealed by molecular studies. 相似文献
7.
JOHN A. DARLING MARK J. BAGLEY JOE ROMAN CAROLYN K. TEPOLT JONATHAN B. GELLER 《Molecular ecology》2008,17(23):4992-5007
The European green crab Carcinus maenas is one of the world's most successful aquatic invaders, having established populations on every continent with temperate shores. Here we describe patterns of genetic diversity across both the native and introduced ranges of C. maenas and its sister species, C. aestuarii, including all known non‐native populations. The global data set includes sequences from the mitochondrial cytochrome c oxidase subunit I gene, as well as multilocus genotype data from nine polymorphic nuclear microsatellite loci. Combined phylogeographic and population genetic analyses clarify the global colonization history of C. maenas, providing evidence of multiple invasions to Atlantic North America and South Africa, secondary invasions to the northeastern Pacific, Tasmania, and Argentina, and a strong likelihood of C. maenas × C. aestuarii hybrids in South Africa and Japan. Successful C. maenas invasions vary broadly in the degree to which they retain genetic diversity, although populations with the least variation typically derive from secondary invasions or from introductions that occurred more than 100 years ago. 相似文献
8.
Test of colonisation scenarios reveals complex invasion history of the red tomato spider mite Tetranychus evansi 总被引:1,自引:0,他引:1
The spider mite Tetranychus evansi is an emerging pest of solanaceous crops worldwide. Like many other emerging pests, its small size, confusing taxonomy, complex history of associations with humans, and propensity to start new populations from small inocula, make the study of its invasion biology difficult. Here, we use recent developments in Approximate Bayesian Computation (ABC) and variation in multi-locus genetic markers to reconstruct the complex historical demography of this cryptic invasive pest. By distinguishing among multiple pathways and timing of introductions, we find evidence for the "bridgehead effect", in which one invasion serves as source for subsequent invasions. Tetranychus evansi populations in Europe and Africa resulted from at least three independent introductions from South America and involved mites from two distinct sources in Brazil, corresponding to highly divergent mitochondrial DNA lineages. Mites from southwest Brazil (BR-SW) colonized the African continent, and from there Europe through two pathways in a "bridgehead" type pattern. One pathway resulted in a widespread invasion, not only to Europe, but also to other regions in Africa, southern Europe and eastern Asia. The second pathway involved the mixture with a second introduction from BR-SW leading to an admixed population in southern Spain. Admixture was also detected between invasive populations in Portugal. A third introduction from the Brazilian Atlantic region resulted in only a limited invasion in Europe. This study illustrates that ABC methods can provide insights into, and distinguish among, complex invasion scenarios. These processes are critical not only in understanding the biology of invasions, but also in refining management strategies for invasive species. For example, while reported observations of the mite and outbreaks in the invaded areas were largely consistent with estimates of geographical expansion from the ABC approach, historical observations failed to recognize the complex pathways involved and the corresponding effects on genetic diversity. 相似文献
9.
L. L. Esterhuizen K. G. Mabasa S. W. van Heerden H. Czosnek J. K. Brown M. E. C. Rey 《Journal of Applied Entomology》2013,137(1-2):122-135
The whitefly Bemisia tabaci cryptic species complex contains some important agricultural pest and virus vectors. Members of the complex have become serious pests in South Africa (SA) because of their feeding habit and their ability to transmit begomovirus species. Despite their economic importance, studies on the biology and distribution of B. tabaci in SA are limited. To this end, a survey was made to investigate the diversity and distribution of B. tabaci cryptic species in eight geographical locations (provinces) in SA, between 2002 and 2009, using the mitochondrial cytochrome oxidase I (mtCOI) sequences. Phylogenetic analysis revealed the presence of members from two endemic sub‐Saharan Africa (SSAF) subclades coexisting with two introduced putative species. The SSAF‐1 subclade includes cassava host‐adapted B. tabaci populations, whereas the whiteflies collected from cassava and non‐cassava hosts formed a distinct subclade, referred to as SSAF‐5, and represent a new subclade among previously recognized southern Africa clades. Two introduced cryptic species, belonging to the Mediterranean and Middle East–Asia minor 1 clades, were identified and include the B and Q types. The B type showed the widest distribution, being present in five of the eight provinces explored in SA, infesting several host plants and predominating over the indigenous haplotypes. This is the first report of the occurrence of the exotic Q type in SA alongside the more widely distributed B type. Furthermore, mtCOI PCR‐RFLP was developed for the SA context to allow rapid discrimination between the B, Q and SSAF putative species. The capacity to manage pests and disease effectively relies on knowledge of the identity of the agents causing the damage. Therefore, this study contributes to the understanding of South African B. tabaci species diversity, information needed for the development of knowledge‐based disease management practices. 相似文献
10.
DANIEL SIMBERLOFF MARTIN A. NUÑEZ NICHOLAS J. LEDGARD ANIBAL PAUCHARD DAVID M. RICHARDSON MAURO SARASOLA BRIAN W. VAN WILGEN SERGIO M. ZALBA RAFAEL D. ZENNI RAMIRO BUSTAMANTE EDUARDO PEÑA SILVIA R. ZILLER 《Austral ecology》2010,35(5):489-504
The history of conifers introduced earlier elsewhere in the southern hemisphere suggests that recent invasions in Argentina, Brazil, Chile and Uruguay are likely to increase in number and size. In South Africa, New Zealand and Australia, early ornamental introductions and small forestry plantations did not lead to large‐scale invasions, while subsequent large plantations were followed with a lag of about 20–30 years by troublesome invasions. Large‐scale conifer plantation forestry in South America began about 50–80 years later than in South Africa, Australia and New Zealand, while reports of invasions in South America lagged behind those in the latter nations by a century. Impacts of invading non‐native conifers outside South America are varied and include replacement of grassland and shrubland by conifer forest, alteration of fire and hydrological regimes, modification of soil nutrients, and changes in aboveground and belowground biotic communities. Several of these effects have already been detected in various parts of South America undergoing conifer invasion. The sheer amount of area planted in conifers is already very large in Chile and growing rapidly in Argentina and Brazil. This mass of reproductive trees, in turn, produces an enormous propagule pressure that may accelerate ongoing invasions and spark new ones at an increasing rate. Regulations to control conifer invasions, including measures to mitigate spread, were belatedly implemented in New Zealand and South Africa, as well as in certain Australian states, inspired by observations on invasions in those nations. Regulations in South America are weaker and piecemeal, but the existing research base on conifer invasions elsewhere could be useful in fashioning effective regulations in South America. Pressure from foreign customers in South Africa has led most companies there to seek certification through the Forestry Stewardship Council; a similar programme operates in Australia. Such an approach may be promising in South America. 相似文献
11.
Tetranychus evansi Baker & Pritchard is an important pest of Solanaceae in several countries. Introduced accidentally to Africa, it presently
occurs in many countries of that continent. In some of them, it is considered a key pest. The suspected area of origin of
this mite is South America. The objective of the present study was to identify phytoseiid mites on solanaceous plants in association
with T. evansi in south and southeast Brazil for introduction in the African continent for use in a classic biological control program.
Almost 1,400 predatory mites of the family Phytoseiidae were collected, on 22 solanaceous species. The Amblyseiinae were the
most diverse group in this study. Twenty-three of the species found belong to this subfamily, while only three belong to the
Typhlodrominae and two to the Phytoseiinae. The most abundant and most frequent phytoseiid species were Phytoseius guianensis De Leon and Galendromus annectens (De Leon) of the Phytoseiinae and Typhlodrominae, respectively. The most frequent and abundant species of Amblyseiinae was
Neoseiulus tunus (De Leon). Phytoseius guianensis and N. tunus were never found in association with T. evansi and G. annectens was found only once in association with it. Two factors suggested Phytoseiulus longipes Evans as the most promising predator found in this study. It could walk very well on tomato leaves infested by T. evansi, without being hampered by the profuse webbing produced by the prey and by the trichomes. In addition, several specimens
of both sexes including eggs and nymphs of the predator were found associated with T. evansi on three different plant species and in two different periods of the year, when T. evansi was the only arthropod present on the leaves. 相似文献
12.
The predation pressure put on primates by diurnal birds of prey differs greatly between continents. Africa and South America
have specialist raptors (e.g. crowned hawk-eagle Stephanoaetus coronatus and harpy eagle Harpia harpyja) whereas in Asia the only such specialist’s (Philippine eagle Pithecophaga jefferyi) distribution is largely allopatric with primates. The almost universal absence of polyspecific groups in Asia (common in
Africa and South America) may indicate reduced predation pressure. As such there is almost no information on predation pressures
on primates in Asia by raptors. Here we report successful predation of a juvenile banded langur Presbytis femoralis (~2 kg) by a changeable hawk-eagle Spizaetus cirrhatus. The troop that was attacked displayed no signs of being alarmed, and no calls were made before the event. We argue that
in insular Southeast Asia, especially, large Spizaetus hawk-eagles (~2 kg) are significant predators of arboreal colobines. Using data on the relative size of sympatric Spizaetus hawk-eagles and colobines we make predictions on where geographically we can expect the highest predation pressure (Thai–Malay
Peninsula) and which colobines are least (Nasalis larvatus, Trachypithecus auratus, P. thomasi) and most (P. femoralis, T. cristatus) affected. 相似文献
13.
V.S. Duarte R.A. Silva V.W. Wekesa F.B. Rizzato C.T.S. Dias I. Delalibera Jr. 《Biological Control》2009,51(1):81-90
The tomato red spider mite, Tetranychus evansi (Acari: Tetranychidae) was recently introduced in Africa and Europe, where there is an increasing interest in using natural enemies to control this pest on solanaceous crops. Two promising candidates for the control of T. evansi were identified in South America, the fungal pathogen, Neozygites floridana and the predatory mite Phytoseiulus longipes. In this study, population dynamics of T. evansi and its natural enemies together with the influence of environmental conditions on these organisms were evaluated during four crop cycles in the field and in a protected environment on nightshade and tomato plants with and without application of chemical pesticides. N. floridana was the only natural enemy found associated with T. evansi in the four crop cycles under protected environment but only in the last crop cycle in the field. In the treatments where the fungus appeared, reduction of mite populations was drastic. N. floridana appeared in tomato plants even when the population density of T. evansi was relatively low (less than 10 mites/3.14 cm2 of leaf area) and even at this low population density, the fungus maintained infection rates greater than 50%. The application of pesticides directly affected the fungus by delaying epizootic initiation and contributing to lower infection rates than unsprayed treatments. Rainfalls did not have an apparent impact on mite populations. These results indicate that the pathogenic fungus, N. floridana can play a significant role in the population dynamics of T. evansi, especially under protected environment, and has the potential to control this pest in classical biological control programs. 相似文献
14.
Komi K.M. Fiaboe Rafael L. Fonseca Gilberto J. de Moraes Callistus K.P.O. Ogol Markus Knapp 《Biological Control》2006,38(3):373-379
The red spider mite Tetranychus evansi Baker and Pritchard is a pest of tomato in East and Southern Africa. It is probably native to South America. Three models were established to identify priority areas for the search of natural enemies in South America for classical biological control of this pest in Africa. The models were based on the concept of “fundamental ecological niche”, predicting regions in South America that have similar environmental conditions to areas where the mite is a problem in Africa, using Desktop-GARP (Genetic Algorithm for Rule-set Production). Based on the model established with data sets from Kenya and Zimbabwe, it was determined that priority areas include areas in Brazil, Argentina, Paraguay and Uruguay, as well as some restricted areas in other South American countries. 相似文献
15.
B. P. Hurley B. Slippers B. D. Wingfield P. Govender J. E. Smith M. J. Wingfield 《Biological invasions》2010,12(4):729-733
The fungus gnat, Bradysia difformis (Sciaridae: Diptera) has recently been recorded for the first time from South Africa where it has been found in forestry
nurseries. The presence of this insect in all the major forestry nurseries as the dominant and only sciarid species raises
intriguing questions regarding its origin and population genetic structure. A 395 bp portion of the mitochondrial COI gene
was analysed from B. difformis individuals collected from four nursery populations in South Africa and three nursery populations in Europe. Shared haplotypes
between South African and European populations indicated a historical connection. South African populations showed high genetic
diversity and low genetic differentiation. These patterns most likely reflect multiple and/or relatively large introductions
of B. difformis into South Africa from its origin combined with subsequent and continued movement of plants between nurseries. 相似文献
16.
Aquatic plant invasions are often associated with long‐distance dispersal of vegetative propagules and prolific clonal reproduction. These reproductive features combined with genetic bottlenecks have the potential to severely limit genetic diversity in invasive populations. To investigate this question we conducted a global scale population genetic survey using amplified fragment length polymorphism markers of the world’s most successful aquatic plant invader –Eichhornia crassipes (water hyacinth). We sampled 1140 ramets from 54 populations from the native (South America) and introduced range (Asia, Africa, Europe, North America, Central America and the Caribbean). Although we detected 49 clones, introduced populations exhibited very low genetic diversity and little differentiation compared with those from the native range, and ~80% of introduced populations were composed of a single clone. A widespread clone (‘W’) detected in two Peruvian populations accounted for 70.9% of the individuals sampled and dominated in 74.5% of the introduced populations. However, samples from Bangladesh and Indonesia were composed of different genotypes, implicating multiple introductions to the introduced range. Nine of 47 introduced populations contained clonal diversity suggesting that sexual recruitment occurs in some invasive sites where environmental conditions favour seedling establishment. The global patterns of genetic diversity in E. crassipes likely result from severe genetic bottlenecks during colonization and prolific clonal propagation. The prevalence of the ‘W’ genotype throughout the invasive range may be explained by stochastic sampling, or possibly because of pre‐adaptation of the ‘W’ genotype to tolerate low temperatures. 相似文献
17.
The invasion of tilapia can result in substantial impacts on native communities. Thus, understanding the spatial dynamics of invasions may help prevent future introductions and mitigate impacts. This study estimated the environmentally suitable areas for occurrence of eight tilapia species (genera Coptodon, Oreochromis, Pelmatolapia, and Sarotherodon) in the Americas and their invasive potential using Ecological Niche Models (ENMs). The United States is the most invaded country, receiving all tilapia species. In South America, the southeast and south regions of Brazil are highlighted as the areas where two species are concentrated. The ENMs predicted that all tilapia species have high invasive potential in the Americas, and despite having more tilapias in North America, South and Central Americas are more susceptible to tilapia invasion. All South American basins were predicted to harbor tilapia species that have not yet arrived on the subcontinent. Our study evidences the need to implement management measures and governmental policies in the Americas to deal with problems caused by tilapia introductions. In North America, the focus is on the control of tilapia populations and in Central and South America priority should be given to contention of introduction processes. 相似文献
18.
Ferrero M de Moraes GJ Kreiter S Tixier MS Knapp M 《Experimental & applied acarology》2007,41(1-2):45-53
The tomato red spider mite, Tetranychus evansi, is reported as a severe pest of tomato and other solanaceous crops from Africa, from Atlantic and Mediterranean Islands,
and more recently from the south of Europe (Portugal, Spain and France). A population of the predaceous mite Phytoseiulus longipes has been recently found in Brazil in association with T. evansi. The objective of this paper was to assess the development and reproduction abilities of this strain on T. evansi under laboratory conditions at four temperatures: 15, 20, 25 and 30°C. The duration of the immature phase ranged from 3.1
to 15.4 days, at 30 and 15°C, respectively. Global immature lower thermal threshold was 12.0°C. Immature survival was high
at all temperatures tested (minimum of 88% at 30°C). The intrinsic rate of increase (r
m) of P. longipes ranged from 0.091 to 0.416 female/female/day, at 15 and 30°C, respectively. P. longipes would be able to develop at a wide range of temperatures feeding on T. evansi and has the potential to control T. evansi populations. 相似文献
19.
Kathrin Feldberg Jörn Hentschel Rosemary Wilson David S. Rycroft David Glenny Jochen Heinrichs 《Journal of Biogeography》2007,34(4):688-698
Aim The cosmopolitan genus Herbertus is notorious for having a difficult taxonomy and for the fact that there is limited knowledge of species ranges and relationships. Topologies generated from variable molecular markers are used to discuss biogeographical patterns in Herbertus and to compare them with the geological history of continents and outcomes reported for other land plants. Location Africa, Asia, Azores, Europe, southern South America, northern South America, North America, New Zealand. Methods Phylogenetic analyses of nuclear ribosomal internal transcribed spacer and chloroplast (cp) trnL–trnF sequences of 66 accessions of Herbertus and the outgroup species Triandrophyllum subtrifidum and Mastigophora diclados were used to investigate biogeographical patterns in Herbertus. Areas of putative endemism were defined based on the distribution of species included in the analyses. Maximum parsimony analyses were undertaken to reconstruct ancestral areas and intraspecies migration routes. Results The analyses reveal species‐level cladograms with a correlation between genetic variation and the geographical distribution of the related accessions. The southern South American Herbertus runcinatus is sister to the remainder of the genus, which is split into two main clades. One contains the Neotropical–African Herbertus juniperoideus and the New Zealand/Tasmanian Herbertus oldfieldianus. An African accession of H. juniperoideus is nested within Neotropical accessions. The second main clade includes species that inhabit Asia, the Holarctic, Africa, and northern South America. Maximum parsimony analyses indicate that this clade arose in Asia. Herbertus sendtneri originated in Asia and subsequently colonized the Holarctic and northern South America. An Asian origin and colonization into Africa is indicated for H. dicranus. Main conclusions The current distribution of Herbertus cannot be explained by Gondwanan vicariance. A more feasible explanation of the range is a combination of short‐distance dispersal, rare long‐distance dispersal events (especially into regions that faced floral displacements as a result of climatic changes) extinction, recolonization, and diversification. The African Herbertus flora is a mixture of Asian and Neotropical elements. Southern South America harbours an isolated species. The molecular data indicate partial decoupling of molecular and morphological variation in Herbertus. Biogeographical patterns in Herbertus are not dissimilar to those of other groups of bryophytes, but elucidation of the geographical ranges requires a molecular approach. Some patterns could be the result of maintenance of Herbertus in the inner Tropics during glacial maxima, and dispersal into temperate regions in warm phases. 相似文献
20.
María Salinas Laura Altet Cristina Clavel Ramón Miguel Almela Alejandro Bayón Isabel Burguete Armand Sánchez 《Conservation Genetics》2011,12(1):1-13
Wild populations of many species are declining as a result of habitat destruction and climate change but also through the
over-collection for wild meat and the pet trade. With a long history of trade around the Mediterranean, populations of the
spur-thighed tortoise (Testudo graeca graeca) have become highly disturbed. In this study we utilise a molecular approach to investigate the diversity, population admixture
and structure of T. g. graeca populations in northern Africa and southern Spain, as well as to obtain an insight into the origin of newly established populations
in the south of Europe. We infer this from the sequencing of two partial regions of the mitochondria (12s rRNA + cyt b) and genotyping at 16 microsatellite markers in 448 tortoises. Our results are consistent with the hypothesis that Spanish
populations were founded from North Africa, the consequence of multiple introductions or exchanges in genetic material as
a result of trans-oceanic dispersal. Despite the trade of individuals between both sides of the Gibraltar Strait, our analysis
of population structure showed clear differences between both the African and European populations, suggesting an incipient
evolutionary lineage in southeast of Spain. As such, these populations possess unique genetic identities and should be treated
as different management units. Surprisingly, the genetic data identified a great deal of diversity contained within pet (captive)
stock and also allowed us to infer hybrids among individuals with another species of terrestrial tortoise from northern Spain
(T. hermanni hermanni). Additionally, our results provide insight into the local movement and trade of individuals that has occurred around the
Mediterranean basin (between northern Africa and southern Spain) and as such provides guidance for the effective management
of T. g. graeca captive stock and the illegal trafficking. 相似文献