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1.
Morphological variation among populations of Leporinus friderici (Bloch), an anostomid fish of widespread neotropical distribution, has been hypothesized but never conclusively demonstrated. We used multivariate procedures to examine patterns of morphometric variation among populations of L. friderici from three South American biogeographic regions: the Paraná-Paraguay River and Amazon River basins of Brazil, and the Marowijne River basin of Suriname. Samples from the southern Paraná-Paraguay basin are completely distinct from the northern Amazonian and Suriname regions in principal components analysis, primarily on the basis of body elongation and orbit differcnces. Samples from the two northern regions were separated in a size-free canonical variates analysis by differences in relative body depth. These results emphasize a need for further studies of neotropical fish species with similar distribution patterns.  相似文献   

2.
Aim The plant diversity of one location on the Guiana Shield, Kaieteur National Park in Guyana, is used to examine the various hypothesized origins of the flora and to evaluate which may best explain the current plant distributions. Location Kaieteur National Park is located on eastern edge of the Potaro Plateau in central Guyana, South America. The species examined have distributions that vary from local to global. Methods The distribution patterns of the families, genera and species known from Kaieteur are examined using generalized distribution patterns. Results Data on distribution patterns, elevation and habitat were gathered from 131 flowering plant families, 517 genera and 1227 species. These plants represent all taxa that are currently known to occur in the area of the original Kaieteur National Park. Families tend to have cosmopolitan or pantropical distribution, genera are mostly neotropical and at the species level, most species are restricted to the Guiana Shield (c. 40%), northern South America (69%) or neotropical (96%) in distribution, each level inclusive of the previous. Conclusions The flora at the study site in Kaieteur National Park has its strongest affinity with the Guiana Shield; 42.1% of the species have a distribution that corresponds with the Shield or is more restricted within the Shield. There is a distinct flora on the Guiana Shield and its affinities lie with the flora of northern South American and beyond that, the neotropics. The flora is not closely affiliated with the floras of the Brazilian Shield, the Amazon, the Andes, the eastern coastal forests of Brazil, southern South America, or Africa as has been previous suggested.  相似文献   

3.
The overwintering potential of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), in cold winter areas within its northern distribution is a key element in understanding its ecology. Recent studies have suggested that although originating in tropical Africa, the fly has become adapted to the cold weather that prevails within its northernmost areas of distribution. We address the question of whether the Mediterranean fruit fly has expanded its overwintering range to include the mountains of central Israel. Doing so would imply that the fly has developed either a behavioral or a physiological mechanism to cope with low temperature and/or damp conditions in combination with cold. We monitored adult populations year round, sampling fruit, calculating expected emergence days for overwintering flies, and studying adults captured within dense and sparse apple orchards. We also performed several manipulative experiments to study preimago ability to survive the winter under natural or seminatural conditions. The study was conducted in the central mountains of Israel at 700-m altitude from 1994 to 2003. Comparison experiments also were conducted at 400 m and at sea level. Our results show 1) no adults captured during the winter and spring, 2) an absence of new infestations during the winter and spring, and 3) inability of preimago stages to overwinter in the central mountains of Israel. Thus, we conclude that the fly does not overwinter in the central mountains of Israel. We discuss the ecological and applied significance of our findings.  相似文献   

4.
Before its eradication from North America, the subtropical‐tropical new world screwworm fly Cochliomyia hominivorax (Coquerel) invaded southwestern temperate areas of the U.S.A., where it caused myiasis in wildlife and livestock. Outbreaks of the fly occurred during years when adult migrants were carried northward on North American monsoon winds from the northern areas of Mexico and south Texas. We deconstruct, retrospectively, the biology and the effect of weather on the eradication of the fly in North America. Screwworm was found to be an ideal candidate for eradication using the sterile insect technique (SIT) because females mate only once, whereas males are polygynous, and, although it has a high reproductive potential, field population growth rates are low in tropical areas. In northern areas, eradication was enhanced by cool‐cold weather, whereas eradication in tropical Mexico and Central America is explained by the SIT. Despite low average efficacy of SIT releases (approximately 1.7%), the added pressure of massive SIT releases reduced intrinsically low fly populations, leading to mate‐limited extinction. Non‐autochthonous cases of myiasis occur in North America and, if the fly reestablishes, climate warming by 2045–2055 will expand the area of favourability and increase the frequency and severity of outbreaks.  相似文献   

5.
The mainly neotropical genus Calliandra Benth. (Leguminosae–Mimosoideae–Ingeae) is reported for the first time as native in continental Africa. There are two species known, C. gilbertii Thulin & Hunde sp. nov. in E Kenya and Somalia and C. redacta (J. H. Ross) Thulin & Hunde comb. nov. in South Africa near the Namibia border. On pollen morphological grounds they are supposed to be most related to certain neotropical species but the pollen does not agree entirely with any previously known group of the genus. The distribution of C gilbertii and C. redacta stresses the phytogeographical link between the arid zones of northern and southern Africa.  相似文献   

6.
The neotropical freshwater family Potamotrygonidae appears to be the only stingray group that has radiated in a non-marine environment. To assess the affinities of potamotrygonids to other rays, a phylogenetic analysis was undertaken using 39 morphological characters from 18 stingray groups. The single tree produced (CI = 0.80, RI = 0.88) suggests that neotropical freshwater rays are a monophyletic group, and that within Potamotrygonidae, Paratrygon is basal to a clade composed of Plesiotrygon and Potamotrygon. The sister group to potamotrygonids was determined to be amphi-American Himantura —these taxa share synapomorphies of the ventral mandibular musculature and the hyomandibular/mandibular articulation. The topology suggests that potamotrygonids are derived from a freshwater-invading ancestor that was distributed along the northern coast of South America (Pacific and Caribbean) prior to the emergence of the isthmus of Panama. This hypothesis conflicts with parasite-based biogeographic scenarios of a stricdy Pacific origin for potamotrygonids. General systematic results concerning urolophids, dasyatids, and pelagic myliobatoid stingrays are also discussed.  相似文献   

7.
Two nuclear honeybee DNA probes, 12R1C1 and 2A2, were reported previously to detect restriction fragment patterns specific to African and neotropical African honeybee populations. Individual drones and workers from several additional Old and New World populations, African and European, were tested further with these probes. With probe 12R1C1, only two of several Hhal fragment patterns were seen among haploid drone progeny of each queen bee, indicating that the patterns represented alleles at a single locus. Four alleles detected by probe 12R1C1 were described previously, three of which had been found only in populations of African descent. In this study, one of the three was found at a low frequency among samples from western Europe, northern Mexico, and the United States. However, ten additional alleles were discovered in South African drones, six of which were seen also in neotropical African colonies. With probe 2A2, only one or the other of two Alul restriction fragments was detected in drones indicating that the fragments represented alles at a single locus. One of the two alleles, seen previously only in populations of African descent, was found at a very low frequency in bees from western Europe and northern Mexico.  相似文献   

8.
Aim The extent to which cryptic species contribute to neotropical diversity remains inadequately investigated. Based on its highly distinctive morphology, the giant harlequin beetle, Acrocinus longimanus, is currently described as a single species, ranging from southern Mexico to northern Argentina. However, the discovery of cryptic species in Cordylochernes scorpioides, a pseudoscorpion with obligate dependence on the harlequin beetle for dispersal, strongly suggests the existence of barriers to gene flow in A. longimanus. The aim of this study was therefore to determine whether levels of DNA divergence between geographical populations provided evidence of genetically distinct lineages in the harlequin beetle. Location Trinidad and Panamá. Methods Sequencing of 1245 bp of the mitochondrial cytochrome oxidase I (COI) gene of A. longimanus from seven locations in Trinidad and Panamá. Results Mitochondrial haplotype diversity in the harlequin beetle shows limited evidence of geographical structuring, with a maximum sequence divergence between populations of only 1.29%. This is an order of magnitude less than the level of COI divergence between harlequin beetle riding pseudoscorpions from the same geographical locations. Main conclusions The molecular data on populations from northern South America and Panamá are consistent with the current, morphologically based classification of A. longimanus as a single, pan‐neotropical species. In addition, the relatively low level of population divergence detected in this study indicates that speciation in the hitchhiking pseudoscorpion has occurred in the absence of significant barriers to gene flow in its beetle host. It is proposed that, in the harlequin beetle, the phylogenetic signal of colonization and vicariance associated with the formation of the Isthmus of Panamá has been obscured, although not fully erased, by historical and contemporary gene flow.  相似文献   

9.
The South American fruit fly, Anastrepha fraterculus (Wiedemann), is one of two fruit fly species of economic importance in Argentina, which along with the exotic Mediterranean fruit fly, Ceratitis capitata (Wiedemann) produce annual losses of nearly US$ 90 million for fruit production in this country.Biological control may contribute to integrated approaches to manage both pestiferous species.Information on survival, reproduction and population growth parameters, critical for successful augmentation of natural enemies, is provided for three fruit fly neotropical parasitoids, Aganaspis pelleranoi (Hymenoptera: Figitidae), Opius bellus and Doryctobracon crawfordi (Hymenoptera: Braconidae). A. pelleranoi had the highest intrinsic reproductive rate (r), survival time and reproductive time, followed by O. bellus. Meanwhile D. crawfordi showed the lowest values for reproductive and population growth parameters.  相似文献   

10.
Worldwide, the highest diversity of vascular epiphytic plants resides in the Neotropics. The general pattern of taxonomic composition of the neotropical epiphytic flora has been described, but information regarding the magnitude and geographic distribution of species richness is lacking. In this paper, we carried out a regional scale analysis in order to provide an overview of the richness, composition and geographic affinities among several neotropical epiphyte floras. Our database comprised 7,524 flowering epiphyte species (48 % of the estimated total of neotropical epiphytes) from eight representative localities with politically-defined boundaries. The epiphyte quotient (e.g., percentage of epiphyte species in the total flora) per locality ranged from 5.2–27.7 % (mean: 17.5 %) of the flowering plants. Ecuador represented the most species diverse locality (4,247 spp.), followed by Costa Rica (2,611 spp.). At the family level, the epiphyte composition among localities was roughly homogeneous and dominated by emblematic epiphytic groups: Orchidaceae, Bromeliaceae, and Araceae. However, the generic composition of the epiphytic floras was more heterogeneous. Ecuador and Cuba showed the highest epiphyte endemism (37 and 26 %, respectively), and in some cases vascular epiphytes represented 30 % or more of the total endemic flowering plants at a particular locality. From the available information, four main regional epiphyte floras were identified: the northwestern Andean region, the northern and southern Mesoamerican regions; Cuba as a representative of the Caribbean region remained as a separated group, though weakly related to the Mesoamerican groups. This study identified important geographic localities as targets for the conservation of neotropical epiphyte diversity.  相似文献   

11.
We studied the medicinal plants used by the Popoluca of the Sierra de Santa Marta (eastern Mexico). Using Moerman’s method of regression analysis we determined which ethnomedically used taxa are over-represented in the Popolucan pharmacopoeia (e.g., Asteraceae) and which are underrepresented (e.g., Orchidaceae). Moerman et al. (1999) found high correlation between the holarctic pharmacopoeias and assumed that apart from the relatedness of the northern floras a “global pattern of human knowledge“ may account for this finding. Although the Popoluca dwell in a habitat dominated by a neotropical flora but intermixed with important holarctic elements, they include considerably fewer neotropical taxa in their pharmacopoeia as one would expect if the historical transmitted knowledge were influencing their selection. This finding confirms the theory stated by Moerman et al. However, the Popoluca include some neotropical taxa in their pharmacopoeia and thus a moderate correlation exists between the Popolucan pharmacopoeia and the neotropical pharmacopoeia analysed by Moerman et al. We therefore conclude that apart from historically transmitted knowledge about specific taxa the “global pattern of human knowledge” addressed by Moerman et al. is largely based on “common selection criteria.”  相似文献   

12.
Palms are a monophyletic group with a dominantly tropical distribution; however, their fossil record in low latitudes is strikingly scarce. In this paper, we describe fossil leaves, inflorescences, and fruits of palms from the middle to late Paleocene Cerrejón Formation, outcropping in the Ranchería River Valley, northern Colombia. The fossils demonstrate the presence of at least five palm morphospecies in the basin ca. 60 Ma. We compare the morphology of the fossils with extant palms and conclude that they belong to at least three palm lineages: the pantropical Cocoseae of the subfamily Arecoideae, the monotypic genus Nypa, and either Calamoideae or Coryphoideae. The fossil fruits and inflorescences are among the oldest megafossil records of these groups and demonstrate that the divergence of the Cocoseae was more than 60 Ma, earlier than has previously been thought. These fossils are useful in tracing the range expansion or contraction of historical or current neotropical elements and also have profound implications for the understanding of the evolution of neotropical rainforests.  相似文献   

13.
Abstract 1. Diversification of some highly host‐specific herbivorous insects may occur in allopatry, without shifts in host use. Such allopatric divergence may be accelerated by sexual selection operating on courtship displays. Wing size and shape may affect visual and vibrational courtship displays in tephritid fruit flies. Geometric morphometric methods were used to examine wings of six sympatric cryptic species in the neotropical genus Blepharoneura. All six species feed on flowers of the same species of host (Gurania spinulosa), a neotropical vine in the Cucurbitaceae. Three of the fly species court and mate in close proximity on the host. Thus, courtship behaviours could serve as important reproductive isolating mechanisms. Two sets of hypotheses were tested: (i) species differ in wing shape and wing size; and (ii) species are sexually dimorphic in wing size and wing shape. Wing size differed among a few species, but wing shape differed significantly among all six species. Sexual dimorphism in wing size was found in only one species, but sexual dimorphism in wing shape was found in two of the three species known to court on the same host plant. In the two sexually dimorphic species, wing shape differed among males, but not among females. This suggests that selection for reproductive character displacement might accelerate divergence in wing shape.  相似文献   

14.
基于CLIMEX的桔小实蝇在中国适生区的预测   总被引:40,自引:2,他引:38  
侯柏华  张润杰 《生态学报》2005,25(7):1570-1574
桔小实蝇Bactroceradorsalis(Hendel),属双翅目Diptera,果实蝇科Tetriphitidae,主要分布在热带和亚热带地区。温度和湿度是影响桔小实蝇分布的重要气候因子。根据桔小实蝇对温湿度等气候因子的反应,采用CLIMEX软件对桔小实蝇在中国大陆的适生区进行了预测。设置了CLIMEX中的相应参数17个:发育起点温度DV0、生长最适宜温度范围DV1~DV2、致死高温DV3、有效发育积温PDD。生长发育所需最低土壤湿度临界SM0、最适宜湿度范围SM1~SM2、最高土壤湿度临界SM3。冷胁迫日度临界DTCS及其积累速率DHCS,热胁迫临界温度TTHS及其积累速率THHS,干旱胁迫临界SMDS及其积累速率HDS,湿胁迫SMWS及其积累速率HWS。以印度和夏威夷为已知适生分布区,反复调试修正上述这些参数值,使之与已知广泛分布的地区达到最大程度的吻合。然后用优化后的参数和中国大陆85个气象站点的气象资料模拟桔小实蝇在中国大陆的适生分布,结果显示:广东、海南、香港、广西、四川、云南、湖南、湖北、福建、江西、浙江等11个省(区)是桔小实蝇的适生分布区。主要分布在我国的华南和西南大部分地区,以及华中和华东的部分地区。根据CLIMEX模拟结果的EI值大小,将桔小实蝇在我国大陆的适生分布情况进一步划分为最适宜、次适宜、适宜和非适宜4个气候区,即华南地区全部以及广西省全境是桔小实蝇的最适宜分布区,除桂林(EI=17)外,其余气象点的EI值均大于40;西南地区的四川、云南两省及福建沿海地区是桔小实蝇的次适宜分布区,平均EI值为29.7;适宜分布区包括湖南、湖北、江西、浙江的少数地区,除赣州(EI=17)外,其余点的EI值均小于10;长江以北的广大地区是桔小实蝇的非适宜区,这些地区不适合桔小实蝇生存。  相似文献   

15.
Neotropical rainforests host a rich community of fruit-eating animals, among them neotropical scatter-hoarding rodents that bury seeds in soil. These animals perform an important community-building process because the seeds germinate and establish seedlings away from the parent plant. In three recent studies, researchers have demonstrated a comparable role for paleotropical rodents in southeast Asia. With the discovery that a frugivorous kangaroo behaves similarly to its neotropical rodent counterpart, a new level has been reached in our understanding of the evolution of tropical forests.  相似文献   

16.
Opius bellus is a neotropical larval-prepupal parasitoid known to attack the pestiferous fruit fly, Anastrepha fraterculus. Due to interest in the use of native parasitoids in forthcoming fruit fly biocontrol programmes in Argentina, O. bellus was colonised for the first time using laboratory-reared A. fraterculus larvae. A series of experiments were conducted to (1) best achieve an efficient parasitoid rearing by determining optimal larval host age, host:parasitoid ratio and host exposure time and (2) assess their potential as biological control agents by determining reproductive parameters. The most productive exposure regimen was: 7–9 d-old (early and middle third-instars) A. fraterculus larvae for 4 h at a 4:1 host:parasitoid ratio; this array of factors was sufficient to achieve the highest average adult emergence (48%) and an offspring sex ratio at equitable proportion. Increasing both host:parasitoid ratio further than 4:1 and the host exposure time beyond 4 h did not significantly enhance parasitoid female offspring yield. Females produced eggs for 29.5 ± 1.4 days. At 32 days of age, 50% of the females were still alive. The majority of the progeny were produced by females between 20 and 24 d-old. At 26°C, gross fecundity rate, net reproductive rate, intrinsic rate of increase and mean generation time were 20.7 ± 4.2 offspring/female, 9.6 ± 2.5 females/newborn females, 0.06 ± 0.01 females/female/day and 8.4 ± 0.2 days, respectively. The long lifespan and reproductive parameters suggest that this parasitoid species has suitable attributes for mass-rearing.  相似文献   

17.
Climate change is a major threat to species worldwide, yet it remains uncertain whether tropical or temperate species are more vulnerable to changing temperatures. To further our understanding of this, we used a standardised field protocol to (1) study the buffering ability (ability to regulate body temperature relative to surrounding air temperature) of neotropical (Panama) and temperate (the United Kingdom, Czech Republic and Austria) butterflies at the assemblage and family level, (2) determine if any differences in buffering ability were driven by morphological characteristics and (3) used ecologically relevant temperature measurements to investigate how butterflies use microclimates and behaviour to thermoregulate. We hypothesised that temperate butterflies would be better at buffering than neotropical butterflies as temperate species naturally experience a wider range of temperatures than their tropical counterparts. Contrary to our hypothesis, at the assemblage level, neotropical species (especially Nymphalidae) were better at buffering than temperate species, driven primarily by neotropical individuals cooling themselves more at higher air temperatures. Morphology was the main driver of differences in buffering ability between neotropical and temperate species as opposed to the thermal environment butterflies experienced. Temperate butterflies used postural thermoregulation to raise their body temperature more than neotropical butterflies, probably as an adaptation to temperate climates, but the selection of microclimates did not differ between regions. Our findings demonstrate that butterfly species have unique thermoregulatory strategies driven by behaviour and morphology, and that neotropical species are not likely to be more inherently vulnerable to warming than temperate species.  相似文献   

18.
A new species of sand fly, Pintomyia (Pifanomyia) falcaorum is described from an amber originated from the northern mountain range of Dominican Republic. The male sand fly specimen is well preserved and most features used in Phlebotominae taxonomy are seen with remarkable clarity.  相似文献   

19.
Conn JE  Mirabello L 《Heredity》2007,99(3):245-256
Phylogenetic and population genetic data support the Pliocene or Pleistocene divergences of the co-distributed hematophagous insect vectors, the sand fly Lutzomyia longipalpis s.l., the mosquitoes Anopheles darlingi and A. albitarsis s.l., and the triatomines Rhodnius prolixus and R. robustus. We examined patterns of divergence and distribution in relation to three hypotheses of neotropical diversification: Miocene/Pliocene marine incursion, Pliocene/Pleistocene riverine barriers and Pleistocene refugia. Only R. prolixus has a pattern concordant with the refugia hypothesis, and R. robustus conforms to the marine incursion predictions. A. darlingi partially fits the refugia hypothesis. For L. longipalpis s.l. and A. albitarsis s.l., elements of both incursion and refugia hypotheses seem to fit, suggesting perhaps an interaction of factors determining their distribution patterns.  相似文献   

20.
A new species of Almeidea (Rutaceae) belonging to the neotropical tribe Galipeeae (subtribe Galipeinae) is described and illustrated. This new species, Almeidea albiflora, is known so far only from a few collections made in small disturbed forest remnants in the vicinity of Cachoeiro de Itapemirim, in the state of Espírito Santo, and by a single collection from northern Rio de Janeiro state, both in the domain of the Atlantic Forest, Eastern Brazil. Diagnostic features, like white petals, sericeous ovary and distal secondary axes as long as the proximal ones are identified. Pollen morphology is also described, and brief discussions of the relationships of the new taxon to other species of Almeidea, as well as comments on its conservation status, are provided.  相似文献   

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