福寿螺线粒体DNA COⅠ基因序列测定及分类地位

对国内6个地区共29个福寿螺(Apple Snails)个体mtDNA COⅠ基因进行了扩增和序列分析,并结合GenBank中报道的福寿螺6个种Pomacea canaliculata、P.insularum、P.diffusa、P.haustrum、P.paludosa、P.camena和Pila属P.conica的同源序列,对国内入侵福寿螺的分类地位与分子系统发育进行了分析。结果表明,扩增的mtDNA COⅠ基因序列长度为619bp,序列间未见插入和缺失,其中核苷酸多态位点99个,简约信息位点80个;碱基A、T、C、G平均含量分别为23.6%、39.1%、16.6%和20.7%,A+T的含量(62.7%)明显高于C+G的含量(37.3%);6个地区的福寿螺共有13种单倍型,广州、钦州和吉安分别有3种单倍型,茂名、厦门和成都分别有2种单倍型,而广州、厦门和钦州3个地区之间共享一种单倍型。进一步的分子遗传距离分析表明,这6个地区福寿螺个体与P.diffusa、P.haustrum、P.paludosa和P.camena的遗传距离为0.114～0.191,而与P.insularum和P.canaliculata的同源性较高,其中单倍型1、2、3、7、8、10、11、12与P.canaliculata的遗传距离为0～0.074,单倍型4、5、6、9、13与P.insularum的遗传距离为0.011～0.063。构建的分子系统树显示7个分支,分别为Pomacea属6个种和Pila属P.conica,其中单倍型1、2、3、7、8、10、11、12与Pomacea canaliculata聚成一支,单倍型4、5、6、9、13与P.insularum聚成一支。序列同源性、遗传距离和系统进化树分析结果表明,国内入侵福寿螺有P.canaliculata和P.insularum两个种,而且这两个种在入侵扩散过程中已相互混杂。本研究为今后开展福寿螺的资源调查、控制和管理等提供科学依据。     

温度对福寿螺生物学特性的影响及高低温适应机制研究进展

在全球气候变化背景下, 福寿螺在我国及全球进一步扩散。极强的生态耐受力及快速适应力是福寿螺能够在入侵地区迅速扩散的重要原因。其中, 环境温度对福寿螺的生存、生长、发育及繁殖至关重要, 是影响福寿螺分布、扩散及暴发的重要因素之一。文章在综述温度耐受范围的基础上, 总结了福寿螺高低温适应的生理生化及分子机制, 并对从温度适应性角度揭示入侵机制的研究前景进行展望。当前, 福寿螺温度适应的生理生化机制研究主要针对化合物以及相关酶活性变化开展, 分子机制研究主要集中在HSP基因的表达差异上。在染色体水平基因组完成测序的基础上, 福寿螺快速适应性进化的生理生态耐受性机制和表型可塑性机制有待深入开展。     

Impact of invasive apple snails on the functioning and services of natural and managed wetlands

At least 14 species of apple snail (Ampullariidae) have been released to water bodies outside their native ranges; however, less than half of these species have become widespread or caused appreciable impacts. We review evidence for the impact of apple snails on natural and managed wetlands focusing on those studies that have elucidated impact mechanisms. Significant changes in wetland ecosystems have been noted in regions where the snails are established: Two species in particular (Pomacea canaliculata and Pomacea maculata) have become major pests of aquatic crops, including rice, and caused enormous increases in molluscicide use. Invasive apple snails have also altered macrophyte community structure in natural and managed wetlands through selective herbivory and certain apple snail species can potentially shift the balance of freshwater ecosystems from clear water (macrophyte dominated) to turbid (plankton dominated) states by depleting densities of native aquatic plants. Furthermore, the introductions of some apple snail species have altered benthic community structure either directly, through predation, or indirectly, through exploitation competition or as a result of management actions. To date much of the evidence for these impacts has been based on correlations, with few manipulative field or mesocosm experiments. Greater attention to impact monitoring is required, and, for Asia in particular, a landscape approach to impact management that includes both natural and managed-rice wetlands is recommended.     

Genetic exchange between two freshwater apple snails, Pomacea canaliculata and Pomacea maculata invading East and Southeast Asia

Two species of apple snails, Pomacea canaliculata and Pomacea maculata (formerly Pomacea insularum), have invaded many countries of East and Southeast Asia from their native range in South America. This study investigated the genetic structure of the two species invading these areas. Phylogenetic analysis based on sequences of the nuclear gene elongation factor 1-alpha (EF1α) detected two well-supported clades (Clade C and Clade M). Both P. canaliculata and P. maculata were represented in each clade. Some snails had both Clade C and Clade M EF1α sequences. These results suggest genetic exchange between snails of the two clades. A mating experiment between P. canaliculata with Clade C EF1α sequences and P. maculata with Clade M EF1α sequences resulted in viable F1 progeny under laboratory conditions. The genetic exchange was also inferred in some populations collected from Argentina, suggesting an existence of hybrid in the native range. Simple identification of EF1α types using a restriction enzyme, ApaLI, detected significant geographical structure of the EF1α variants in the invaded area. The divergent geographical structure could have resulted from either the founder effect or the bridgehead effect, although further genetic analysis is needed to clarify this. Average individual egg weight, which is an indicator of egg size, was higher in P. canaliculata than P. maculata in both field and laboratory reared samples, suggesting that some (probably most) P. canaliculata and P. maculata invading East and Southeast Asia still maintain species-specific populations.     

Genetic diversity and molecular markers in introduced and Thai native apple snails (Pomacea and Pila)

The genetic diversity and species-diagnostic markers in the introduced apple snail, Pomacea canaliculata and in the native Thai apple snails; Pila ampullacea, P. angelica, P. pesmei, and P. polita, were investigated by restriction analysis of COI and are reported for the first time. Twenty-one composite haplotypes showing non-overlapping distributions among species were found. Genetic heterogeneity analysis indicated significant differences between species (P < 0.0001) and within P. pesmei (P < 0.0001) and P. angelica (P < 0.0004). No such heterogeneity was observed in Pomacea canaliculata (P > 0.0036 as modified by the Bonferroni procedure), P. ampullacea (P = 0.0824-1.000) and P. polita (P = 1.0000). A neighbor-joining tree based on genetic distance between pairs of composite haplotypes differentiated all species and indicated that P. angelica and P. pesmei are closely related phylogenetically. In addition, the 16S rDNA of these species was cloned and sequenced. A species-specific PCR for P. canaliculata was successfully developed with a sensitivity of detection of approximately 50 pg of the target DNA template. The amplification of genomic DNA (50 pg and 25 ng) isolated from the fertilized eggs, and juveniles (1, 7, and 15 d after hatching) of Pomacea canaliculata was also successful, and suggested that Pomacea canaliculata and Pila species can be discriminated from the early stages of development.     

Wetland Restoration and Invasive Species: Apple snail (Pomacea insularum) Feeding on Native and Invasive Aquatic Plants

The apple snail Pomacea insularum is an aquatic invasive gastropod native to South America that has the potential to cause harm to aquatic ecosystems, wetland restoration, and agriculture. To predict the potential impact of this snail on aquatic ecosystems, we tested the feeding rate of P. insularum , under laboratory nonchoice experiments, for 3 species of invasive macrophytes and 13 species of native aquatic plants that are important for wetland restoration and health. High levels of consumption were recorded for four native species ( Ceratophyllum demersum , Hymenocallis liriosme , Ruppia maritima , and Sagittaria lancifolia ) and three invasive species ( Colocasia esculenta , Alternanthera philoxeroides , and Eichhornia crassipes ). In contrast, less than 10% of the biomass of Spartina alterniflora , Scirpus californicus , Thalia dealbata , and Typha latifolia was consumed by P. insularum over the test period. The palatability of macrophytes was negatively correlated with dry matter content, making our results generalizable to all regions where this invader may be present. Based on our results, wetland restoration in areas invaded by P. insularum should focus on emergent structural species with low palatability. Apple snails should not be considered as agents of biocontrol for invasive plants; although apple snails fed on invasive plants at a high rate, their consumption of many native species was even greater.     

Feeding and growth of native,invasive and non-invasive alien apple snails (Ampullariidae) in the United States: Invasives eat more and grow more

The United States hosts one native and five non-native species of aquatic apple snails (Ampullariidae). All are currently found in or around the Everglades in Florida. Two of these introduced species have devastated wetlands in Southeast Asia, but little is known about how they may impact the Everglades. To evaluate potential impacts of introduced apple snails relative to the native species, we investigated plant species preference, consumption rates, growth rates, and growth efficiencies in five introduced and the single native species across eight native macrophytes common in the Everglades. Three of the non-native snails are invasive, one has shown no tendency to expand, and one appears to have minimal direct impact on macrophytes due to its diet. All snails exhibited similar feeding preferences, with Utricularia sp. being the most preferred, Bacopa caroliniana, Sagittaria latifolia, and Nymphaea odorata being of intermediate preference, and Eleocharis cellulosa, Pontederia cordata, Panicum hemitomon and Typha sp. being least preferred (avoided as foods). Consumption and growth was minimal for P. diffusa on all macrophytes. On Utricularia sp. and Bacopa caroliniana, the invasive species Pomacea insularum and P. canaliculata tended to eat more, grow more, and have higher conversion efficiencies than the native P. paludosa or the non-invasive P. haustrum. These contrasts were more often significant for P. insularum than for P. canaliculata. The greater rates of expansion by the invasive species may derive from their enhanced feeding and growth rates.     

Radular ultrastructure of South American Ampullariidae (Gastropoda: Prosobranchia).

The radula of five species of South American Ampullariidae was analysed by Scanning Electron Microscope (SEM) with the purpose of enlarging new studies on the systematic of this family. The studied species were Pomacea canaliculata (Lamarck, 1822), Pomacea scalaris (d'Orbigny, 1835), Pomella (P.) megastoma (Gray, 1847), Asolene (A.) platae (Maton, 1809) and Felipponea neritiniformis (Dall, 1919). The central tooth shows different attributes which provide the means for generic determination; the analysis of the central tooth, the lateral and marginal ones by SEM adds further information for species differentiation.     

Compositional similarity and the distribution of geographical range size for assemblages of native and non-native species in urban floras

There is evidence that, within a region, non-native species introduced from nearby sources (extralimital native) promote homogenization and non-native species introduced from distant sources (exotic) promote differentiation of species composition. A possible explanation for these associations is that they are related to differences in the distribution of geographical range size. We test this by examining geographical ranges, delineated within a defined region, for assemblages of vascular plants in eight urban floras in the USA. Across floras, native species had the largest, least variable ranges and the greatest proportion of shared species. Exotic species had the most variable ranges with concentrations of species with small and large ranges and the lowest proportion of shared species. Extralimital natives had concentrations of species with intermediate-sized ranges and intermediate proportions of shared species. These results suggest that patterns of compositional similarity were associated with the relative strength and equality of two opposing patterns within species range size distributions: species with small vs. large ranges. In general, concentrations of species with small ranges promoted low levels and concentrations of species with large ranges promoted high levels of compositional similarity. However, patterns documented for exotic species will likely continue to develop, possibly taking on new forms, depending on how geographical distributions and the rate of introductions of exotic species change over time. Our findings also suggest that processes underlying these patterns have operated at two spatiotemporal scales. The first scale reflects historical consequences of anthropogenic activities occurring within regional extents that have promoted the introduction of extralimital natives; the second scale reflects modern consequences of anthropogenic activities operating at an increasingly global extent that have promoted the introduction of exotic species.     

Exceeding its own limits: range expansion in Argentina of the globally invasive apple snail Pomacea canaliculata

Hydrobiologia - Pomacea canaliculata is a freshwater snail native to southern South America. The aims of this work are to update its distribution in Argentina and to analyze through niche models...     

Multiple introductions of two invasive Centaurea taxa inferred from cpDNA haplotypes

Knowing the origin of invasive taxa, whether multiple introductions have occurred, and levels of genetic variation relative to the native range, is vital to conducting rigorous tests of hypotheses to explain biological invasions. We explore phylogeographical relationships of two Eurasian knapweed taxa that are invasive in North America, Centaurea diffusa and C. stoebe micranthos (Asteraceae), using chloroplast DNA intron sequences. We also gathered data from C. stoebe stoebe , hybrids between C. diffusa and C. stoebe stoebe ( C. x psammogena ), and three other species in the genus. We sequenced 213 individuals from Eurasia and North America, and found 22 haplotypes. Centaurea diffusa has lower haplotype diversity and allelic richness in the introduced range relative to the native range. Even with reduced variation, the data suggest at least two introductions of C. diffusa . There is a trend towards reduced variation in C. stoebe micranthos , but it is not significant. One of the haplotypes found in North American C. stoebe micranthos matches a haplotype from a taxon other than C. stoebe micranthos in Europe. This suggests introgression of the chloroplast between taxa, or possibly the invasion of another Centaurea taxon into North America. Additionally, C. diffusa , C. stoebe micranthos , and C. stoebe stoebe share several haplotypes, including their most common haplotype. This suggests ongoing hybridization between the species or incomplete segregation. These data can guide further exploration for the origins of these species, and point out locations within the introduced range with unique and diverse genetic makeup.     

DNA bar-coding reveals source and patterns of <Emphasis Type="Italic">Thaumastocoris peregrinus</Emphasis> invasions in South Africa and South America

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.     

福寿螺的过冷却研究

福寿螺是IUCN认定的世界100种恶性外来入侵物种之一,在华南地区已对水稻生产造成严重危害。福寿螺属于热带软体动物,采用万用电表联接热敏电阻法研究了福寿螺在低温胁迫下的过冷却点,并探讨了不同个体福寿螺在过冷却发生后的死亡率和体内组织损伤。结果表明: 1)各种螺高的福寿螺冷却点均值为-6.96 ℃,范围在-6.21--7.32 ℃之间,恢复最高体温均值为-4.07 ℃,范围在-3.07--4.93 ℃之间,过冷却后维持时间均值为45.97 min,范围在18.60-75.34 min;2)福寿螺的过冷却点大小受螺高影响,螺高35 mm≤H<45 mm的福寿螺过冷却点显著高于5 mm≤H<15 mm、15 mm≤H<25 mm、25 mm≤H<35 mm体型的福寿螺,5-35 mm螺高的福寿螺过冷却点变化稳定;3)福寿螺在发生过冷却阶段的死亡率在23.33%-36.67%之间,不同体型的福寿螺之间没有显著性差异;4)过冷却后福寿螺死亡率随暴露时间的延长而提高,0到15 min内由20.9%提高到100%,过冷却后暴露时间对福寿螺死亡率影响较大;5)发生过冷却15 min后取出的福寿螺,染色后其外套膜有少量红色出现,而肾部和消化腺部未呈现明显红色,低温胁迫已经对福寿螺组织造成了显著损伤。本研究结果对于进一步探索福寿螺的生态适应性、扩散北界及福寿螺的越冬机制有一定参考价值。     

Herbivore preference for native vs. exotic plants: generalist herbivores from multiple continents prefer exotic plants that are evolutionarily naïve

Enemy release and biotic resistance are competing, but not mutually exclusive, hypotheses addressing the success or failure of non-native plants entering a new region. Enemy release predicts that exotic plants become invasive by escaping their co-adapted herbivores and by being unrecognized or unpalatable to native herbivores that have not been selected to consume them. In contrast, biotic resistance predicts that native generalist herbivores will suppress exotic plants that will not have been selected to deter these herbivores. We tested these hypotheses using five generalist herbivores from North or South America and nine confamilial pairs of native and exotic aquatic plants. Four of five herbivores showed 2.4-17.3 fold preferences for exotic over native plants. Three species of South American apple snails (Pomacea sp.) preferred North American over South American macrophytes, while a North American crayfish Procambarus spiculifer preferred South American, Asian, and Australian macrophytes over North American relatives. Apple snails have their center of diversity in South America, but a single species (Pomacea paludosa) occurs in North America. This species, with a South American lineage but a North American distribution, did not differentiate between South American and North American plants. Its preferences correlated with preferences of its South American relatives rather than with preferences of the North American crayfish, consistent with evolutionary inertia due to its South American lineage. Tests of plant traits indicated that the crayfish responded primarily to plant structure, the apple snails primarily to plant chemistry, and that plant protein concentration played no detectable role. Generalist herbivores preferred non-native plants, suggesting that intact guilds of native, generalist herbivores may provide biotic resistance to plant invasions. Past invasions may have been facilitated by removal of native herbivores, introduction of non-native herbivores (which commonly prefer native plants), or both.     

入侵生物金苹果螺在滇池流域的首次记（英文）

2004年10月,中国科学院昆明动物研究所首次发现金苹果螺(Pomacea canaliculata)入侵重要的水源保护区嵩明白邑黑龙潭。金苹果螺起源于中南美洲,在亚洲,它通过有意或无意的传播而逐渐扩散到菲律宾、越南、泰国、老挝、柬埔寨、马来西亚、印尼、巴布几内亚、韩国、日本和中国的南部。金苹果螺已成为水稻产区的最大害虫,给农业生产带来巨大的损失。为防止金苹果螺在云南扩散,目前已经实施了严格的预防、控制措施,同时开展了公众保护教育宣传活动。     

西湖水域外来生物福寿螺的种类鉴定及种群遗传多样性研究

为了解杭州西湖景区外来生物福寿螺的分布现状和群体遗传变异特征,研究详细调研了西湖景区福寿螺的分布现状,并针对连续六年采集的福寿螺样本开展了分子鉴定及种群遗传多样性研究.调查结果表明,西湖福寿螺集中发生在苏堤以西,其中西北部的西里湖、茅家埠、杭州花圃及岳湖水域的发生密度高,在西南部的乌龟潭、浴鹄湾等水域发生密度较低.在6...     

Food Preference and Reproductive Plasticity in an Invasive Freshwater Snail

The freshwater apple snail Pomacea canaliculata has become a major crop pest in southeast Asia and Hawai'i and threatens natural wetland habitats in these regions and elsewhere. Deliberately introduced as a potential human food resource, it has also been proposed as a possible biocontrol agent against aquatic weeds. Various factors may facilitate its rapid invasion of new areas; we focus on two: growth rate and food preference. Our field observations and laboratory experiments suggest that in Hawai'i P. canaliculata reaches reproductive maturity in 10 months or more, less time than in its native temperate and seasonal Argentina, where it takes 2 years, but longer than in parts of southeast Asia, where it may take as little as 2 months. This increased growth rate, and thence reproductive rate, probably facilitate rapid population growth. Although P. canaliculata is usually considered an indiscriminate generalist macrophytophagous feeder, laboratory experiments indicated preferences among the dominant plants at our field site and growth rate differences when constrained to feed only on one of these plants. Water hyacinth (Eichhornia crassipes), a major invasive weed, was not preferred in food choice experiments, and snails offered only water hyacinth on which to feed did not differ in growth rate from unfed snails. Another important invasive weed, water lettuce (Pistia stratiotes), was also not preferred, but snails fed on it did grow, though not as quickly as those fed on green-leaf lettuce. Among the food plants offered in the experiments the native Vigna marina was the most preferred. Therefore, although a generalist, P. canaliculata exhibits some discrimination among food plants. We recommend that it not be introduced for use as a biological control agent for aquatic weeds.     

Threat of non-native crayfish introductions into Turkey: global lessons

Introductions of crayfish species from their home range to new environments have been carried out in many parts of the world. The most important introduced crayfish species are Procambarus clarkii, Pacifastacus leniusculus, Cherax destructor, C. quadricarinatus, Orconectes limosus, O. rusticus and Astacus leptodactylus. The environmental impact of crayfish introductions can be positive, negative or neutral. However, native crayfish populations in Europe have been negatively affected by introductions of non-indigenous crayfish species from America. Negative effects of non-native crayfish introductions included displacement of native crayfish species, transfer of disease (crayfish plague), consumption of fish eggs, reduction of fish stocks, consumption of large amounts of macrophytes, indirect and direct effects on other invertebrates and upsetting production in rice fields. As a result of non-native crayfish introductions, the natural harvest and crayfish industry in Europe have been severely affected. Large quantities of Turkish A. leptodactylus were harvested (approximately 7,000 tonnes annually) and exported to Europe before the crayfish plague was observed in these populations. The total harvest of A. leptodactylus in Turkey reduced dramatically to 320 in 1991 after the plague. Therefore, although Turkey currently has no known non-native crayfish species, there is a threat of non-native crayfish introduction in order to increase crayfish productions and subsequent harvest. The North American spiny-cheek crayfish, O. limosus, has been spreading quickly down the River Danube and could soon reach neighboring countries including Turkey. The North American signal crayfish, P. leniusculus is known from Greece and could be a threat to native stocks if it is introduced into Turkey for aquaculture. Additional threats may come from the release of other North American species, which are widely available through the aquarium trade. We conclude that the spread of non-native crayfish introductions throughout Turkey will increase local problems, because introductions of non-native crayfish in many parts of the world have been known to have caused important reductions in population density and numbers of native crayfish species. Furthermore, freshwater ecosystems may be altered by such introductions and the economic viability of native crayfish species fisheries could be severely reduced in Turkey.     

蓖麻籽提取液对福寿螺毒杀效果及作用机制

采用生物浸泡法,以草本植物蓖麻籽提取液制备植物源毒杀剂,研究不同提取液浓度(0、0.5、1.5、3.0、4.5、6.0 g/L)对福寿螺毒(Pomacea canaliculata Lam)杀作用效果,并通过福寿螺在亚致死浓度1.58(LC25)、3.82(LC50)和6.05 g/L(LC75)处理条件下的肝脏组织生...     

Neglected native or undesirable alien? Resolution of a conservation dilemma concerning the pool frog Rana lessonae

Introduced species often pose serious threats to biodiversity, but occasionally confusion arises as to whether a species really is introduced or is in fact an overlooked native. A recent UK conservation dilemma has centred on the status of the pool frog Rana lessonae. This species has been the subject of documented introductions from central and southern Europe since the early 1800s, the accepted position being that all UK R. lessonae populations are descended from these introductions. However, a closer examination of early UK literature sources, and recent discoveries of isolated, native R. lessonae populations in Sweden and Norway, led some herpetologists to question whether the species was in fact present as a native at some locations prior to the introductions. Research was initiated along four major lines of enquiry: genetic, bioacoustic, archaeozoological and archival. A high degree of convergence among the genetic and bioacoustic investigations demonstrated that the potentially native UK pool frogs were closely related to Scandinavian frogs, thus ruling out introductions from further south as a potential origin. Subfossil evidence of pool frogs was found from ca. 1000 years before present, demonstrating that the species occurred in the UK prior to known introductions. Archival sources produced no historical support for introductions from northern Europe. The postglacial history inferred for these northern populations is consistent with the known climatic and geographical conditions. Taken together, the evidence for the native status of the pool frog is compelling, and furthermore the UK population appears to be part of a distinct northern clade.