First record of Synidotea laevidorsalis (Miers, 1881) (Crustacea: Isopoda) in Europe (Gironde estuary,France)

This note reports on the presence of a well established population of the isopod Synidotea laevidorsalis (Miers) in the Gironde estuary (southwestern France). This species is new for the European fauna. S. laevidorsalis is a nonendemic cool-temperate to subtropical, shallow-water species which was probably introduced into the study area from Asia. In the salinity range of 1 to 10 g 1^-1 of the Gironde the species constitutes an important component of the brackish-water hyperbenthic community. The population was already present in 1975 when it was misidentified as the native species Idotea emarginata (Fabricius).     

The genusPicris (Asteraceae,Lactuceae) in Tropical Africa

Three species of the genusPicris L. are native in Tropical Africa:P. abyssinica Sch. Bip. (Ethiopia),P. xylopoda Lack, spec. nova (Nigeria, Ethiopia) andP. humilis DC. (Senegal, Mali). There are indications that the two perennial species,P. abyssinica andP. xylopoda, are related to and have evolved from a primitive Central Asiatic stock in a manner parallel to many African species ofCrepis L.P. humilis, on the other hand, is a small annual plant with a high number of derived characters. The introduced species of European origin growing south of the Sahara are briefly mentioned.     

Invasive mosquitoes, larval competition, and indirect effects on the vector competence of native mosquito species (Diptera: Culicidae)

Invasive arthropods that vector pathogens have the potential to influence pathogen transmission both directly, by becoming a novel pathogen vector, or indirectly, by interacting with native vectors. Adult mosquito size is influenced by food availability in the larval stage, and smaller, nutrient-deprived mosquitoes are, in some studies, more efficient viral vectors in the laboratory. This is the first study to examine the indirect impacts that larval competition between Aedes albopictus, an introduced mosquito species, and Ochlerotatus triseriatus, a native mosquito species and the primary vector for La Crosse virus (LACV) in the US, has on native mosquito larval survival, adult size, and vector competence. A. albopictus presence decreased Oc. triseriatus larval survival, but surviving Oc. triseriatus females were larger, potentially owing to a release from intraspecific competition. These larger, native females were more likely to develop both midgut and disseminated LACV infections than females emerging from monospecific treatments. Collectively, these results suggest a need to better understand the ecology of both native and invasive vector species, their interactions, and the potential for those interactions to alter vector-borne disease transmission.     

Suitability of exotic and native lady beetle eggs (Coleoptera: Coccinellidae) for development of lady beetle larvae

Predation upon lady beetle (Coleoptera: Coccinellidae) eggs in the field is most often instances of egg cannibalism by larvae or adults while the majority of the remaining predation events upon coccinellid eggs is done by other species of Coccinellidae. Thus the recent introduction and establishment of Harmonia axyridis in the US could negatively affect native species of Coccinellidae via egg predation. However, little is known regarding the suitability of interspecific coccinellid eggs as a food source for larval development. In this study, it was found that native first or third instar Coleomegilla maculata and Olla v-nigrum larvae were incapable of surviving to the adult stage when provided solely exotic H. axyridis eggs. In stark contrast, H. axyridis larvae survived equally well when cannibalizing eggs or eating eggs of either native species. When C. maculata and O. v-nigrum were grouped as ‘native’ and compared with the exotic H. axyridis, more native eggs were attacked than exotic eggs and a higher percentage of eggs was attacked by H. axyridis larvae. Native and exotic larvae attacked a similar percentage of native eggs but native larvae attacked significantly fewer exotic eggs than did exotic larvae. These data suggest that H. axyridis may prey upon the eggs of these native species, when encountered in the field, compared with the likelihood of the native species preying upon H. axyridis eggs. Therefore, eggs of the native species C. maculata and O. v-nigrum will continue to be subjected to cannibalism and also to possible predation by other native species and the exotic H. axyridis.     

Host specificity testing and suitability of the parasitoidMicroctonus hyperodae (Hym.: Braconidae,Euphorinae) as a biological control agent ofListronotus bonariensis (Col.: Curculionidae) in New Zealand

The behaviour of the parasitoidMicroctonus hyperodae Loan was studied under quarantine conditions to determine its likely host range in New Zealand. The species was imported from South America as a potential biological control agent of Argentine stem weevil,Listronotus bonariensis (Kuschel). The study involved systematic evaluation of the parasitoid's behaviour when exposed to 24 non-host weevil species; all but three of these were native to New Zealand. Of those tested, four were found to sustain someM. hyperodae development. However, further examination showed that in all but one species,Irenimus aequalis (Broun), parasitoid development was impeded, with up to 50% of the larvae becoming encapsulated. Overall, those weevil species that were attacked produced only 19% of the parasitoids derived fromL. bonariensis controls. As an adjunct to this quarantine study, a review of the habitats of the native weevil and target pest populations indicated that refugia would probably exist for native alpine species. I. aequalis was not considered to be threatened byM. hyperodae as this weevil has benefited from the advent of European agricultural systems to the extent that it is now recognised as a minor pest. In view of its relatively oligophagous behaviour, the parasitoid was recommended as suitable for release.      

A genetic contribution to the taxonomy ofOenothera sect.Oenothera (including subsectionsEuoenothera,Emersonia, Raimannia andMunzia)

Based on an analysis of results from experimental hybridization, the plants assigned byMunz toOenothera subg.Oenothera and subg.Raimannia, now divided into approximately 76 species, are referred to a single section,Oenothera. This section is in turn divided into five subsections:Euoenothera, Munzia, Raimannia, Emersonia, and an undescribed group of three species related toOenothera pubescens. Euoenothera is maintained in the traditional sense, and includes about 14 species of North America, widely naturalized elsewhere.Munzia consists of 45 species, comprising three series, and native to South America.Raimannia is restricted to a group of approximately 11 North American species.Emersonia comprises four rather heterogenous species of northern Mexico and southern New Mexico, of whichOenothera macrosceles, O. maysillesii, andO. organensis have been described. Within these four subsections, interspecific hybrids can be made in general, although plastid differentiation often leads to incompatibilities. With varying degrees of difficulty, hybrids were produced in all intersectional combinations involvingEuoenothera, Emersonia, Munzia, andRaimannia, the most difficult being those betweenEmersonia andRaimannia. Based on their habit and distribution,Emersonia species, and especiallyOenothera maysillesii, appear to resemble most closely the common ancestor of the section,Euoenothera andMunzia to have been derived from it or its common ancestor, andRaimannia perhaps to be more closely related to the phylogenetic branch that leads toEuoenothera.     

Giants invading the tropics: the oriental vessel fern, Angiopteris evecta (Marattiaceae)

The Oriental vessel fern, Angiopteris evecta (G.Forst.) Hoffm. (Marattiaceae), has its native range in the South Pacific. This species has been introduced into other localities since the 18th century and is now listed as an invasive species in several regions (Jamaica, Hawaii and Costa Rica). The purpose of our study is (1) to trace the distributional history of the species, and (2) to model its potential future range based on climatic conditions. The native range and the history of introduction are based on the existing literature and on 158 specimens from 15 herbaria, together with field observations. As there are taxonomic problems surrounding A. evecta, we limited our analysis to samples from the Pacific, most closely resembling the type from Tahiti. We modelled the potential range using GARP species distribution modelling with basic climatic variables, elevation, and location in relation to the coast. Analysis of past records shows that the species is able to colonise new ecosystems with relative ease. The modelling reveals that the species could be cultivated over a much wider range than where it currently is grown. The escape of cultivated plants into nature is probably due to distance from natural areas and is limited by local ecological factors, such as soil conditions or competitors. The predicted distribution in Asia and Madagascar is similar to the native distribution of the entire genus Angiopteris. It can therefore be assumed that most Angiopteris species have similar climatic preferences, and the absence of A. evecta in this predicted region may be due to dispersal limitation. In the Americas there is no native Angiopteris, but our climatic model predicts a vast potential habitat in tropical America; an invasion of A. evecta should be anticipated here in localities where the species is cultivated. Vessel ferns are known to alter the natural environment, which may reduce local biodiversity. Since A. evecta is not yet widely cultivated, it is advisable to restrict the trade and spread of the species and to discourage its cultivation as an ornamental. The global climate data available for modelling is however not detailed enough to predict the spread of A. evecta on a local or regional scale.     

Tumbleweed (Salsola, section Kali) species and speciation in California

Tumbleweeds (Salsola species, section Kali) are road side and rangeland pest plants throughout the 48 contiguous states in the US. Three described tumbleweed species and two undescribed Salsola taxa occur in California. The known species are Russian thistle, Salsola tragus, introduced from Eurasia in the 1800s, Russian barbwire thistle, S. paulsenii, which grows in the desert regions of California, and is also native to Eurasia, and the recently identified S. kali subspecies austroafricana, possibly native to South Africa. Our goals were to investigate karyology, genome size, and molecular genetic affinities of the described species and the other taxa within their ranges in California using recently developed microsatellite loci, dominant nuclear DNA markers (RAPD and ISSR), and DNA sequence data. Chromosome counts and genome size assessments made with flow cytometry were compared. These analyses indicated that one undescribed taxon is a new allopolyploid hybrid between S. tragus and S. kali subspecies austroafricana, and the other undescribed taxon appears to be a complex hybrid involving all three described species. The invasion potentials for the hybrid taxa are unknown. Tumbleweeds are the focus of biological controls efforts but the identification of suitable agents for the hybrid taxa may be problematic because of the large amount of genetic variability encompassed within this evolving Salsola complex.     

Soil water exploitation after fire: competition between Bromus tectorum (cheatgrass) and two native species

Summary Causes for the widespread abundance of the alien grass Bromus tectorum (cheatgrass) after fire in semiarid areas of western North America may include: (1) utilization of resources freed by the removal of fireintolerant plants; and (2) successful competition between B. tectorum and individual plants that survive fire. On a site in northwestern Nevada (USA), measurements of soil water content, plant water potential, aboveground biomass production, water use efficiency, and B. tectorum tiller density were used to determine if B. tectorum competes with either of two native species (Stipa comata and Chrysothamnus viscidiflorus) or simply uses unclaimed resources. Soil water content around native species occurring with B. tectorum was significantly lower (P<0.05) than around individuals without B. tectorum nearby. Native species had significantly more negative plant water potential when they occurred with B. tectorum. Aboveground biomass was significantly higher for native species without B. tectorum. However, the carbon isotope ratio of leaves for native species with B. tectorum was not significantly different from individuals without B. tectorum. Thus, B. tectorum competes with native species for soil water and negatively affects their wate status and productivity, but the competition for water does not affect water use efficiency of the native species. These adverse effects of B. tectorum competition on the productivity and water status of native species are also evident at 12 years after a fire. This competitive ability of B. tectorum greatly enhances its capability to exploit soil resources after fire and to enhance its status in the community.     

警惕杰克贝尔氏粉蚧Pseudococcus jackbeardsleyi Gimpel & Miller在中国大陆扩散

杰克贝尔氏粉蚧原产于新热带区,是新近传入中国大陆的一种外来生物,主要危害水果、蔬菜、园林植物和粮食作物。该虫于2012年首次在我国海南乐东被发现,寄主植物为丝瓜;之后又在新疆乌鲁木齐的花卉市场被发现,寄主植物为来自广东或福建的盆景人参榕。杰克贝尔氏粉蚧寄主范围广泛,涉及50科200多种,且极易随农产品的贸易活动进行远距离传播扩散,对我国农林产业的安全生产构成了潜在巨大威胁。概述了杰克贝尔氏粉蚧的地理分布和生物学特征,浅析了其在我国的传播扩散趋势,并从物种鉴定、生物防治和检验检疫处理等方面提出了防控建议,以期为有效预防和控制该种粉蚧在我国的进一步传播扩散提供参考。     

中国禾本科植物新资料(I)

报道了2种禾本科植物,曲序黄花茅[Anthoxanthum flexuosum（Hook.f.）Veldkamp]在西藏的新分布,外来物种弗吉尼亚须芒草（Andropogon virginicus L.）在江西的归化,并提供了它们详细的形态学描述、图版、分布及生境等信息。此外,还讨论了弗吉尼亚须芒草的潜在入侵危险。     

Host specificity ofAceria (Eriophyes) malherbe, [Acari: Eriophyidae], a biological control agent for the weed,Convolvulus arvensis [Convolvulaceae]

The host specificity of the gall mite,Aceria (Eriophyes) malherbe (Nalepa), from Greece was studied under quarantine conditions at Albany, California USA. Of the species, ecotypes, or strains tested, onlyConvolvulus andCalystegia spp. supported gall formation and mite reproduction. Although 2 of the native, North AmericanCalystegia species that served as laboratory hosts are threatened or endangered species,A. malherbe is considered safe for release in the USA as a biological control agent of the weed,Convolvulus arvensis (L.).      

Diploid male production in a rare and locally distributed bumblebee, Bombus florilegus (Hymenoptera, Apidae)

The European bumblebee B. terrestris was recently introduced in Japan for agricultural purposes and has now become naturalized. The naturalization of this exotic species may have great detrimental effects on closely related native Japanese bumblebees. The Japanese bumblebee Bombus florilegus is a rare and locally distributed species found in the Nemuro Peninsula of Hokkaido, Japan. In order to assess its population genetics, we estimated the genetic structure of B. florilegus in 16 breeding colonies (queen, workers, and males) and 20 foraging queens by analyzing microsatellite DNA markers. Of the 36 queens analyzed by genotyping and dissection, 32 had been inseminated by a male. The remaining 4 had not been inseminated at all. Of the 4 nonmated queens, one was triploid. Diploid males were found in 4 breeding colonies. Based on the microsatellite data, it appears that B. florilegus has low reproductive success. Since matched mating and nonmating within local populations are high, the extinction risk is correspondingly higher. Our results suggest that conservation of the Japanese B. florilegus is required in order to protect it from both habitat destruction and the naturalization of alien species. Received 19 July 2007; revised 13 October 2007; accepted 15 October 2007.     

Competitive effects of the invasive shrub,Lonicera maackii (Rupr.) Herder (Caprifoliaceae), on the growth and survival of native tree seedlings

Invasive plants are often associated with reduced cover of native plants, but rarely has competition between invasives and natives been assessed experimentally. The shrub Lonicera maackii, native to northeastern Asia, has invaded forests and old fields in numerous parts of eastern North America, and is associated with reduced tree seedling density in Ohio forests. A field experiment was conducted to test the effects of established L. maackii on the survival and growth of transplanted native tree species. The experiment examined above-ground competition (by removing L. maackii shoots) and below-ground competition (by trenching around transplanted seedlings). The effects of above-ground competition with L. maackii were generally more important than below-ground competition, though both were detected. Shoot treatment was the key determinant for the survival of all species except P. serotina, whereas trenching only enhanced survival for A. saccharum caged and P. serotina, and only in the shoot removal treatment. For the surviving seedlings, L. maackii shoot removal increased growth of A. saccharum seedlings protected with cages, but actually reduced the growth of unprotected Q. rubra and A. saccharum seedlings, indicating that L. maackii shoots confer some protection from deer browsing. Significant interactions between root and shoot treatment on Q. rubra growth parameters, specifically greatest growth in the shoot present & trenched treatment, is attributed to protection from deer browsing combined with release from below-ground competition. Despite this protective function of L. maackii shoots, the overall effect of this invasive shrub is increased mortality of native tree seedlings, suggesting it impacts the natural regeneration of secondary forests.     

An invasive aster (Ageratina adenophora) invades and dominates forest understories in China: altered soil microbial communities facilitate the invader and inhibit natives

Exotic plant invasion may alter underground microbial communities, and invasion-induced changes of soil biota may also affect the interaction between invasive plants and resident native species. Increasing evidence suggests that feedback of soil biota to invasive and native plants leads to successful exotic plant invasion. To examine this possible underlying invasion mechanism, soil microbial communities were studied where Ageratina adenophora was invading a native forest community. The plant–soil biota feedback experiments were designed to assess the effect of invasion-induced changes of soil biota on plant growth, and interactions between A. adenophora and three native plant species. Soil analysis showed that nitrate nitrogen (NO₃⁻-N), ammonium nitrogen (NH₄⁺-N), and available P and K content were significantly higher in a heavily invaded site than in a newly invaded site. The structure of the soil microbial community was clearly different in all four sites. Ageratina adenophora invasion strongly increased the abundance of soil VAM (vesicular-arbuscular mycorrhizal fungi) and the fungi/bacteria ratio. A greenhouse experiment indicated that the soil biota in the heavily invaded site had a greater inhibitory effect on native plant species than on A. adenophora and that soil biota in the native plant site inhibited the growth of native plant species, but not of A. adenophora. Soil biota in all four sites increased A. adenophora relative dominance compared with each of the three native plant species and soil biota in the heavily invaded site had greater beneficial effects on A. adenophora relative dominance index (20% higher on average) than soil biota in the non-invaded site. Our results suggest that A. adenophora is more positively affected by the soil community associated with native communities than are resident natives, and once the invader becomes established it further alters the soil community in a way that favors itself and inhibits natives, helping to promote the invasion. Soil biota alteration after A. adenophora establishment may be an important part of its invasion process to facilitate itself and inhibit native plants.     

The decline of native coccinellids (Coleoptera: Coccinellidae) in the United States and Canada

Reviewing published coccinellid surveys we found that the number of adventive species has increased steadily over the last century while the average proportion of native individuals has remained fairly constant until 1987 followed by a rapid decrease between 1987 and 2006. Seven long-term studies indicated that the total density of coccinellids increased by an average of 14% following establishment of adventive species, but this increase was not significant and in 4 of 7 cases the total density of coccinellids actually decreased following establishment. Similarly, no significant difference was found in comparisons of diversity across all studies. These results illustrate that even with multiple long-term data sets it is currently difficult to make any general conclusions regarding the impact adventive coccinellids have had on native coccinellid assemblages. However, it is clear that specific systems and species have seen major shifts in recent years. For example, adventives have become the dominant species in a third of the assemblages where they are found. Focusing on two formerly common native species, Adalia bipunctata and Coccinella novemnotata, we show they have become rare in their former ranges and discuss potential explanations for this phenomenon.     

The genetic diversity, relationships, and potential for biological control of the lobate lac scale, Paratachardina pseudolobata Kondo & Gullan (Hemiptera: Coccoidea: Kerriidae)

The lobate lac scale Paratachardina pseudolobata Kondo & Gullan (Kerriidae) is a polyphagous pest of woody plants in Florida (U.S.A.) the Bahamas, Christmas Island (Australia) and it has been reported from Cuba. Its recent appearance as a pest in these places indicates that this scale is introduced; however, its native range is unknown. Until 2006, this pest species was identified mistakenly as Paratachardina lobata (Chamberlin) [now P. silvestri (Mahdihassan)], which is native to India and Sri Lanka. Quarantine laboratory acceptance trials with Indian P. silvestri parasitoids indicated a strong immune response from P. pseudolobata. Gregarious development of encyrtid wasps was the only observed parasitism, but parasitization levels were below 3%. Identification of the native range of P. pseudolobata would facilitate the search for natural enemies better adapted to the scale. Sequence data from the D2–D3 region of the nuclear large subunit ribosomal RNA gene (LSU rRNA, 28S) and the mitochondrial gene cytochrome oxidase I (COI) distinguished P. pseudolobata from the morphologically similar species P. silvestri and P. mahdihassani Kondo & Gullan, and showed P. pseudolobata to be more closely related to these Indotropical species than to an Australian species of Paratachardina Balachowsky. Paratachardina pseudolobata was genetically uniform throughout its exotic range, consistent with a single geographic origin, although lack of variation in these genes is not unusual for scale insects. Molecular identification of morphologically similar Paratachardina species was possible using the D2–D3 region of 28S, despite its length variation, suggesting that this gene region might be suitable as a non-COI barcoding gene for scale insects.     

Bullying the Bullies: The Selective Control of an Exotic, Invasive Annual (Rapistrum rugosum) by Oversowing with a Competitive Native Species (Gaillardia pulchella)

Mechanical, biological, and chemical attempts to control invasive plants can be expensive, ecologically damaging, and frequently unsuccessful. This study proposes using the intrinsic biological attributes of the threatened plant community by artificially increasing the density of competitive native species to selectively suppress the growth of the invasive. Evidence from agricultural weed control suggests that oversowing infested areas with species with biological traits similar to those of the invasive species not only reduces productivity of the invasive species but also may eliminate environmental damage associated with standard control techniques. Annual bastard cabbage (Rapistrum rugosum), a Eurasian exotic, is an invader of native plant communities in the continental United States. Control with herbicides has been problematic due to high mortality of adjacent native species and subsequent perpetuation of a disturbed state that facilitates further regeneration of R. rugosum from the seed bank. In a randomized field experiment, sowing native Indian blanket (Gaillardia pulchella) over established seedling colonies of R. rugosum resulted in significant reduction of R. rugosum productivity (F= 3.43; p < 0.05). The highest sowing rate of G. pulchella resulted in a 72% reduction in aboveground productivity of R. rugosum that translated to an estimated 83% decrease in seed set, without significant suppression of adjacent native species. It is proposed that enriching threatened or infested plant communities with selected native species with matching phenologies and competitive characteristics has advantages over conventional control methods in that (1) it reduces the threat to nontarget organisms; (2) once installed, the species could self‐regenerate; and (3) it does not perpetuate a disturbed (early‐successional) state that might aggravate the problem. This may serve as an alternative technique to protect and restore native plant communities.     

Contribution of cocoa plantations to the conservation of native ants (Insecta: Hymenoptera: Formicidae) with a special emphasis on the Atlantic Forest fauna of southern Bahia,Brazil

By maintaining a forest-like structure, shaded cocoa plantations contribute to the conservation of ants that usually live in the soil, leaf litter or canopy of tropical forests. Here we synthesize the available information on the diversity and community structure of ants in shaded cocoa plantations in the Atlantic forest region of Brazil, compare ant assemblages in cocoa agroforests with forests and other forms of agriculture, and discuss how these shaded plantations contribute to the conservation of the ants in the Atlantic Forest region. We also discuss ants of economical importance and of special interest, including Camponotus, Dolichoderus, Gnamptogenys, Pachycondyla, Pseudomyrmex and other litter dwelling genera. We discuss the situation of the tramp ant Wasmannia auropunctata in the Bahian cocoa-producing region where it is considered as native, and that of the two cryptobiotic genera Thaumatomyrmex and Typhlomyrmex, as well as that of proven and possible endangered army ant and Ponerini species. A total of 192 ant species from four strata were found in extensive sampling of a cocoa plantation with a relatively simple shade canopy (comprised primarily of Erythrina). Species richness in the cocoa plantations corresponded roughly to that of low diversity native forests, and species composition of cocoa plantations was most similar to native habitats (forest and mangroves) while ant composition in other agricultural habitats was most similar to that of urban areas. Although occurrences of Wasmannia auropunctata were similar in cocoa plantations and forests, abundance of Thaumatomyrmex and Typhlomyrmex, generally thought to be rare ants, was relatively high in cocoa plantations. These results, from cocoa plantations with relatively simple shade, demonstrate the importance of cocoa for ant conservation in the Atlantic forest region of Brazil. It is likely that cocoa plantations with a greater number of vegetation strata and higher tree species richness (such as traditional cabruca plantations) provide even more important habitat for ants generally and for ant species of conservation concern.     

Isolation and characterization of microsatellite loci of Lycopodium fordii Bak. (Lycopodiaceae, Pteridophyta)

Lycopodium fordii Bak. (Lycopodiaceae, Pteridophyta) is a gardening plant with a native, fragmentary distribution in Taiwan. In this study, we described the development of eleven microsatellite loci in L. fordii for genetic studies. These new markers were tested in 16 individuals of three populations. The number of alleles ranged from 1 to 5 and the expected heterozygosity from 0.41746 to 0.72222. Four of the nine polymorphic loci were significantly deviated from Hardy-Weinberg expectations due to the heterozygote deficiency. The microsatellite markers have also been proved as informative genetic markers for other 15 Lycopodium species.