与特殊固氮模式草本菊科寄主植物有关的Sphenorhina属沫蝉（半翅目：沫蝉科）

据观察,沫蝉科Sphenorhina属的3个种都以菊科的Crassocephalum cerpidioides和Chromolaena ordorata 作为寄主植物,热带菊科植物与固氮植物有关,沫蝉可以作为菊科一些固氮植物的间接指示物,目前尚未得到很好研究。     

Global amphibian declines: a perspective from the Caribbean

Recent concern over the possibility of a global decline in amphibians prompted this assessment of the West Indian species. At the species level, the West Indian amphibian fauna (156 species, all frogs and toads) has not undergone a general decline, and no species is known to be extinct. However, one Puerto Rican species (Eleutherodactylus karlschmidti) has not been seen in over ten years despite considerable search effort. Seven other species, including the Puerto Rican livebearing frog (E. jasperi), have not been seen recently, although their present status cannot be determined until additional effort is made to locate them. Two stream-associated species on Hispaniola (E. semipalmatus and Hyla vasta) appear to have declined in recont years, probably due to the alteration of riparian habitats by deforestation. Other vertebrate groups in the West Indies, such as mammals, have been more affected by human-caused environmental degradation than have amphibians. Large-scale extinctions of frogs and other forest-dwelling species are not expected to occur until forest cover reaches very low levels. Haiti is on the brink of such extinctions with less than 1% of its forest cover remaining. Two recommendations are made to help curtail the expected loss of biodiversity: (i) import charcoal to replace that produced by burning native trees (used as cooking fuel), as an immediate measure, and (ii) control human population growth, as a long-term solution.     

Identifying indicator plant species of habitat quality and invasibility as a guide for peri-urban forest management

A floristic survey has been carried out in a peri-urban forest, the Sonian Forest in Brussels, to identify indicator plant species in the herbaceous layer, which could be used as an aid within the framework of a more sustainable management of the forest. Three hundred and seventy two (372) taxa have been identified, 33 of which are non-native (i.e. non-indigenous species regarding the study area, whether invasive or not). Criteria of habitat quality that have been chosen are the species richness, the commonness of the habitat, based on constitutive species, and its invasibility (vulnerability for invasion). On the basis of a comparison of the value of these criteria when each considered (potential indicator) species is present or not, 17 species have been recognised as reliable indicators of at least one of these three criteria. In particular, vegetation types containing either Anthriscus sylvestris, Galeopsis tetrahit or Senecio ovatus were found to be more susceptible to invasion than other habitats. The way to how the predictability of invasions might be effectively used as a management tool is discussed. Furthermore, we found a positive significant correlation (Bonferroni corrected probabilities) between the species richness and luminosity factor (derived from Ellenberg's indices), and the proportion of grassland and wetland species. The species richness was significantly negatively correlated with the proportion of woodland species. An increase in commonness was significantly correlated with a decrease in the proportion of geophytes. The usefulness of these results as an ecological basis for forest management is discussed.     

Species concepts and the recognition of ancestors

Whether or not ancestral species can be recognised depends on the species concept adopted. A “metaspecies”; is a species that completely lacks autapomorphies, and which might (or might not) be ancestral to other species. Such taxa have been identified among both living and fossil organisms. Under the most commonly‐used species concepts (biological, evolutionary, phenetic, phylogenetic, ecological, recognition and cohesion), “metaspecies”; can be assumed to be ancestral. Even if the known members of a metaspecies are not ancestral to anything, parsimony dictates that the (as yet unknown) ancestral lineage is identical to the metaspecies and, under these species concepts, assignable to the same species. Only the cladistic and monophyletic species concepts would deny “metaspecies”; ancestral status, but these species concepts are problematical and have never been used by practising systematists.     

Are species names proper names?

The nature of species names has been a source of controversy, and has played a role in developing ideas about the status of species, such as the species‐as‐individuals hypothesis. Some argue that species names are Millian proper names: names that have no meaning. Others have countered that species names are Millian general names that have stipulative definitions. Here I argue that species names belong to neither category. In particular, unlike Millian proper names, species names have unique referents and are connotative. Further, species names are names of intension that, unlike Millian general names, refer to specific collective entities. Because species names have unique properties not associated with Millian general or proper names, but recognizing the similarity to proper names in most respects, I propose that they be categorized as extra‐proper names.
     

Naturally prion resistant mammals

Each known abnormal prion protein (PrP^Sc) is considered to have a specific range and therefore the ability to infect some species and not others. Consequently, some species have been assumed to be prion disease resistant as no successful natural or experimental challenge infections have been reported. This assumption suggested that, independent of the virulence of the PrP^Sc strain, normal prion protein (PrP^C) from these ‘resistant’ species could not be induced to misfold. Numerous in vitro and in vivo studies trying to corroborate the unique properties of PrP^Sc have been undertaken. The results presented in the article “Rabbits are not resistant to prion infection” demonstrated that normal rabbit PrP^C, which was considered to be resistant to prion disease, can be misfolded to PrP^Sc and subsequently used to infect and transmit a standard prion disease to leporids. Using the concept of species resistance to prion disease, we will discuss the mistake of attributing species specific prion disease resistance based purely on the absence of natural cases and incomplete in vivo challenges. The BSE epidemic was partially due to an underestimation of species barriers. To repeat this error would be unacceptable, especially if present knowledge and techniques can show a theoretical risk. Now that the myth of prion disease resistance has been refuted it is time to re-evaluate, using the new powerful tools available in modern prion laboratories, whether any other species could be at risk.     

Extinctions of vascular plants in Spain

The catalogue of extinct plants in Spain, comprising 27 taxa is updated. Included are four species not previously classified as extinct in Spain: Cyclamen purpurascens, Grammitis quaerenda, Stratiotes aloides and Vallisneria spiralis. We analyze the causes of extinction and explore the possible influence of botanical collections in species loss. The obtained data suggest that habitat loss has been the main cause of extinction and the impact of collecting is demonstrated to be irrelevant. We list the 21 species that have been designated as extinct in previous catalogues but which no longer have that status, 14 of them having been recovered thanks to botanical exploration and collection works.     

C-band variability and phylogeny of Lacertidae

The karyology of various species from the family Lacertidae (Reptilia, Sauria) has been studied with conventional and C-banding techniques.The study shows that this family is not so conservative from a karyological viewpoint as considered till now. In fact a higher diploid number than that generally observed in most species of Lacertidae and supernumerary chromosomes have been observed in three of the species investigated. Moreover an evident interand intraspecific variability has been found in the C-banding pattern of the various species studied. The situation found in Podarcis sicula is particularly remarkable. Different C-banding patterns have been observed in three different subspecies and in two populations of the same subspecies. These variations do not show a well defined trend and their role in the evolution of lacertid lizards is discussed.The C-banding analysis evidences also the existence in two of the species studied of a female sex heteromorphism, in which the W chromosome has the same shape and size as the Z, but differs from it in being completely heterochromatic. This situation reminds that observed in some snakes and suggests that in lacertid lizards the evolution of sex chromosomes might have followed the same steps previously hypothesized for ophidians.     

Transformation of Mycoplasma capricolum and Examination of DNA Restriction Modification in M. capricolum and Mycoplasma mycoides subsp. mycoides

Plasmids pIKΔ and pIKΔ-erm have recently been developed as mycoplasmal cloning vectors. In this report, we demonstrate that these plasmids can replicate in Mycoplasma capricolum, a mycoplasmal species for which transformation had not previously been characterized. Both plasmids are stably maintained at a higher copy number than in their parental species, Mycoplasma mycoides subsp. mycoides. We have also examined the possibility of one or more restriction-modification systems affecting transformation frequencies in both species.     

Production and efficiency of protozoa

Despite the chronic and debilitative nature of the infection they cause, several species of microsporidia and neogregarines offer a good potential as microbial control agents, particularly against insect pests of high economic thresholds. Techniques for mass production of protozoa have usually involved per os, inoculation or injection of the protozoa into their usual or alternate hosts. The spores are harvested subsequently from heavily infected host tissues by grinding, filtration, and differential centrifugation. Although fresh spores are used in most field tests, the spores of many species can be stored with high survival either frozen or in water at low temperatures (0–4°C) for up to several months. Sunlight or ultraviolet (UV) radiation is a serious factor limiting spore persistence. However, the protozoa do not appear to be significantly limiting spore persistence. However, the protozoa do not appears to be significantly more susceptible to UV radiation than other insect pathogens and persistence can be prolonged with UV protectants. Most field tests with protozoa have involved the application of spores in sprays and have usually resulted in a high degree of infection in the target host species. The potential for control of few species has been improved by formulation of spores in to baits, and the potential of other species will likely increase if suitable bait formulation can be devised in the future. One species, Nosema locustae, formulated as a bait, has been successfully used to control grasshoppers on rangelands. Limited laboratory and field studies have also suggested that increased short-term control might be obtained if candidate protozoan species can be combined with certain insecticides. While recent and increased efforts have been devoted to assess the potential of protozoa as microbial control agents, potential hazards to nontarget organism have been investigated for only three species. Their close relation taxonomically to protozoa pathogenic for mammals will necessitate careful evaluation of the safety of candidate control species for nontarget organisms.     

Evolutionary consequences of ecological release in Caribbean Anolis lizards

On the large islands of the Greater Antilles, multi-species communities of Anolis lizards are composed of species specialized to use particular habitats; similar sets of specialized species have evolved independently on each island. We studied species of anoles found on small Caribbean islands. Because these islands contain at most only one other species of anole, we predicted that species on these islands should not be as specialized as Greater Antillean species; rather, they might be expected to exhibit a generalized morphology and a greater breadth of habitat use. Our findings, however, do not confirm these predictions. Lesser Antillean species do not exhibit greater breadth of habitat use than Greater Antillean species, nor do they exhibit a generalized morphology. Most species are ecologically and morphologically similar to specialized trunk-crown anoles of the Greater Antilles, although some species exhibit morphologies unlike those seen in Greater Antillean species. Among descendants of specialized Greater Antillean species occurring on one-or two-species islands, most descendants of trunk-crown species have diverged relatively little, whereas several descendants of trunk-ground anoles have diverged considerably. Consequently, we propose that ancestral species in the Greater Antilles may have been trunk-crown anoles.     

Molecular identification of two Trichogramma species (Hymenoptera: Trichogrammatidae) in Korea

Trichogramma wasps parasitize eggs of various insect species. Several Trichogramma species have been commercialized to manage Lepidopteran agricultural pests. Correct species identification is essential for successful biological control. However, the microscopic size and morphological similarity of Trichogramma species makes correct identification very difficult. Internal transcribed spacer (ITS)-2 gene sequences have been used to identify Trichogramma species. Using this molecular marker, Trichogramma species that are commercially available in Korea were identified as Trichogramma ostriniae and Trichogramma brassicae. The latter has not previously been reported in Korea. Additionally, Cadra cautella and Sitotroga cereallela eggs (host eggs of the commercialized Trichogramma species in Korea) were infected with Wolbachia. However, Trichogramma were not infected with the bacterium. This indicates that horizontal transfer of Wolbachia does not occur from host to wasp.     

Was istAcrosiphonia arcta?

No answer to this question is presented in this article. Two species, morphologically alike, differ in their life-cycles. One of these species has hitherto been found only once in a culture ofSpongomorpha aeruginosa, which was started using zoospores ofCodiolum petrocelidis. It has never been found in natural environments at Helgoland. This species has a heteromorphic life-cycle: a monoecious gametophyte which alternates with a unicellular sporophytical stage. Gametes do not develop parthenogenetically. The other species is a monoecious diplont, common at Helgoland and designated asAcrosiphonia arcta. It will not be possible to assign a name to these forms unless life-cycles of species from type-localities have been studied. In general, life-cycles are not significant for the characterization of units higher than genera. The order of Acrosiphoniales is characterized by operculate sporangia and gametangia respectively, as well as by the shape of the vegetative thallus.     

A warning for ecologists and conservation biologists using species checklists: How the European marine fauna ‘lost’ all of its 16 <Emphasis Type="Italic">Discodoris</Emphasis> species (Mollusca: Gastropoda)

The European marine fauna used to be considered to include 16 species of Discodoris sea slugs until a recent worldwide revision demonstrated that there is not a single Discodoris species in European waters. This exemplary case illustrates the fact that species checklists do not accurately represent biodiversity unless they are based on sound taxonomic work in which (1) the status of every available species name has been addressed, i.e. whether it is valid, synonymous, or of doubtful application, and (2) classification reflects phylogenetic relationships. It is argued that taxonomic revisions are critically needed, because the status of species names can only be addressed properly through revisions. It is discussed that fields which depend on taxonomic data, such as conservation biology and ecology, might be affected deeply if problematic species names (synonyms and nomina dubia) have not been recognized. Consequently, it is proposed that a taxon that has not been revised be red-flagged in checklists, so that non-taxonomists will know which species names should be applied with caution or not at all.     

Trichome studies in Parthenium hysterophorus and their taxonomic importance

In Parthenium hysterophorus L. four trichome types i.e. (1) cylindrical hair, (2) moniliform hair, (3) simple multiseriate hair and (4) shaggy hair, have been recognized mostly on the basis of their structural differences. In the past, these types have not been observed in any species of Parthenium studied so far. Out of these four, two types i.e. cylindrical and moniliform hairs are known to occur in the Compositae and remaining two i.e. simple multiseriate and shaggy hairs are the new forms for the family and have been observed for the first time in presently investigated species. Trichomes are an important taxonomic tool in distinguishing between genera and species. Trichomes of the different species of Parthenium as noticed from their structure are useful in distinguishing these species and even their corresponding organs.     

A comparative location database (CompLDB): map integration within and between species

We have adapted the Location Database (LDB) map-integration strategy of Morton et al. [Ann Hum Genet 56:223–232] (1992) as above to create an integrated map for each of several species for which fully annotated genome sequences are not yet available (sheep, cattle, pig, wallaby), using all types of partial maps for that species, including cytogenetic, linkage, somatic-cell hybrid, and radiation hybrid maps. An integrated map provides not only predictions of the kilobase location of every locus, but also predicts locations (in cM) and cytogenetic band locations for every locus. In this way a comprehensive linkage map and a comprehensive cytogenetic map are created, including all loci, irrespective of whether they have ever been linkage mapped or physically mapped, respectively. High-resolution physical maps from annotated sequenced species have also been placed alongside the integrated maps. This has created a powerful tool for comparative genomics. The LDB map-integration strategy has been extended to make use of zoo-FISH comparative information. It has also been extended to enable the creation of a “virtual” map for each species not yet sequenced by using mapping data from fully sequenced species. All of the partial maps, together with the integrated map, for each species have been placed in a database called Comparative Location Database (CompLDB), which is available for querying, browsing, or download in tabular form at . Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Naturally prion resistant mammals: A utopia?

Each known abnormal prion protein (PrP^Sc) is considered to have a specific range and therefore the ability to infect some species and not others. Consequently, some species have been assumed to be prion disease resistant as no successful natural or experimental challenge infections have been reported. This assumption suggested that, independent of the virulence of the PrP^Sc strain, normal prion protein (PrP^C) from these ‘resistant’ species could not be induced to misfold. Numerous in vitro and in vivo studies trying to corroborate the unique properties of PrP^Sc have been undertaken. The results presented in the article “Rabbits are not resistant to prion infection” demonstrated that normal rabbit PrP^C, which was considered to be resistant to prion disease, can be misfolded to PrP^Sc and subsequently used to infect and transmit a standard prion disease to leporids. Using the concept of species resistance to prion disease, we will discuss the mistake of attributing species specific prion disease resistance based purely on the absence of natural cases and incomplete in vivo challenges. The BSE epidemic was partially due to an underestimation of species barriers. To repeat this error would be unacceptable, especially if present knowledge and techniques can show a theoretical risk. Now that the myth of prion disease resistance has been refuted it is time to re-evaluate, using the new powerful tools available in modern prion laboratories, whether any other species could be at risk.     

Chrysophycean scales as paleoindicators in the sediments of Hall Lake, Washington, U.S.A.

Twelve species of Mallomonas and ten species of other genera of Mallomonadaceae and Paraphysomonadaceae were found in sediments deposited in Hall Lake from about 1850 to the present. One Mallomonas species ( M. portue-ferreae peterfi & As-mund) was found that had not previously been reported from North America. The majority of the species have been described as either generally distributed or characteristic of acid or oligotrophic humic waters. M. heterospina Lund and M. multiunca Asmund, which were restricted to sediments deposited during the operation of a sawmill on the lake, have been collected from very eutrophic to dystrophic waters as well. On the whole the species composition indicates a change in the lake from oligotrophic to more eutrophic conditions.