130,399 research outputs found
No loss of genetic divergence in Torymus sinensis following its release for Dryocosmus kuriphilus control in Europe
No full textArrival, establishment, and further dispersal of non-native natural enemies are considered essential for a successful biological control programme, while among the factors that may determine the success of such a programme, genetic diversity of the introduced population plays an important role in the establishment of a non-native species. The Chinese parasitoid wasp Torymus sinensis Kamijo (Hymenoptera: Torymidae) was initially released in Europe in Italy to control biologically the Asian chestnut gall wasp Dryocosmus kuriphilus Yasumatsu (Hymenoptera: Cynipidae), and reduce the damage induced on sweet chestnut (Castanea sativa Miller). In the following years, T. sinensis was then released in numerous other European countries as a biological control agent of D. kuriphilus. Its presence has also been reported beyond the countries of release due to rapid natural dispersal. To assess the post-release genetic diversity of D. kuriphilus, we screened T. sinensis populations from six European countries and tested the possibility of these populations suffering from frequently observed genetic effects that could threaten its successful establishment in Europe. Our results exhibit that T. sinensis populations have suffered neither from the Allee effect nor from genetic bottleneck after their release and establishment in Europe, something that increases the possibility to effectively control D. kuriphilus in Europe
Tracking the origin and dispersal of the Asian chestnut gall wasp Dryocosmus kuriphilus Yasumatsu (Hymenoptera, Cynipidae) in Europe with molecular markers
No full textThe Asian chestnut gall wasp, Dryocosmus kuriphilus, is an invasive pest causing significant damage to chestnut trees (Castanea spp., Fagaceae). Originating from China, it has recently invaded a wide range of regions in Europe and North America. Understanding the population genetic structure of important invasive pests is very useful for improving the knowledge concerning routes of expansion and colonizing capacity. Despite its economic importance, limited attention has been given to D. kuriphilus origin and spread, or to its genetic structure. In this study, D. kuriphilus populations sampled in eight European countries were screened using both mitochondrial (cytochrome c oxidase subunit 1; COI) and nuclear (internal transcribed spacer 2; ITS2) sequences, and Amplified Fragment Length Polymorphism (AFLP) markers. The molecular markers COI and ITS2 highlighted the presence of a single haplotype in all the studied populations. The recorded mitochondrial haplotype was identical to one of the most widespread haplotypes occurring in the native area (China). AFLP results indicated that D. kuriphilus individuals belong to two genetically distinct clusters without any further geographic clustering. These results suggest that D. kuriphilus populations in Europe could be the result of a single introduction of a Chinese founder population characterized by two genetically distinct lineages that subsequently spread rapidly across Europe. However, the possibility that populations originated from multiple introductions of the same Chinese mitochondrial haplotype cannot be excluded. The reported results provide useful information concerning this invasive species, potentially facilitating integrated pest management
Tracking the origin and dispersal of the Asian chestnut gall wasp Dryocosmus kuriphilus Yasumatsu (Hymenoptera, Cynipidae) in Europe with molecular markers.
No full textThe Asian chestnut gall wasp, Dryocosmus kuriphilus, is an invasive pest causing
significant damage to chestnut trees (Castanea spp., Fagaceae). Originating from
China, it has recently invaded a wide range of regions in Europe and North
America. Understanding the population genetic structure of important invasive
pests is very useful for improving the knowledge concerning routes of expansion
and colonizing capacity. Despite its economic importance, limited attention has
been given to D. kuriphilus origin and spread, or to its genetic structure. In this
study, D. kuriphilus populations sampled in eight European countries were screened
using both mitochondrial (cytochrome c oxidase subunit 1; COI) and nuclear (internal
transcribed spacer 2; ITS2) sequences, andAmplified Fragment Length Polymorphism
(AFLP) markers. The molecular markers COI and ITS2 highlighted the presence of a
single haplotype in all the studied populations. The recorded mitochondrial haplotype
was identical to one of the most widespread haplotypes occurring in the native area
(China). AFLP results indicated that D. kuriphilus individuals belong to two genetically
distinct clusters without any further geographic clustering. These results suggest
that D. kuriphilus populations in Europe could be the result of a single introduction
of a Chinese founder population characterized by two genetically distinct lineages
that subsequently spread rapidly across Europe. However, the possibility that populations
originated from multiple introductions of the same Chinese mitochondrial
haplotype cannot be excluded. The reported results provide useful information concerning
this invasive species, potentially facilitating integrated pest management
Saphonecrus kuriphilusi Melika & Memtsas & Nicholls & Avtzis 2018, new species
No full textSaphonecrus kuriphilusi Melika & Avtzis, new species Figs 1–8 Type material. HOLOTYPE female: GREECE, Avgi (municipality of Langadas, Thessaloniki), and 13 female paratypes with the same labels as the holotype. The female holotype and seven paratypes are deposited in PHMB, four paratypes in Forest Research Institute, Greece and two paratypes in USNM. Other material examined. Five females with the same labels as the holotype. Etymology. The species is named after the inducer of its host gall, Dryocosmus kuriphilus. Diagnosis. Saphonecrus kuriphilus, new species morphologically most closely resembles S. gallaepomiformis and S. barbotini. It also somewhat resembles species in the S. connatus / S. symbioticus clade; however, in S. kuriphilusi the head, mesosoma and metasoma are typically brown, and if black than only partially so, while in S. connatus and S. symbioticus the head and mesosoma are always black, the metasoma is black or dark brown. Morphological characters for the differentiation of the newly described species from S. gallaepomiformis / S. barbotini and S. connatus / S. symbioticus are provided in Table (see also Figs 9–28). Description. FEMALE. Head yellow, except dark brown to black triangular area between antennal toruli and central ocellus, ocellar triangle, occiput; antenna, mandibles yellow with darker tips; mouthparts, maxillary and labial palps yellow; legs including coxae yellow; wing veins yellow; tegula yellow; propleuron, mesopleuron, mesopleural triangle, metasoma laterally reddish brown; rest of mesoscutum black; nucha and metasoma reddish brown; ventral spine of hypopygium yellow. Head coriaceous, lower face, frons, gena, vertex, occiput, postocciput, postgena with dense white setae. Head slightly broader than high, rounded in anterior view, with broadest part level with torulus; slightly broader than mesosoma, 1.8´as broad as long in dorsal view. Eye 2.5´as high as length of malar space, eyes slightly converging ventrally. Malar sulcus absent, delicate striae radiating from clypeus and reaching eye. Clypeus small, coriaceous, with indistinct radiating striae, ventrally straight, not emarginate; epistomal sulcus indistinct; anterior tentorial pit small, distinct; clypeo-pleurostomal line indistinct. Lower face with striae radiating from clypeus and reaching torulus, extending into space between eye and torulus. Frons, interocellar area and vertex alutaceous, without striae and punctures. Transfacial distance slightly shorter than height of eye; distance between eye and torulus slightly greater than diameter of torulus; diameter of torulus 2.8´as large as distance between toruli. POL 2.0´as long as OOL and 2.0´as long as LOL; OOL 1.6´as long as length of lateral ocellus. Occiput alutaceous. Gena alutaceous, with white setae, not broadened behind eye, invisible in anterior view behind eye. Antenna with 12 flagellomeres, pedicel 1.4´as long as broad; F1 1.2´as long as F2 and 1.4´as long as pedicel; F3 1.2´as long as F2, F4 slightly longer than F3; F5=F6=F7; subsequent flagellomeres gradually shorten but do not broaden until apex; F11 1.2´as long as F10; placoid sensillae from F4. Mesosoma 1.3´as long as high in lateral view. Pronotum coriaceous, laterally with interrupted delicate rugae, area between rugae alutaceous; lateral pronotal carina absent. Propleuron alutaceous, with some transverse striae basally. Mesoscutum with short white setae, with interrupted short delicate transverse rugae; area between rugae alutaceous, distance between rugae longer than width of ruga. Notaulus incomplete, reaching to 1/2–3/4 of mesoscutum length, broader posteriorly, narrowing till pronotum, with smooth bottom. Anterior parallel and median mesoscutal lines absent, parapsidal lines indicated by smooth, glabrous sculpture, parascutal carina present, extending to anterior edge of tegula. Dorsoaxillar area alutaceous, with setae, lateroaxillar area smooth. Mesoscutellum slightly longer than broad, uniformly rugose, disk of mesoscutellum rounded, laterally not emarginate. Scutellar foveae transverse, broader than high, slightly impressed, with smooth bottom; separated by distinct coriaceous median carina. Mesopectus smooth, with parallel longitudinal striae, area between striae smooth. Metapleural sulcus reaching posterior margin of mesopectus in upper half of its height. Metascutellum shorter than ventral impressed area; metanotal trough smooth, without setae. Propodeum coriaceous, with uniform dense short white setae on lateral and central parts; lateral propodeal carina thin, straight, parallel. Nucha with longitudinal parallel rugae. Forewing as long as body, with long, dense cilia on margin, wing surface covered with dense short setae, radial cell open, 2.9´as long as broad; R1 and Rs nearly reaching wing margin; areolet large, triangular, Rs+M distinct, not reaching basalis, its projection reaches basalis at half its height. Legs with white setae, posterior surface of hind coxae with denser setae, tarsal claws simple, without basal lobe. Metasoma as long as head+mesosoma, 1.3´as long as high in lateral view. Petiole with longitudinal parallel rugae dorsally and laterally. Syntergite with row of sparse setae anterolaterally, smooth, glabrous; posterodorsally not incised, with delicate punctures dorsally; subsequent tergites and hypopygium with delicate micropunctures; prominent part of ventral spine of hypopygium as long as broad in ventral view. Body length 2.2–2.4 mm (n = 10). MALE. Unknown. Biology. This species was reared from galls of Dryocosmus kuriphilus, collected from Castanea sativa in late April. Distribution. Currently known only from Greece (Avgi, municipality of Langadas, Thessaloniki). Comments. The two-gene phylogenetic analysis places Saphonecrus kuriphilusi new species sister to the trans-Palaearctic Saphonecrus lineage comprising S. connatus and S. symbioticus, and near to but distinct from the Western Palaearctic lineage containing Saphonecrus gallaepomiformis and S. barbotini (Fig 29). This is in contrast to the morphology of these species, which would suggest a closer relationship of S. kuriphilusi to the lineage containing S. gallaepomiformis and S. barbotini. This may imply that the morphological characters used to define these close species relationships may be poor, as is observed in other cynipid inquilines (Ács et al. 2010; Kaartinen et al. 2010). Alternatively, given that support for the basal nodes within the clade containing these species is not strong, further DNA data should be obtained to help determine the closest relatives of this new species. Irrespective of the relationships among them, it is clear that together these five species are more closely allied to Synophrus Hartig than other Saphonecrus species, confirming the previously-demonstrated polyphyly of Saphonecrus (Ács et al. 2010, Bozsó et al. 2014, Schwéger et al. 2015b). The association S. kuriphilusi new species with Castanea galls represents a novel ecological interaction, and phylogenetic relationship of S. kuriphilusi new species with other Saphonecrus (and Synophrus) species associated with Quercus may provide indication as to the possible local oak galls from which this new inquiline species has been recruited onto D. kuriphilus galls on Castanea. Each of the major lineages within Saphonecrus defined by Schwéger et al. (2015b) are associated with cynipid galls induced on only a single genus of host plants. The disagreement between results of phylogenetic analyses based on morphology and DNA data with regard to the closest relatives of this new species also has implications about the native host plant species of the new species, i.e., whether it has shifted from native galls on Quercus section Cerris (the host plant group for S. barbotini / S. gallaepomiformis) or from native galls on Quercus section Quercus (the host plant group for S. connatus / S. symbioticus). Further research is needed to clarify what species of oak cynipid host galls it normally attacks. The recruitment of an inquiline onto invading D. kuriphilus populations is potentially exciting for natural biocontrol of this pest species by native parasitoids. Rates of parasitism by Chalcidoidea species attacking an invasive oak cynipid species in the United Kingdom increased after inquilines first started using the invading species’ galls (Schönrogge et al. 1995). If the same happens with D. kuriphilus galls, we might expect parasitism by native parasitoids to increase, with potential deterimental effects on the pest’s populations.Published as part of Melika, George, Memtsas, George I., Nicholls, James A. & Avtzis, Dimitrios N., 2018, New species of cynipid inquiline, Saphonecrus kuriphilusi (Hymenoptera: Cynipidae: Synergini), from Dryocosmus kuriphilus galls in Greece, pp. 109-120 in Zootaxa 4441 (1) on pages 111-116, DOI: 10.11646/zootaxa.4441.1.6, http://zenodo.org/record/130193
MeSH term explosion and author rank improve expert recommendations
No full textInformation overload is an often-cited phenomenon that reduces the productivity, efficiency and efficacy of scientists. One challenge for scientists is to find appropriate collaborators in their research. The literature describes various solutions to the problem of expertise location, but most current approaches do not appear to be very suitable for expert recommendations in biomedical research. In this study, we present the development and initial evaluation of a vector space model-based algorithm to calculate researcher similarity using four inputs: 1) MeSH terms of publications; 2) MeSH terms and author rank; 3) exploded MeSH terms; and 4) exploded MeSH terms and author rank. We developed and evaluated the algorithm using a data set of 17,525 authors and their 22,542 papers. On average, our algorithms correctly predicted 2.5 of the top 5/10 coauthors of individual scientists. Exploded MeSH and author rank outperformed all other algorithms in accuracy, followed closely by MeSH and author rank. Our results show that the accuracy of MeSH term-based matching can be enhanced with other metadata such as author rank
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
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