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Surveying native egg parasitoids and predators of the invasive Halyomorpha halys in Northern Italy
No full textThe invasive Halyomorpha halys (Heteroptera: Pentatomidae) is a key pest of fruits in the Emilia-Romagna region of Italy. For the development of a sustainable management programme, knowledge of its native natural enemy community and its efficacy is essential. A three-year field survey was conducted exposing H. halys egg masses in different types of habitats to investigate the efficacy of native natural enemies in reducing the H. halys populations in the Emilia-Romagna region, where the stinkbug was first detected in 2012. Over the first year of the study, sentinel eggs from laboratory cultures were stapled to the underside of leaves in various host trees, whereas in following years H. halys adults were directly caged on branches in sleeve cages to allow natural oviposition. Over the examined years, low rates of parasitism (1%–3%) and predation (2%–5%) were observed. Parasitism was caused exclusively by the generalist parasitoid Anastatus bifasciatus
Halyomorpha halys (Hemiptera, Pentatomidae): ten years after in Europe
No full textWe describe the situation of the invasion of Halyomorpha halys (HH) in Europe, since its discovery in Switzerland in 2007, but with effective presence since 2004. After a relative stagnation for many years, the dispersal of H. halys seems to increase, probably due to growing populations and passive transport by human activities. We suppose that it is not possible to stop the invasion of this species in Europe due to global warming but mostly to ecological characteristics such as high dispersal capability especially with human assistance , a broad host spectrum, a high female fecundity, and a high overwintering survival. The particularly mild winter 2013-2014 in France and Western Europe may further contribute to its progressive dispersal. It is likely that H. halys is already much wider distributed than previously assumed because it is easily confused with the native species, Raphigaster nebulosa. Most recently H. halys was recorded from Hungary, which is nearly 1,000 km east of its centre of distribution in Switzerland. In France, H. halys was first recorded in the Alsace in 2012, but in fall 2013 it was also discovered 400 km further west in Paris and Ile de France. The ongoing dispersal in western France will be monitored and prevention methods will be investigated.
After the first occurrence in 2012, a “citizen-science” type of survey allowed to detect many specimens of H. halys in different areas of Northern Italy, with a bigger nucleus centred in the territory of first detection, in the Emilia Romagna region. As this region has extended areas cultivated with high value fruit crops, field monitoring is currently being performed to verify H. halys presence and damage
A survey of native parasitoids ofHalyomorpha halysin Northern Italy and Switzerland
No full textIntroduction: The brown marmorated stink bug, Halyomorpha halys,is an Asian polyphagous species that has become an invasive crop pest in North America and Europe. After its first detection in Switzerland in 2004, it was subsequently found in other European countries such as Italy, where, since 2012, it has rapidly spread in the northern regions, becoming a threat to many crops, especially
in pear and peach orchards.
Results/Conclusion: Overall, most egg parasitism was due to the generalist parasitoid Anastatus sp. (Eupelmidae) and, at a lower level, to various Scelionidae species (e.g. Trissolcus cultratus). In northern Italy, the amount of parasitized eggs ranged from 3.1% in 2014 to 0.9% in 2015 in Emilia Romagna, and from 0.3% on exposed egg-masses to 21.4% on egg-masses collected in a natural habitat in 2015 in Piedmont. Overall parasitism in Switzerland was 4.4% in 2013
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Variation in levels of acceptance, developmental success, and abortion of Halyomorpha halys eggs by native North American parasitoids
Get PDFUsing native North American parasitoid species (Hymenoptera: Scelionidae) that often unsuccessfully attack the eggs of the invasive brown marmorated stink bug Halyomorpha halys (Hemiptera: Pentatomidae), we assessed variation in traits that may determine the parasitoids’ ability to adapt to the invasive host by either exploiting or avoiding H. halys eggs (acceptance, developmental success). We also assessed variation in the parasitoids’ ability to induce H. halys host egg abortion, which may contribute to biological control of H. halys in invaded areas. The first set of experiments evaluated intra- and interspecific variation using standardized laboratory tests with iso-female lines of Telenomus podisi and Trissolcus euschisti that included matching of detailed behavioural observations of acceptance with developmental outcomes. In a second set of experiments, we assessed how variation in developmental ability and abortion induction may affect levels of biological control by indigenous parasitoid species. We examined a broader sample of parasitoids that emerged from field collections of egg masses of an indigenous north American stink bug Podisus maculiventris in a region newly invaded by H. halys. Results from the first set of experiments showed high levels of acceptance of H. halys eggs among iso-female lines of parasitoids, but offspring development success was almost zero. H. halys egg abortion due to unsuccessful parasitism was often very low and varied among iso-female lines only for T. podisi. In the second set of experiments we never observed increases in abortion levels of Halyomorpha halys eggs above natural levels, even for the two species (T. euschisti and T. podisi) that were observed to oviposit in and abort H. halys eggs in the first set of experiments. We conclude that while there may be some variation in behavioural and physiological parameters mediating acceptance and abortion of H. halys eggs by native North American egg parasitoids, there does not appear to be significant variation in developmental success. Moreover, current biological control impact of H. halys eggs via host egg abortion is likely very low
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