30 research outputs found

    Mikrosporidien des Eichenprozessionsspinners, Thaumetopoea processionea (L.) (Lep., Thaumetopoeidae) in den Eichenwäldern Ostösterreichs

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    Since the late 1990s, the oak processionary moth, Thaumetopoea processionea (L.), has been occurring at high population densities in eastern Austria. Particularly, infestations in areas of human settlement have created increasing interest in this insect due to health problems caused by the urticating hairs of the larvae. New methods for biological control are desirable. Like essentially all forest Lepidoptera, T. processionea is host for entomopathogenic microsporidia. These obligatory parasitic protists have been evaluated as biocontrol agents against an other oak pest, Lymantria dispar (Weiser & Novotny, 1987; Jeffords & al., 1988). Life history traits of T. processionea make this insect an even more promising target for the use of microsporidia. The larvae are highly gregarious and stay together in nests made of larval silk for resting periods and molting. Microsporidia utilize several pathways for horizontal transmission that would be aided by these features: spores can be released after host death from cadavers as well as from living larvae via silk or feces. Additionally, many microsporidia are vertically transmitted (summarized in Maddox & al., 1998). In this project, T. processionea larvae from various regions in eastern Austria were screened for the natural occurrence of microsporidia. One isolate, Endoreticulatus sp., was further studied and mass produced in a laboratory host, L. dispar, that is easy to rear and does not pose a health hazard for people working with the insects. An inoculative release was attempted on isolated trees infested with T. processionea.In einem zweij√§hrigen Screening untersuchten wir das Auftreten von Mikrosporidien bei Thaumetopoea processionea an verschiedenen Standorten in Ost√∂sterreich. In neun von 18 Populationen wurden Mikrosporidiosen nachgewiesen, die Pr√§valenzen lagen zwischen 1,9 % und 15,4 %. Basierend auf lichtmikroskopischen Befunden waren die gefundenen Pathogene den Gattungen Endoreticulatus, Nosema, Cystosporogenes und Vairimorpha zuzuordnen. Endoreticulatus sp. vermochte im Labor Raupen von Lymantria dispar zu infizieren. Das erlaubte die einfache Produktion von Inokulum sowie Untersuchungen mit einem ungef√§hrlichen Wirtsinsekt. Laborversuche mit L. dispar zeigten einen langsamen Krankheitsverlauf, der aber in signifikant erh√∂hter Mortalit√§t resultierte (nur 26 % der oral inokulierten Tiere entwickelten sich zu Imagines), sowie eine effiziente horizontale √úbertragung. Eine inokulative Freilassung wurde versucht: dazu wurden Endoreticulatus-Sporen in w√§ssriger Suspension auf Bl√§tter isoliert stehender, von T. processionea befallenen Eichen ausgebracht. Die Inokulation war erfolgreich, allerdings auf niedrigem Niveau ‚Äď die maximale Infektionsrate lag bei 9,5 %

    Vitalnost spora mikrosporidija izoliranih iz gusjenica gubara (Lymantria dispar) nakon dugotrajne pohrane u tekuńáem duŇ°iku

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    Data on the viability of microsporidian isolates from Lymantria dispar after long-term storage in liquid nitrogen are presented. Eight microsporidian isolates from L. dispar were tested for their infectivity against L. dispar larvae: ¬≠Vairimorpha disparis, Nosema lymantriae, Nosema portugal, Nosema sp. (Poland), Nosema sp. (Ebergassing), Nosema sp. (Germany), Nosema sp. (Schweinfurt) and Nosema sp. (Veslec). The survival of spores in liquid nitrogen was ¬≠studied in detail for N. portugal and Nosema sp. (Ebergassing) which had been stored in liquid nitrogen almost 19 years and used for individual per oral infections while the other six isolates were used only in surface contamination per oral experiments. Our study confirms that storage in liquid nitrogen is a suitable option for long-term storage of Nosema and Vairimorpha species from lepidopteran hosts. Spores survived for up to 19 years; however, the experiments show that there is a significant loss of viability. In some cases, spores had lost viability already after 7 years in liquid nitrogen. We recommend producing fresh material every 5 years to maintain collections in liquid nitrogen. No material that had been stored in liquid nitrogen for extended periods should be used for infection experiments.U radu se prikazuju rezultati preŇĺivljenja mikrosporidija izoliranih iz gubara (Lymantria dispar) nakon dugotrajne pohrane u tekuńáem duŇ°iku. Infektivnost osam mikrosporidijskih L. dispar izolata testirano je na lińćinkama gubara: Vairimorpha disparis, Nosema lymantriae, Nosema portugal, Nosema sp. (Poljska), Nosema sp. (Ebergassing), Nosema sp. (Njemańćka), Nosema sp. (Schweinfurt) and Nosema sp. (Veslec). PreŇĺivljenje spora u tekuńáem duŇ°iku detaljno je prańáeno kod N. portugal i Nosema sp. (Ebergassing) koje su tako ńćuvane skoro 19 godina i aplicirane oralnom infekcijom i ponaosob na svaku pojedinu lińćinku gubara. Ostalih 6 izolata aplicirano je povrŇ°inskom kontaminacijom hranjivog supstrata, takońĎer oralnim infekcijskim putem. Od 8 mikrosporidijskih izolata apliciranih povrŇ°inskom kontaminacijom samo kod 4 izolata, Vairimorpha disparis, Nosema lymantriae, Nosema sp. (Ebergassing) i Nosema sp. (Poljska), doŇ°lo je do uspjeŇ°ne infekcije lińćinki gubara. Dok je kod svih testiranih lińćinki (100%) uspjeŇ°no realizirana infekcija sporama prve tri mikrosporidije, tek 21,1% tretiranih lińćinki uspjeŇ°no je inficirano sporama Nosema sp. (Poljska). Na kraju inkubacijskog razdoblja, kod svih lińćinki inficiranih sa sva 4 izolata disekcijom je utvrńĎen visok stupanj zaraze; tkiva su bila ispunjena sporama. Mikroskopska pretraga lińćinki L. dispar individualno tretiranih sporama Nosema portugal uz tri razlińćite doze (100, 1000 i 10000 spora) pokazala je da su spore N. portugal izgubile infektivnost nakon 19 godina pohrane u tekuńáem duŇ°iku; niti jedna od testiranih lińćinka nije bila zaraŇĺena. Naprotiv, spore Nosema sp. (Ebergassing) zadrŇĺale su infektivnost nakon istog razdoblja pohrane u tekuńáem duŇ°iku od 18,75 godina. Niti jedna od testiranih lińćinki nije zaraŇĺena nakon oralnog unosa od 100 spora. Oralna aplikacija od 1000 spora po lińćniki rezultirala je ukupnom uspjeŇ°nom infekcijom 4,1% lińćinki, a aplikacija od 10000 spora s 68,8% inficiranih lińćinki. U svim uspjeŇ°nim sluńćajevima uspjeŇ°no zaraŇĺenih lińćinki, na kraju inkubacijskog razdoblja infekcija je bila dobro razvijena, a masno tijelo prepuno spora. IstraŇĺivanje je potvrdilo da je pohrana mikrosporidija Nosema i Vairimorpha vrsta i domańáina iz reda leptira prikladna opcija za dugotrajno ńćuvanje izolata. Spore su preŇĺivjele i do 18 i pola godina, iako je tijekom eksperimenta zamijeńáen i znańćajan pad njihove infektivnosti. U pojedinim sluńćajevima spore su odumrle veńá nakon 7 godina pohrane u tekuńáem duŇ°iku. Preporuka je da prilikom skladiŇ°tenja i pohrane mikrosporidijskih izolata u tekuńáem duŇ°iku svakih 5 godina repozitorij obnavlja svjeŇĺim izolatima. Materijal koji se dulje vrijeme skladiŇ°ti u tekuńáem duŇ°iku nije prikladan i ne bi se smio koristiti u infektoloŇ°kim testovima

    Untersuchungen zum Gegenspielerkomplex von Lymantria dispar während einer Massenvermehrung auf einer bekannten Gradationsfläche

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    We have been surveying a gypsy moth, Lymantria dispar (Lep., Lymantriidae), population in the oak forest of Klingenbach near Eisenstadt, Austria, since 1992. During the last gradation from 1993 to 1996, we studied the natural enemy complex at this site in comparison with other locations where no outbreak occurred (HOCH et al. 2001). During the latency years, an experimental study on the impact of predators on L. dispar pupal populations was performed (GSCHWANTNER et al. 2002). The population density was recorded regularly; in the winter 2001/02, the egg mass surveys indicated a rising population after seven years of latency. We used this opportunity to study the parasitoid complex in the progradation phase. This phase of gypsy moth population dynamics was not studied in our previous work. Moreover, it allowed us to repeat the investigation during the outbreak after 11 years.Seit 1992 f√ľhren wir in einem Eichenmischwald bei Klingenbach, nahe Eisenstadt, √Ėsterreich, Abundanzerhebungen des Schwammspinners, Lymantria dispar (Lep., Lymantriidae) mittels Eigelegez√§hlungen durch. Im Jahre 2002 zeichnete sich nach sieben Jahren der Latenz ein Anstieg der Populationsdischte ab. Die Zahl von 1,2 Gelegen/Baum im Winter 2002/03 deutete auf eine beginnende Massenvermehrung. Die Dichte an Eigelegen war im folgenden Winterhalbjahr mit 9,7 pro Baum extrem hoch. Durch stadienspezifische Aufsammlungen von L. dispar Raupen oder Puppen und deren Zucht im Labor ermittelten wir die durch Parasitoide verursachte Mortalit√§t sowohl im Progradationsjahr 2003 als auch im Jahr der Kulmination 2004. Generell war die Mortalit√§t der Raupen und Puppen sehr gering. Im Jahr der Progradation vermochte einzig Parasetigena silvestris (Dipt., Tachinidae) nennenswerte Mortalit√§t von 23,7% bei Altraupen zu verursachen. Die sehr warme, trockene Witterung im Mai-Juni 2003 bedingte eine ausgesprochen schnelle Raupenentwicklung. Im Fr√ľhjahr 2004 zeigten die Raupenaufsammlungen noch geringere Parasitierungsraten. Es dominierten P. silvestris und Blepharipa sp. (Dipt., Tachinidae) mit 8,5% bzw. 8,0% bei den Altraupen. Aufsammlungen von Puppen im Jahr 2004 zeigten anhand der ypischen Fra√übilder eine Mortalit√§t durch Calosoma spp. (Col., Carabidae) von 13% an den Zweigen des Baumbestandes bis 38% in der Strauchschicht. Die Ergebnisse unserer Untersuchung zum Antagonistenkomplex in der Phase der Progradation und Kulmination werden im Vergleich mit entsprechenden Daten aus der letzten Gradation 1993 diskutiert

    Courtship behaviour and vibrational communication of the planthopper Apartus michalki (Wagner, 1948): (Hemiptera: Fulgoromorpha: Cixiidae)

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    Paarungsverhalten und Vibrationskommunikation von Apartus michalki (Wagner, 1948) (Hemiptera: Fulgoromorpha: Cixiidae). ‚Äď Cixiidae ben√∂tigen, wie alle sich sexuell reprodu- zierende Taxa, eine Reihe von Erkennungsmerkmalen, um potentielle Paarungspartner zu identifizieren und zu lokalisieren (specific mate recognition system = SMRS). Zwar ist der Einsatz von akustischen und/oder substratgebundenen Signalen als Teil des SMRS bei Hemipteren bekannt und weit verbreitet, die Kenntnisse zum Paarungsverhalten bei Cixiiden sind jedoch noch l√ľckenhaft. In diesem Beitrag dokumentieren wir zum ersten Mal die Vibrationskommunikation bei Apartus michalki zusammen mit weiteren Beobachtungen zum Paarungsverhalten dieser Art.Cixiidae require a set of clues in order to recognize and localize potential conspecific partners for mating (specific mate recognition system = SMRS). The use of acoustic and/or vibrational signals as part of the SMRS is ubiquitous in Hemiptera. However, the general knowledge of the mating behaviour of Cixiidae is still patchy. Here we report for the first time evidence for vibrational communication in Apartus michalki along with observations of the courtship behaviour

    Finding efficient strategies in 3-versus-2 small-sided games of youth soccer players

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    Most existing game analysis attempts do not consider situational context information sufficiently for the assessments of tactical behaviour. The purpose of this case study was to apply a new analysis approach, so far only used for 1-versus-1 analyses in soccer, to small-sided games and to identify and analyse therewith the efficiency of tactical patterns in 3-versus-2 game play. Therefore, 279 games, performed by an elite youth soccer team, were recorded by video and a position tracking system. The data was processed by the new approach, including unsupervised machine learning routines and artificial intelligence methods. Two crucial moments were used to analyse the occurring tactical patterns for the specific game: T0 (time instant of the shot) and T1 (time instant of the last action before the shot). For both moments typical tactical patterns, considering the spatio-temporal context of the situations were found. By combining the patterns of both moments, hidden tactical strategies were identified and their efficiencies calculated. The most significant result is that offence attempts have the highest scoring probability when played via the wings near to the goal line and the final pass, before the shot, is given against the playing direction into the centre of the field

    Worldwide tests of generic attractants, a promising tool for early detection of non-native cerambycid species

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    A large proportion of the insects which have invaded new regions and countries are emerging species, being found for the first time outside their native range. Being able to detect such species upon arrival at ports of entry before they establish in non-native countries is an urgent challenge. The deployment of traps baited with broad-spectrum semiochemical lures at ports-of-entry and other high-risk sites could be one such early detection tool. Rapid progress in the identification of semiochemicals for cerambycid beetles during the last 15 years has revealed that aggregation-sex pheromones and sex pheromones are often conserved at global levels for genera, tribes or subfamilies of the Cerambycidae. This possibly allows the development of generic attractants which attract multiple species simultaneously, especially when such pheromones are combined into blends. Here, we present the results of a worldwide field trial programme conducted during 2018-2021, using traps baited with a standardised 8-pheromone blend, usually com-plemented with plant volatiles. A total of 1308 traps were deployed at 302 sites covering simultaneously or sequentially 13 European countries, 10 Chinese provinces and some regions of the USA, Canada, Australia, Russia (Siberia) and the Caribbean (Martinique). We intended to test the following hypotheses: 1) if a species is regularly trapped in significant numbers by the blend on a continent, it increases the prob-ability that it can be detected when it arrives in other countries/continents and 2) if the blend exerts an effective, generic attraction to multiple species, it is likely that previously unknown and unexpected spe-cies can be captured due to the high degree of conservation of pheromone structures within related taxa. A total of 78,321 longhorned beetles were trapped, representing 376 species from eight subfamilies, with 84 species captured in numbers greater than 50 individuals. Captures comprised 60 tribes, with 10 tribes including more than nine species trapped on different continents. Some invasive species were captured in both the native and invaded continents. This demonstrates the potential of multipheromone lures as ef-fective tools for the detection of 'unexpected' cerambycid invaders, accidentally translocated outside their native ranges. Adding new pheromones with analogous well-conserved motifs is discussed, as well as the limitations of using such blends, especially for some cerambycid taxa which may be more attracted by the trap colour or other characteristics rather than to the chemical blend

    Ascertaining the knowledge of the general public and stakeholders in the forestry sector to invasive alien species - a Pan-European study

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    Against the background of the phenomenon of globalisation, which has increasingly intensified in recent decades, invasive alien species (IAS) have led to biological invasions that have resulted in multiple negative effects on economies, human health, and especially on the environment. In order to control invasive alien species, preventive actions are considered the most effective methods. In this context, society can actively participate in the process of early detection and preventing the spread of these organisms, but there is a need to raise public awareness. In order for this process to take place in the most efficient way, it is necessary to initially evaluate the knowledge of the general public to IAS. Through a questionnaire that was circulated in ten European countries and had over two thousand respondents, this study aimed to investigate the level of knowledge of some stakeholders in the forestry sector regarding IAS. The results showed that a vast majority of respondents who participated in the study had heard about IAS and provided a correct definition of these organisms. Most of the respondents in this study heard for the first time about IAS from school, the Internet, or journal articles. Data analysis also showed that stakeholders in the forestry sector (foresters, forest owners, and members of environmental NGOs) were more likely than the other respondents to be aware of the impact of IAS. The results of this study offer an insight to researchers and decision makers assessing the differences of opinion regarding invasive alien species, and the necessary steps that could be adopted in the process of raising awareness in society

    Corythucha arcuata (Say, 1832) (Hemiptera, Tingidae) in its invasive range in Europe : perception, knowledge and willingness to act in foresters and citizens

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    The oak lace bug (OLB) Corythucha arcuata (Say, 1832) is an invasive alien species (IAS) that potentially could have many negative impacts on European oak health. Certain measures can be applied to counteract these effects. However, these measures may not be acceptable for forest managers or other stakeholder groups, such as private forest owners, environmental NGOs or the general public. Thereby, we set out to study the perception and knowledge of foresters and other stakeholders on the health status of European oak forests affected by oak lace bug and to investigate what forest health management measures would be acceptable to these target groups. An online survey questionnaire was designed and distributed via social networks, as well as professional networks via e-mails. The survey questionnaire was completed by 2084 respondents from nine European countries: Austria, Croatia, Belgium, France, Hungary, Italy, Romania, Serbia and Slovenia. Even though only a little over 60% of respondents reported they had noticed the discolouration of oak leaves caused by OLB, almost all (93%) considered it to be a problem. As respondents come from a country where C. arcuata is widespread and established, people%s general knowledge and awareness of OLB began to increase. The survey revealed that foresters thought that the insect affected photosynthesis, acorn crop and the aesthetics of the trees, but cannot cause death of trees. However, they assume that the value of the wood would decrease (this fact is also supported by the respondents who are connected to an environmental NGO), but that OLB does not affect property value. However, forest owners claim that the value of the property can be affected and that people would avoid entering the forest. In terms of potential control methods, respondents preferred biological or mechanical measures over chemical ones. We consider this study to be a good basis for further research on the topic of perception, knowledge and attitudes related to OLB since we can expect that the IAS, such as OLB, will certainly spread to European countries that were not included in this survey
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