Zur Biologie des nicht identifizierten invasiven Weberknechtes Leibunum sp. (Arachnida: Opiliones)

Since about the year 2000 an unidentified, introduced harvestman of the genus Leiobunum has been rapidly invading Europe. The published records are from the Netherlands, Germany, Austria and Switzerland. A population of Leiobunum sp. in the Netherlands was studied frequently during the day and night. Its life cycle, hunting strategy, diet and accompanying harvestman species were recorded, and mating, male-male fights and ovipositing behaviour studied, as well as the spider species preying on this Leiobunum species. Food items were collected, indicating that its food consists of a wide range of live as well as dead invertebrates including spent spider prey scavenged for at ground level. Vegetable matter like berries, as well as bird droppings were also consumed. The mating strategy is very complex. A male guards an egg depositing female and he defends her against other advancing males, resulting in male-male fights. The guarding male frequently mates. Also courtship behaviour has been observed, including nuptial feeding with a fluid, probably originating from the accessory penal glands and delivered by the male into the female’s stomotheca via sacs located on the distal part of the penis truncus. Eggs are deposited in holes and crevices of walls.Seit dem Jahr 2000 breitet sich eine eingeschleppte und bislang nicht identifizierte Weberknechtart der Gattung Leiobunum rasch in West- und Mitteleuropa aus. Die publizierten Funde stammen aus den Niederlanden, Deutschland, Österreich und der Schweiz. Während regelmäßiger, vorwiegend nächtlich durchgeführter Beobachtungen einer großen niederländischen Population, wurden Lebenszyklus, Jagdverhalten, Nahrung, begleitende Weberknechtarten, sich von diesen Weberknechten ernährende Spinnen, sowie Paarungsverhalten und Eiablage studiert. Die Weberknechte sind nachtaktiv und halten sich tagsüber meist in großen Ansammlungen vorwiegend an Mauern und Hauswänden auf. Leiobunum sp. ernährt sich räuberisch von verschiedensten kleinen Insekten. Einen weiteren beträchtlichen Anteil an seiner Nahrung bilden tote Insekten und andere wirbellose Tiere, sowie von Spinnen aus ihren Netzen entfernte Beutetiere, die von den Weberknechten am Boden gesammelt werden. Auch Vogelkot und pflanzliches Material wie z. B. Beeren werden verzehrt. Als äußerst kompliziert erwies sich das Paarungsverhalten. Bei der Eiablage bewacht das Männchen das Weibchen und verteidigt es gegen jedes weitere sich nähernde Männchen. Während dieser Bewachung kommt es mehrmals zur Paarung. Das Männchen scheint dem Weibchen dabei regelmäßig als Brautgeschenk eine Flüssigkeit darzubieten, die innerhalb der häutigen Membrane im distalen Teil des Penistruncus gespeichert ist. Die Eier werden in Spalten von vertikalen Strukturen abgelegt

A critical rationalist approach to organizational learning: testing the theories held by managers

The common wisdom is that Popper's critical rationalism, a method aimed at knowledge validation through falsification of theories, is inadequate for managers in organizations. This study falsifies this argument in three phases: first, it specifies the obstructers that prevent the method from being employed; second, the critical rationalist method is adapted for strategic management purposes; last, the method and the hypotheses are tested via action research. Conclusions are that once the obstructers are omitted the method is applicable and effective

The applicability of a use value-based file retention method

The determination of the relative value of files is important for an organization while determining a retrieval service level for its files and a corresponding file retention policy. This paper discusses via a literature review methods for developing file retention policies based on the use values of files. On basis of these results we propose an enhanced version of one of them. In a case study, we demonstrate how one can develop a customized file retention policy by testing causal relations between file parameters and the use value of files. This case shows that, contrary to suggestions of previous research, the file type has no significant relation with the value of a file and thus should be excluded from a retention policy in this case. The case study also shows a strong relation between the position of a file user and the value of this file. Furthermore, we have improved the Information Value Questionnaire (IVQ) for subjective valuation of files. However, the resulting method needs software to be efficient in its application. Therefore, we developed a prototype for the automatic execution of a file retention policy. We conclude with a discussio

The Hegelian Inquiring System and Critical Triangulation Tools for the Internet Information Slave

This paper discusses informing, i.e. increasing people’s understanding of reality by providing representations of this reality. The Hegelian inquiry system is used to explain the nature of informing. Understanding the Hegelian inquiry system is essential for making informed decisions where the reality can be ambiguous and where sources of bias and manipulation have to be understood for increasing the level of free-informed choice. This inquiry system metaphorically identifies information masters and slaves, and we propose critical dialectic information triangulation (CDIT) tools for information slaves (i.e. non-experts) in dialect interactions with informative systems owned by supposed information masters. The paper concludes with suggestions for further research on informative triangulation tools for the internet and management information systems

An unidentified harvestman Leiobunum sp. alarmingly invading Europe (Arachnida: Opiliones)

Etwa seit dem Jahr 2000 breitet sich eine bisher nicht identifizierte Art der Gattung Leiobunum C. L. Koch, 1839 schnell in Mitteleuropa aus. Nachweise ab dem Jahr 2004 sind aus den Niederlanden (wahrscheinlich dem Land des ersten Auftretens in Europa), Deutschland, Österreich und der Schweiz bekannt. Die wahrscheinlich eingeschleppte Art besiedelt bisher lediglich Wände von Gebäuden und seltener felsähnliche Biotope in Wäldern. Adulte Individuen ruhen tagsüber selten einzeln oder in eng geklumpten Gruppen aus Dutzenden bis Hunderten von Individuen an leicht abgedunkelten Stellen in Mauerwinkeln, an glatten Hauswänden und überhängenden Dachtraufen. Jungtiere leben am Boden. Diese Art verfügt über ein großes Vermehrungspotential mit früher Reifezeit und ist in der Lage, schnell große Populationen aufzubauen und sich rasch über große Distanzen auszubreiten. Heimische Weberknechtarten scheinen durch sie verdrängt zu werden. Die Herkunft dieses Leiobunum ist bislang unbekannt. Genitalmorphologisch bestehen Ähnlichkeiten zu europäischen und nordamerikanischen Arten.Since about the year 2000 a hitherto unidentified species of the genus Leiobunum C. L. Koch, 1839, has rapidly invaded central and western Europe. Records are known from The Netherlands (probably the country of first occurrence in Europe), Germany, Austria and Switzerland. This introduced species, until now, mainly inhabits walls of buildings and rocky environments. Adults characteristically aggregate during daytime into groups of up to 1.000 individuals. The species is described and details on its present distribution, habitat preference, phenology and behaviour are presented

Total data quality management: a study of bridging rigor and relevance

Ensuring data quality is of crucial importance to organizations. The Total Data Quality Management (TDQM) theory provides a methodology to ensure data quality. Although well researched, the TDQM methodology is not easy to apply. In the case of Honeywell Emmen, we found that the application of the methodology requires considerable contextual redesign, flexibility in use, and the provision of practical tools. We identified team composition, toolsets, development of obvious actions, the design of phases, steps, and actions, and sessions as vital elements of making an academically rooted methodology applicable. Such an applicable methodology, we name “well articulated”, because it incorporates the existing academic theory and it is made operational. This enables the methodology to be systematically beta tested and made useful for different organizational conditions

Service Semantics Classification: an Approach Towards Modular Service Ontology

Since service systems are becoming increasingly complex in emerging technology, business, legal and economics environments, service abstractions are necessary to master this complexity. However, the term ‘service’ means different things to different people in different disciplines, which implies that any attempt to define general purpose service abstractions must address the disambiguation of the term. Service ontologies and service knowledge management efforts mainly aim at elucidating service semantics. Each discipline has multiple biased service-related concepts, so that in order to build comprehensive multi-disciplinary service models, the service-related concepts of the involved disciplines have to be integrated and structured in a consistent way. We claim that this requires a modular approach in which general purpose service semantics can be further extended or specialised with domain-specific concepts. Service-related and domain-specific concepts can be integrated and structured in many different ways. This paper proposes a semantics classification scheme based on service aspects that are essential for a services ecosystem

Service Elements Valuation Using an Enterprise Architecture Language

This article defines a service as an architecture of processes, software and infrastructure elements for serving people. An architecture language therefore is a means to structure and analyze the values of service elements and the service as a whole. We provide a value-based perspective, which first includes a review of the concept of value in the context of service architectures for services. Here we conclude that multiple, even competing, values are at stake for different parts of a service. Second, the paper discusses a method for the valuation of a service using competing value constructs. We also demonstrate by a case how a formal architecture language can be used to calculate service values. Finally, the results are discussed and suggestions for further research are given