163 research outputs found

    A new genus of Podonominae (Diptera: Chironomidae) in Late Eocene Rovno amber from Ukraine

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    The genus Palaeoboreochlus Baranov et Andersen, n. gen. is erected based on P. inornatus Baranov et Andersen, n. sp. described from a male found in Late Eocene Rovno amber. The new genus groups with Boreochlus Edwards in the tribe "Boreochlini".publishedVersio

    New extreme morphologies as exemplified by 100 million-year-old lacewing larvae

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    Larvae of the group Holometabola (beetles, wasps, flies, moths and others) differ significantly in their morphology from their corresponding adults. In most larvae, appendages and other structures protruding from the body (antennae, palps, legs, trunk processes) appear less elongate than in their corresponding adults, providing the impression that these larvae are restricted to a certain degree in developing more elongate structures. We provide here numerous counterexamples of larvae of lacewings (Neuroptera). These include different forms of elongated antennae, mandibles, maxillae, labial palps, legs, trunk processes and neck regions. Most of these examples are larvae preserved in different types of 100 million-year-old amber. The longest neck region was found in an extant specimen. All these examples demonstrate that certain branches of Neuroptera indeed had larval forms that possessed strongly elongated structures. Hence there is no principal constraint that hinders holometabolan larvae to develop such structures

    First record of gynandromorphy in fossil Chironomidae (Diptera) from Late Eocene Rovno amber

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    First record of Diamesa thomasi Serra-Tosio, 1970, from Croatia

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    Information Quality and Large Scale Project Budget Tracking

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    Abstract: The acceptance of the "E-Russia" project by the government of the Russian Federation presents a significant challenge to existing management structures. Particularly apparent is the need to be able to optimize the financial aspects of a project of this magnitude. Large project budget monitoring and control, including effective warnings regarding impending trends and deviations, is an imposing task. In normal circumstances this is done retrospectively and with minimal predictive capability. By implementing appropriate analytical techniques along with determinations of non-linear instability in existing trends, dramatic improvement in project control can be attained. Additionally, appropriate models exist that enable the availability of public funding sources to be more accurately analyzed and projected. The risk factors in both the expense and funding components are more readily visible and early corrective measures may be applied to mitigate these risks. These techniques offer the potential to more readily assess the relevance and impact of the data normally collected and yields pertinent information that exposes a much more accurate view of the project from a management and financial perspective. EXTENDED ABSTRACT The government of the Russian Federation has proposed and accepted the principle objectives of the project "E-Russia." This project intends to significantly expand the scope and reach of computer communications throughout the federation and foster the development of three key objectives: • Enhance educational opportunities • Promote business development • Provide individuals with access to information The acceptance of this project has been subject to considerable discussion and controversy. Some of the pertinent criticism has centered on the need to develop improved auditing and management of projects of this size and scope. While information quality now approaches ISACA (Information Systems Audit and Control Association) standards in many areas, the accumulated experience and judgment within government and industry to effectively manage and cope with the implications of a project of this size may be somewhat lacking. This paper is part of a series of steps intended to foster increased awareness of strategic management of information and its quality pertinent to large scale IT projects. For "E-Russia" as with all large scale projects there are several elements of methodology that are essential to the organization and management of the project. First, the 'Maturity Model&apos

    Bioturbation enhances the aerobic respiration of lake sediments in warming lakes

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    While lakes occupy less than 2% of the total surface of the Earth, they play a substantial role in global biogeochemical cycles. For instance, shallow lakes are important sites of carbon metabolism. Aerobic respiration is one of the important drivers of the carbon metabolism in lakes. In this context, bioturbation impacts of benthic animals (biological reworking of sediment matrix and ventilation of the sediment) on sediment aerobic respiration have previously been underestimated. Biological activity is likely to change over the course of a year due to seasonal changes of water temperatures. This study uses microcosm experiments to investigate how the impact of bioturbation (by Diptera, Chironomidae larvae) on lake sediment respiration changes when temperatures increase. While at 5°C, respiration in sediments with and without chironomids did not differ, at 30°C sediment respiration in microcosms with 2000 chironomids per m2 was 4.9 times higher than in uninhabited sediments. Our results indicate that lake water temperature increases could significantly enhance lake sediment respiration, which allows us to better understand seasonal changes in lake respiration and carbon metabolism as well as the potential impacts of global warming

    Christelenkidae, a new extinct family based on a new taxon from Eocene Baltic amber (Diptera: Acalyptratae), with X-ray synchrotron microtomography imaging of its structures

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    A new family of Diptera Acalyptratae, Christelenkidae Roháček fam. nov., is established for Christelenka multiplex Roháček gen. et sp. nov., an unusual extinct taxon described from a unique male specimen preserved in Baltic amber (Mid-late Eocene, ca 48–34 Ma). Apart from detailed examination by light microscopy and photography, the holotype of the new species has also been studied by means of X-ray synchrotron microtomography with the aim of obtaining additional morphological data for consideration of its relationships. Because of a very peculiar combination of morphological characters, the new family is tentatively considered a separate lineage of Acalyptratae having no apparent sister-group relationship with any of the known families. Its probable relationships to some families of Opomyzoidea and Ephydroidea are discussed

    Checklist of aquatic Diptera (Insecta) of Plitvice Lakes National Park, Croatia, a UNESCO world heritage site

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    Studies on aquatic Diptera in the Plitvice Lakes National Park (Croatia) conducted in the last 50 years have produced 157 species and 7 taxa of aquatic Diptera placed in 13 families. Samples were collected at 25 sampling sites representing the four main types of karst aquatic habitats: spring, stream, tufa barriers and lakes. All records of all the aquatic families of Diptera in Plitvice Lakes NP are summarized, including previously unpublished data. Twelve species new for Plitvice Lakes NP are recorded for the first time, belonging to the families: Chironomidae – Labrundinia longipalpis (Goetghebuer, 1921), Nilothauma brayi (Goetghebuer, 1921), Potthastia longimanus Kieffer, 1922, Polypedilum (Polypedilum) nubeculosum (Meigen, 1804), Tanytarsus brundini Lindeberg, 1963; Dixidae – Dixella autumnalis (Meigen, 1838); Scathophagidae – Acanthocnema latipennis Becker, 1894 and Stratiomyidae – Oxycera pardalina Meigen, 1822, Oxycera limbata Loew, 1862, Oxycera turcica Ustuner & Hasbenli, 2004, Nemotelus pantherinus (Linnaeus, 1758), Oplodontha viridula (Fabricius, 1775). The most species-rich family was the Chironomidae with 62 species (and an additional seven taxa), followed by the Empididae with 22 species and Limoniidae with 19 species. The highest number of species was recorded in springs. The relatively low number of species in certain families and the complete absence of some aquatic families shows that further research into the aquatic Diptera in Plitvice Lakes NP is needed.publishedVersio

    35 million-year-old solid-wood-borer beetle larvae support the idea of stressed Eocene amber forests

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    Eocene amber is an important window into the past about 35 million years ago. The large quantities of resin produced by this forest of the past, resulting in amber, triggered the idea of a forest under stress. Recent findings of higher abundances of hoverfly larvae in Eocene amber, in the modern fauna often associated with wood-borer larvae, provided a hint that wood-borer larvae may have contributed to this stress. Yet, so far only few such larvae have been reported. We have compiled a dozen additional wood-borer larvae in amber, including a giant one of at least 35 mm length in Rovno amber. Heavily damaged fossils furthermore indicate that larger larvae of this type were prone to oxidation and that, at least some, enigmatic tube-like tunnels in larger amber pieces may represent remains of large wood-borer larvae. This find strongly indicates that wood-borer larvae were not rare, but common in the Eocene amber forest, which is compatible with the high abundances of hoverfly larvae and further supports the idea of a forest under stress. Whether the possible higher abundances of wood-borer larvae were the cause of the stress or a symptom of an already stressed forest remains so far unclear

    Revisiting global trends in freshwater insect biodiversity

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    A recent global meta-analysis reported a decrease in terrestrial but increase in freshwater insect abundance and biomass (van Klink et al., Science 368, p. 417). The authors suggested that water quality has been improving, thereby challenging recent reports documenting drastic global declines in freshwater biodiversity. We raise two major concerns with the meta-analysis and suggest that these account for the discrepancy with the declines reported elsewhere. First, total abundance and biomass alone are poor indicators of the status of freshwater insect assemblages, and the observed differences may well have been driven by the replacement of sensitive species with tolerant ones. Second, many of the datasets poorly represent global trends and reflect responses to local conditions or nonrandom site selection. We conclude that the results of the meta-analysis should not be considered indicative of an overall improvement in the condition of freshwater ecosystems. This article is categorized under: Water and Life > Conservation, Management, and Awarenes
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