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1. Periphytic diatoms, macrophytes, benthic macroinvertebrates and fish were sampled with standard methods in 185 streams in nine European countries to compare their response to degradation. Streams were classified into two main stream type groups (i.e. lowland, mountain streams); in addition, the lowland streams were grouped into four more specific stream types. 2. Principal components analysis with altogether 43 environmental parameters was used to construct complex stressor gradients for physical–chemical, hydromorphological and land use data. About 30 metrics were calculated for each sample and organism group. Metric responses to different stress types were analysed by Spearman Rank Correlation. 3. All four organism groups showed significant response to eutrophication/organic pollution gradients. Generally, diatom metrics were most strongly correlated to eutrophication gradients (85% and 89% of the diatom metrics tested correlated significantly in mountain and lowland streams, respectively), followed by invertebrate metrics (91% and 59%). 4. Responses of the four organism groups to other gradients were less strong; all organism groups responded to varying degrees to land use changes, hydromorphological degradation on the microhabitat scale and general degradation gradients, while the response to hydromorphological gradients on the reach scale was mainly limited to benthic macroinvertebrates (50% and 44% of the metrics tested correlated significantly in mountain and lowland streams, respectively) and fish (29% and 47%). 5. Fish and macrophyte metrics generally showed a poor response to degradation gradients in mountain streams and a strong response in lowland streams. 6. General recommendations on European bioassessment of streams were derived from the results.  相似文献   
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The bot fly Gruninomyia mira Szpila & Pape, gen.n. , sp.n. is described from Iran, North Khorasan, based on a single adult male and with no larval or host data. The monotypic genus shows a mixture of features otherwise found in either the rodent/lagomorph‐parasitizing oestromyine clade (Oestroderma + Oestromyia) or the artiodactyl‐parasitizing hypodermatine clade (Hypoderma + Pallasiomyia + Pavlovskiata + Przhevalskiana + Strobiloestrus) of subfamily Hypodermatinae. A morphology‐based phylogenetic analysis is marginally in favour of a position of Gruninomyia Szpila & Pape, gen.n. as sister taxon of (Oestroderma + Oestromyia). The COI barcode sequence is provided for the new species, and a phylogenetic analysis based on this marker for Oestridae retrieved from GenBank is in agreement with the conclusions based on morphological data. This published work has been registered in ZooBank: http://zoobank.org/urn:lsid:zoobank.org:pub:8F0CBE07‐4E74‐4186‐B690‐2C97D7ED7DA7 .  相似文献   
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The conditions for the evolution of andromonoecy and male-function-controlled overproduction of fertile flowers in hermaphrodites are considered using the evolutionarily stable strategy (ESS) approach. Andromonoecy and male-function-controlled floral display are promoted if further increase in pollen amount per flower is disadvantageous and/or increase in the number of polliniferous units is advantageous; the costs of attractive organs and pollen per flower are relatively low while the cost of ovules per flower and the cost per fruit are relatively high; the probability of setting a fruit from a pistillate flower is high; male fertility increases with the resources devoted to flowering; and if selfing is relatively low. Assumptions and predictions of the model are discussed.  相似文献   
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Boissier described several taxa in Anthriscus , summarized in his Flora orientalis account. The names include A. lamprocarpa, A. kotschyi, A. ruprechtii, A. tenerrima, A. t. var. leiocarpa, A. anatolica, A. macrocarpa, A. nemorosa var. mollis, A. n. var. glabra; the hst four are still recognized as separate species. These names are typified in this paper, based on the material in Boissier herbarium at G.  相似文献   
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The available data for Sarcophagidae in GenBank were analysed in order to reconstruct the most comprehensive phylogeny to date. GenBank was explored for nine markers that are commonly used in various molecular and phylogenetic studies of flesh flies. We obtained data for 187 species and constructed an aligned dataset with 9241 characters. However, the matrix suffered from 74% missing data due to a low number of sequences for some markers and in most of the cases only short fragments of the analysed genes were available. The reconstructed tree was taxonomically biased towards the subfamilies Paramacronychiinae (12% of the described species) and Sarcophaginae (8.6% of the described species) and specifically the genus Sarcophaga. The third subfamily Miltogramminae was represented by only 0.7% of described species. Moreover, about half of the included species were of forensic importance, while the percentage of such species in the entire family was estimated at 7%. Many nodes had very low support, so in order to increase the support and thereby identify a ‘core topology’, we pruned ‘rogue’ taxa and applied different substitution models. Both strategies improved support considerably, although some nodes still were left unresolved. An analysis of the distribution of bootstrap values across chronograms showed that the weakest phylogenetic signal is restricted to that part of the tree which coincides with the onset of rapid radiations mainly within the genus Sarcophaga. Our study is concordant with phylogenies obtained by other authors, with the most noteworthy exception being the subfamily Paramacronychiinae emerging as paraphyletic with regard to the Miltogramminae, which is in strong conflict with morphological evidence. We discuss the new findings in the light of traditional taxonomical classifications of Sarcophagidae and recent molecular studies.  相似文献   
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An attempt is made to explain the formation of smooth trilobite resting traces ( Rusophycus ) and some features associated with crawling and digging trails, Cruziana. Smooth resting traces are frequently current orientated, and it is thought that the scouring action of water currents was largely responsible for their formation. In Cruziana the V-shaped herringbone pattern points in an opposite direction to that of the line of movement. Sets of scratches which make up this pattern explain some aspects of appendage movement.  相似文献   
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Abstract.  The nominal taxon Acanthosoma chrysalis Mayer, 1844 is revised, and a lectotype is designated. The species, which was described from Germany from a number of alleged parasites encysted in the peritoneal wall of the stomach of edible frogs, is shown to be based on first instar larvae of blow flies (Calliphoridae). Argued from the shape and configuration of mouthhooks and abdominal cuticular spines, Acanthosoma Mayer, 1844 is shown to be a junior synonym of Onesia Robineau-Desvoidy, 1830 , syn.n. , and A. chrysalis is shown to be a junior synonym of O. floralis Robineau-Desvoidy, 1830 , syn.n. This species is an obligate parasitoid of earthworms, and it is hypothesized that first instar larvae enter the frogs through infected earthworms.  相似文献   
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