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In the Carboniferous no one undoubtedly aquatic insect remain is found. Mayflies and stoneflies were the oldest aquatic insects found in the Early Permian. Permian was the time when the aquatic insects became diverse and probably colonized different types of waters. Only one mayfly is found in the Early Triassic. The Middle and Late Triassic aquatic insect assemblages are characterized by combination of Paleozoic and Mesozoic elements. Diverse and widespread lacustrine insects are typical for the Jurassic. Recent families of aquatic insects appeared in the Early Cretaceous. The Late Cretaceous assemblages are considerably impoverished. The Cenozoic is the time of recolonization of lacustrine habitats.
The authors investigated aquatic insects (32 species) as vectors of aquatic zoosporic fungi parasitic on fishes in six bodies of water of various trophic state. A total of 127 zoosporic fungus species were noted, with predominance by the Oomycetes (99) and Chytridiomycetes species (24). Out of these 127 species, 28 are known as parasites or necrotrophs of fishes.
True flies (Diptera, Insecta) are one of the most important groups of aquatic insects in respect of the number of families and abundance of individuals. The goals of this study were to determine emergence patterns and the main ecological factors that influence dipteran family abundance and emergence at barrage lake outlets. Differences in abundance and variations between microhabitats were examined. The study was carried out in Plitvice Lakes National Park (Dinaric karst region, Croatia) at outlets of three barrage lakes. On each site several microhabitats, which differ in substrate and water velocity were selected. The selected substrates were moss on tufa, particulate tufa with detritus, pebbles and silt. Sampling of dipteran adults was conducted at the end of every month during 2007/2008 with 6 emergence traps placed at each site. Simuliidae and Chironomidae were the most abundant families among the 13 families present. Temperature influenced the start of emergence and the duration of flight period. All three lake outlets differed in abundance of individuals, especially the lowest barrage lake outlet which can be contributed to the lowest levels of organic seston and highest rates of tufa deposition. For Chironomidae, Simuliidae and aquatic Empididae statistically significant positive correlation between abundance and current velocity was observed. The least favoured substrate for all Diptera families was silt, while moss was the preferred one.
In order to evaluate the ecological health condition of Zhanghe River Watershed, an adapted Benthic Index of Biotic Integrity (B-IBI) was developed. Macro-invertebrates were sampled at 12 monitoring stations which were grouped into two condition categories (reference and impaired stations) according to the level of degradation. A total of 47 benthic macroinvertebrates taxa were identified, in which aquatic insects 33 taxa, Mollusca 8, Annalida 3 and Crustacea 3 taxa. Based on macro-invertebrate assemblages characters of this area, 18 candidate biological metrics in four categories, including taxonomic richness, community composition, pollution tolerance, trophic guild, and value distribution, were chosen. In which, four metrics were excluded because of low values or narrow distribution range. Discriminatory power between reference and impaired stations was analysed using box-plots, and six metrics were excluded because the medians of the box-plot inside the inter quartile range. Of all the rest eight metrics, four were not suitable for B-IBI index system because of their high Pearson correlation (| r | 0.75). Finally, total taxa, percentage of Crustacea and Mollusca, percentage of tolerant taxa and percentage of predators were screened out to form a B-IBI index system. Ratio scoring method for B-IBI index was used to get a uniform score. Evaluation criterion was established based on the 25 percentiles value of reference stations. Assessment results using B-IBI showed 5 of sampling stations were in ‘healthy’ and ‘sub-healthy’ state, 3 were in ‘fair’ state, and 4 were in ‘poor’ or ‘very poor’ state of the whole watershed.
Nematomorph larvae are known to enter aquatic insect larvae where they can encyst or present a limited development. These paratenic hosts serve only as vehicles to reach the definitive hosts and then complete their life cycle. In this work, through experimental infections it was proved that Dasyhelea necrophila (Ceratopogonidae) larvae can be considered as potential paratenic hosts of Paragordius varius (Nematomorpha) larvae. Although the D. necrophila larvae were infected by ingestion, in one pupa where the parasitic larva entered the respiratory horn it is possible that the penetration could have been performed through one of the spiracles of the respiratory horn. The parasitic larvae did not form cysts covered by a gelatinous substance but presented different levels of melanization.
The effects of pollution on the biodiversity and genome response of Chironomidae larvae (Diptera, Insect) were evaluated in the trace metal contaminated water environments. No change on the Chironomid species diversity was found. The higher concentrations of trace metals (Cd, Pb, Cr, and Zn) affect the genome of 5 cytogenetically studied Chironomid species: Chironomus bernensis, C. plumosus, C. sp.1. Kiefferulus tendipediformis (cytotype 2), Glyptotendipes cauliginellus (syn. Glyptotendipes gripekoveni). Genome instability of Chironomid larvae was manifested by two ways: 1. Fixed chromosome rearrangements; homozygous inversions and tandem fusions created new gene linkage groups and show an intensive microevolutionary process of species. 2. Somatic structural (inversions, deficiencies, deletions, breaks); and functional alterations (decreasing the activity of the key structures: Balbiani rings (BRs) and Nucleolar Organizer (NOR)) in salivary gland chromosomes of cytogenetically studied Chironomidae species. Detecting somatic rearrangements in salivary gland chromosomes of these widely distributed aquatic insects is potentially one of the best validated bioassay and can be used as a cost effective early warning signals of environmental damage in freshwater basins.
Larvae of seven Hydracarina species from the genera Hydrachna and Eylais were the parasites of 12 host species of Cymatia bonsdorffi, C. coleoptrata, Corixa dentipes, C. sahlbergi, C. linnaei, Sigara concinna, S. praeusta, S. striata, S. falleni, S. distincta, Notonecta glauca, Nepa cinerea. The parasites were most abundant on Heteroptera species which were numerous in the lakes. Differentiation of parasite occurrence was analysed with respect to sex and stage of development of the hosts. A detailed description has been given as to the parasitism by Hydrachna cruenta upon S. striata and S. falleni.
Research was performed on the activity of Heteroptera and Coleoptera in four water bodies in Olsztyn (Poland). In general, the majority of Coleoptera showed nocturnal activity. The majority of beetles were predatory. In the case of Heteroptera, there was only a small difference between diurnal and nocturnal activity.
The article presents a study of water beetles of Rogalin Landscape Park in the western part of Poland. New data about 10 species of rare aquatic beetle and information about the most interesting species in faunistic terms are given. It is the first landscape park in Wielkopolska Lowland whose water beetles have been comprehensively studied. A list of all aquatic beetles known from Rogalin Landscape Park is also presented.
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