Search results for "Systematic"
showing 10 items of 7608 documents
Effect of starvation on parasite-induced mortality in a freshwater snail (Potamopyrgus antipodarum).
1999
The level of host exploitation is expected, under theory, to be selected to maximise (subject to constraints) the lifetime reproductive success of the parasite. Here we studied the effect of two castrating trematode species on their intermediate snail host, Potamopyrgus antipodarum. One of the trematode species, Microphallus sp., encysts in the snail host and the encysted larvae “hatch” following ingestion of infected snails by birds. The other species, Notocotylus gippyensis, by contrast, releases swimming larvae; ingestion of the snail host is not required for, and does not aid, transmission to the final host. We isolated field-collected snails for 3 months in the laboratory, and followed…
Energy use, diapause behaviour and northern range expansion potential in the invasive Colorado potato beetle
2011
Summary 1. As organisms expand their range towards northern latitudes they will encounter selective factors like harsh winter conditions. The ability to cope with and adapt to harsh winters may depend on the variability and evolutionary potential of relevant traits. 2. One adaptation in insects is winter diapause. It is characterized by changes in physiology, behaviour or in both. Physiological changes include lowered metabolic rate that enhances survival by saving limited energy reserves during overwintering. Active behavioural changes like burrowing into the soil allow individuals to escape harsh conditions. 3. We examined variation in overwintering body mass, resting metabolic rate (CO2 …
Vier Dekaden Weberknechtforschung mit dem 64. Band der ‚Tierwelt Deutschlands‘ – Rückblick, aktueller Stand und Ausblick
2021
A short history of the Opiliones volume in ‘Die Tierwelt Deutschlands’ published by Martens (1978) is presented. The area under consideration comprises Central Europe expanded by large parts of Scandinavia, the British Isles, non-Mediterranean France, Benelux, the complete Alps and in the south-east those parts of Romania and Croatia whose fauna was sufficiently well known. Additions and changes which appeared since 1978 are highlighted: new species discovered in this area, taxonomic changes, important distributional records, as well as changes of faunal composition due to human-mediated influences and climate change are addressed. Perspectives for further research concern faunal inventory …
Analysis of the epiphytic bryophyte diversity of Sicily
2009
Sicilian epiphytic bryophyte diversity, based on literature and unpublished data, is assessed both quantitatively and qualitatively. The total number of taxa found on trees or shrubs is 133 (116 mosses and 17 liverworts). Among them, 38 are customary epiphytic, 21 cortico-saxicolous, 13 are indifferent and 61 occasionally epiphytic taxa. The most represented families are Orthotrichaceae (19.1%), which consists above all of several typically corticicolous species, Pottiaceae (19.1%) and Brachytheciaceae (12.6%) which both include many taxa that mainly colonize rock or ground substrates. From the chorological point of view, temperate taxa (33.8%) prevail, followed by oceanic-Mediterranean tax…
A Complete Description and Conservation Assessment of Riella affinis Howe & Underwood (Riellaceae, Sphaerocarpales) New to Continental Europe
2019
Riella affinis Howe & Underwood is a rare species that is thus far known from eight populations worldwide. Only half of these were recorded in the last 50 years and none were recollected since first reported. Study of a Spanish population of R. cossoniana Trab., recorded in 2002 from Las Lomas, Malaga province, revealed that it belongs to R. affinis. The correct identity of the populations, which had not been available for study, was already suggested by reproductive and ecological characteristics of the plants mentioned in the original publication. The three main lagoons from the Las Lomas endorheic system, where the plants had been recorded, were sampled and living plants of R. affinis we…
A Revision of theniveaGroup of the Shore-Fly GenusDitrichophoraCresson (Diptera: Ephydridae)
2010
ABSTRACT Species of the nivea group (genus Ditrichophora Cresson) are revised. The group now includes four species of which one, D. gulkana (Alaska and Mongolia), is newly described. The group is now known to have a Holarctic distribution with two species, D. gulkana and D. nivea, being the first reported from the Nearctic Region. Another Asian species, D. brunnicosa, previously placed in Diclasiopa, is transferred to this group (genus Ditrichophora) and is also reported from Mongolia. To facilitate identification of these rare species, we have included diagnoses of the tribe, genus, and species group and have also provided an annotated key to Holarctic genera of the tribe Discocerinini and…
What is the origin of the Scottish populations of the European endemic Cherleria sedoides (Caryophyllaceae)?
2015
Cherleria sedoides L. (Minuartia sedoides (L.) Hiern) is a montane perennial which, with some species in Minuartia sect. Spectabiles, is more closely related to Scleranthus than to other Minuartia species and is therefore best restored to the reinstated and redefined genus Cherleria. Reconstruction of the ancestral area of the clade containing C. sedoides suggests that it evolved in the Alps or the Balkan peninsula. The species now has an unusual distribution, being present in the mountains of southern Europe and Scotland but absent from the Arctic. Three historical scenarios that might have led to the presence of the species in Scotland are outlined and tested by a molecular analysis compa…
Long-term dynamics of Collembola in a pine forest ecosystemProceedings of the Xth international Colloquium on Apterygota, České Budějovice 2000: Apte…
2002
Summary Biomonitoring data on soil Collembola collected over a six year period (1992-1997) in Scots pine ( Pinus sylvestris L.) forest in the Northern Vidzeme Biosphere Reserve, northern Latvia, are analysed. Monitoring was conducted in three plots: young (30-40 years), middle-aged (50—70 years), and old (150—200 years) pine stands. Sampling was performed once a year, in late August or early September, according to a systematic sampling scheme. One hundred soil cores (5 cm 2 × 10 cm) were taken within each plot every year, Collembola were extracted from the cores by using a modified high gradient extractor. During the monitoring period, there was a tendency of climate warming between 1992 a…
Why are wasps so intimidating: field experiments on hunting dragonflies (Odonata: Aeshna grandis)
2003
Abstract The mechanisms of aposematism (unprofitability of prey combined with a conspicuous signal) have mainly been studied with reference to vertebrate predators, especially birds. We investigated whether dragonflies, Aeshna grandis, avoid attacking wasps, Vespula norwegica, which are an unprofitable group of prey for most predators. As a control we used flies that were painted either black or with yellow and black stripes. The dragonflies showed greater aversion to wasps than to flies. Black-and-yellow-striped flies were avoided more than black ones, suggesting that aposematic coloration on a harmless fly provides a selective advantage against invertebrate predators. There was no signifi…
Allium therinanthum (Amaryllidaceae), a new species from Israel
2014
Allium therinanthum, a new species of A. sect. Codonoprasum, is described and illustrated from southern Mt. Hermon (Israel). It is a late-flowering diploid species (2n = 16), growing on calcareous substrates of the mountain belt. It is a narrowly distributed geophyte, showing morphological relationships mainly with A. tardiflorum, a typical autumnal species also occurring in Israel within the pinewoods of Mt. Carmel. The morphology, karyology, leaf anatomy, ecology, conservation status and taxonomical relations are examined for both species. A taxonomic comparison with the most allied late flowering species of the sect. Codonoprasum is provided.