51 research outputs found

    Oribatid communities and heavy metal bioaccumulation in selected species associated with lichens in a heavily contaminated habitat

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    The study examines oribatid communities and heavy metal bioaccumulation in selected species associated with different microhabitats of a post-smelting dump, i.e. three lichen species of Cladonia with various growth forms and the slag substrate. The abundance of oribatids collected from the substrate was significantly lower than observed in lichen thalli. The morphology and chemical properties of lichens, and to some extent varying concentrations of heavy metals in thalli, are probably responsible for significant differences in oribatid communities inhabiting different Cladonia species. Some oribatids demonstrate the ability to accumulate zinc and cadmium with unusual efficiency, whereas lead is the most effectively regulated element by all species. A positive correlation was found between Zn content in all studied oribatids and their microhabitats. Oribatids exploring different food resources, i.e. fungivorous and non-fungivorous grazers, show considerable differences in bioconcentrations of certain elements

    Sensory Integration Regulating Male Courtship Behavior in Drosophila

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    The courtship behavior of Drosophila melanogaster serves as an excellent model system to study how complex innate behaviors are controlled by the nervous system. To understand how the underlying neural network controls this behavior, it is not sufficient to unravel its architecture, but also crucial to decipher its logic. By systematic analysis of how variations in sensory inputs alter the courtship behavior of a naĂŻve male in the single-choice courtship paradigm, we derive a model describing the logic of the network that integrates the various sensory stimuli and elicits this complex innate behavior. This approach and the model derived from it distinguish (i) between initiation and maintenance of courtship, (ii) between courtship in daylight and in the dark, where the male uses a scanning strategy to retrieve the decamping female, and (iii) between courtship towards receptive virgin females and mature males. The last distinction demonstrates that sexual orientation of the courting male, in the absence of discriminatory visual cues, depends on the integration of gustatory and behavioral feedback inputs, but not on olfactory signals from the courted animal. The model will complement studies on the connectivity and intrinsic properties of the neurons forming the circuitry that regulates male courtship behavior

    Dismantling the treasured flagship lichen Sticta fuliginosa (Peltigerales) into four species in Western Europe

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    In the framework of a worldwide project on the phylogeny of the lichen genus Sticta, dedicated sampling was performed in four regions of Western Europe, roughly along an East-West line between N 48°02’ E 07°01’ and N 52°01’ W 09°30’, ranging from France/Vosges to Ireland/Kerry. Five clearly distinct ITS haplotypes were detected for isidia-producing species where only two were expected. Subtle anatomical and morphological characters, together with a strongly supported 4-loci molecular phylogeny, permit to distinguish, besides the easily recognized S. canariensis and S. limbata: ‱ the two « well-known » S. fuliginosa and S. sylvatica whose type collections have been carefully reassessed; the former is widespread in both hemispheres, while the latter is correctly identified only from continental Europe and the Andes in Colombia; the barcode ITS of S. fuliginosa differs by a single substitution from S. limbata (with a single exception), and the 4-loci phylogenetic tree does not resolve them as distinct lineages, most probably highlighting a very recent divergence and incomplete lineage sorting; ‱ three species that were formely included in S. fuliginosa: the resurrected S. ciliata Taylor, belonging to a complex group yet to be disentangled and occurring in the Neotropics, Africa, Macaronesia and Western Europe, and two species described as new for science, S. fuliginoides, found in continental Europe, the Canary Islands, eastern North America and Colombia, and S. atlantica only known from Ireland and the Azores archipelago. Molecular inferences demonstrate active divergence and dispersion within S. ciliata that may require recognition of further species. Fresh material can be identified with a morphological and anatomical preliminary key provided here. We propose that the taxonomy of all lichen species be urgently reviewed in the light of molecular data in an evolutionary context, particularly those used as bioindicators of environmental change and woodland management

    Focus on poleward shifts in species' distribution underestimates the fingerprint of climate change

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    Species are largely predicted to shift poleward as global temperatures increase, with this fingerprint of climate change being already observed across a range of taxonomic groups and, mostly temperate, geographic locationsÂč⁻⁔. However, the assumption of uni-directional distribution shifts does not account for complex interactions among temperature, precipitation and species-specific tolerances⁶, all of which shape the direction and magnitude of changes in a species' climatic niche. We analysed 60 years of past climate change on the Australian continent, assessing the velocity of changes in temperature and precipitation, as well as changes in climatic niche space for 464 Australian birds. We show large magnitude and rapid rates of change in Australian climate over the past 60 years resulting in high-velocity and multi-directional, including equatorial, shifts in suitable climatic space for birds (ranging from 0.1 to 7.6 km yr⁻Âč, mean 1.27 km yr⁻Âč). Overall, if measured only in terms of poleward distribution shifts, the fingerprint of climate change is underestimated by an average of 26% in temperate regions of the continent and by an average of 95% in tropical regions. We suggest that the velocity of movement required by Australian species to track their climatic niche may be much faster than previously thought and that the interaction between temperature and precipitation changes will result in multi-directional distribution shifts globally
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