microhabitat
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Deserts exert strong selection pressures on plants, but the underlying genomic drivers of ecological adaptation and subsequent speciation remain largely unknown. Here, we generated de novo genome assemblies and conducted population genomic analyses of the psammophytic genus Pugionium (Brassicaceae). Our results indicated that this bispecific genus had undergone an allopolyploid event, and the two parental genomes were derived from two ancestral lineages with different chromosome numbers and structures. The postpolyploid expansion of gene families related to abiotic stress responses and lignin biosynthesis facilitated environmental adaptations of the genus to desert habitats. Population genomic analyses of both species further revealed their recent divergence with continuous gene flow, and the most divergent regions were found to be centered on three highly structurally reshuffled chromosomes. Genes under selection in these regions, which were mainly located in one of the two subgenomes, contributed greatly to the interspecific divergence in microhabitat adaptation.
The risks of depletion of energy reserves and encountering lethally low temperatures are considered as two important mortality factors that may limit winter survival of mosquito, Culex pipiens f. pipiens populations. Here we show that the autumn females carry lipid reserves, which are safely sufficient for at least two overwintering periods, provided the females diapausing at temperatures typical for underground spaces (0 °C - 8 °C) would continuously rest at a standard metabolic rate (SMR). The overwintering females, however, switch from SMR to much higher metabolic rate during flight, either seeking for optimal microhabitat within the shelter or in response to disturbances by air current or predator attack. These behaviors result in fast oxidation of lipid reserves and, therefore, the autumn load of energy reserves may actually limit winter survival under specific circumstances. Next, we show that the level of females' cold hardiness is physiologically set relatively weak for overwintering in open field, above-ground habitats, but is ecologically entirely sufficient for overwintering in most underground spaces. The characteristics of suitable overwintering shelters are: no or limited risk of contact with ice crystals, no or limited air movements, winter temperatures relatively stable between +2 and + 6 °C, winter minimum does not drop below -4 °C for longer than one week, or below -8 °C for longer than 1 day.
An integrative approach employing molecular, morphological and geographical data were applied to species delimitation among Deuteraphorura congeners occupying caves of the Western Carpathian Mts. A new species of Deuteraphorura from the Western Carpathians is described. D. muranensis sp. nov. belongs among species with 4 pso at the hind margin of the head and possesses highly troglomorphic features. It is conspicuous with its distinctly elongated claws and long, hair-like body chaetae. The status of the new species was confirmed by DNA barcoding based on the mitochondrial COI marker. Populations of D. kratochvili (Nosek, 1963), the most widespread species, were studied in detail. Both ABGD and PTP analyses brought results congruent with geography, i.e. the molecular and geographic distance of the populations were positively correlated. However, some molecular separation based on pairwise distance and the number of substitutions was indicated within two of the studied populations. Despite the indistinct morphological differences, the tested populations were well isolated both geographically and genetically, which indicates that each studied population may represent a cryptic species. The troglomorphy of cave Collembola at the northernmost border of the distribution of cave-adapted species in the Europe is discussed. It is clear that the level of troglomorphy is closely associated with conditions of the microhabitat occupied by the individual subterranean species. The results of our study enhance the importance of the Western Carpathians regarding the diversity pattern of obligate cave species in Europe.
- MeSH
- členovci anatomie a histologie klasifikace genetika fyziologie MeSH
- ekosystém MeSH
- fyziologická adaptace MeSH
- jeskyně * MeSH
- respirační komplex IV genetika MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Evropa MeSH
- Slovenská republika MeSH
Peatland vegetation is composed mostly of mosses, graminoids and ericoid shrubs, and these have a distinct impact on peat biogeochemistry. We studied variation in soil microbial communities related to natural peatland microhabitats dominated by Sphagnum, cotton-grass and blueberry. We hypothesized that such microhabitats will be occupied by structurally and functionally different microbial communities, which will vary further during the vegetation season due to changes in temperature and photosynthetic activity of plant dominants. This was addressed using amplicon-based sequencing of prokaryotic and fungal rDNA and qPCR with respect to methane-cycling communities. Fungal communities were highly microhabitat-specific, while prokaryotic communities were additionally directed by soil pH and total N content. Seasonal alternations in microbial community composition were less important; however, they influenced the abundance of methane-cycling communities. Cotton-grass and blueberry bacterial communities contained relatively more α-Proteobacteria but less Chloroflexi, Fibrobacteres, Firmicutes, NC10, OD1 and Spirochaetes than in Sphagnum. Methanogens, syntrophic and anaerobic bacteria (i.e. Clostridiales, Bacteroidales, Opitutae, Chloroflexi and Syntrophorhabdaceae) were suppressed in blueberry indicating greater aeration that enhanced abundance of fungi (mainly Archaeorhizomycetes) and resulted in the highest fungi-to-bacteria ratio. Thus, microhabitats dominated by different vascular plants are inhabited by unique microbial communities, contributing greatly to spatial functional diversity within peatlands.
- MeSH
- Bacteria klasifikace genetika izolace a purifikace metabolismus MeSH
- brusnice s jedlými plody růst a vývoj mikrobiologie MeSH
- houby klasifikace genetika izolace a purifikace metabolismus MeSH
- lipnicovité růst a vývoj mikrobiologie MeSH
- methan metabolismus MeSH
- mikrobiota MeSH
- půda chemie MeSH
- půdní mikrobiologie * MeSH
- rašeliníky růst a vývoj mikrobiologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
The ecology of earwigs in natural forest ecosystems is poorly understood. We used sweeping to determine the population densities of adult earwigs, by sex and species, on ten tree species in a temperate floodplain forest in southern Moravia (Czech Republic). We also determined the relationships between the properties of tree species and earwig density and diet as indicated by digestive tract contents. The densities and diet composition of earwigs differed between the three detected earwig species [Apterygida media (Hagenbach, 1822), Chelidurella acanthopygia (Genè, 1832) and Forficula auricularia Linnaeus, 1758] and among tree species. Earwig densities were related to lichen coverage and fungal coverage on the trees. The diet of earwigs was associated with specific leaf area, herbivore damage to the leaves, and light exposure of the trees. A. media was the most abundant of the three earwig species. Although the contents of its digestive tract changed depending on available food resources, A. media appeared to preferentially consume soft-bodied insect herbivores and fungi associated with wounds caused by herbivores rather than plant material. Therefore, this species has the potential to help reduce the population densities of soft-bodied pests of forest trees.
- MeSH
- dieta * MeSH
- hmyz * MeSH
- hustota populace MeSH
- lesy * MeSH
- preference v jídle MeSH
- stromy * MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Česká republika MeSH
Overwintering insects are categorized either as freeze tolerant or freeze avoiding (supercooling) based on their ability or inability, respectively, to tolerate the formation of ice in their body. The freeze tolerant insects set their supercooling point (SCP) higher for winter to stimulate freezing at higher temperatures, while freeze avoiding insects survive winter in a supercooled state by depressing their SCP. Some supercooling insects, however, were found to survive in frozen state when freezing occurred through inoculation by external ice at mild subzero temperatures. Here, we assessed the potential relevance of inoculative freezing and freeze tolerance strategy in an insect that was so far considered as a classical example of a 'supercooler', the linden bug (Pyrrhocoris apterus). Microclimatic conditions of the overwintering microhabitat of P. apterus (leaf litter layer with buffered temperature fluctuations, mild sub-zero extremes, high humidity, and presence of ice) present a potentially high risk of inoculative freezing. We found that P. apterus is highly susceptible to inoculation by external ice. The temperature at which inoculative freezing occurred (above -3°C) was much higher compared to SCP (-16 °C to -20 °C in winter). The insects were inoculated through body openings and across cuticle and were able to survive after freezing. There was, however, a distinct critical ice fraction, corresponding to 38.7-42.8% of total body water, beyond which survival rapidly decreased to zero. We found that P. apterus adaptively reduces the actual ice fraction below critical ice fraction for winter season. Since many insect species overwinter in habitats similar to that of P. apterus, the ability to tolerate freezing after inoculation by external ice crystals could be much more common among 'supercooling' insects than it is currently appreciated.
Glaciers and ice sheets are a peculiar biome with characteristic abiotic and biotic components. Mountain glaciers are predicted to decrease their volume and even to melt away within a few decades. Despite the threat of a disappearing biome, the diversity and the role of microscopic animals as consumers at higher trophic levels in the glacial biome still remain largely unknown. In this study, we report data on tardigrades and rotifers found in glacial mosses on Mount Stanley, Uganda, and describe a new tardigrade species. Adropion afroglacialis sp. nov. differs from the most similar species by having granulation on the cuticle, absence of cuticular bars under the claws, and a different macroplacoid length sequence. We also provide a morphological diagnosis for another unknown tardigrade species of the genus Hypsibius. The rotifers belonged to the families Philodinidae and Habrotrochidae. In addition, we discuss the diversity of microinvertebrates and potential role of tardigrades and rotifers on mountain glaciers as top consumers. As for any organism living apparently exclusively in glacial habitats on tropical glaciers, their extinction in the near future is inevitable, possibly before we can even discover their existence.
The biochemical responses of rock-inhabiting cyanobacteria towards native environmental stresses were observed in vivo in one of the Earth's most challenging extreme climatic environments. The cryptoendolithic cyanobacterial colonization, dominated by Chroococcidiopsis sp., was studied in an ignimbrite at a high altitude volcanic area in the Atacama Desert, Chile. Change in the carotenoid composition (red-shift) within a transect through the cyanobacteria dominant microbial community (average thickness ~1 mm) was unambiguously revealed in their natural endolithic microhabitat. The amount of red shifted carotenoid, observed for the first time in a natural microbial ecosystem, is depth dependent, and increased with increasing proximity to the rock surface, as proven by resonance Raman imaging and point resonance Raman profiling. It is attributed to a light-dependent change in carotenoid conjugation, associated with the light-adaptation strategy of cyanobacteria. A hypothesis is proposed for the possible role of an orange carotenoid protein (OCP) mediated non-photochemical quenching (NPQ) mechanism that influences the observed spectral behavior. Simultaneously, information about the distribution of scytonemin and phycobiliproteins was obtained. Scytonemin was detected in the uppermost cyanobacteria aggregates. A reverse signal intensity gradient of phycobiliproteins was registered, increasing with deeper positions as a response of the cyanobacterial light harvesting complex to low-light conditions.
- MeSH
- biologické pigmenty MeSH
- ekosystém MeSH
- fluorescenční mikroskopie MeSH
- karotenoidy chemie metabolismus MeSH
- konfokální mikroskopie MeSH
- mikrobiologie životního prostředí MeSH
- pouštní klima * MeSH
- sinice * izolace a purifikace metabolismus MeSH
- spektrální analýza MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Ecological studies of peatland testate amoebae are generally based on totals of 150 individuals per sample. However, the suitability of this standard has never been assessed for alkaline habitats such as spring fens. We explored the differences in testate amoeba diversity between Sphagnum and brown-moss microhabitats at a mire site with a highly diversified moss layer which reflects the small-scale heterogeneity in groundwater chemistry. Relationships between sampling efficiency and sample completeness were explored using individual-based species accumulation curves and the effort required to gain an extra species was assessed. Testate amoeba diversity differed substantially between microhabitats, with brown mosses hosting on average twice as many species and requiring greater shell totals to reach comparable sample analysis efficiency as for Sphagnum. Thus, for samples from alkaline conditions an increase in shell totals would be required and even an overall doubling up to 300 individuals might be considered for reliable community description. Our small-scale data are likely not robust enough to provide an ultimate solution for the optimization of shell totals. However, the results proved that testate amoebae communities from acidic and alkaline environments differ sharply in both species richness and composition and they might call for different methodological approaches.
Ericoid mycorrhiza represents a key adaptation of the Ericaceae plants to facilitate their establishment in harsh conditions. The Ericaceae are a large family of flowering plants, with global distribution. However, our current knowledge about the ericoid mycorrhizal fungal diversity and ecology largely relates to the Northern Hemisphere. Our study focused on the assembly of root-associated fungal (RAF) communities of Erica dominans in two types of microhabitats of contrasting moisture along an elevation gradient in Drakensberg mountains in South Africa. RAF communities were determined by 454-sequencing of the internal transcribed spacer (ITS) region of ribosomal DNA. The majority of RAF showed affinity to the orders Helotiales, Pezizales, and Pleosporales. Microhabitat type as well as elevation had significant but weak effect on RAF community composition. We identified two putative ericoid mycorrhizal fungi, the ecological niches of which were differentiated between the studied microhabitats. Our study also provides one of the first comprehensive data about RAF communities of Ericaceae on African continent and shows the occurrence of the most studied ericoid mycorrhizal fungus Pezoloma ericae (belonging to P. ericae aggregate) in roots of Ericaceae host plant in Africa.
- MeSH
- Ericaceae mikrobiologie MeSH
- kořeny rostlin mikrobiologie MeSH
- mykorhiza klasifikace fyziologie MeSH
- půda * MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Jihoafrická republika MeSH
