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showing 10 items of 10735 documents
Characterizing the pigment composition of a variable warning signal of Parasemia plantaginis larvae
2010
Summary 1. Aposematic animals advertise their defences to predators via warning signals that often are bright colours combined with black patterns. Predation is assumed to select for large pattern elements and conspicuousness of warning signals because this enhances avoidance learning of predators. However, conspicuousness of the colour pattern can vary among individuals of aposematic species, suggesting that warning signal expression may be constrained by opposing selection pressures. If effective warning signals are costly to produce, variation in signal expression may be maintained via physiological trade-offs. To understand the costs of signalling that might underlay both physiological …
Drosophila Evolution over Space and Time (DEST) : A New Population Genomics Resource
2021
Drosophila melanogaster is a leading model in population genetics and genomics, and a growing number of whole-genome datasets from natural populations of this species have been published over the last years. A major challenge is the integration of disparate datasets, often generated using different sequencing technologies and bioinformatic pipelines, which hampers our ability to address questions about the evolution of this species. Here we address these issues by developing a bioinformatics pipeline that maps pooled sequencing (Pool-Seq) reads from D. melanogaster to a hologenome consisting of fly and symbiont genomes and estimates allele frequencies using either a heuristic (PoolSNP) or a…
Pulsed-resource dynamics increase the asymmetry of antagonistic coevolution between a predatory protist and a prey bacterium
2011
Temporal resource fluctuations could affect the strength of antagonistic coevolution through population dynamics and costs of adaptation. We studied this by coevolving the prey bacterium Serratia marcescens with the predatory protozoa Tetrahymena thermophila in constant and pulsed-resource environments for approximately 1300 prey generations. Consistent with arms race theory, the prey evolved to be more defended, whereas the predator evolved to be more efficient in consuming the bacteria. Coevolutionary adaptations were costly in terms of reduced prey growth in resource-limited conditions and less efficient predator growth on nonliving resource medium. However, no differences in mean coevol…
Life history and spatial distribution of the enchytraeid wormCognettia sphagnetorum(Oligochaeta) in metal-polluted soil: Below-ground sink-source pop…
2001
We studied the life history, metal-avoidance behavior, spatial distribution, and population growth of enchytraeid worms (Cognettia sphagnetorum [Oligochaeta]) originating from two sites: one uncontaminated, and another patchily polluted by heavy metals. Effects of patchy soil contamination on populations were studied in microcosms. In uncontaminated soil, worms from the polluted site had lower viability and reduced growth rate as juveniles but higher growth rate as adults compared to worms from the unpolluted site. They were also smaller in size at fragmentation (reproduction). Worms from the polluted site reached a larger population size than worms from the unpolluted site. Hence, worms fr…
Gadoria (Antirrhineae, Plantaginaceae): A new genus, endemic from Sierra de Gádor, Almería, Spain
2017
The surprising discovery of a population of a new species of Antirrhineae (Plantaginaceae) has also given rise to the description of a new genus situated in the subtribe Maurandyinae: Gadoria falukei. This is supported by the characteristics of the flower, pollen grains, seeds and capsule, and phylogenetic results based on DNA sequences. The species is endemic from Sierra de Gádor, Almería, Spain. Scanning electron microscopy was used to explore micromorphology of the capsule, indument, and seed and pollen grains ornamentation. Additionally, chromosomal number, preliminary insights on reproductive biology, phylogenetic position within Antirrhineae, ecological data and conservation status of…
Effects of Acifluorfen-methyl on cucumber cotyledons : porphyrin accumulation
1988
Abstract The nitrodiphenyl ether herbicide acifluorfen-methyl and the pyridine derivative LS 82-556 induce porphyrin accumulation in green cucumber cotyledons. When experiments are done with intact plants absorbing the herbicide through the roots, that accumulation is light-dependent. 3-(3,4-Dichlorophenyl)-1,1-dimethylurea (DCMU) which prevents cellular damages under these conditions (M. Matringe and R. Scalla, Pestic. Biochem. Physiol. 26 , 150 (1986), also inhibits porphyrin accumulation. In contrast, when detached cotyledons are cut into pieces and floated on herbicide solutions, porphyrins accumulate in the dark. Accordingly, DCMU does not inhibit porphyrin accumulation or protect the …
Assessing coastal habitats with Juniperus sp. pl. in the Iberian Peninsula and on the Balearic Islands
2021
Coastal habitats with Juniperus sp. pl. represent the mature stage in the ecological succession of dune ecosystems. Maritime junipers (Juniperus macrocarpa), prickly junipers (J. navicularis) and c...
A haplotype-resolved, de novo genome assembly for the wood tiger moth (Arctia plantaginis) through trio binning
2020
ABSTRACT Background Diploid genome assembly is typically impeded by heterozygosity because it introduces errors when haplotypes are collapsed into a consensus sequence. Trio binning offers an innovative solution that exploits heterozygosity for assembly. Short, parental reads are used to assign parental origin to long reads from their F1 offspring before assembly, enabling complete haplotype resolution. Trio binning could therefore provide an effective strategy for assembling highly heterozygous genomes, which are traditionally problematic, such as insect genomes. This includes the wood tiger moth (Arctia plantaginis), which is an evolutionary study system for warning colour polymorphism. F…
la prospection systématique d’un fond de rivière : l’exemple du Doubs
2020
La présentation des méthodes mises en œuvre et des résultats obtenus à l’occasion d’une opération de prospection subaquatique systématique menée sur la rivière Doubs, en amont de Verdun-sur-le-Doubs (Saône-et-Loire), illustre en grandeur réelle l’intérêt de la démarche adoptée, fondée sur des principes simples, dans la perspective d’un inventaire systématique du patrimoine fluvial immergé. La diversité des vestiges découverts et leur répartition sur la longue durée en soulignent la pertinence mais également, s’il en était encore besoin, la réalité du formidable potentiel archéologique que recèlent les cours d’eau. The presentation of the methods used and results obtained during a systematic…
Predation on Multiple Trophic Levels Shapes the Evolution of Pathogen Virulence
2009
The pathogen virulence is traditionally thought to co-evolve as a result of reciprocal selection with its host organism. In natural communities, pathogens and hosts are typically embedded within a web of interactions with other species, which could affect indirectly the pathogen virulence and host immunity through trade-offs. Here we show that selection by predation can affect both pathogen virulence and host immune defence. Exposing opportunistic bacterial pathogen Serratia marcescens to predation by protozoan Tetrahymena thermophila decreased its virulence when measured as host moth Parasemia plantaginis survival. This was probably because the bacterial anti-predatory traits were traded o…