Search results for " Structure"
showing 10 items of 25475 documents
An account on the taxonomy and molecular diversity of a marine rock-pool dweller, Tigriopus fulvus (Copepoda, Harpacticoida)
2019
[ES] El género de copépodos Tigriopus Norman, 1869 se distribuye en todo el mundo en charcas de rocas costeras y se considera que actualmente incluye 14 especies válidas. Tigriopus fulvus (Fischer 1860), con sus subespecies Tigriopus fulvus adriaticus Van Douwe 1913 y Tigriopus fulvus algiricus Monard 1935, y Tigriopus minutus Bozic 1960 han sido descritos para el área del Mediterráneo, pero la diversidad real del género es desconocida actualmente. El objetivo de este estudio fue evaluar la identidad real de las poblaciones mediterráneas de Tigriopus y dilucidar su taxonomía y patrón de diversidad genética. Con este fin, se secuenció un fragmento del gen de ADN mitocondrial (citocromo c oxi…
Eight decades of sampling reveal a contemporary novel fish assemblage in coastal nursery habitats.
2015
In order to adequately monitor biodiversity trends through time and their responses to natural or anthropogenic impacts, researchers require long time series that are often unavailable. This general lack of datasets that are several decades or longer makes establishing a background or baseline of diversity metrics difficult - especially when attempting to understand species composition changes against a backdrop of climate and ecological variability. Here, we present an analysis of a community of juvenile nearshore fishes based on nearly 8 decades of highly standardized Norwegian survey records. Using multivariate statistical techniques, we: (i) characterize the change in taxonomic communit…
Differences in nutritional quality of parts of Vitis vinifera berries affect fitness of the European grapevine moth
2006
International audience; The European grapevine moth, Lobesia botrana (Denis & Schiffermuller) (Lepidoptera: Tortricidae), is a major grapevine pest in Europe. The larva is polyphagous and able to develop on more than 25 plant species, several of them being more suitable than Vitaceae for the fitness of L. botrana. Larvae normally eat the pulp of the berry, but may also consume the seeds according to the development stage of the berry and the larval density per bunch. Understanding the effect on individual fitness of such feeding behaviour is important to assess how suitable the different berry tissues are for this insect. We offered to the larvae either entire berries, seeds, or pulp with s…
Is maternal thyroid hormone deposition subject to a trade-off between self and egg because of iodine?
2021
ABSTRACT Maternal hormones constitute a key signalling pathway for mothers to shape offspring phenotype and fitness. Thyroid hormones (THs; triiodothyronine, T3; and thyroxine, T4) are metabolic hormones known to play crucial roles in embryonic development and survival in all vertebrates. During early developmental stages, embryos exclusively rely on exposure to maternal THs, and maternal hypothyroidism can cause severe embryonic maldevelopment. The TH molecule includes iodine, an element that cannot be synthesised by the organism. Therefore, TH production may become costly when environmental iodine availability is low. This may yield a trade-off for breeding females between allocating the …
Fiddler crabs and their above-ground sedimentary structures: a review
2020
AbstractFiddler crabs are abundant, semi-terrestrial crustaceans inhabiting tropical, subtropical and warm temperate coasts worldwide. Some species build above-ground sedimentary structures at or near the opening to their burrows. The functions and shapes of these constructions vary interspecifically and according to the sex of the builder. Here, we compile the dispersed reports on these structures, suggest uniform naming for different shapes, review explanations for their functions and explore associations between the attributes of builders and their structures. We found that 47 fiddler crab species build at least one type (or subtype) of structure, including chimneys, hoods, pillars, semi…
Molecular characterization of <em>Vitis vinifera</em> L. local cultivars from volcanic areas (Canary Islands and Madeira) using SSR marke…
2019
Aim: This study characterises and identifies 79 grapevine accessions from the Canary Islands and 14 from Madeira using simple sequence repeat (SSR) analysis.Methods and Results: A kit of 20 microsatellites or simple sequence repeats (SSRs) were used to obtain the molecular profiles of the 93 accessions in this study. The results allowed us to identify four new cultivars (Bienmesabe tinto, Burra volcanica, Vallera, Verijadiego negro), two new colour mutations (Listan rosa, Mollar cano rosado) and two unknown molecular profiles from Madeira. Furthermore, we propose that eight names of varieties be included in the Vitis International Variety Catalogue (VIVC) as prime names, and 38 accession na…
Lack of specialist nidicoles as a characteristic of mite assemblages inhabiting nests of the ground-nesting wood warbler, Phylloscopus sibilatrix (Av…
2021
AbstractBird and mammal nests provide microhabitats that support a range of other species, including invertebrates. However, the variation between communities of nest-dwelling invertebrates in different nests is poorly understood. The major aim of this study was to analyze the assemblage structure of mites from the suborder Uropodina (Acari: Mesostigmata) and from superfamily Crotonioidea (Acari: Oribatida) inhabiting nests of the wood warbler, Phylloscopus sibilatrix (Aves: Passeriformes), located on a forest floor in Białowieża Forest, in eastern Poland. We also assessed the correlation between the nest material used by the birds with the assemblage structure of Uropodina mites, and compa…
Chemical host detection and differential attraction in a parasitic pea crab infecting two echinoids
2011
Mechanisms of host detection and host choice are important for mobile parasites or symbionts that frequently move among host individuals. The parasitic pea crab Dissodactylus primitivus is an ectoparasite exploiting asymmetrically two spatangoid echinoid hosts, Meoma ventricosa and Plagiobrissus grandis. The entire life cycle takes place on M. ventricosa, while only adults colonize P. grandis, the host where female's fecundity is the greatest. Dissodactylus primitivus frequently exhibits host-switching, a behaviour that raises the question of host detection. To test if adult crabs are able to detect potential hosts and are attracted to the host where their fitness is greater, crab olfactory…
Comparative host–parasite population structures: disentangling prospecting and dispersal in the black-legged kittiwake Rissa tridactyla
2005
Although much insight is to be gained through the comparison of the population genetic structures of parasites and hosts, there are, at present, few studies that take advantage of the information on vertebrate life histories available through the consideration of their parasites. Here, we examined the genetic structure of a colonial seabird, the black-legged kittiwake ( Rissa tridactyla ) using seven polymorphic microsatellite markers to make inferences about population functioning and intercolony dispersal. We sampled kittiwakes from 22 colonies across the species’ range and, at the same time, collected individuals of one of its common ectoparasites, the tick Ixodes uriae . Parasites were …
Modelling vertical and lateral seed bank movements during mouldboard ploughing
2000
Abstract The vertical distribution of weed seeds in the soil is of fundamental importance because seedling emergence depends on seed depth. The lateral displacement of the earth during mouldboard ploughing contributes to the dispersal of the weeds inside the tilled field. In order to model vertical and lateral seed displacements during ploughing, an existing model describing soil particle movements for different ploughing characteristics (depth and width) and soil structures was tested on a multilocal field trial. The trials were carried out in 1996 and 1997 and comprised two soil textures and three soil structures; tillage was performed with a mouldboard plough at varying ploughing widths …