Search results for "DOM"
showing 10 items of 12668 documents
The effect of maze complexity on maze-solving time in a desert ant
2019
One neglected aspect of research on foraging behavior is that of the effect of obstacles that increase habitat complexity on foraging efficiency. Here, we explored how long it takes individually foraging desert ant workers (Cataglyphis niger) to reach a food reward in a maze, and examined whether maze complexity affects maze-solving time (the time elapsed till the first worker reached the food reward). The test mazes differed in their complexity level, or the relative number of correct paths leading to the food reward, vs. wrong paths leading to dead-ends. Maze-solving time steeply increased with maze complexity, but was unaffected by colony size, despite the positive correlation between co…
Co-inertia multivariate approach for the evaluation of anthropogenic impact on two commercial fish along Tyrrhenian coasts
2019
Abstract Aliphatic hydrocarbon levels were determined by the GC/MS technique in fish livers of Engraulis encrasicolus (Ee) and Trachurus trachurus (Tt), collected from a particular area of the Mediterranean Sea, called GSA 10, which is located exactly in Tyrrhenian Sea between Campania coast and North Sicily coast. The aim was to evaluate their potential use as specific bioindicators towards this class of contaminants. Both Tt and Ee are considered to be pollution monitoring bioindicators, due to their dominance in marine communities and economic fishing interest. Ee showed a higher tendency to bioaccumulate TAHs, due to the lower quantity of fatty acids in liver tissues with respect to Tt.…
Cryptogams signify key transition of bacteria and fungi in Arctic sand dune succession
2019
SummaryPrimary succession models focus on aboveground vascular plants. However, the prevalence of mosses and lichens, i.e. cryptogams, suggests they play a role in soil successions. Here, we explore whether effects of cryptogams on belowground microbes can facilitate progressive shifts in sand dune succession.We linked aboveground vegetation, belowground bacterial and fungal community, and soil chemistry in six successional stages in Arctic inland sand dunes: bare sand, grass, moss, lichen, ericoid heath and mountain birch forest.Compared to the bare sand and grass stages, microbial biomass and the proportion of fungi increased in the moss stage, and later stage microbial groups appeared de…
The antioxidant power of horseradish, Armoracia rusticana, underlies antimicrobial and antiradical effects, exerted in vitro
2018
Armoracia rusticana (AR) was tested for antimicrobial and antioxidants power. The compound demonstrated to inhibit fish pathogens such as Vibrio anguillarum, V. harvey, V. alginolyticus, Aeromonas hydrophila, A. salmonicida, Photobacterium damselae subspecie piscicida, Tenacibaculum marinum and Pseudomonas anguilliseptica,. The total phenolic content and the reducing power resulted higher in the water extract of AR, respect to the hydroalcoolic. In vitro test demonstrated that AR significantly protect cells against death, induced by oxidative stress.
Influence of Riverine Input on Norwegian Coastal Systems
2020
Coastal ecosystems are of high ecological and socioeconomic importance and are strongly influenced by processes from land, sea, and human activities. In this study, we present physical, chemical, and biological observations over two consecutive years from three study regions along the Norwegian coast that represent a broad latitudinal gradient in catchment and oceanographic conditions (∼59–69°N): outer Oslofjord/southern Norway, Runde/western Norway, and Malangen/northern Norway. The observations included river monitoring, coastal monitoring, and sensor-equipped ships of opportunity (“FerryBox”). The riverine discharge and transports were an order of magnitude higher, and the spatiotemporal…
New insight into the colonization processes of common voles: inferences from molecular and fossil evidence.
2008
Biologie et Gestion des Populations, Campus International de Baillarguet, Montferrier/Lez, FranceElucidating the colonization processes associated with Quaternary climatic cycles is important in order to understand the distribution of biodiversity and the evolutionary potential of temperate plant and animal species. In Europe, general evolutionary scenarios have been defined from genetic evidence. Recently, these scenarios have been challenged with genetic as well as fossil data. The origins of the modern distributions of most temperate plant and animal species could predate the Last Glacial Maximum. The glacial survival of such populations may have occurred in either southern (Mediterranea…
Effects of mowing on fungal endophytes and arbuscular mycorrhizal fungi in subalpine grasslands
2013
International audience; In French subalpine grasslands, cessation of mowing promotes dominance of Festuca paniculata, which alters plant diversity and ecosystem functioning. One of the mechanisms underpinning such effects may be linked to simultaneous changes in the abundance of fungal symbionts such as endophytes and arbuscular mycorrhizal fungi. In field conditions, mowing reduced the abundance of the endophyte Neotyphodium sp. in leaves of F. paniculata by a factor of 6, and increased mycorrhizal densities by a factor of 15 in the soil. In greenhouse experiments, the mycorrhizal colonization of Trifolium pratense and Allium porrum increased 3- fold and 3.8- fold respectively in mown vs u…
The mycorrhizal soil infectivity and arbuscular mycorrhizal fungal spore communities in soils of different aged fallows in Senegal
2001
This work was carried out to determine the influence of the duration of fallow and of physico-chemical components of soils on the distribution of endomycorrhizal fungal spores and the mycorrhizal soil infectivity. The mycorrhization of indigenous plants from the fallows was examined and it was concluded that, except for Cassia obtusifolia, fungal colonization was poorly developed. No correlation was established between spore populations and duration of fallow or between grazed and fenced areas. The relationships between abundance of mycorrhizal spores and the physico-chemical characteristics of the soils were markedly variable among species of mycorrhizal fungi. The results did not provide …
Changes in body mass and hormone levels between wintering and spring staging areas in Dark-bellied brent geese Branta bernicla bernicla
2006
International audience; Wintering migratory geese generally replenish protein stores lost during migration before building up their fat stores (Gauthier et al. 1992). Dark-bellied brent geese Branta bernicla bernicla winter mainly along the coasts of France, England and the south-western part of the Netherlands, and stage from March till late May mainly in the Wadden Sea, stretching from the northern Netherlands to Denmark (Ebbinge et al. 1999). During spring, geese accumulate body stores needed both for their long-distance migration to the breeding grounds and for reproduction (Spaans et al. 1993, Ebbinge and Spaans 1995). Dark-bellied brent geese, migrating about 5000 km between the winte…
Reproductive monopoly enforced by sterile police workers in a queenless ant
2004
In societies of totipotent insects, dyadic dominance interactions generate a hierarchy that often underlies an extreme reproductive skew. Subordinates remain infertile but can maximize their indirect fitness benefits through collective power (worker policing): interference with challenging high-rankers can prevent an untimely replacement of the reproductive. However, police workers only benefit if they favor individuals with high fertility. In the monogynous queenless ant Streblognathus peetersi, we used behavioral, physiological, and chemical methods to show that police workers have the primary role in the selection of the reproductive, and that they probably use reliable information about…