Search results for "ECOLOGY"
showing 10 items of 15385 documents
SPECIES RICHNESS WITHIN FAMILIES OF FLOWERING PLANTS
1994
Variation in species and genus richness among families of flowering plants was examined with respect to four classification variables: geographical distribution, growth form, pollination mode, and dispersal mode. Previous studies have estimated rates of species proliferation from age and contemporary diversity. Here we found that the earliest appearances in the fossil record are correlated with contemporary familial species richness, abundance in the fossil record, and the independent variables considered in this analysis. Thus, we believe that the fossil record does not provide reasonable estimates of the ages of families and that the rate of species proliferation cannot be calculated from…
Effects of water stress on emission of volatile organic compounds by Vicia faba, and consequences for attraction of the egg parasitoid Trissolcus bas…
2017
When plants are damaged by herbivorous insects, blends of volatile organic compounds (VOCs) are induced and released and can also be used by parasitoids to locate hosts. The aim was to determine whether VOCs induced by water stress affect the plant-herbivore-para- sitoid system represented by broad bean (Vicia faba; Fabales: Fabaceae) stink bug (Nezara viridula; Hetero- ptera: Pentatomidae) egg parasitoid (Trissolcus basalis; Hymenoptera: Platygastridae). The effects of water stress (expressed as the percentage fraction of transpirable soil water [FTSW] supplied) alone and in combination with N. viridula damage (feeding plus oviposition) were deter- mined according to: (1) the behavioural r…
Ecological genomics of adaptation to unpredictability in experimental rotifer populations
2019
AbstractElucidating the genetic basis of phenotypic variation in response to different environments is key to understanding how populations evolve. Facultatively sexual rotifers can develop adaptive responses to fluctuating environments. In a previous evolution experiment, diapause-related traits changed rapidly in response to two selective regimes (predictable vs unpredictable) in laboratory populations of the rotifer Brachionus plicatilis. Here, we investigate the genomic basis of adaptation to environmental unpredictability in these experimental populations. We identified and genotyped genome-wide polymorphisms in 169 clones from both selective regimes after seven cycles of selection usi…
Use of DNA barcoding in the assignment of commercially valuable fish species from Romania
2017
DNA barcoding is a molecular technique frequently used either for biodiversity monitoring and fish conservation or in the identification of the species of origin for raw and processed food from restaurants or fish markets. The most important aspect of this technique is that it works for all stages of life and can be used to distinguish between closely related taxa. Also, the technique has been used to unmask attempts of frauds in fish markets where more desirable and expensive fish are sometimes substituted with lower valued species. Our study aims to test the utility of the COI barcoding gene in the correct identification of several economically and ecologically valuable fish species, and …
Behavioural, ecological, and evolutionary aspects of diversity in frog colour patterns
2016
The role of colours and colour patterns in behavioural ecology has been extensively studied in a variety of contexts and taxa, while almost overlooked in many others. For decades anurans have been the focus of research on acoustic signalling due to the prominence of vocalisations in their communication. Much less attention has been paid to the enormous diversity of colours, colour patterns, and other types of putative visual signals exhibited by frogs. With the exception of some anecdotal observations and studies, the link between colour patterns and the behavioural and evolutionary ecology of anurans had not been addressed until approximately two decades ago. Since then, there has been eve…
Pace-of-life in a social insect: behavioral syndromes in ants shift along a climatic gradient
2017
Lay SummaryLinks between behavioral traits can shift with the local climate. We show that behavioral associations with temperature not only occur across, but also within populations. At warmer sites ant colonies increased their exploration and foraging activity, but were less aggressive. Moreover, at these warmer sites, more positive links were found between behaviors within populations compared to colder sites, where more negative links prevailed. Our study suggests that associations between behaviors shift along climatic gradients.
Crop density rather than ruderal plants explains the response of ancient segetal weeds
2018
AbstractThe influence of ruderal species and crop density on ancient segetal weeds was examined. The experiment was carried out on experimental plots with three different sewing densities of winter triticale. Weeding of ruderal taxa was applied on half of the plots to explore the relation between segetal and ruderal weeds. Variation in species composition by environmental variables was analysed by running Redundancy Analysis (RDA) combined with performing forward selection and variation partitioning for “weeding” and “crop density” as explanatory variables. Additionally, the effect of crop density and weeding was tested separately for segetal and ruderal species along the seasons with the u…
How do cuticular hydrocarbons evolve? Physiological constraints and climatic and biotic selection pressures act on a complex functional trait
2017
Cuticular hydrocarbons (CHCs) cover the cuticles of virtually all insects, serving as a waterproofing agent and as a communication signal. The causes for the high CHC variation between species, and the factors influencing CHC profiles, are scarcely understood. Here, we compare CHC profiles of ant species from seven biogeographic regions, searching for physiological constraints and for climatic and biotic selection pressures. Molecule length constrained CHC composition: long-chain profiles contained fewer linear alkanes, but more hydrocarbons with disruptive features in the molecule. This is probably owing to selection on the physiology to build a semi-fluid cuticular layer, which is necessa…
Variation in the immune state of Gammarus pulex (Crustacea, Amphipoda) according to temperature: are extreme temperatures a stress?
2017
9 pages; International audience; Temperature is known to impact host-parasite interactions in various ways. Such effects are often regarded as the consequence of the increased metabolism of parasites with increasing temperature. However, the effect of temperature on hosts' immune system could also be a determinant. Here we assessed the influence of temperature on the immunocompetence of the crustacean amphipod Gammarus pulex. Amphipods play a key ecological role in freshwater ecosystems that can be altered by several parasites. We investigated the consequences of three weeks of acclimatization at four temperatures (from 9 °C to 17 °C) on different immunological parameters. Temperature influ…
Phylogeography, evolutionary history and effects of glaciations in a species (Zootoca vivipara) inhabiting multiple biogeographic regions
2018
[Aim]: During glaciations, the distribution of temperate species inhabiting the Northern Hemisphere generally contracts into southern refugia; and in boreo‐alpine species of the Northern Hemisphere, expansion from Northern refugia is the general rule. Little is known about the drivers explaining vast distributions of species inhabiting multiple biogeographic regions (major biogeographic regions defined by the European Environmental Agency). Here we investigate the fine‐scale phylogeography and evolutionary history of the Eurasian common lizard (Zootoca vivipara), the terrestrial reptile with the world's widest and highest latitudinal distribution, that inhabits multiple biogeographic region…