Search results for "DAP"
showing 10 items of 3579 documents
European catfish (Silurus glanis) as a freshwater apex predator drives ecosystem via its diet adaptability
2017
AbstractApex predators play a key role in ecosystem stability across environments but their numbers in general are decreasing. By contrast, European catfish (Silurus glanis), the European freshwater apex predator, is on the increase. However, studies concerning apex predators in freshwaters are scarce in comparison to those in terrestrial and marine ecosystems. The present study combines stomach content and stable isotope analyses with diet preferences of catfish to reveal its impact on the ecosystem since stocking. Catfish niche width is extremely wide in comparison to the typical model predator, Northern pike (Esox lucius). Catfish and pike have different individual dietary specialization…
Lakes in the era of global change: moving beyond single‐lake thinking in maintaining biodiversity and ecosystem services
2020
The Anthropocene presents formidable threats to freshwater ecosystems. Lakes are especially vulnerable and important at the same time. They cover only a small area worldwide but harbour high levels of biodiversity and contribute disproportionately to ecosystem services. Lakes differ with respect to their general type (e.g. land-locked, drainage, floodplain and large lakes) and position in the landscape (e.g. highland versus lowland lakes), which contribute to the dynamics of these systems. Lakes should be generally viewed as ‘meta-systems’, whereby biodiversity is strongly affected by species dispersal, and ecosystem dynamics are contributed by the flow of matter and substances among locati…
How partnerships end in guillemots Uria aalge : chance events, adaptive change, or forced divorce?
2007
Divorce in socially monogamous species can result from different mechanisms, for example, chance events, active desertion of the partner, or the intrusion of a third individual ousting the partner. We compared the predictions associated with such mechanisms with data from common guillemots (Uria aalge) breeding on the Isle of May, Scotland. The data cover the years 1982--2005 and show a yearly divorce rate of 10.2%. In most divorces (86%), one of the original partners moved to another breeding site, whereas the other bird stayed and bred with a new partner. On average, movers had a significantly lower breeding success after divorce, stayers were largely unaffected, whereas the incoming bird…
The Strategic Reference Gene: an organismal theory of inclusive fitness
2019
How to define and use the concept of inclusive fitness is a contentious topic in evolutionary theory. Inclusive fitness can be used to calculate selection on a focal gene, but it is also applied to whole organisms. Individuals are then predicted to appear designed as if to maximise their inclusive fitness, provided that certain conditions are met (formally when interactions between individuals are 'additive'). Here we argue that applying the concept of inclusive fitness to organisms is justified under far broader conditions than previously shown, but only if it is appropriately defined. Specifically, we propose that organisms should maximise the sum of their offspring (including any accrued…
Water temperature, not fish morph, determines parasite infections of sympatric Icelandic threespine sticklebacks (Gasterosteus aculeatus)
2013
Parasite communities of fishes are known to respond directly to the abiotic environment of the host, for example, to water quality and water temperature. Biotic factors are also important as they affect the exposure profile through heterogeneities in parasite distribution in the environment. Parasites in a particular environment may pose a strong selection on fish. For example, ecological differences in selection by parasites have been hypothesized to facilitate evolutionary differentiation of freshwater fish morphs specializing on different food types. However, as parasites may also respond directly to abiotic environment the parasite risk does not depend only on biotic features of the hos…
Identification and biological traits of a planthopper from the genus Pentastiridius (Hemiptera: Cixiidae) adapted to an annual cropping rotation
2009
International audience; Cixiid planthoppers have been shown to vector phloem-limited prokaryotes associated with plant diseases world-wide. In eastern France, an emerging disease of sugar beet called syndrome basses richesses has been associated with phloem-restricted bacteria transmitted by a cixiid planthopper within the genus Pentastiridius. Early investigation suggested the species being Pentastiridius beieri. On the basis of a morphological and phylogenetic study we report the identification of the planthopper as Pentastiridius leporinus. Furthermore we report some biological traits of the species, which shows a surprising ecological adaptation to an annual cropping rotation sugar beet…
Lobesia botrana larvae develop faster in the presence of parasitoids.
2013
3 pages; International audience; To combat parasitism hosts often rely on their immune system, which is the last line of defense. However, the immune system may not always be effective, and other non-immunological defenses might be favored to reduce the cost of parasite infection. Here we report that larvae of the moth Lobesia botrana can rapidly accelerate their development and reach maturity earlier in response to cues perceived at a distance from parasitoids. Such a phenotypically plastic life history shift, induced by the perception of deadly enemies in the environment, is likely to be an adaptive defensive strategy to prevent parasitoid attack, and has important implications in host-pa…
Eco-genetics of desiccation resistance in Drosophila.
2021
International audience; Climate change globally perturbs water circulation thereby influencing ecosystems including cultivated land. Both harmful and beneficial species of insects are likely to be vulnerable to such changes in climate. As small animals with a disadvantageous surface area to body mass ratio, they face a risk of desiccation. A number of behavioural, physiological and genetic strategies are deployed to solve these problems during adaptation in various Drosophila species. Over 100 desiccation-related genes have been identified in laboratory and wild populations of the cosmopolitan fruit fly Drosophila melanogaster and its sister species in large-scale and single-gene approaches…
Eutrophication and browning influence Daphnia nutritional ecology
2019
Climate change and land-use practices can enhance lake eutrophication and browning, which influence phytoplankton composition by decreasing the availability of food high in nutritional quality (algae) and increasing the abundance of low-quality food (terrestrial detritus, bacteria) for herbivorous zooplankton. Nutritionally valuable algae for zooplankton are rich in essential biomolecules such as amino acids, polyunsaturated fatty acids (PUFAs), sterols, and phosphorus. We performed laboratory experiments and showed a stronger positive relationship between zooplankton (Daphnia) cumulative offspring number and availability of high-quality algae (Cryptophytes: Rhodomonas/Cryptomonas; and Chry…
Usability and acceptability assessment of an empathic virtual agent to prevent major depression
2016
In Human-Computer Interaction, the adaptation of the content and the way of how this content is communicated to the users in interactive sessions is a critical issue to promote the acceptability and usability of any computational system. We present a user-adapted interactive platform to identify and provide an early intervention for symptoms of depression and suicide. In particular, we describe the work performed to assess users' system acceptability and usability. An empathic Virtual Agent is the main interface with the user, and it has been designed to generate the appropriate dialogues and emotions during the interactions according to the detected user's specific needs. This personalizat…