Search results for "competition"
showing 10 items of 1409 documents
Eutrophic status influences the impact of pesticide mixtures and predation on Daphnia pulex populations
2021
Abstract Pesticides, nutrients, and ecological stressors such as competition or predation co‐occur in freshwater ecosystems impacted by agriculture. The extent to which combinations of these stressors affect aquatic populations and the role of nutrients availability in modulating these responses requires further understanding. In this study, we assessed how pesticides affecting different taxonomic groups and predation influence the response of Daphnia pulex populations under different trophic conditions. An outdoor experiment was designed following a factorial design, with the insecticide chlorpyrifos, the herbicide diuron, and the predation by Notonecta sp. individuals as key stressors. Th…
The Role of (E)-2-octenyl Acetate as a Pheromone of Bagrada hilaris (Burmeister): Laboratory and Field Evaluation
2020
The pentatomid bug Bagrada hilaris is a key pest of brassicaceous crops in several areas of the world. Previous studies suggest that mate location of this species is mediated by volatile chemicals produced by males, among which the main compound is (E)-2-octenyl acetate. However, the possible attraction of males, females, and nymphs to this compound has not yet been specifically tested. In this study, we tested the response of B. hilaris females, males, and nymphs to (E)-2-octenyl acetate using an electroantennogram (EAG) and olfactometer in the presence or absence of a host plant. Moreover, (E)-2-octenyl acetate as an attractant lure in field trap bioassays was evaluated. EAG recordings sh…
Competition between marine mammals and fisheries in contemporary harvested marine ecosystems
2019
Competitive interactions between marine mammals and fisheries represent some of the most complex challenges in marine resource management worldwide. The development of commercial fisheries and recovering marine mammal populations have contributed to a decrease in fish availability. Whilst ecosystem-based fisheries management (EBFM) can counteract this decrease, achieving the EBFM objectives faces certain major obstacles including insufficient or unreliable data, inapplicable assessment models, as well as inadequate management decisions that do not account for fisheries-induced morphological alterations (FIMA) and marine mammal management. Despite a body of evidence addressing various aspect…
Out in the open : behavior’s effect on predation risk and thermoregulation by aposematic caterpillars
2020
Abstract Warning coloration should be under strong stabilizing selection but often displays considerable intraspecific variation. Opposing selection on color by predators and temperature is one potential explanation for this seeming paradox. Despite the importance of behavior for both predator avoidance and thermoregulation, its role in mediating selection by predators and temperature on warning coloration has received little attention. Wood tiger moth caterpillars, Arctia plantaginis, have aposematic coloration, an orange patch on the black body. The size of the orange patch varies considerably: individuals with larger patches are safer from predators, but having a small patch is beneficia…
Species interactions, environmental gradients and body size shape population niche width
2021
1. Competition for shared resources is commonly assumed to restrict population-level niche width of coexisting species. However, the identity and abundance of coexisting species, the prevailing environmental conditions, and the individual body size may shape the effects of interspecific interactions on species’ niche width. 2. Here we study the effects of interspecific and intraspecific interactions, lake area and altitude, and fish body size on the trophic niche width and resource use of a generalist predator, the littoral-dwelling large, sparsely rakered morph of European whitefish (Coregonus lavaretus; hereafter LSR whitefish). We use stable isotope, diet and survey fishing data from 14 …
Bio-inspired evolutionary dynamics on complex networks under uncertain cross-inhibitory signals
2019
Given a large population of agents, each agent has three possiblechoices between option 1 or 2 or no option. The two options are equally favorable and the population has to reach consensus on one of the two options quickly and in a distributed way. The more popular an option is, the more likely it is to be chosen by uncommitted agents. Agents committed to one option can be attracted by those committed to the other option through a cross-inhibitory signal. This model originates in the context of honeybee swarms, and we generalize it to duopolistic competition and opinion dynamics. The contributions of this work include (i) the formulation of a model to explain the behavioral traits of the ho…
The ‘Open Garden of Politics’: The impact of open primaries for candidate selection in the British Conservative Party
2016
International audience; Since 2003, hundreds of open primaries for the selection of parliamentary candidates have been held by the British Conservative Party as a means of democratising party organisation and enhancing representativeness. In the run-up to the 2015 general election, only 26 primaries could be identified. This article will apply the analytical framework provided by Hazan and Rahat to demonstrate that the relative failure of the experiment in terms of intra-party competition, participation, representation and responsiveness is counterbalanced by the benefits brought by this procedure, both as a tool of party branding at the national level and as a strategy for raising the prof…
The organization of the defense support system: an economic geography perspective
2017
In the context of restricted budgetary resources and the growing cost of maintenance, repair, and overhaul (MRO) activities, a major issue for modern armed forces is to sustain defense platforms. A possible method consists of realizing economies of scale through the concentration of maintenance activities, which involves the spatial reorganization of existing industrial sites dedicated to MRO. This article provides a formalized framework to discuss the optimal organization for the MRO of defense platforms in space. The public planner organizes the maintenance of defense platforms with only two possible spatial configurations. In the dispersed configuration, two industrial production units i…
The consequences of supply gaps in two‐dimensional policy spaces for voter turnout and political support: The case of economically left‐wing and cult…
2019
Parties with left-wing positions on economic issues and right-wing (i.e., authoritarian) positions on cultural issues have been historically largely absent from the supply side of the policy space of Western European democracies. Yet, many citizens hold such left-authoritarian issue attitudes. This article addresses the hypotheses that left-authoritarian citizens are less likely to vote, less satisfied with the democratic process and have lower levels of political trust when there is a left-authoritarian supply gap. Using data for 14 Western European countries from the European Social Survey 2008 in the main analysis, it is shown that left-authoritarians are less likely to vote and exhibit …
Language constraints in producing prefiguration posters for a scientific exhibition
1997
The museographic transposition of scientific knowledge leads notably to the preparation of exhibition posters. This is a delicate operation, on account of the constraints imposed by space, language, concepts and the text. These difficulties are even greater in the case of bovine reproduction biotechnologies, such as cloning, where knowledge is not yet stable. This paper deals with the choices made during the phase of museographic transposition. First of all, based on an epistemological approach, a historical analysis of knowledge-building underpins the choice of information to be presented. Language is then selected according to the linguistic analysis of a series of articles which popular…