Search results for "Competition"

Speed-accuracy trade-off and its consequences in a scramble competition context.

2014

Abstract: Animals foraging in groups commonly respond to the presence of others by increasing their foraging rate, an increase that could come at the expense of prey detection accuracy. Yet the existence and consequences of such so-called 'speed-accuracy trade-offs' in group-foraging animals remain unexplored. We used group-feeding zebra finches, Taeniopygia guttata, to determine how search speed affects food detection accuracy and how a potential speed-accuracy trade-off influences feeding success. We found significant between-individual differences in hopping speed as well as evidence that faster individuals were more likely to overlook food, demonstrating the existence of a trade-off bet…

Larval size in acanthocephalan parasites : Influence of intraspecific competition and effects on intermediate host behavioural changes

2012

Abstract Background Parasites often face a trade-off between exploitation of host resources and transmission probabilities to the next host. In helminths, larval growth, a major component of adult parasite fitness, is linked to exploitation of intermediate host resources and is influenced by the presence of co-infecting conspecifics. In manipulative parasites, larval growth strategy could also interact with their ability to alter intermediate host phenotype and influence parasite transmission. Methods We used experimental infections of Gammarus pulex by Pomphorhynchus laevis (Acanthocephala), to investigate larval size effects on host behavioural manipulation among different parasite sibshi…

How can a country like Canada be inhospitable to an influence of yardstick competition on regulation?

2007

The London Stock Exchange: Strategic Corporate Governance Restructuring After Demutualization

2014

International audience; This study uses the London Stock Exchange (LSE), forced to demutualize due to major changes in its business environment, notably due to increased competition and technological advances, as field experiment to study corporate governance restructuring to adapt to new market conditions. The LSE improved its financial situation after demutualization and is an example of successful corporate governance restructuring. The LSE significantly restructured the composition of its board of directors following demutualization. The number of exchange members on the LSE board decreased after demutualization while the number of independent directors increased, pointing to a more “mo…

How to model crop-weed competition for soil resources: Connecting the STICS soil submodel to the FLORSYS weed dynamics model

2020

International audience

Trait distribution within winter wheat fields can partly be explained by disturbances and competition for resources

2013

International audience; Weed species are not homogeneously distributed into field elements (Cordeau et al. 2012)*.In a field, weed species are mainly competing with the crop and constrained by management practice (i.e.disturbances). In the crop edge, less unfavorable conditions for weed development (i.e.absence of direct crop competition,l ess frequent disturbances could explain the greater diversity of weeds.To understand this observation, a functional approach base dont raits known to respond both to disturbances and to competitive or facilitative interactions can be used.Our assumptions are that(i)the crop edge is likely to all owawi derrange of ecological strategies thus promoting speci…

Mise en évidence du rôle de la diversité dans la dynamique des communautés d'adventices et des interactions adventices/cultures

2020

The main challenge of 21st century agriculture is to provide sufficient food for a growing to identify cropping systems which maintain crop productivity, minimize reliance on synthetic herbicides and nitrogen fertilizers, and promote weed diversity. We hypothesized that cropping system diversification, either at the annual scale through the introduction of cover crops, or at the plurennial scale through a diversification of the crop sequence and associated weed management tools, could be a viable means to reach these objectives. More specifically, we hypothesized that cropping system diversification could (i) contain weed abundance and thereby, allow a reduction of herbicide use and an incr…

Effets de la variabilité inter-individuelles et des interactions intra-guildes sur les stratégies d'approvisionnement de carabes consommateurs de gra…

2017

Making a choice requires, implicitly, an investment of time in one behaviour at the expense of an investment in another. Being choosy would increase the risk of losing many food item opportunities to competitors, and is directly in conflict with other essential tasks such as predator avoidance. Individuals are thus expected to adjust their level of choosiness in response to the competition and predation context. The available behavioural ecological theory and the empirical ecology of carabids would suggest that competition and predation interference induces changes in the foraging behaviour of carabid individuals. Carabids typically operate within communities in which competition and predat…

Morphology and yield response to weed pressure by corn hybrids differing in canopy architecture

2001

Abstract Recently, corn ( Zea mays L.) hybrids accumulating more leaf area above the ear, maturing earlier, yielding better in narrower row spacings and tolerating higher population densities than conventional hybrids have been developed. However, no research has been conducted to assess their ability to compete with weeds. The objective of this study was to quantify morphological and grain yield responses of hybrids with differing canopy architectures to the presence and absence of weeds. Field experiments were conducted in 1996, 1997, and 1998 at Ste. Anne de Bellevue, Quebec and in 1996 at Ottawa, Ontario. Three hybrids, leafy reduced-stature (LRS), late maturing big leaf (LMBL), and con…

Contamination of rapeseed harvest by volunteers of other varieties : a study of intergenotypic competition

2004

Rapeseed volunteers in rapeseed crops can cause contamination in harvest through pollen and seeds. The aim of the study was to predict pollen and seed production by volunteers in winter rapeseed crops according to the genotypes of the crop and the volunteers. Firstly an experimental analysis of intraspecific competition was carried out in 2000 and 2001 on two and six genotypes, respectively. The main competition period begins with vegetation onset and affects pollen and seed production of the volunteers. Relations between density, height, yield and number of flowers were developed based on results from experiments and literature. Knowing the densities and heights of volunteers and crop on t…