نتایج جستجو برای: prey density

تعداد نتایج: 428600  

2007
John F. Piatt Ann M. A. Harding Michael Shultz Suzann G. Speckman Thomas I. van Pelt Gary S. Drew Arthur B. Kettle

In his seminal paper about using seabirds as indicators of marine food supplies, Cairns (1987, Biol Oceanogr 5:261–271) predicted that (1) parameters of seabird biology and behavior would vary in curvilinear fashion with changes in food supply, (2) the threshold of prey density over which birds responded would be different for each parameter, and (3) different seabird species would respond diff...

2013
Chris B. Thaxter Francis Daunt David Grémillet Mike P. Harris Silvano Benvenuti Yutaka Watanuki Keith C. Hamer Sarah Wanless

Understanding how prey capture rates are influenced by feeding ecology and environmental conditions is fundamental to assessing anthropogenic impacts on marine higher predators. We compared how prey capture rates varied in relation to prey size, prey patch distribution and prey density for two species of alcid, common guillemot (Uria aalge) and razorbill (Alca torda) during the chick-rearing pe...

2007
Ximena E. Bernal Rachel A. Page A. Stanley Rand Michael J. Ryan

Predators and parasites that eavesdrop on the mating signals of their prey often preferentially select individuals within a prey/host species that produce specific cues. Mechanisms driving such signal preferences are poorly understood. In the túngara frog Physalaemus pustulosus, conspecific females, frog-eating bats, and blood-sucking flies all prefer complex to simple mating calls. In this stu...

2006
Anson H. Hines

The interactive effects of predator density and prey distribution on the foraging behavior of an important estuarine predator were studied, at a fine temporal scale, using ultrasonic telemetry. The movement and agonistic activity of individual blue crabs Callinectes sapidus were monitored in large field enclosures, in which the density of crabs and the distribution of patches of bivalve prey Ma...

Journal: :The American naturalist 2003
Natalia Sapoukhina Yuri Tyutyunov Roger Arditi

We study a reaction-diffusion-advection model for the dynamics of populations under biological control. A control agent is assumed to be a predator species that has the ability to perceive the heterogeneity of pest distribution. The advection term represents the predator density movement according to a basic prey taxis assumption: acceleration of predators is proportional to the prey density gr...

2011
Éric Lucas Jay A. Rosenheim

Heteropteran predators constitute an important component of predatory guilds in terrestrial and aquatic ecosystems. Most heteropteran species have generalist diets, and intraguild predation has been documented in most heteropteran families. Zoophytophagous species also frequently engage in intraguild interactions. An increase in extraguild prey density is often predicted to reduce intraguild pr...

2006
DOUGLAS W. MORRIS

Numerous ecological models evaluate how predators influence the abundance of their prey. Prey dynamics in these models often reflect a compromise between prey reproductive potential, density-dependent competition, and the direct consumption of prey by predators. But predators and prey play a complex evolutionary game where prey behavior, and its effect on distribution and abundance, depends on ...

Journal: :Bulletin of mathematical biology 2008
J M Lee T Hillen M A Lewis

Spatially moving predators are often considered for biological control of invasive species. The question arises as to whether introduced predators are able to stop an advancing pest or foreign population. In recent studies of reaction-diffusion models, it has been shown that the prey invasion can only be stopped if the prey dynamics observes an Allee effect. In this paper, we include prey-taxis...

Journal: :Journal of theoretical biology 2004
Vlastimil Krivan Ivo Vrkoc

Predator-prey models consider those prey that are free. They assume that once a prey is captured by a predator it leaves the system. A question arises whether in predator-prey population models the variable describing prey population shall consider only those prey which are free, or both free and handled prey together. In the latter case prey leave the system after they have been handled. The c...

2003
Debasis Mukherjee D. MUKHERJEE

We present a Gause type predator–prey model incorporating delay due to response of prey population growth to density and gestation. The functional response of predator is assumed to be of Holling type II. In absence of prey, predator has a density dependent death rate. Sufficient criterion for uniform persistence is derived. Conditions are found out for which system undergoes a Hopf–bifurcation...

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