ectomyelois ceratoniae zeller (lepidoptera.: pyralidae), is the key pest of pomegranate in iran. trichogramma wasps could be used as effective agents of biological control that can also be used effectively in ipm programs. the effect of host density on parasitism of trichogramma brassicae was studied by exposing densities of 4, 8, 10, 20, 40, 60, 80 and 120 eggs of factitious host (sitotroga ce...

This article re-analyses a prey-predator model with a refuge introduced by one of the founders of population ecology Gause and his co-workers to explain discrepancies between their observations and predictions of the Lotka-Volterra prey-predator model. They replaced the linear functional response used by Lotka and Volterra by a saturating functional response with a discontinuity at a critical p...

This work aims to examine the global behavior of a Gause type predator-prey model considering two aspects: (i) the functional response is Holling type III and, (ii) the prey growth is affected by the Allee effect. We prove the origin of the system is an attractor equilibrium point for all parameter values. It has also been shown that it is the ω-limit of a wide set of trajectories of the system...

The Rosenzweig-MacArthur predator-prey model is the building block in modeling food chain, webs and ecosystems. There are a number of hidden assumptions involved derivation. For instance prey population growth logistic without predation but also with predation. In order to reveal these we will start modelling resource-predator-prey system closed spatially homogeneous environment. This allows us...

Abstract. Toxin producing phytoplankton (TPP) plays an important role in aquatic systems. To observe the role of TPP, we consider a three species food chain model consisting of TPP-zooplankton-fish population. The similar type of model considered by Upadhyay et al. [1] for terrestrial ecosystem and obtained chaotic dynamics in some region of parametric space. We modify their models by taking in...

In this paper, regulation of selective harvesting of a prey-predator fishery with Beddington-DeAngelis functional response [1,2] is discussed, considering taxation as a control instrument and harvesting effort as a dynamic variable. The Beddington-DeAngelis functional response is similar to the Holling type II [3] functional response but contains one extra term describing mutual interference by...