Dynamics of a delayed Lotka–Volterra competition model with directed dispersal

We consider a diffusive Lotka–Volterra competition system with stage structure, where the intrinsic growth rates and the carrying capacities of the species are assumed spatially heterogeneous. Here, we also assume each of the competing populations chooses its dispersal strategy as the tendency to have a distribution proportional to a certain positive prescribed function. We give the effects of dispersal strategy, delay, the intrinsic growth rates and the competition parameters on the global dynamics of the delayed reaction diffusion model. Our result shows that competitive exclusion occurs when one of the diffusion strategies is proportional to the carrying capacity, while the other is not; while both populations can coexist if the competition favors the latter species. Finally, we point out that the method is also applied to the global dynamics of other kinds of delayed competition models.     

Competition in a patchy environment with cross-diffusion in a three-dimensional Lotka–Volterra system

In this paper, we formulate a three-dimensional competitive Lotka–Volterra system in two patches in which the per capita migration rate of each species is influenced not only by its own density but also by another’s density. That is to say, there is cross-diffusion present in the Lotka–Volterra system. We first show that there is a critical value of the bifurcation parameter at which the system undergoes a Turing bifurcation under the effect of cross-diffusion, in theory. At the same time, we also give the results of numerical studies. Our work illustrates that the cross-migration response is an important factor that should not be ignored for this kind of system.     

Global asymptotic stability of a Lotka–Volterra competition model with stochasticity in inter-specific competition

In the paper we first propose a two-species Lotka–Volterra competition model with the stochastic terms related to the inter-specific competition rates and the coexistence equilibrium of the deterministic model. Then we establish the global asymptotic stability of the coexistence equilibrium. Finally, we provide some discussions and numerical examples to illustrate our mathematical results.     

Global stability and pattern formation in a nonlocal diffusive Lotka–Volterra competition model

A diffusive Lotka–Volterra competition model with nonlocal intraspecific and interspecific competition between species is formulated and analyzed. The nonlocal competition strength is assumed to be determined by a diffusion kernel function to model the movement pattern of the biological species. It is shown that when there is no nonlocal intraspecific competition, the dynamics properties of nonlocal diffusive competition problem are similar to those of classical diffusive Lotka–Volterra competition model regardless of the strength of nonlocal interspecific competition. Global stability of nonnegative constant equilibria are proved using Lyapunov or upper–lower solution methods. On the other hand, strong nonlocal intraspecific competition increases the system spatiotemporal dynamic complexity. For the weak competition case, the nonlocal diffusive competition model may possess nonconstant positive equilibria for some suitably large nonlocal intraspecific competition coefficients.     

Singularity of Lotka‐Volterra models under unfoldings

In this paper, we classify the singularity of a Lotka‐Volterra competitive model with a Gaussian competition function and non‐Gaussian carrying capacity functions. These functions need not be completely different to affect adaptive dynamics of the model. For instance, it will be seen how ostensibly similar models can actually give rise to quite different behaviors due to their properties under unfolding. The use of Gaussian‐like carrying capacity functions can also show the sensitivity of the model to assumptions on the carrying capacity function's shapes. The classification is achieved using singularity theory of fitness functions under dimorphism equivalence. We also investigate the effect of the presence of unfolding and bifurcation parameters on the evolution of the system near its singular points. Particularly, we study the adaptive dynamics of the system near the singularity by focusing on ESS and CvSS types, and dimorphisms. Mutual invasibility plots are used to show regions of coexistence.     

Coexistence and bistability of a competition model with mixed dispersal strategy

In this paper, we investigate a Lotka–Volterra competition model with Danckwerts boundary conditions in a one-dimensional habitat where one species assumes pure random diffusion while another one undergoes mixed movement (both random and directed movements). We focus on the joint influence of advection rate, intrinsic growth rate and interspecific competition coefficient on the competition outcomes. It turns out that there exist some critical curves which separate the stable region of the semitrivial steady states from the unstable one. The locations of these curves determine whether coexistence or bistability occurs. More precisely, there are various tradeoffs between advection rate, intrinsic growth rate and interspecific competition coefficient that allow the transition of competition outcomes including competition exclusion, coexistence and bistability. We illustrate our results in various parameter spaces.     

Coexistence solutions of a periodic competition model with nonlinear diffusion

This paper is concerned with a spatially heterogeneous Lotka–Volterra competition model with nonlinear diffusion and nonlocal terms, under the Dirichlet boundary condition. Based on the theory of Leray–Schauder’s degree, we give sufficient conditions to assure the existence of coexistence periodic solutions, which extends some results of G. Fragnelli et al.     

Influence of feedback controls on an autonomous Lotka–Volterra competitive system with infinite delays

In this paper, we consider an autonomous Lotka–Volterra competitive system with infinite delays and feedback controls. The extinction and global stability of equilibriums are discussed using the Lyapunov functional method. If the Lotka–Volterra competitive system is globally stable, then we show that the feedback controls only change the position of the unique positive equilibrium and retain the stable property. If the Lotka–Volterra competitive system is extinct, by choosing the suitable values of feedback control variables, we can make extinct species become globally stable, or still keep the property of extinction. Some examples are presented to verify our main results.     

A discrete prey–predator model preserving the dynamics of a structurally unstable Lotka–Volterra model

Leslie's method to construct a discrete two dimensional dynamical system dynamically consistent with the Lotka–Volterra type of competing two species ordinary differential equations is applied in a newly extended manner for the Lotka–Volterra prey–predator system which is structurally unstable. We show that, independently of the time step size, the derived discrete prey–predator system is dynamically consistent with the continuous counterpart, keeping the nature of neutrally stable periodic orbit. Further, we show that the extended method to construct the discrete prey–predator system can provide a dynamically consistent model also for the logistic Lotka–Volterra one.     

Categories of chaos and fractal basin boundaries in forced predator–prey models

Biological communities are affected by perturbations that frequently occur in a more-or-less periodic fashion. In this communication we use the circle map to summarize the dynamics of one such community – the periodically forced Lotka–Volterra predator–prey system. As might be expected, we show that the latter system generates a classic devil's staircase and Arnold tongues, similar to that found from a qualitative analysis of the circle map. The circle map has other subtle features that make it useful for explaining the two qualitatively distinct forms of chaos recently noted in numerical studies of the forced Lotka–Volterra system. In the regions of overlapping tongues, coexisting attractors may be found in the Lotka–Volterra system, including at least one example of three alternative attractors, the separatrices of which are fractal and, in one specific case, Wada. The analysis is extended to a periodically forced tritrophic foodweb model that is chaotic. Interestingly, mode-locking Arnold tongue structures are observed in the model’s phase dynamics even though the foodweb equations are chaotic.     

Positive periodic solutions of nonautonomous delay competitive systems with weak Allee effect

This paper considers a nonautonomous Lotka–Volterra type multispecies competitive system with weak Allee effect and delays. The model has the intraspecific competition terms defined by sign changing functions which depend on population density monotonically and time periodically. An existence theorem of positive periodic solutions is established using the coincidence degree theory. Furthermore, for the case of constant delays, a sufficient condition for the positive periodic solution to be globally attractive is proved with the Lyapunov method so that the system attains permanence.     

Global Dynamics of the Lotka‐Volterra Competition‐Diffusion System: Diffusion and Spatial Heterogeneity I

In the first part of this series of three papers, we investigate the combined effects of diffusion, spatial variation, and competition ability on the global dynamics of a classical Lotka‐Volterra competition‐diffusion system. We establish the main results that determine the global asymptotic stability of semitrivial as well as coexistence steady states. Hence a complete understanding of the change in dynamics is obtained immediately. Our results indicate/confirm that, when spatial heterogeneity is included in the model, “diffusion‐driven exclusion” could take place when the diffusion rates and competition coefficients of both species are chosen appropriately.© 2016 Wiley Periodicals, Inc.     

The diffusive Lotka–Volterra competition model in fragmented patches I: Coexistence

It is an ecological imperative that we understand how changes in landscape heterogeneity affect population dynamics and coexistence among species residing in increasingly fragmented landscapes. Decades of research have shown the dispersal process to have major implications for individual fitness, species’ distributions, interactions with other species, population dynamics, and stability. Although theoretical models have played a crucial role in predicting population level effects of dispersal, these models have largely ignored the conditional dependency of dispersal (e.g., responses to patch boundaries, matrix hostility, competitors, and predators). This work is the first in a series where we explore dynamics of the diffusive Lotka–Volterra (L–V) competition model in such a fragmented landscape. This model has been extensively studied in isolated patches, and to a lesser extent, in patches surrounded by an immediately hostile matrix. However, little attention has been focused on studying the model in a more realistic setting considering organismal behavior at the patch/matrix interface. Here, we provide a mechanistic connection between the model and its biological underpinnings and study its dynamics via exploration of nonexistence, existence, and uniqueness of the model’s steady states. We employ several tools from nonlinear analysis, including sub-supersolutions, certain eigenvalue problems, and a numerical shooting method. In the case of weak, neutral, and strong competition, our results mostly match those of the isolated patch or immediately hostile matrix cases. However, in the case where competition is weak towards one species and strong towards the other, we find existence of a maximum patch size, and thus an intermediate range of patch sizes where coexistence is possible, in a patch surrounded by an intermediate hostile matrix when the weaker competitor has a dispersal advantage. These results support what ecologists have long theorized, i.e., a key mechanism promoting coexistence among competing species is a tradeoff between dispersal and competitive ability.     

Extinction in a nonautonomous competitive Lotka–Volterra system

A nonautonomous competitive Lotka–Volterra system is considered in this work. Sufficient conditions on the coefficients are given to guarantee that all but one of the species are driven to extinction. It is shown that these conditions are weaker than those of Montes de Oca and Zeeman [F. Montes de Oca, M.L. Zeeman, Extinction in nonautonomous competitive Lotka–Volterra systems, Proc. Amer. Math. Soc. 124 (1996) 3677–3687].     

Coexistence in a strongly coupled system describing a two-species cooperative model

This paper is concerned with a cooperative two-species Lotka–Volterra model. Using the fixed point theorem, the existence results of solutions to a strongly coupled elliptic system with homogeneous Dirichlet boundary conditions are obtained. Our results show that this model possesses at least one coexistence state if the birth rates are big and cross-diffusions are suitably weak.     

Traveling wave front in diffusive and competitive Lotka–Volterra system with delays

Existence of travelling wave front solution is established for diffusive and competitive Lotka–Volterra system with delays. The approach used in this paper is the upper-lower solution technique and the monotone iteration. The same results are suitable to Belousov–Zhabotinskii model with delays and cooperative Lotka–Volterra system with delays.     

Existence and stability of almost periodic solutions of nonautonomous competitive systems with weak Allee effect and delays

In this paper, a class of nonautonomous Lotka–Volterra type multispecies competitive systems with weak Allee effect and delays are considered. By using Mawhin’s continuation theorem of coincidence degree theory, we obtain some sufficient conditions for the existence of almost periodic solutions for the Lotka–Volterra system. On the case of no delays of Allee effects, by constructing a suitable Lyapunov function, we get a sufficient condition for the globally attractivity of the almost periodic solution for the Lotka–Volterra system. Moreover, we also present an illustrative example to show the effectiveness of our results.     

A 3D competitive Lotka–Volterra system with three limit cycles: A falsification of a conjecture by Hofbauer and So

For three-dimensional competitive Lotka–Volterra systems, Zeeman [M.L. Zeeman, Hopf bifurcations in competitive three-dimensional Lotka–Volterra systems, Dyn. Stab. Syst. 8 (1993) 189–217] identified 33 stable nullcline equivalence classes. Among these, only classes 26–31 may have limit cycles. Hofbauer and So [J. Hofbauer, J.W.-H. So, Multiple limit cycles for three dimensional Lotka–Volterra equations, Appl. Math. Lett. 7 (1994) 65–70] conjectured that the number of limit cycles is at most two for these systems. In this paper, we construct three limit cycles for class 29 without a heteroclinic polycycle in Zeeman’s classification.     

Hopf bifurcation in time-delayed Lotka–Volterra competition systems with advection

In this paper, we study time-delayed reaction–diffusion systems with advection subject to Lotka–Volterra competition dynamics over one-dimensional domains. These systems model the population dynamics of two groups of competing species, with one dispersing randomly and the other a combination of random and biased dispersal (to avoid competition). We show that time-delay(s) in the interspecific competition mechanism can induce instability of the homogeneous equilibrium to the reaction–advection–diffusion systems, and further promote the appearance of time-oscillating spatially inhomogeneous distributions of the species. Our results indicate that these time-delayed systems (both single and double time-delays) can be used to model the well-observed time-periodic distributions of interacting species in natural fields, compared to the systems without time-delay(s).     

Has the iPhone cannibalized the iPad? An asymmetric competition model

Product cannibalization is a well‐known phenomenon in marketing, describing the case when a new product steals sales from another product under the same brand. A special case of cannibalization may occur when the older product reacts to the competitive strength of the newer one, absorbing the corresponding market shares. We show that such cannibalization occurred between two Apple products, the iPhone and the iPad, and the first has succeeded at the expense of the second. We propose an innovation diffusion model for asymmetric competition, Lotka‐Volterra with asymmetric competition, allow to test the presence and the extent of the inverse cannibalization phenomenon. A nondimensional representation of the model helps showing the effects of cannibalization on life cycle length.