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The paper focuses on studying the global dynamics of a simple prey–predator model. The model incorporates cooperative hunting behavior among predators and takes into account the effect of harvesting on the predator population. The interaction between the prey and predator follows the Crowley–Martin functional response. The study involves analyzing the equilibrium points of the system and investigating their stability properties through mathematical analysis. Various types of bifurcations, including Hopf bifurcation, saddle–node bifurcation, and transcritical bifurcation, are numerically demonstrated in the figures, highlighting the dynamic behavior of the model. One of the intriguing findings of the study is the occurrence of bistability and tristability in the model. To incorporate stochasticity into the model, white noise is added to the deterministic system. This allows for the examination of transitions between different steady states in the stochastic system. We have conducted an analysis of species persistence and extinction in relation to the presence of noise. The paper presents the stochastic sensitivity function (SSF) technique and the use of confidence ellipses to assess the likelihood of such transitions occurring in the system. Overall, the study provides insights into the complex dynamics of prey–predator interactions, considering factors such as cooperation, harvesting, and stochasticity. The results contribute to our understanding of population dynamics and the potential effects of environmental and human-induced perturbations on ecosystem stability. • Study on a cooperative prey-predator model with harvesting. • Bifurcations like saddle-node, Hopf, and transcritical, have been explored. • Bistability and tristability are observed in the proposed model system. • Critical radius of transition is determined by evaluating the confidence ellipses. • Noise in the stochastic system leads to transitions between different equilibria. [ABSTRACT FROM AUTHOR]

This manuscript deals with an epidemic model with partial immunity having nonlinear incidence and saturated treatment. Positivity and boundedness of the solutions have been established here. We discuss local stability of all equilibria. The proposed system experiences various types of bifurcations, namely Transcritical, Saddle–node, Hopf, and Bogdanov–Takens bifurcation of co-dimension 2. The system is reduced to a two-dimensional system using center manifold theorem to deduce normal form for Bogdanov–Takens bifurcation of co-dimension 2 when two eigenvalues at the endemic equilibrium point becomes zero. Whether deterministic model overestimates the condition for disease propagation, to observe this we also analysis stochastic model. We derive the condition for extinction, persistence in mean and stationary distribution. All theoretical findings are justified by numerical simulations. Finally, to check validity of the model, we fit it with real reported influenza data of Canada. • SIRS model with logistic growth, saturated type incidence and treatment. • Bogdanov–Takens bifurcation normal form using Center manifold theorem. • Introduction of stochasticity in the model and it's analysis. • Model is validated fitting with real influenza outbreak data of Canada. [ABSTRACT FROM AUTHOR]

In an ecological system, omnivores are often significantly important as they feed upon more than one trophic level in a food chain model. Intraguild predation is a special kind of omnivory that is ubiquitous in many ecological communities. A lot of field experiments suggest that the experience over a time duration in the recent past affects the growth rate of all species at the present time. Here, we have considered the Caputo type fractional ordered three-species food chain model. The memory effect is explained in terms of the order of the fractional derivative. Intermediate, top predators feed upon prey by Holling type I functional response and the top predator consumes intermediate predator by Holling type II functional response. Here, we established the existence and uniqueness of the solution of the considered system. Also, we prove the positivity and boundedness of the system solution. All possible feasible equilibrium points with required parametric conditions are discussed in the text. The local stability of all feasible equilibrium points and the parametric conditions of global stability of all non-trivial equilibrium points are discussed. The memory effect can stabilize the system from the periodic oscillatory situation which has been proved through the Hopf bifurcation analysis. Finally, some numerical simulation has been carried out to make significant comments on the dynamics of the considered system about the memory effect and other system parameters. It is clear from the numerical simulations that the order of fractional derivative can be taken as the indicator of chaos control. The biological interpretations make the article most significant from the ecological point of view. • Dynamics of a three-dimensional fractional-order system with intraguild predation. • Hopf bifurcation analysis with respect to the memory parameter. • Study of Transcritical and Hopf bifurcation by one parameter bifurcation diagram. • Memory effect cannot stabilize saddle or unstable node equilibrium point. • Chaos and periodicity controll by the memory effect. [ABSTRACT FROM AUTHOR]

• We have proposed a tri-topic food chain model with one prey and two predators such as- prey, first predator and second predator. • All the biological parameters (except the conversion efficiency of the species) are considered as interval-valued. • Using linear parametric representation of interval, it is shown that the system in interval form is equivalent with the system in parametric form. • The positivity, boundedness, stability and transcritical bifurcation conditions of the proposed model are discussed. • Finally, the dynamics of the proposed model has been illustrated with the help of some numerical simulations. Currently, proper modeling of a biological system in an uncertain situation is a challenging task for researchers. Facing this challenge, in this article, a new concept of interval representation named as linear parametric representation is introduced by which a biological system in an uncertain situation can be formulated mathematically in a precise way. The aim of this work is to formulate a three species imprecise food chain model with one prey and two competing predators in an interval environment. Here, all the biological parameters except the conversion efficiency of the species are considered interval-valued. And interactions among the species are taken as Holling Type I functional response. Using the linear parametric representation of interval, a system in the interval form has been converted in the parametric form. Positivity and boundedness of the solutions of the proposed imprecise system are verified. Then, conditions of local stability, global stability and transcritical bifurcation of equilibrium points of the proposed system are established. Thereafter, all the theoretical results of this work are validated by a numerical example with interval-valued parametric data and results are presented pictorially. Finally, some biological implications of the obtained results are discussed and a fruitful conclusion has been made. [ABSTRACT FROM AUTHOR]