In this paper, a Lotka-Volterra cooperation system with single feedback control is proposed and studied. We investigate the local stability and the global stability of the system. Our study shows that with suitable restriction on the coefficients of the feedback control variable, the system can still remain globally stable or become extinct, which shows that the feedback control variable plays a very important role in the dynamics behaviors of the system.
A non-autonomous allelopathic phytoplankton model with feedback controls is considered in this paper. By constructing some suitable Lyapunov type extinction functions, some sufficient conditions for the extinction of the system are obtained. For the autonomous case, by constructing a suitable Lyapunov function, we show that one species is extinct and the rest species is globally attractive. Our results supplement some known results.
A predator-prey system with Holling-IV functional response is investigated. It is shown that the system has a positive equilibrium, which is a cusp of co-dimension 2 under certain conditions. When the parameters vary in a small neighborhood of the values of parameters, the model undergoes the Bogdanov-Takens bifurcation. Dif- ferent kinds of bifurcation phenomena are exhibited, which include the saddle-node bifurcation, the Hopf bifurcation and the homo-clinic bifurcation. Some computer simulations are presented to illustrate the conclusions.
An autonomous stage-structured ratio-dependent cooperative system, which was proposed by Muhammadhaji, Teng and Abdurahman, is revisited in this paper. By introducing a new lemma and using the iterative method, a set of sufficient conditions which guarantee the global attractivity of the positive equilibrium is obtained. It is shown that the conditions which guarantee the permanence of the system are enough to ensure the global attractivity of the system. Our result not only complements but also supplements one of the main results of Muhammadhaji, Teng and Abdurahman （Permanence and extinction analysis for a delayed ratio-dependent cooperative system with stage structure, Afr. Mat.（2013）DOI 10.1007/s13370-013-0162-6）.
