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Biological invasion theory is one of important subjects in a biological control, an environmental preservation problem, a propagation of infectious diseases. I propose an propagation speed of traveling waves induced by an invasion of alien species for two-prey, one-predator modesl in which the commensalism induced by a predator between two prey species is considered. I investigate a spreading phenomenon and a minimal propagation speed for two cases that invader species is one species or more than one species. By numerical simulations and mathematical analysis, I conclude that the minimal speed is contingent only on the mobility of invasive species, furthermore, on that of one invader species even if two invader species invade at the same time. It is also shown that the commensalism via predator species affects spreading phenomena and a propagation speed, which is contingent on the type and the number of invasive species.

We propose a two-prey, one-predator model involving the effect of the carcass. We consider a commensal interaction that a prey species eats the remains of the other prey species’ carcass given by their predator. Under some biological assumptions, we construct two ODE models. We analyze the linear stability and prove the permanence of the two models. We also show that the effect of the remains of the carcass leads to chaotic dynamics for biologically reasonable choices of parameters by numerical simulations. Finally, we discuss the dynamical results and the coexistent regions of the three species.