M. A. Tsyganov, J. Brindley, A. V. Holden, V. N. Biktashev
Submitted to Phys. Rev. Letters: 2003/05/05. Accepted subject to technical reivisions: 2003/09/24. Reference: Phys. Rev. Lett., 91:218102, 2003
We consider a system of partial differential equations describing two spatially distributed populations in a ``predator-prey'' interaction with each other. The spatial evolution is governed by three processes, positive taxis of predators up the gradient of prey (pursuit), negative taxis of prey down the gradient of predators (evasion) and diffusion resulting from random motion of both species. We demonstrate a new type of propagating wave in this system. The mechanism of propagation of these waves essentially depends on the taxis and is entirely different from waves in reaction-diffusion system. Unlike typical reaction-diffusion waves, which annihilate on collision, these ``taxis'' waves can often penetrate through each other and reflect from impermeable boundaries.
postscript (708K)