Permanence of periodic Holling type predator-prey system with stage structure for prey

In this paper, we study the permanence of the following periodic Holling type predator-prey system with stage structure for prey x(1)(t) = a(t)x(2)(t) - b(t)x(1)(t) - d(t)x(1)(2)(t) - e(t)x(1)(y)(t)/p(t)+x(1)(y)(y) y(t), x(2)(t) = c(t)x(1)(t) - f(t)x(2)(2)(t), y(t) = y(t) (-g(t) + h(t)(x)(1)y(t)/p(t) + x(1)(y)(t) -q(t)y(t) ) Sufficient and necessary condition which guarantee the predator and the prey species to be permanent is obtained. Some new results are obtained. (c) 2006 Elsevier Inc. All rights reserved.