On a non-selective harvesting prey-predator model with Hassell-Varley type functional response

In this paper, a nonautonomous delayed prey-predator model with non-selective harvesting and Hassell-Varley type functional response is investigated. Some sufficient conditions are obtained for the existence of positive periodic solutions to the system using the continuation theorem of coincidence degree theory. Moreover, the obtained results are different from the previous works. Numerous are conducted to illustrate the feasibility of the obtained results. (C) 2014 Elsevier Inc. All rights reserved.