第25卷第2期, 2012年4月 宁波大学学报(理工版) 首届中国高校优秀科技期刊奖
Vol.25 No.2, Apr. 2012 JOURNAL OF NINGBO UNIVERSITY ( NSEE ) 浙江省优秀科技期刊一等奖
Existence of Periodic Solution for a Predator-prey
System with Feedback Control
WANG Cai-li, ZHANG Jian-xun
*
( Faculty of Science, Ningbo University, Ningbo 315211, China )
Abstract: A Hassell-Varely type predator-prey system with feedback controls is studied. Using the
comparison, continuation theorems and coincidence degree theorem, the existence of positive periodic
solutions for the system is proven. Also, a set of sufficient conditions for global stability is derived through
constructing a Lyapunov function.
Key words: Hassell-Varely type; predator-prey; coincidence degree theorem; Lyapunov function; global
stability
CLC number: O175 Document code: A Article ID: 1001-5132(2012)02-0051-06
In 1969, Hassell and varley
[1]
introduced a general
predator-prey system, in which the functional response
dependents on the predator density in different way. It is
called a Hassell-varley (HV for short) type functional
response which take the following form:
d
(1 ) ,
d
(0,1),
d
(),
d
x x cxy
rx
tKmyx
yfx
yd
t
my x
γ
γ
γ
⎧
=−−
⎪
+
⎪
∈
⎨
⎪
=−+
⎪
+
⎩
(1)
where
is called the HV constant. In the typical
predator-prey interaction where predators do not form
groups, one can assume that terrestrial
1
= , producing
the so-called ratio-dependent PP system. For terrestrial
predators that form a fixed number of tight groups, it is
often reasonable to assume
1/ 2
. For aquatic preda-
tors that form a fixed number of tights groups,
1/3
may be more appropriate. A unified mechanistic approa-
ch was provided by Cosner
[2]
, where the HV functional
response was derived. Hsu
[3]
studied system (1) and
presented a systematic global qualitative analysis to it.
However, the logistic growth does not fit well for
some populations. For example, the Gompertz growth
ln( / )
'xKx
provides an excellent fit to empirical
growth curves for avascular tumors and vascular tumors
in their early stages
[4-5]
. Indeed, many data have shown
that per capita growth functions of populations are well
fitted by logarithmic regressions, for example, the Gom-
pertz model has been almost universally used to descry-
be the growth of microorganisms
[6-7]
, some creature
[8-9]
,
and the innovation diffusion such as digital cellular tele-
phones
[10-11]
, and the references cited therein.
Motivated by the above reasons, we consider a HV
type predator-prey model with controls,
11111
12
11
21
22222
21
22
21
1 1 11 11
22222
() ()[ () ()ln ()
() ()
() ()],
() ()
() ()[ () ()ln ()
() ()
() ()],
() ()
() () () () () (),
() () () () ()
x' t x t a t b t x t
ctxt
dtut
mx t x t
x' t x t a t b t x t
ctxt
dtut
mx t x t
u' t t t u t t x t
u't t tu t t
γ
γ
αβ γ
αβ γ
=− −
−
+
=− +
−
+
=− +
=− +
2
(0,1),
(),xt
γ
⎧
⎪
⎪
⎪
⎪
⎪
∈
⎨
⎪
⎪
⎪
⎪
⎪
⎩
(2)
Received date: 2011−06−28. JOURNAL OF NINGBO UNIVERSITY ( NSEE ): http://3xb.nbu.edu.cn
The first author: WANG Cai-li ( 1987− ), Female, Zhoukou Henan, post of graduate student, research domain: biological mathematics.
E-mail: luzizhijia@126.com
*Corresponding author: ZHANG Jian-xun ( 1959− ), male, Qishan Shanxi, professor, research domain: biological mathematics.
E-mail: zhangjianxun@nbu.edu.cn