We study positive solutions to a steady state reaction diffusion equation arising in population dynamics, namely,
$ \begin{equation*} \label{abs} \left\lbrace \begin{matrix}-\Delta u = \lambda u(1-u) ;\; x\in\Omega\\ \frac{\partial u}{\partial \eta}+\gamma\sqrt{\lambda}[(A-u)^2+\epsilon]u = 0; \; x\in\partial \Omega \end{matrix} \right. \end{equation*} $
where $ \Omega $ is a bounded domain in $ \mathbb{R}^N $; $ N > 1 $ with smooth boundary $ \partial \Omega $ or $ \Omega = (0,1) $, $ \frac{\partial u}{\partial \eta} $ is the outward normal derivative of $ u $ on $ \partial \Omega $, $ \lambda $ is a domain scaling parameter, $ \gamma $ is a measure of the exterior matrix ($ \Omega^c $) hostility, and $ A\in (0,1) $ and $ \epsilon>0 $ are constants. The boundary condition here represents a case when the dispersal at the boundary is U-shaped. In particular, the dispersal is decreasing for $ u<A $ and increasing for $ u>A $. We will establish non-existence, existence, multiplicity and uniqueness results. In particular, we will discuss the occurrence of an Allee effect for certain range of $ \lambda $. When $ \Omega = (0,1) $ we will provide more detailed bifurcation diagrams for positive solutions and their evolution as the hostility parameter $ \gamma $ varies. Our results indicate that when $ \gamma $ is large there is no Allee effect for any $ \lambda $. We employ a method of sub-supersolutions to obtain existence and multiplicity results when $ N>1 $, and the quadrature method to study the case $ N = 1 $.
Citation: |
[1] |
W. C. Allee, The Social Life of Animals, W. W. Norton & Company, Inc., New York, 1938.
![]() |
[2] |
R. S. Cantrell and C. Cosner, Density dependent behavior at habitat boundaries and the Allee effect, Bulletin of Mathematical Biology, 69 (2007), 2339-2360.
doi: 10.1007/s11538-007-9222-0.![]() ![]() |
[3] |
J. T. Cronin, Movement and spatial population structure of a prairie planthopper, Ecology, 84 (2003), 1179-1188.
![]() |
[4] |
R. Dhanya, E. Ko and R. Shivaji, A three solution theorem for singular nonlinear elliptic boundary value problems, J. Math. Anal. Appl., 424 (2015), 598-612.
doi: 10.1016/j.jmaa.2014.11.012.![]() ![]() ![]() |
[5] |
R. Dhanya, R. Shivaji and B. Son, A three solution theorem for a singular differential equation with nonlinear boundary conditions, Topol. Methods Nonlinear Anal., 74 (2011), 6202-6208.
doi: 10.1016/j.na.2011.06.001.![]() ![]() ![]() |
[6] |
J. Goddard Ⅱ, Q. Morris, C. Payne and R. Shivaji, A diffusive logistic equation with U-shaped density dependent dispersal on the boundary, Topol. Methods Nonlinear Anal., 53 (2019), 335-349.
![]() ![]() |
[7] |
J. Goddard Ⅱ, Q. Morris, S. Robinson and R. Shivaji, An exact bifurcation diagram for a reaction diffusion equation arising in population dynamics, Bound. Value Probl., 2018 (2018), 1-17.
doi: 10.1186/s13661-018-1090-z.![]() ![]() ![]() |
[8] |
J. Goddard Ⅱ, Q. Morris, R. Shivaji and B. Son, Bifurcation curves for singular and nonsingular problems with nonlinear boundary conditions, Electron. J. Differential Equations, 2018 (2018), 1-12.
![]() ![]() |
[9] |
J. Goddard Ⅱ and R. Shivaji, Stability analysis for positive solutions for classes of semilinear elliptic boundary-value problems with nonlinear boundary conditions, Proc. Roy. Soc. Edinburgh Sect. A, 147 (2017), 1019-1040.
doi: 10.1017/S0308210516000408.![]() ![]() ![]() |
[10] |
F. Inkmann, Existence and multiplicity theorems for semilinear elliptic equations with nonlinear boundary conditions, Indiana Univ. Math. J., 31 (1982), 213-221.
doi: 10.1512/iumj.1982.31.31019.![]() ![]() ![]() |
[11] |
F. J. Odendaal, P. Turchin and F. R. Stermitz, Influence of host-plant density and male harassment on the distribution of female euphydryas anicia (nymphalidae), Oecologia, 78 (1989), 283-288.
doi: 10.1007/BF00377167.![]() ![]() |
[12] |
C. V. Pao, Nonlinear Parabolic and Elliptic Equations, Plenum Press, New York, 1992.
![]() ![]() |
[13] |
M. A. Rivas and S. Robinson, Eigencurves for linear elliptic equations, ESAIM Control Optim. Calc. Var., 25 (2019), Art. 45, 25 pp.
doi: 10.1051/cocv/2018039.![]() ![]() ![]() |
[14] |
A. M. Shapiro, The role of sexual behavior in density-related dispersal of pierid butterflies, The American Naturalist, 104 (1970), 367-372.
doi: 10.1086/282670.![]() ![]() |
[15] |
J. Shi and R. Shivaji, Persistence in reaction diffusion models with weak Allee effect, J. Math. Biol., 52 (2006), 807-829.
doi: 10.1007/s00285-006-0373-7.![]() ![]() ![]() |
[16] |
R. Shivaji, A remark on the existence of three solutions via sub-super solutions, Nonlinear Analysis and Applications, Lecture Notes in Pure and Applied Mathematics, 109 (1987), 561-566.
![]() ![]() |
Habitat
An example that illustrates U-shaped density dependent dispersal (
Eigencurve
Bifurcation diagrams for (1.4)
Shape of a positive solution
Plot that illustrates the existence of
The graph of
Evolution of bifurcation diagrams for (1.8) as
Bifurcation diagrams for (1.8) for several values of
Picture that illustrates that if
The plot illustrates the existence of