Fig. 4.

The phase plane for Case (iii) with high honey-bee production rate, $2(\mu +k\gamma )A<\alpha$. As above, the dashed lines represent the M nullclines along which $g(N,M)=0$ and the solid line represents the N nullcline along which $f(N,M)=0$. The phase plane exhibits bistable properties such that there are two locally stable equilibrium points, the origin and $N_2^{\ast }$, separated by an unstable equilibrium $N_1^{\ast }$