function x=semelparous(N)

c11=0; c21=0; c22=0; c32=0; c33=0.01; c13=0.004; m1=0.25; m2=0.25; n=1.1;
b=n/((1-m1)*(1-m2));
x1(1)=45; x2(1)=1; x3(1)=1;
for i=2:N,
    x1(i)=b*x3(i-1)/(1+c11*x1(i-1)+c13*x3(i-1));
    x2(i)=(1-m1)*x1(i-1)/(1+c21*x1(i-1)+c22*x2(i-1));
    x3(i)=(1-m2)*x2(i-1)/(1+c32*x2(i-1)+c33*x3(i-1));
end
x=[x1;x2;x3]';

% x=semelparous(100);
% plot3(x(:,1),x(:,2),x(:,3));grid
% plot(x);grid