Bifurcations in nonlinear integral models of biological systems

A bifurcation analysis is suggested for nonlinear integral models of age-distributed biological populations. The analysis shows that the integral model of one-species population with intra-species competition has zero and positive stationary states for some values of a bifurcation parameter. The nontrivial positive stationary state is initially stable and becomes unstable as the parameter grows. The obtained results are discussed and compared with the corresponding results in differential and difference models.