Time delays produced by essential nonlinearity in population growth models

It is pointed out that the asymptotic general solution to the ϕ-model equation for a periodic carrying capacityK(t) andt≳r ⁻¹ is identical in form to the generalized logistic equation solution with a built-in developmental time delay τ(≲r ⁻¹) and associated parameter ranges of primary biological interest. In the case of the ϕ-model equation, the time delay is a purely dynamical consequence of the nonlinear form featured by the population growth rate.