DYNAMICS OF EXPERIMENTAL POPULATIONS OF NATIVE AND INTRODUCED BLOWFLIES (DIPTERA, CALLIPHORIDAE) - MATHEMATICAL-MODELING AND THE TRANSITIONFROM ASYMPTOTIC EQUILIBRIUM TO BOUNDED OSCILLATIONS

The equilibrium dynamics of native and introduced blow flies is modell ed using a density-dependent model of population growth that takes int o account important features of the life-history in these flies. A the oretical analysis indicates that the product of maximum fecundity and survival is the primary determinant of the dynamics. Cochliomyia macel laria, a blowfly native to the Americas and the introduced Chrysomya m egacephala and Chrysomya putoria, differ in their dynamics in that the first species shows a damping oscillatory behavior leading to a one-p oint equilibrium, whereas in the last two species population numbers s how a two-point limit cycle. Simulations showed that variation in fecu ndity has a marked effect on the dynamics and indicates the possibilit y of transitions from one-point equilibrium to bounded oscillations an d aperiodic behavior. Variation in survival has much less influence on the dynamics.