ABSTRACT
We combined two models to investigate the theoretical dynamics of five exotic and native blowfly species in response to the Allee effect by using demographic parameters estimated from experimental populations. Most of the results suggest stabilization of dynamic behavior in response to the Allee effect. However, the results depended on the magnitude of the demographic parameters of each species, and also indicated chaotic fluctuations and limit cycles. The results are discussed in the context of larval aggregation, an important biological process for blowflies, which naturally incorporates the Allee effect.
Subject(s)
Animals , Diptera , Brazil , Models, Theoretical , Population DynamicsABSTRACT
In this study we investigated the population dynamics of Chrysomya albiceps (Wiedemann) with laboratory experiments, employing survival analysis and stage structure mathematical models, emphasizing survival among life stages. The study also assessed the theoretical influence of density dependence and cannibalism during immature stages, on the population dynamics of the species. The survival curves were similar, indicating that populations of C. albiceps exhibit the same pattern of survival among life stages. A strong nonlinear trend was observed, suggesting density dependence, acting during the first life stages of C. albiceps. The time-series simulations produced chaotic oscillations for all life stages, and the cannibalism did not produce qualitative changes in the dynamic behavior. The bifurcation analysis shows that for low values for survival, the population reaches a stable equilibrium, but the cannibalism results in chaotic oscillations practically over all the parametric space. The implications of the patterns of dynamic behavior observed are discussed.
Subject(s)
Animals , Diptera , Diptera/growth & development , Ecosystem , Life Cycle Stages , Models, Theoretical , Population DynamicsABSTRACT
In this study, the seasonal variation of fecundity, wing and tibia length were investigated in natural populations of Chrysomya albiceps (Wiedemann, 1819) in an attempt to determine the changes in life history of the species as a function of seasonality. A relative constant temporal trajectory was found for fecundity, wing and tibia length over twenty-four months. Positive correlations between fecundity and wing size, fecundity and tibia size and wing and tibia sizes were observed. The implications of these results for population dynamics of C. albiceps are discussed.
Neste estudo, a variação sazonal da fecundidade, comprimentos de asa e tíbia foram investigadas em populações naturais de Chrysomya albiceps (Wiedemann, 1819) como uma forma de determinar as variações bionômicas da espécie em função da sazonalidade. Uma trajetória temporal constante foi encontrada para fecundidade, comprimentos de asa e tíbia durante vinte e quatro meses. Correlações positivas entre fecundidade e comprimento de asa, fecundidade e comprimento de tíbia e comprimentos de asa e tíbia foram observadas. As implicações destes resultados para a dinâmica populacional de C. albiceps foram discutidas.