Stochastic dynamics in exotic and native blowflies: an analysis combining laboratory experiments and a two‐patch metapopulation model

Abstract

In this study we explored the stochastic population dynamics of three exotic blowfly species, Chrysomya albiceps, Chrysomya megacephala and Chrysomya putoria, and two native species, Cochliomyia macellaria and Lucilia eximia, by combining a density-dependent growth model with a two-patch metapopulation model. Stochastic fecundity, survival and migration were investigated by permitting random variations between predetermined demographic boundary values based on experimental data. Lucilia eximia and Chrysomya albiceps were the species most susceptible to the risk of local extinction. Cochliomyia macellaria, C. megacephala and C. putoria exhibited lower risks of extinction when compared to the other species. The simultaneous analysis of stochastic fecundity and survival revealed an increase in the extinction risk for all species. When stochastic fecundity, survival and migration were simulated together, the coupled populations were synchronized in the five species. These results are discussed, emphasizing biological invasion and interspecific interaction dynamics.

Allee effect in exotic and introduced blowflies

“…Native blowfly species in Brazil have apparently shown strong resistance to biological invasion since the exotic species introduction, in spite of their decline in population numbers (Serra et al 2007). This population performance could be associated with the stability previously mentioned.…”

“…However, exotic species are generally at low density during an invasion process, the conditions in which the Allee effect takes place (Tobin et al 2009). The mathematical modeling scenario previously studied in blowflies indicates that exotic species exhibit high demographic values, tending to exhibit cyclic dynamics, and native species trend toward stability (Godoy et al 2001, Serra et al 2007.…”

“…The exotic blowfly species (Diptera: Calliphoridae) Chrysomya albiceps (Wiedemann 1819), C. megacephala (Fabricius 1794), and C. putoria (Wiedemann 1830) were introduced into Brazil about 30 years ago, and have displaced native species such as Cochliomyia macellaria (Fabricius 1775) and, to a lesser extent, Lucilia eximia (Wiedemann 1819) (Guimarães et al 1978, Silva et al 2003. This episode has motivated several studies on the population dynamics of introduced and native blowfly species, in an attempt to better understand their ecological patterns of fluctuation as well as the potential impact of biological invasion on the structure of the local fauna , Serra et al 2007. The most recent studies include investigations of population dynamics by connecting laboratory experiments with mathematical models, focusing on density dependence, spatial structure, and stochasticity (Castanho et al 2006, Serra et al 2007.…”

“…This episode has motivated several studies on the population dynamics of introduced and native blowfly species, in an attempt to better understand their ecological patterns of fluctuation as well as the potential impact of biological invasion on the structure of the local fauna , Serra et al 2007. The most recent studies include investigations of population dynamics by connecting laboratory experiments with mathematical models, focusing on density dependence, spatial structure, and stochasticity (Castanho et al 2006, Serra et al 2007.…”

“…The causes of cycles in insect populations have received considerable attention from ecologists and entomologists because they are often associated with density-dependent mechanisms (Hassell 1975, Muller 1986. A densitydependent mathematical model developed by Prout & McChesney (1985) to study population dynamics in experimental populations of Drosophila melanogaster has been successfully employed in studies of blowfly population dynamics (Godoy et al 2001, Godoy 2007, Serra et al 2007.…”