Seasonal population dynamics in Lucilia eximia (Wiedemann) (Diptera: Calliphoridae)

Abstract

Neotropical Entomology 35(6):753-756 (2006) Dinâmica Populacional Sazonal em Lucilia eximia (Wiedemann) (Diptera: Calliphoridae) RESUMO -Neste estudo variações sazonais da fecundidade, tamanhos de asa e tíbia foram investigadas em populações naturais de Lucilia eximia (Wiedemann), na tentativa de determinar as alterações bionômicas da espécie, associadas à sazonalidade. Exemplares de L. eximia foram coletados mensalmente em Botucatu, SP, durante dois anos e as fêmeas adultas dissecadas para estimar a fecundidade. O tamanho do corpo foi estimado por medições de asa e tíbia. A fecundidade e o tamanho do corpo foram analisados sazonalmente. Uma trajetória temporal relativamente constante foi encontrada para fecundidade e tamanhos de asa e tíbia durante os 24 meses de estudo. Fortes correlações positivas entre tamanhos de asa e tíbia, fecundidade e tamanho de asa e fecundidade e tamanho de tíbia foram observadas. A manutenção dos valores estáveis em L. eximia indica que a espécie sofreu pouca infl uência sazonal durante o período analisado. Esse resultado confi rma o perfi l demográfi co e bionômico estável da espécie a despeito das variações climáticas sazonais observadas na área de estudo.PALAVRAS-CHAVE: Mosca-varejeira, sazonalidade, fecundidade, tamanho corpóreo ABSTRACT -In this study the seasonal variation of fecundity, wing and tibia sizes were investigated in natural populations of Lucilia eximia (Wiedemann) as an attempt to determine the variations in life history of the species associated to seasonality. Specimens of L. eximia were monthly collected in Botucatu, São Paulo, Brazil, during two years and the adult females dissected to estimate fecundity. Body size was estimated by measuring wing and tibia. Fecundity and body size were seasonally analysed. A relatively constant temporal trajectory was found for fecundity, wing and tibia size over twenty-four months. Strong positive correlations between wing and tibia size, fecundity and wing and fecundity and tibia were observed. The maintenance of stable values in L. eximia indicates that it has suffered little seasonal infl uence over the period analysed. This result confi rms the demographics and life history stable profi le of the species in spite of seasonal climatic changes observed in the study area. KEY WORDS: Blowfl y, fecundity, body sizeLucilia Robineau-Desvoidy species are named greenbottles because of their brilliant metallic green coloration, which appears to vary with age (Smith 1986). However, the species of the genus Lucilia are also considered as blowfl y, since they exhibit the same synanthropic and feeding behavior observed in other Calliphoridae species (Stevens & Wall 1996). Adults, especially males, are frequently found on fl owers where they feed on the nectar (Smith 1986). Most species of Lucilia are saprophagous, breed in carrion and dung, usually being the fi rst to appear in carrion in sunlight (Archer & Elgar 2003). In Brazil the most common Lucilia species is Lucilia eximia Wiedemman (Moura et al. 1997). L. eximia is a nearctic...

Allee effect in exotic and introduced blowflies

“…In addition, the results from previous studies designed to investigate the variation of demographic parameters in natural populations of blowflies show a spectrum of parameter values compatible with the numbers used in this study (Reigada & Godoy 2005, Gião & Godoy 2006, Riback & Godoy 2008.…”

“…Lucilia eximia requires at least twice its estimated value to exhibit changes, since its experimentally obtained fecundity was very low. Nevertheless, natural populations of this species show fecundity values significantly higher than the numbers found in laboratory, justifying the arbitrary change in the simulations (Gião & Godoy 2006).…”

“…Unfortunately there is no comparable long-term study focusing on real-world observations of population patterns. However, the spectrum of oscillations in natural populations of exotics is probably wider than native species because of the magnitude of their survival and fecundity in natural conditions (Ullyett 1950, Reigada & Godoy 2005, Gião & Godoy 2006, Riback & Godoy 2008.…”

“…The values were employed taking into account the maximum and minimum boundaries of survival and fecundity observed in natural populations (Ullyett 1950, Reigada & Godoy 2005, Gião & Godoy 2006, Riback & Godoy 2008). This procedure allowed us to determine the critical values for a change of equilibrium in each species.…”

The influence of temperature and humidity on abundance and richness of Calliphoridae (Diptera)

“…The short interval between generations at high temperatures (Queiroz & Milwardde-Azevedo, 1991;Krüger et al, 2010) and the high predation capacity of C. albiceps are factors that can be affect the abundance of other Calliphoridae that colonizes ephemeral resources, such as L. eximia during the southern hemisphere summer. Models to check the influence of randomness on population fluctuations of C. albiceps and L. eximia, based on data of South American populations have shown that intrinsic factors such as predation are more important than the extrinsic (environmental factors) to explain the variation in the abundance of these two species (Godoy et al, 2001;Silva et al, 2003;Gião & Godoy, 2006). This observation supports the third explanation of Moretti et al (2008) and Krüger et al (2010) aforementioned and is supported by the observed data in southern Brazil to explain the antagonistic fluctuation of C. albiceps and L. eximia.…”