Larval aggregation and competition for food in experimental populations of Chrysomya putoria (Wied.) and Cochliomyia macellaria (F.) (Dipt., Calliphoridae)

Abstract

In blow~ies\ larval aggregation in patches of food can be both intra! and interspeci_c\ depending upon the degree to which competitors are clumped among the patches[ In the present study\ the implications of spatial aggregation for larval competition was investigated in experimental populations of the introduced blow~y Chrysomya putoria and the native Cochliomyia macellaria\ using data from survival to adulthood in a range of single! and double!species larval cultures[ The reduction in C[ macellaria survival rate in the presence of C[ putoria suggests that the former species is the inferior competitor[ The results on survival to adulthood for both species in single! and double!species cultures can be explained in the light of the relationship between the level of intra! and interspeci_c aggregation and the e.ciency of the larval feeding process[ The possible implications of these results for the population biology of both species in natural environments are discussed[

The dynamics of intraguild predation in Chrysomya albiceps Wied. (Diptera: Calliphoridae): interactions between instars and species under different abundances of food

“…Based on an isocline analysis of an intraguild predation model, Polis et al (1989) showed that if two species coexist without intraguild predation then adding intraguild predation can lead to exclusion of the intraguild prey from the system. Reis et al (1999) observed that C. putoria and C. macellaria coexisted where there is no C. albiceps larvae. Both intraguild predators and prey can coexist only if the intraguild predators are less inferior than the intraguild prey in exploiting a common resource (Holt & Polis 1997).…”

“…In this study, C. albiceps showed higher survival in most of the two-species experiments, suggesting that predation offers more advantages to C. albiceps than competition for food and cannibalism (Faria et al 1999(Faria et al , 2004. However, interspecifi c competition might be more advantageous than intraspecifi c competition, with the preference generally depending on the strength of the interactions between the species (Reis et al 1999).…”

“…The survival was estimated for each larval density and treatment by recording the number of adults obtained in the experiments. Three replicates (Grassberger et al 2003) were used for the density of 200 and fi ve for the density of 1000 based on a previous work (Reis et al 1999). …”

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

“…Thus, it is possible that the population density of blowfl ies is strongly associated with seasonality, since competitive ability has been considered temporally different among species and populations (Reis et al 1999).…”

Larval dispersal and predation in experimental populations of Chrysomya albiceps and Cochliomyia macellaria (Diptera: Calliphoridae)

“…Statistical analysis of the frequency distribution of dispersing blowfly larvae revealed that aggregated patterns of distribution emerge as a consequence of dispersal, LDBF and MNR have been supported by research fellowships from Fapesp (01/13920-3, 01/06368-2); GSR and CJVZ have been supported by research fellowships from Capes and CNPq, respectively.rufifacies (Macquart), C. putoria and C. megacephala, and the native species C. macellaria have been carried out (Wells & Greenberg 1992a,b,c, Faria et al 1999, Reis et al 1999, Faria & Godoy 2001, no systematic study associating blowfly larval predation and dispersal is available in the literature. Here, we investigated the larval aggregation patterns of C. albiceps and C. macellaria in single and double species experiments in order to evaluate the possible associations between predation and dispersal.…”