Larval predation on different instars in blowfly populations

Chrysomya albiceps (Diptera: Calliphoridae) é uma predadora facultativa sobre outras moscas-varejeiras, durante o terceiro instar larval. Nesse estudo, nos investigamos a taxa de predação de C. albiceps sobre larvas de primeiro, segundo e terceiro instar de C. megacephala e C. macellaria comparando a vulnerabilidade dos instares larvais frente à predadora. Para as presas de primeiro e segundo instar, C. albiceps apresentou maior taxa de predação sobre C. megacephala. Já sobre larvas de terceiro instar a predadora consumiu mais C. macellaria. O comportamento de C. albiceps sobre as duas espécies de presas sugere uma mudança na estratégia de forrageio da predadora e essa mudança pode ter influencia sobre a comunidade de dípteros necrófagos.

Abstract (english)

During its larval stage, Chrysomya albiceps (Diptera: Calliphoridae) is a facultative predator on other blowflies. In this study, we evaluated the predation by third instar larvae of C. albiceps on first, second and third instar larvae of Chrysomya megacephala and Cochliomyia macellaria in no-choice experiments in order to compare the vulnerability of larval instars to predation. With first and second instar prey the highest predation rate by C. albiceps was on C. megacephala. For third instar prey, the highest predation rate was on C. macellaria. With second instar prey, there was complete predation on C. megacephala within 90 min, whereas in C. macellaria only 55% of the larvae were eaten by 90 min. For third instar prey most predation on C. macellaria (80%) occurred within 90 min, whereas in C. megacephala only 35% of the larvae were eaten by 90 min. Chrysomya albiceps changes the predatory behavior on its preys depending on which instar and species it will consume.