Coexistence and intraguild competition of Chrysomya albiceps and Lucilia sericata larvae: case reports and experimental studies applied to forensic entomology

When the red-lined carrion beetle disrupts successional dynamics on large vertebrate carcasses

In a field study of insect colonization on domestic pig carcasses, the typical colonization sequence took a different turn midway through decomposition when Necrodes surinamensis (Fabricius) (Coleoptera: Silphidae) dramatically increased in abundance on some carcasses. This provided an opportunity to test the prediction that N. surinamensis would aggregate at clumped carcasses but not as much at dispersed carcasses, thus leaving enough resources in less heavily colonized habitat patches to support weaker competitors, as predicted by the aggregation model of coexistence. Larger aggregations of this silphine beetle resulted in the collapse of blow fly (Diptera: Calliphoridae) maggot populations due to intraguild predation, and a decline or exclusion of late-successional insect species. This phenomenon has been reported in a European Necrodes species but it is the first time it is documented with N. surinamensis, a widespread species in North America. Substantial increases in adult and larval populations of N. surinamensis were first documented on clumped carcasses and were not as pronounced on dispersed carcasses. The specifics of N. surinamensis aggregations are discussed with reference to ecological and forensic implications, including the fact that feeding by N. surinamensis larvae makes the remains appear to have been altered by scavengers and decomposing for longer than they have.

Size does matter: intraspecific geometric morphometric analysis of wings of the blowfly Chrysomya albiceps (Diptera: Calliphoridae)

Blowflies have forensic, sanitary and veterinary importance, as well as being pollinators, parasitoids and ecological bioindicators. There is still little work with real data and from experiments assessing the relationship between blowflies' morphologic features and environmental and demographic factors. The present work tests whether the variation, in the shape and size, of Chrysomya albiceps (Wiedemann, 1819) wings is influenced by the following factors: 1) time; 2) temperature; 3) sex and; 4) different types of carcasses (pig, dog/cat and whale). Male and female wings from four different sites collected in six different years were used to obtain wing size and shape of C. albiceps. Analyses between wing shape and the variables tested had low explanatory power, even though they had statistical support. However, it was possible to identify differences in wing shape between males and females, with good returns in sex identification. The comparison between wing size and the variables tested showed that wing size has a negative relationship with temperature, significant differences between sexes, slight variation over time and no influence by carcass types. Furthermore, wing size influenced wing shape. Understanding population-specific characteristics of C. albiceps provide important insights about how the species reacts under specific conditions.