Date of Award

2014

Publication Type

Doctoral Thesis

Degree Name

Ph.D.

Department

Biological Sciences

Keywords

Calliphoridae, Carrion, Coexistence, Ecology, Entomology, Forensic Entomology

Supervisor

VanLaerhoven, Sherah

Rights

info:eu-repo/semantics/openAccess

Abstract

Resource partitioning can lead to species coexistence. In a field study, temporal and spatial partitioning were examined by testing the effects of season and habitat on the structure of the blow fly community on domestic pig carcasses, Sus scrofa domesticus in southwestern Ontario, Canada. Blow fly communities did not differ between field and forest habitats, however there were seasonal differences. Fall was characterized by having more species and higher levels of species evenness, diversity, and niche overlap than spring and summer. On a finer scale, effects of arrival order were examined in laboratory experiments with three blow fly species: Phormia regina, Lucilia sericata, and the introduced species Chrysomya rufifacies. Arrival order of adults was varied in combinations of two species: "L. sericata and P. regina" and "L. sericata and C. rufifacies". Both positive and negative priority effects were recorded, with species having altered colonization patterns temporally and spatially in response to presence of another species, even at low density (i.e. minimal competition). Blow flies sometimes selected oviposition sites other than the natural orifices predicted by previous studies, such as the neck and cheek regions or between legs. Delays in colonization, particularly for P. regina and C. rufifacies, occurred in response to the absence of heterospecifics. Additional experiments with larvae determined that C. rufifacies and P. regina benefitted from the presence of L. sericata due to predation (for C. rufifacies) or the presence of compound(s) that may aid in the digestion of the resource and increase nutrient availability (for P. regina). In summary, adult and larval experiments indicate that species interactions and differences in arrival order can affect colonization times, the distribution of eggs over a resource, larval interactions and offspring fitness. On a larger scale, temporal partitioning (i.e. seasonal effects) can promote coexistence in blow flies, however, spatial partitioning (i.e. habitat effects) was not evident. This study demonstrates the importance of ADD standardization, emphasizes the need to understand species interactions between native and non-native species, and highlights the need for more ecological studies regarding habitat and seasonal differences within the carrion community

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