Larval aggregation and competition for resources in populations of Lucilia sericata and Phormia regina

Blow flies (Diptera: Calliphoridae) are commonly used to estimate the post mortem interval of unattended death when this interval is greater than 48 hours. This estimate utilizes the developmental biology and behaviour of these first arriving insects. Female blow flies typically engage in aggregated egg laying, resulting in larval feeding masses once the eggs hatch. These masses often vary in density and species composition and have the potential to impact fitness through different species interactions. This research studies the effects of temperature, density, species interactions and mechanisms of coexistence of two forensically significant blow flies Lucilia sericata Meigen and Phormia regina Meigen (Diptera: Calliphoridae). The density and developmental temperatures experienced by the larvae during development was manipulated in the presence of conspecifics (chapter 2) and hetero-specifics (chapter 3) in the laboratory. Several life history traits were measured; survival, development time and adult body size. The results of this study indicated that the life history traits measured exhibited plasticity with varying temperature, blow flies had decreased survival and adult body size at high developmental temperatures. Blow flies had increased survival and adult body size with density at 15℃ decreased adult body size with density at 25℃ and decreased survival and adult body size with density at 35℃. Phormia regina had higher survival when developing with in the presence of Lucilia sericata at 25℃ and 35℃. Both blow flies had larger adult body size while developing in the presence of each other at 25℃ and 15℃ perhaps due to the presence of compounds secreted during larval feeding that aid in digestion and increase nutrient availability