Using an ecological framework to resolve issues in forensic entomology: Exploring temperature mediation of species interactions within blow fly (Diptera: Calliphoridae) communities

The blow flies Lucilia sericata Meigen, Phormia regina Meigen and Calliphora vicina Robineau-Desvoidy (Diptera: Calliphoridae) are important decomposers that specifically colonize carrion. Adult flies must make oviposition decisions that impact the survival of their offspring and may be influenced by abiotic and biotic conditions. Although a great deal of research has been conducted regarding their development under different environmental conditions, the influence of species interactions has been scarcely investigated. The objective of my dissertation was to examine the effects of temperature, relative humidity and species interactions on the oviposition behaviour and development of these blow flies.;To accomplish this, I manipulated the temperatures that adult blow fly populations experienced and measured how this affected decisions when ovipositing with conspecifics (Chapter 2) and after heterospecifics (Chapter 3) in the laboratory. These observations were then validated in semi-natural conditions in the field (Chapter 5). The development and eclosion success of blow fly eggs was measured over a range of relative humidities (Chapter 4) and larval development was recorded over multiple temperatures in the presence of conspecifics and heterospecifics (Chapter 6). I predicted that oviposition decisions exhibit plasticity with varying temperature, but shifts in oviposition would be influenced to a greater extent by heterospecifics to either avoid competition or benefit from facilitation. I predicted that species interactions would either facilitate faster development, greater survival and larger adults or lowered survival and smaller adults due to competition. The results indicate that mediation of oviposition decisions by temperature are species-specific, but for P. regina, 25°C may be a switching point between facilitation and competition outcomes with heterospecifics. Differential effects of relative humidity on egg eclosion at different temperatures may provide a partial mechanism, as well as developmental impacts on adult size in the presence of heterospecifics.