Within the field of community ecology, there have been many theories proposed to explain how various communities assemble themselves, with a considerable amount of debate between the validity of neutral and non-neutral models as a driving mechanism for community assembly patterns. In order to determine the mechanism of assembly within the primary consumer guild of the carrion insect community (i.e. the sarcosaprophytic guild which feeds directly upon the muscle/soft tissue), freshly emerged Phormia regina (Meigen) and Lucilia sericata (Meigen) adults were separated and placed in mesh cages to create five different treatment colonies where both the sequence and species available for colonization varied. Once females were fully gravid, fetal pig carcasses (Sus scrofa) were placed within each treatment colony for 24-48 hours (depending upon treatment conditions). Colonization events were recorded with respect to time of oviposition and location. After the designated colonization period ended, piglets were removed and egg mass surface area and depth were recorded.
Results determined that egg laying locations differed between L. sericata and P. regina with P. regina exhibiting behavioural plasticity with respect to their preference for oviposition sites due to the presence/absence of L. sericata. Also, the quantity of eggs deposited by females of each species varied with respect to the species type and introduction sequence, with L. sericata exhibiting a more aggressive colonization behavior, thus laying more eggs overall than P. regina. However, in treatments where P. regina was introduced subsequent to colonization of the resource by L. sericata, P. regina females laid significantly more eggs indicating that previous colonization by other blow fly species may act to increase survival of P. regina. Though the overall mechanism of assembly is neutral with respect to both species' ability to become an early resource colonizer, there is an underlying priority effect of L. sericata on P. regina, with L. sericata acting to facilitate and promote the colonization potential of P. regina. These findings suggest that there are multiple underlying mechanisms that interact to provide the framework for understanding the patterns and processes involved in community assembly theory.