Investigation into the Microbiome of Blow Fly Eggs Using MicroSEQTM ID

There is little published research characterizing the microbiome associated with blow fly eggs and how they may affect the colonization behaviors of certain blow fly species. Once deposited, blow fly eggs are rapidly introduced to a diverse range of microorganisms, which can vary depending on the species of blow fly, the environment, and the decomposition stage of the substrate (Junqueira et al., 2017). Since blow flies are among the first insects to colonize decomposing remains, the microbial communities present on their eggs could serve as key indicators of the decomposition stage at the time of egg-laying, thus providing a potential new method for refining PMI, or post-mortem interval, estimations (Joseph et al., 2011). In this study, the egg microbiomes of three blow fly species were studied: Lucilia sericata (Meigen), Phormia regina (Meigen), and Calliphora vicina (Robineau-Desvoidy). For each species, eggs were collected and swabbed within one hour of deposition and plated onto both tryptic soy agar (TSA) and 5% sheep’s blood agar. From these plates, individual microbial strains were identified and plated on TSA or blood agar to create isolate colonies to be used for species-level identifications using the MicroSEQTM ID workflow. MicroSEQTM ID provided an easy, efficient, and reliable sequencing method for identifying egg-associated microbes, and this study demonstrated that 5% sheep’s blood agar was useful in identifying hemolytic-specific microbial strains. The specific microorganisms identified in this experiment demonstrated that the microbiome associated with blow fly eggs is highly complex and diverse, and has many consistent and species-specific aspects between blow flies. This study highlighted the relevance of using MicroSEQTM ID and blood agar in a variety of contexts beyond forensic entomology and how the microbiomes of blow fly eggs could play a role in colonization behavior.