Mysteries of the maggot mass microbiome: Microbial communities of Calliphoridae larvae throughout carrion decomposition

It is well known from insects, such as blow flies and carrion beetles, that colonize after death that decomposing vertebrate remains are an important ephemeral resource within an ecosystem. However, the microbes that also colonize this resource are still largely underexplored and it is unknown how they interact with the insects that forensic entomologists commonly use to estimate a minimum postmortem interval (PMImin) range. To better understand community dynamics at the microscopic level throughout decomposition, we conducted a survey study using swine carcasses and sampled the epinecrotic microbial communities of the mouth, skin, and anal region of each carcass; the internal larval microbiome; and the microbiome of the maggot mass. Sampling occurred every twelve hours at 0700 and 1900 for eight days, the amount of time for the carcasses to fully decompose and larvae to migrate away for pupation. Samples were collected using sterile cotton tipped swabs which were stored at -20^oC until they could be extracted. The predominant blow fly colonizers identified were Phormia regina, Lucilia coeruleiviridis, and Cochliomyia macellaria with P. regina being the most abundant and used for internal microbiome analysis. Using 16S amplicon metagenomic sequencing, we were able to characterize the bacteria and archaea communities over time. Ultimately, these data will be used to validate models developed from a previous study that investigated the forensic applications of bacterial succession patterns on decomposing swine carrion which will likely enable investigators to devise better methods for collecting insect evidence and improve accuracy of estimating the PMImin.