Characterization of bacterial communities in American burying beetle (Nicrophorus americanus) secretions through gram staining, MALDI-TOF analysis, and 16S sequencing

The American burying beetle (Nicrophorus americanus) is a federally threatened necrophagous insect that provides biparental care to its offspring using vertebrate carrion. Nicrophorus beetles prepare a brood ball by first burying a carcass, then removing the fur or feathers and digestive tract, and finish by covering the carcass in oral and anal secretions. Both the beetles and the bacteria present in their secretions produce antimicrobial agents that prevent the carcass from decomposing and help preserve it for consumption throughout the duration of larval development. In order to identify the bacteria present in American burying beetle secretions, bacterial colonies were isolated from a pair of lab-bred beetles. Using Gram-staining, matrix assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF) analysis, and 16S sequencing, thirteen isolates of aerobic bacteria were identified. Of these bacteria, two were identified as Myroides odoratimimus, which has been reported in flesh flies to reduce the growth of other microbes, including some human pathogens. Another two isolates were identified as Proteus nr. vulgaris, which exhibits antimicrobial effects in blow flies, protecting maggots from harmful microorganisms. Follow-up studies are comparing the bacteria from wild-caught American burying beetles and other closely related Nicrophorus. Characterizing the burying beetle secretion microbiome aids in understanding how the bacteria interact and function to preserve carrion at environmental temperatures and has implications for antibiotic development and meat preservation.