Burying beetles (also known as carrion beetles) use small carcasses as a source of nutrition for their larvae. Carrion is an ephemeral resource, which is highly nutritious but susceptible to rapid microbial degradation. Unregulated microbial growth can lead to depletion of nutrients, accumulation of toxic metabolites, and the growth of microbial parasites and pathogens. Carrion is the sole source of nutrition for the larvae, and the maintenance of its quality is important for larval survival and development. Despite carrion’s susceptibility to putrefy and quickly turn unpalatable, the burying beetles are seemingly immune to any ill effects of feeding on decaying carcasses. How do the burying beetles cope with a challenging resource such as carrion, despite burying it in the microbe-rich environment of soil?
Results/Conclusions
We demonstrate that the burying beetle Nicrophorus vespilloides successfully manages the carrion microbiota by preventing microbial succession typically associated with putrefaction. Instead, beetles inoculate their gut microbes containing symbiotic bacteria and fungi on the carrion, which prevents deterioration of carrion quality. By comparing beetle-tended carcasses with those that had no access to beetles, we show that the beetles’ gut microbes reduce concentrations of putrefactive polyamines and modify the levels of digestive enzymes. This regulation of the carcass microbiome is adaptive for beetles, for when disrupted, it reduces larval growth. Further, the symbionts were consistently abundant within the family Silphidae that contains several necrophagous beetles. Such regulation of the carrion microbiota and its biochemical properties constitutes an adaptive carrion management strategy by the burying beetles. The study demonstrates how insects modify their habitats to enhance fitness and regulate microbial competitors on an ephemeral resource such as carrion.