The role of parental care in the establishment of the offspring digestive tract microbiome in Nicrophorus defodiens

Abstract

Parental care has evolved to increase offspring fitness. Burying beetles, which breed on small vertebrate carcasses, engage in extensive parental care, including prehatch carcass preservation using oral and anal secretions and direct posthatch care by regurgitating food for offspring. Aspects of parental care, such as regurgitation, may also act as a means of transmitting beneficial microbes to offspring. To explore the contributions of parental care to microbial transmission, we used Illumina high-throughput sequencing of the 16S rRNA gene to characterize bacterial communities found on prepared carcasses and in the digestive tracts of wild-caught and laboratory-reared adults and in the digestive tracts of larvae that either received or did not receive parental care. We found that the digestive tract bacterial communities of larvae receiving parental care were similar to those of their parents, whereas digestive tract bacterial communities of larvae not receiving parental care were dissimilar to those of their parents. All larval digestive tract bacterial communities were dissimilar from those found on prepared carcasses. Furthermore, we found that the digestive tract bacterial communities did not differ significantly between wild-caught nonreproductive adults and F1 and F2 laboratory-reared nonreproductive adults or between laboratory-reared nonreproductive and reproductive adults. While previous work showed that a prepared carcass may serve to inoculate some larval digestive tract bacteria, the results of the present study suggest that this role may be relatively minor and that parental care is crucial in shaping the gut microbiome of offspring, with aspects of this care, such as parental regurgitation, likely being an important component of the transmission process. Furthermore, as wild-reared and laboratory-reared adults did not vary significantly in their digestive tract bacterial communities, our findings suggest that gut microbiome transmittance within our Nicrophorus defodiens model is likely germane to the natural system. • Parental care plays a role in transmitting gut bacteria to larvae in Nicrophorus defodiens. • Larval gut bacterial communities differ when receiving parental care or not. • Core gut bacteria persist throughout the N. defodiens life cycle. • Reproductive and nonreproductive adults have similar gut bacterial communities.