Microbial management as a driver of parental care and family aggregations in carrion feeding insects

Social behaviors and lifestyles have evolved as successful strategies to cope with adverse and challenging living conditions, often by manipulating the immediate environment. These manipulations can extend to the surrounding microbiome, both in terms of combating harmful agents such as pathogens but also by facilitating the growth of beneficial microbes. In contrast to the largely antagonistic role traditionally assigned to microbes in social systems, these host–microbe interactions are receiving increasing attention as potential facilitators of social evolution. Here, we explore this perspective using Nicrophorus burying beetles, a group of insect carrion breeders which offer insights into the evolutionary interactions between sociality and microbial mutualists in a relatively simple family model. Recent studies have demonstrated the constant microbial challenges faced by Nicrophorus nurseries and the costly consequences they entail. Here, we provide an overview of these challenges and then explore the role of microbial mutualists in this social endeavor, focusing on the advantages they confer in terms of development and immunity. Additionally, we discuss how these mutualistic associations may select for committed parental care and more obligate forms of social life by promoting prolonged social associations through vertical transmission. Our review highlights the hypothesis that microbial mutualists not only provide immediate benefits but may also encourage social intera...