Preparing for parenthood: molecular reprogramming precedes parenting in the burying beetle Nicrophorus vespilloides

BACKGROUND: Subsocial insects transition from solitary to social behavior during reproduction. They engage in cooperative and parental care activities that increase their offspring's survival. Elucidating the molecular mechanisms underlying such social transitions is crucial for understanding the genetic basis of social behavior. Burying beetles reproduce on a nutritious yet ephemeral resource. They provide intensive pre-hatching care by burying and preparing a vertebrate carcass, and post-hatching care by feeding the larvae. RESULTS: We analyzed female gene expression during the transition from solitary life to brood care in the subsocial burying beetle Nicrophorus vespilloides. We collected RNA-seq data from the heads and fat bodies of beetles at four different time points: solitary life, early pre-hatching care, late pre-hatching care, and post-hatching care. The most pronounced shift in gene expression occurred during the initial onset of social behavior. Carcass discovery caused massive changes in the transcription of genes involved in metabolism, translation, and immunity. Changes in gene expression between the different brood care phases were comparatively modest: Females upregulated the expression of genes associated with social immunity as parental care intensified. During brood care, they gradually downregulated fecundity-related genes. CONCLUSIONS: The regulatory pattern indicates that carcass discovery triggers an increased metabolism to cope with the demands of brood care, alongside a reduced investment in body maintenance. The overall regulatory pattern indicates a strong investment into the current reproduction bout at the expense of future reproduction.