Takeout gene expression is associated with temporal kin recognition

A key component of parental care is avoiding killing and eating your own offspring. Many organisms commit infanticide of young but switch to parental care at the time when their own offspring would be expected, known as temporal kin recognition. It is unclear why such indirect kin recognition is so common across taxa. One possibility is that conserved mechanisms that regulate timing and feeding in other contexts are co-opted to enable the evolution of temporal kin recognition. Here we determine whether takeout, a gene implicated in coordinating feeding, influences temporal kin recognition in the subsocial beetle the roundneck sexton beetle, Nicrophorus orbicollis. We find that takeout expression is not associated with non-parental feeding changes resulting from hunger, or in the general switch to the full parental care repertoire. However, beetles that accepted and provided care to their offspring had a higher takeout expression than beetles that committed infanticide. Together, these data support the idea that the evolution of temporal kin recognition may be enabled by co-option of mechanisms that integrate feeding behaviour in other contexts.

Methods
We conducted a large-scale experiment where we collected the heads of beetles of both sexes in parental and non-parental contexts to determine how takeout gene expression was associated with each context. Here, we experimentally tested for associations between takeout gene expression and hunger state, the development of parenting, and temporal kin recognition in the subsocial beetle Nicrophorus orbicollis. Raw Ct values, -ΔΔCt, and relative expression values for gene expression data are provided in each context are provided.