Parental care is a genetic capacitor

Parental care is widespread across the animal kingdom and plays a critical role in offspring development. Yet, its broader genetic and evolutionary impacts remain underexplored. Here, using the biparental burying beetle Nicrophorus vespilloides as a model, we show that parental care acts as a genetic capacitor: it allows genetic variation to accumulate while care is present and releases it when care is disrupted. By experimentally manipulating care, we demonstrate that parental care suppresses genetic variation associated with offspring body size, which is released when care is lost. To investigate the underlying molecular mechanisms, we generate a chromosome-scale genome assembly for N. vespilloides, alongside a single-nucleus gene expression atlas and epigenomic datasets from larvae reared with and without parental care. We find that the loss of parental care induces molecular stress, disrupting the expression of the protein chaperone Hsp83, which is a well-known molecular capacitor, alongside other putative mRNA chaperones. Moreover, our results suggest that parental care buffers development by maintaining an open, responsive chromatin landscape and redundant gene regulatory interactions. Overall, our work reveals that parental care shapes the storage, expression and release of genetic variation with broad implications for adaptation and evolution.