Insect homolog of oxytocin/vasopressin associated with parenting of males but not females in a subsocial beetle

Abstract

Parental care is thought to evolve through modification of behavioral precursors, which predicts that the mechanistic changes occur in the genes underlying those traits. The duplicated gene system of oxytocin/vasopressin has been broadly co-opted across vertebrates to influence parenting, from a pre-duplication ancestral role in water balance. It remains unclear whether co-option of these genes for parenting is limited to vertebrates. Here, we experimentally tested for associations between inotocin gene expression and water balance, parental acceptance of offspring, and active parenting in the subsocial beetle Nicrophorus orbicollis, to test whether this single copy homologue of the oxytocin/vasopressin system, has similarly been co-opted for parental care in a species with elaborate parenting. As expected, inotocin was associated with water balance in both sexes. Inotocin expression increased around sexual maturation in both males and females, although more clearly in males. Finally, we found that expression of inotocin was not associated with acceptance of larvae but was associated with a transition to male but not female parenting. Moreover, level of offspring provisioning behavior and gene expression were positively correlated in males but uncorrelated in females. Our results suggest a broad co-option of this system for parenting that may have existed prior to gene duplication, and that inotocin may be associated with flexibility in parenting behavior.

takeout gene expression is associated with temporal kin recognition

“…All observations were conducted by a single observer. Following the addition of larvae, we observed the focal individuals for at least 30 min to detect acceptance or rejection of larvae following established protocols [ 30 ]. If the focal individuals did not respond in this time, pairs were checked every 30 min to identify the onset of acceptance or infanticide.…”