Age interactions influence biparental care behavior and reproductive success.

This article investigates how the ages of male and female burying beetles (Nicrophorus orbicollis), an obligately biparental species, interact to influence parental behavior and reproductive success. Using a full factorial design with young and old beetles, the study found that both sexes increased reproductive effort with age, but age-mismatched pairs (one young and one old) achieved the highest reproductive success, producing more and larger offspring compared to age-matched pairs. Behavioral analyses revealed that male and female care patterns depended on both their own and their partner’s age, with pre-hatching care positively correlated between sexes and post-hatching care negatively correlated. These findings suggest that reproductive senescence can be mitigated by pairing with a younger partner, highlighting potential fitness benefits of age-disassortative mating in biparental care systems.