Saturnid mating duration

[HHuf]

Can anyone tell me how long Luna moths should stay coupled for a
successful mating. A female that emerged yesterday is laying today. I did
not witness any mating and feared she was infertile. There was a male in
with her. A pair that emerged about noon today became active and coupled
around 11pm. They only remained together for approximately 5 minutes. I
this normal? Im used to cecropias mating for 12-24 hours. Thanks.