can moths mate even if they are related?

As long as they’re of the opposite sex, yes.

Yes we can!

Zitat von FriedCookies

As long as they’re of the opposite sex, yes.

Yes, however, after several generations, they loose interest in each other, depends of the species. Citheronia genus is known for not tolerating too much inbreeding, and can go up to F2 only I think. Some won't ever stop, this is how some broods of Antheraea polyphemus end up being black, due to genetic selection. Samia ricini is used for silk production and can be inbred for an incredible amount of generations. Generally, they can go up to F5-6 without any problem (4th or 5th inbred generation)