Parthenogenesis occurred

[Bogertophis]

...I don't get why mine has just started doing this from last year, and none of the years before.

I suspect (?) there might be some sort of "last ditch effort" hormonal trigger when females get older & haven't yet reproduced...a way to save the species from extinction?

Years ago I was given an older rosy boa that was doing poorly in a nature museum & she kept trying to reproduce also...she'd laid slugs in the past, but with me, finally had one live neonate that lived 8 mos. before expiring naturally from defects. She had terrible muscle tone, & thus it was very difficult for her to push out slugs, & I didn't want her to do that again, so I made the difficult choice of giving her a healthy mate, & she "re-paid" me with 5 successful years of healthy, robust baby rosy boas, ALL of which thrived.

When I tried to get her to quit (halfway thru those reproductive years) she nearly died trying to push out the slugs...so that's why I let her re-mate for the remainder: live rosy boas pretty much come out on their own- it was actually easier on her & she lived some years beyond all that, to around 26 years (assuming the museum was correct about her age when she was given to me). Nature IS full of surprises! She was truly an awesome snake & while I had NO intention of ever breeding ANY rosy boas, I was glad to have known her.