I got my wild-caught milk snail Hercules (Otala lactea) in October 2007. A few months ago I got my wild-caught Helix aspersa Buster, who was a juvenile at the time. Both of them have been living happily in the terrarium all this time, mostly ignoring each other.
But a couple of weeks ago one evening I saw Hercules nuzzling Buster. Nuzzling is part of the courtship ritual for snails, a prelude to mating. Since it was late at night I didn't stay up to watch if it proceeded to actual mating. A few days ago I saw Hercules nuzzling Buster again, and again I didn't stay up all night to observe. Snail mating can take up to 12 hours, so I think it's understandable that I didn't stay up to find out what else happened.
. . . So, anyway, yesterday and today Buster has been buried in the terrarium substrate, laying eggs!
I'm wondering if it's possible they're hybrid Helix-Otala eggs. They're in the same subfamily, Helicinae, but I don't know if that's close enough to cross-breed. I put them in the same tank together on the assumption that they would not interbreed.
H. aspersa are not known to self-fertilize, but Otala and Helix are not known to interbreed either (as far as I know). It is not possible Buster has been carrying the eggs all this time because he was a juvenile when I got him.
So, what could be the explanation? Otala and Helix seen nuzzling on more than one occasion just prior to Helix laying eggs . . . Could such a hybrid be possible? (D. said they'd be Frankensnails, lol!) Could Buster have been stimulated just to lay infertile eggs?
I guess in a couple of weeks I'll find out.