Would an adult male Rosy mate with a sub-adult female Rosy?
 

I have a 10 year old male Rosy and a 1 1/2 year old female Rosy. Can I keep them in the same cage during the mating season or will the male try and mate with her? The male was hibernated this winter.

It can happen...
 

It can happen if the female produces the pheromones that stimulate the male's mating response. It would really depend on if the female is biologically ready to mate.
I once had an 18 month old borrego 'accidentally' become gravid. She was already pretty large and ended up having three live young & two DOA's.
Still, I would suggest keeping them separately, but if not, just keep an eye out for amorous behavior from the male. One mating does not guarantee a pregnancy...and I would suggest against it in an 18 month old.

I'll probably buy one of those $150 cages that can hold the ceramic heater in it. I am too paranoid about fire to trust just an aquarium. Next summer (2008) I am going to try and have her mate with the male.

Most care info I've seen on rosys recommends waiting until the female is at least four years old. The waiting is hard, I couldn't do it so I broke down and bought an second female, an adult, so that I could breed her to my male while my little girl was growing up. I bred them last spring and she had four big healthy babies.

You might want to check out cobra brand heat mats: http://www.herpsupplies.com/subcategory.cfm?id=2&sub=25 I use them on all my snakes and they seem much less prone to overheating than other brands. The Zoomed brand heat mats I used had me concerned about fires too. If the heat mat is running hot, you can get a dimmer, rheostat or thermostat to regulate the power supply (to regulate the temperature) to the mat. Using a set up like this, you could bring your costs down considerably if that is a concern.

-Alice