just a guess here, I don't claim to be an expert by any means. I would think that mosquitoes would only bite warm blooded animals, because it's the heat that draws them. Now for the Ants that would depend on how venomous they are, and how many. So I guess I'm saying just depends on the species.
If you have a weak chameleon, they can easily attack and kill it. I have had them get ahold of a baby before. It is hard to balance between killing the ants and not killing the chameleon with chemicals. Tread lightly. That being said, I keep my chameleons outside as much as possible. Pros and cons to everything in life.
It might be okay and there are some ways you can prevent the ants and mosquitos I think, but maybe just go for indoor enclosure and take the chameleon outside every day or so for natural sunlight with supervision? Or use the outdoor enclosure so there doesn't need to be as much supervision, then after a while, take him back to the indoor one for the night.
Anyone object? All in favour? Anyone? Peanut butter?
Yeah, in all seriousness, you don't want to see a cham being devoured by ants. It is hard to remove from your mind. You could always get a smaller enclosure to go under your chams' cage with those ant eating lizards. They can take even the hottest days without coming inside. At summers end, if unwanted, just sell them back to pet store. Come to think of it, I may try that next year. Thanx for the new project. Everyone loves more lizards.
Yes certain species of mosquitos can and will go after chameleons. I photographed Calumma ambreense at Mt. Amber that were covered with them once the chameleons roosted to sleep. This was only seen at lower elevations. Once you got higher on the mountain the cooler temps kept the mosquitos away.
West Nile is a virus spread by a species of mosquito here in the US. I don't know if this species will go after chameleons.
ants HATE vinegar - try to spray around the bottom of your cage - it also destroys the chemical trail they leave - it may not get rid of all, but it will cut the numbers, and discourage others - but - your cage will smell funny for a bit - I use it around mine , but only at the bottom , I keep my cages right on the ground, and let the grass grow tall inside - but they have no bottoms, and are pretty big , but it keeps the ants away