Leos yeah, but I take my blue tongue and most of my species (like leos or chameleons) out and put them in a large rubbermaid bin/outdoor cage (depending on what reptile I am doing depends on the cage) with plenty of shade providing by like simple things in the bin/cage or by trees casting shadows outside. My leos only get around 30-45 minutes of sun around 3pm twice a week, which is still good sun time but the rays are less powerful. My blue tongue gets a couple hours twice a week. I can't make a permanent outdoor cage for my tort yet. We don't own my house and they don't really know about him, but we will be moving and buying our own house soon, so I expect he will get it soon enough. ^^
Ok for vitamin A in insects
Silkworms are the best source...
But I am sitting here do calculations of how many insects they would need (doing what my adult panther eats on a regular basis).
In one sitting they would have to eat 6 crickets, 3 superworms, and 2 silkworms to get even close to what they need daily without a dust (this all adds up to around 110 mg). But the thing is, you are supposed to add a dust to these insects. (I am going off what repashy's would be) So they would actually need closer to 440 IU/mg of vitamin A per day. Though it is fat soluble the body burns through it quickly. So to they would need at least 400 IU/mg to have some extra left over (I am guessing because I haven't done the daily needs of vitamin A for insectivore reptiles) to store up.
But this is of course with insects who are fed well and taken care of. Most people don't go above and beyond with their gutloads. They don't actually know what's going in their gutloads they are commercially buying and what does what as far as food.
So animal protein does make sense. Insects don't naturally carry a lot of retinol, and chameleons even if they do process beta carotene and such, they don't process enough to it where it keeps them from getting vitamin deficient.
(if you want I can provide you with all my data and math XD)
I don't know the nutritional value of geckos XD I didn't mean to come across that way. But I do know how vit A, Vit D, calcium etc. all work. Which the only actual reason you would want to provide geckos instead of insects is for a calcium boost (though you can't give it enough to provide it well). But Vit A and D and various other vitamins like B and certain amino acids would be useful with what they could provide, which insects are extremely low on Vit A and D when raised in captivity and is why a lot of chameleons do poorly on an insect only diet. So few of the common insects that are fed off have no real measurable amounts of vitamin A. I think silkworms... I can't remember at the moment which insect we feed off most in captivity... (will look again) has the most and very few people actually feed them off compared to most. The thing is a huge amount of Vit A and D are both used to create babies for chameleons. Artificial UVB is a poor excuse for helping create natural Vit D for most species. And going up to a 10.0 bulb will not help, it's all about the wavelengths available. That's why my chameleons get natural sun (Ryker relies on it purely for uvb and Hope gets it a couple times a week), my geckos get it twice a week too. My tortoise gets it whenever possible and so does my Blue Tongue. Vit A is given through my personal gutload for all my insects which has preformed Vit A in it and various precusors to Vit A that help it get transferred faster in the insects. I also dust with a really good dust twice a week at least.
