Can you find Scientific facts, that the reason he isn't eating its because it is too dense. lol JK
If you look closely there is a gallon that has been cut open, for the cup feeding method.
Chameleons like to be able to hide so they feel safe.
Considering the number of variables and and well "preferences" of individual chameleons, i would day such a study would be pointless and fruitless!
I agree with psyrocco that cage obstructions such as plants may severely hinder a chameleons ability to capture food.