We're always questioning whether chameleons can convert carotenoids into prEformed vitamin A....this site says...
"It is assumed that the concentrations in groups UV and No originated from low levels of vitamin A in untreated locust nymphs and potentially from the conversion of β-carotenes (not determined in this study) from the gut contents of these locusts. It has been suggested that insectivores may benefit from carotenoids that can be converted when required (39). Hence, a combination of preformed vitamin A and carotenoids may be optimal for veiled chameleons"...
https://academic.oup.com/jn/article/140/11/1923/4630486
Although this does not prove that veiled chameleons can convert enough carotenoids into preformed vitamin A, it is indicating that they can convert at least some...is it not?
"It is assumed that the concentrations in groups UV and No originated from low levels of vitamin A in untreated locust nymphs and potentially from the conversion of β-carotenes (not determined in this study) from the gut contents of these locusts. It has been suggested that insectivores may benefit from carotenoids that can be converted when required (39). Hence, a combination of preformed vitamin A and carotenoids may be optimal for veiled chameleons"...
https://academic.oup.com/jn/article/140/11/1923/4630486
Although this does not prove that veiled chameleons can convert enough carotenoids into preformed vitamin A, it is indicating that they can convert at least some...is it not?