Have you tried egg? Both tegus and ameivas love it. Also if I were you I would put a branch/log in a 45 degree angle inside the enclosure (I'm assuming you have a mesh cover on the top). That will allow for the animal to choose different spots/temperature gradients and will provide hide spots. One thing that both tegus and ameivas love in the wild are spiders, it usually triggers an immediate feeding response.
Regards
Regards