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I think geckos recognise food by its behaviour rather than smell or taste - if it acts like food it is food. I don't think they eat fruit. I tried putting some meat on the end of a straw and imitating the actions of a moth fluttering about and settling nearby, but he ignored it completely - when I touched it to his nose, he just slunk away.
There are always lizards in the house because our cats bring them in, but they are easy to catch and release back into the garden. (I think we have the worlds largest collection of tail-less lizards in our garden). Lizards seem to be much less fussy about what they eat than geckos.
I could catch him and take him outside, but with the veranda rooves gone, and the rest of the house a building site, I am afraid there is nowhere safe to put him.