Reticulated humming frog
Scientists think the tarantulas use chemicals to tell which frog is which.  They have seen young tarantulas catch and pick up small reticulated humming frogs. They catch them the same way they catch frogs that they will eat.  But the tarantulas only touch the reticulated humming frogs with their mouths. Then they put them back down without biting them.  Microhylid frogs, like the reticulated humming frog, make chemicals in their skin that taste bad.  Scientists think this might be why the frogs and spiders started living together.