Large netted enclosures protect the "Jewels of the Rain Forest" from predators and collect them together so visitors can readily observe their feeding, mating, pupation and of course their beautiful fluttering flight.
You can see the Costa Rican glass frog’s heart beating through its abdomen. --The Amphibians and Reptiles of Costa Rica: A Herpetofauna between Two Continents, between Two Seas., Jay M. Savage