Fig. 1.

Área de Conservacion Guanacaste (ACG), northwestern Costa Rica, inside the white polygon covering ∼1,680 km² from 6 km out into the Pacific Ocean, across the dry forest lowlands, over the cloud forested Cordillera Guanacaste (∼1,400- to 2,000-m elevation), and down into the Caribbean rain forest lowlands (∼1,260 km² terrestrial). These are the three major tropical forested ecosystems. In ACG, they cover an area the size of New York City and its suburbs. We currently estimate that this terrestrial and freshwater area (approximate center at latitude 10.83764, longitude −85.61871, 300 m) contains at least a half million species of arthropods, based on our inventory and opportunistic sampling throughout ACG since 1978, and the ∼45,000 species collected by the first year (2014 to 2015) of intense sampling with Malaise traps. One of our standard Townes-type Malaise traps captured no fewer than 14,520 species of true insects during two consecutive years (14).