Many terrestrials are often found close to the water. Among these you will find craneflies, ants, bumblebees, wasps and bees. All of these will occasionally end up on the surface of the water and become the target for many fish species, such as grayling, char, rainbow trout and brown trout.
Most terrestrials that ends up on the water do so by misstake. A strong wind, a heavy rain or cold temperatures will limit there abillities to move or fly.