Many terrestrials are often found close to 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.
Craneflies are around from spring to winter, but are mostly found on the water during late summer and autumn.
Ants are found from the first warm weather during spring to late autumn and will from time to time end up on the surface during all of this period. However, the peak time to fish with imitations of ants are during autumn. As the weather gets cooler and the first frost appears in the morning, many ants will be limited in there possibilities to move correctly. This is particulary true to flying ants and occasionally the amount of ants on surface are in such a quantity, that fish will get selective.
Bees, wasps and bumblebees are very similar to each other and therfor one fly can imitate them all. Just as with ants, the appear during the first warm days in spring and disapear as it gets cold all day long during late autumn early winter. You can find them on the surface during this period, but the peak time is during autumn. As the first frost appears in the morning, they will get sluggish and can sometimes appear to be drunk. During these conditions, it is not at all unusual to find many of them spread out on the surface.