|....................... ......Fly Fishing Yellowstone National Park
Bug Made Easy - Part 4
When the larvae mature they enter the pupal stage of life for a relatively short
time. The cased variety seal themselves inside their cases. The free-living
variety build retreats and stay there until the metamorphosis is complete. You
may be more familiar with a butterfly that lives in a cocoon in its pupa stage of
life. When the pupae come out of their retreats, they are called pharate adults.
They are fully formed but they are still in a skin with their wings compressed.
This is when most of the species are most subject to being eaten by trout. When
we imitate the pupa, we are imitating the pharate adult.
Most of them emerge on the surface of the water but other species may rise to
the surface and run across the water to the banks. Still others climb out onto
rocks or the bank and hatch into adults.
The adult caddisflies mate in the bushes or on the banks or rocks. The females
return to the water and lay their eggs in different ways. Some deposit their eggs
on the surface. Some skitter across the water, knocking them off. Some crawl or
dive to the bottom and deposit their eggs. Most caddisflies die away from the
water but others die during the egg-laying process. You should know the egg-
laying habits of each caddisfly genus, otherwise, you really do not know what
you are doing when you imitate them.
Midges are another important aquatic insect that anglers need to be familiar
with. It is a mistake to think that midges are not an important food item for trout
in the Yellowstone National Park.
Midge larvae look like tiny grub like worms. There are two types, the ones that
burrow in soft bottoms and the free swimmers that hide under rocks, sticks and
other debris. Most of them in the Smokies are the free swimmers.
When the midge larvae change go into the pupae stage of life, they are most
subject to being eaten by trout. Most of these pupae emerge in the surface film.
Often, the pupae have a difficult time breaking through the surface skim and
changing into an adult.
The midge pupae look quite similar to the larvae except they have a wing pad
area that is thicker than the body of the larvae. The midge pupa is the most
important stage of life to imitate with a fly.
The adult midge looks similar to a mosquito. They can be important to anglers
during the time they are mating and depositing their eggs. They are imitated
with tiny dry flies.
Copyright 2009 James Marsh