My, anglers see them very briefly, usually when they fly out as adult insects. In the water, however, the flower larvae live for quite a long time, provided of course, that no fish would get interested in them sooner…
There is such an insect, which not only stimulates the imagination of fly fishermen, but also a great challenge for all fly tying mates. This insect is a bug. Americans call it a caddis, while in England it is referred to as the sedge.
The birdworm image can be easily observed over the water during the period of mass outbreaks of these insects.
A resting bird always folds its long wings over its abdomen. There are very fine hairs on the wings.
There are around three hundred different species of handworms in Europe, of which in Poland approx 240. Many species have adapted to different environmental conditions.
Hawthorn larvae, called padlocks by some anglers, can be found in almost any water – in small ditches, large lakes, fast mountain streams, in meadow streams and practically all rivers.
Cottages only build larvae (sprock) belonging to one of the three large families of cookies. The remaining larvae make nests or live without houses at all. To be precise, it should be said, that more or less 80 percentage of all cookies (their larvae) actually builds cottages.
The larvae make their homes as follows: they surround themselves with a cocoon, and then they stick to it masking materials from the immediate area. The cocoon is never too small, because the larva is constantly "building it" on the front. The most common materials used to build cottages are grains of sand, pieces of snail shells, small pebbles, tiny sticks, bits of decaying leaves and bark (photos 1+2).
Species living in stagnant or slowly flowing water are satisfied with "light" building materials, while species inhabiting faster watercourses are forced to use much heavier materials, for example, grains of gravel (photos 3 + 4).
Species found in swift mountain streams use an even more reliable method: they attach their houses to some large stone and thus avoid being carried away by the water current.
The birdworm larva that builds the house spends quite a lot of time on this, so that her place is as unobtrusive as possible. The ability to blend in with the environment is one of the most important factors in survival, because free-moving larvae are, despite their home, a tasty morsel for many species of fish – grayling and trout swallow the padlocks whole, together with their elaborate houses!
After removing the padlock from the cabin, explains very quickly, why the beetle larva builds it at all – it has no protective shell, it is as soft as a caterpillar and very prone to damage (picture 5).