Anna i Lech
Small water reservoirs are the favorite
places of occurrence of water insects
are the most numerous species in the group of invertebrates. During the process of evolution they get used to living in almost every kind of environment,
including the water environment. Insects include:
dragonflies Odonata, May-flies Ephemeroptera, Plecoptera, Megaloptera, Trichoptera and some species of: Collembola, varied-wing bugs Heteroptera, Planipennia, Diptera, Hymenoptera, Coleoptera and butterflies Lepidoptera. Some insects such as e.g. dragonflies, May-flies or Plecoptera live in the water only as larvae; others such as e.g. water bugs
or some cockchafers are connected with water during their adult lives. Adult insects (the so-called imago) breathe the atmospherical air and have to swim
up to the water surface from time to time. Larvae of water insects do not receive the oxygen from air but from water by gills' growths, gills-tracheas or
by the whole surface of a delicate skin.
Insects play a significant role in the processes occurring in the water environment. Some numerous species are essential elements in the process of
circulation and transformation of organic matter - they are the food for many other animals and the predacious species have an influence on the population
of other water organisms. Man uses a number of species of water insects to estimate the quality of water (the so-called bioindication). Depending on the
specific composition, number and structures of teams of water organisms one can estimate the degree of pollution of the environment where these organisms
live. The larvae of stoneflies Plecoptera, May-flies
Ephemeroptera and caddisflies Trichoptera are the most sensitive to any pollution and the most useful in bioindication.
The aquatic insects of Wigry National Park live in every kind of reservoirs and water-courses starting from the small, periodically drying
drainage ditches to the large lakes and rivers. Despite the common occurrence in nature this group is not recognized to a large degree and will demand some
further intensive research.
are insects connected with the flowing waters. They require clean and well-oxygenated water. Adult individuals have a flattened body, long feelers, opaque
wings where the back wings are larger than the frontal ones, the abdomen equipped with two twigs. Larvae are similar to adults however they are smaller and
they lack the wings. Males die after the act of copulation and females live a bit longer for some time. At this time the female lays from several hundred
to about 2 thousand eggs which are attached to the abdomen by means of secretion. Later on the eggs are placed into water. It takes one to three years to
become the winged adult insect. All young larvae of Plecoptera eat dead organic matter while older larvae are both herbivorous and carnivorous.
Adult insects have retarded mouth organs and during their 4-6 weeks of life they only consume the fat accumulated in the period of life of larva.
Dragonflies and damselflies Odonata
- adult individuals are insects of an average or large body size, large eyes, short feelers and often intensive and rich coloration. Dragonflies, both larvae and adult forms, are predacious.
Depending on the body size the larvae of dragonflies eat water microorganisms, crustaceans, distomas and other parasite animals, eelworms, water insects,
fishes and larvae of amphibians. After the act of copulation the female lays the eggs directly into waters and places them in the tissues of water plants
or in the mud.
mastered different zones of water environments, starting from sediments covering the bottom, where they bore the tunnels, to the zone of water vegetation
where they live on the leaves and stems of plants. Larvae mainly eat algae and small organic parts. Perfect insects live very short - from several hours to
several days. At this time they only consume the reserves accumulated during the life of larva. Their underdeveloped alimentary canal does not allow to
receive the food. After the mating flight the males die while the females lay eggs directly to water or on the surface of water plants. Larvae live about
one year, sometimes even longer.
The case-worm in
are insects similar to butterflies, however their wings in the resting position are always folded like a tile on the abdomen. Adult insects eat the nectar
of flowers. The female lays eggs in packs covered with the jelly-like substance directly to the water or on the plants inclining over water. The eggs'
development lasts from 2 to 4 weeks. Some individuals live inland just about 8 days. Some Trichoptera larvae build cocoons woven from the silken
follicle which is built around using different materials such as: fragments of reed, spruce needles, the shells of molluscs, the grains of sand etc. Larvae living without the cocoon spin the special hunting
nets which are located among the water plants or on the stones. Depending on the species, they eat plants, small water animals and dead fragments of
Aquatic beetles Coleoptera aquatica
are a group of insects which adapted to living in the water environment in a variety of ways. The back limbs of many species were equipped with the thick
natatorial stubbles. Thanks to that these insects are perfect swimmers. Adult insects, despite breathing the atmospherical air, can stay underwater for a
long time. Depending on the species, cockchafers can be herbivorous or carnivorous.
The varied-wing bugs Heteroptera are a group of insects having a characteristic stinging-sucking mouth opening and the differentiated
construction of wings - the frontal wings are chitinous and membrane-like while the back wings are just membrane-like. Some species of bugs settle the
water surface while others live in the water depths. Larvae are similar to adult individuals however they do not have the formed wings. Heteroptera mainly
eat small living and dead water organisms.