Worldwide, these insects number more than 2, 500 species. They appear unexpectedly during the spring thaw, namely at the height of the ice drift. The so-called dragonfly-rodents annually and regularly accompany this stormy season. From here they have the name - stoneflies. These insects are found closer to summer and autumn. But it is these spring ones, though they are plain and unpretentious, that do not go unnoticed by people, since nature is only awakening and meager in the variety of all kinds of insects.
General Description
Plecoptera are amphibiotic insects known from the Permian period. Adult individuals live on land, and larvae live in fresh water. The body of the spring insect (photo is presented in the article) varies in length from 3.5 to 38.0 millimeters, depending on the species. They have multi-segmented long antennas, relatively large, hemispherical-shaped faceted eyes and a pair of simpler small organs of vision. Their body color is different - from brown to greenish, depending on the region of habitat. On the abdomen are two pairs of transparent wings with multiple veins, with the posterior wider than the front. Some species of springflies are short-winged or have no wings at all.
The body of these insects is flattened, and the abdomen ends with two multi-segmented tail long cerci. They are found also short, one-segmented, and in males of some species they are quite strongly modified - they have spikes or hooks.
Distinctive features
Insects of stoneflies do not shine with beauty and do not cause admiration. In addition, they look like earwigs. The mere name of the latter causes some disgust among many. Springflies differ from the mentioned insects in that they are very elongated, flattened and flexible, have membranous front wings that do not condense, like bugs or earwigs, into keratinized formations. At the end of the abdomen there are filiform tail appendages. If you compare them with strong earwigs, they are much thinner.
The most common species and habitats
One of the largest European springflies is the yellow-tailed duckweed. Her body reaches three centimeters in length.
In the Baikal region there are approximately 50 varieties of spring insects belonging to 7 families. In the coastal zones of taiga rivers, green insects are often found, the larvae of which are significantly smaller. They are very light, but as they grow older they acquire a greenish or yellowish color.
Representatives of the family Vesniankovye brown color and larger are also common. In mountain rapid streams and under stones, quite large larvae (up to 2 cm long) of insects of this family are often found. Very mobile and strong larvae are active and voracious predators. Especially they like to hunt for the closest relatives - the mayfly.
The larvae of springtime lettuce live along with the springflies. This variety got its name for its bright green color of an adult insect. Their feature is cylindrical and narrow. In contrast, the larvae of the spring-threadbare larvae have a short, strong and stocky dark body. They are easily distinguished from other families by spreading wing rudiments extending at an angle from the trunk.
In the middle Russian zone, the yellow-footed freckle can most often be found, which can live even in stagnant water bodies, with a low oxygen content. The length of her body varies between 13-27 mm. Adult insects of this species are found from April to September. Their larvae that live in fresh water bodies feed on aquatic plants and decaying organic matter.
Propagation Features
Habitat insects in the habitat are driven. Their larvae develop in water, and during the imago period (adult stage of development of insects) they go to land for molting. Usually they fly weakly, and some have reduced wings. Many varieties, being near the coast, swarm and settle hundreds of meters from breeding places. It is interesting that the female after mating throws packets of eggs into the water, touching the surface of the reservoir in flight with her abdomen. Further, the larvae develop independently.
Reproduction of springflies is very similar to reproduction of dragonflies, up to the drop of eggs clotted into the water. Their eggs are very small. Before conversion to adult insects, larvae are selected on tree trunks, stones (all surface objects). There, the skins discarded by them remain.
Habitats and lifestyle
Vital activity of springflies, like their larvae, is quite stormy. Most prefer to live on the shores of bodies of water with running water. Larvae inhabit mountain streams and other running small waters. In Siberia and in the colder latitudes of the North, the first aquatic insects that are born are the springflies Taeniopteryx nebulosa. In these parts they are called “ice cubs” because the mass exodus of these insects occurs in early April, and at that time the rivers are just opening up from the ice. In the southern habitats, “ice cubs” make their first mass departure in early March, and in more northern latitudes their departure may be delayed until May.
Insects adults lead only a terrestrial way of life, adhering mainly to the coastal zones of water bodies. They usually sit on stones and other surrounding objects, quite rarely taking off. Although they have chosen the shores of fresh water reservoirs, they are not particularly visible there, because they usually settle under stones or under a dust, and also among dense vegetation at the very surface of the soil. Even if insects sit openly, it is difficult to notice them: with folded wings on their backs, they are dark, they practically merge with their place of residence. If disturbed, the freckles quickly flee, hiding in any gap. And they fly near the ground, but more often crawl and run. Most adult springtime insects, like mayflies, are completely without food, but willingly drink water.
Larvae
Larvae lead a bottom lifestyle mainly in flowing waters. Most of them can be found on mountain rivers, among the stones. They avoid water thickets and small overgrown ponds. Due to the fact that the larvae move actively, they consume quite a lot of oxygen. Therefore, they renew the oxygen around them, making rhythmic movements with their abdomen, raising and lowering it (about 100 strokes in one minute). Larvae develop in water for 1-3 years, while undergoing up to 30 molts, which is a record among insects. Like adult stoneflies, they cunningly crawl and run fast, and rarely swim.
Larvae of various small aquatic animals are eaten, which they grab with claws of their legs. Their oral apparatus is gnawing (strongly jagged jaws), but they do not feed in the adult insect stage.
Value
Insect stoneflies are quite sensitive to the purity of the water, and experts on their presence in the ponds judge the degree of its pollution. It should be noted that recently these insects began to disappear from many habitats, which is associated with pollution of water bodies. In general, this leads to the fact that the fish that live in them are left without a basic diet. Springtime larvae are the best food for delicious fish such as trout and salmon.
Little is known about the dangers of these insects for garden plantings. Moreover, it is already clear that they at the stage of an adult insect love only to drink. It is possible that the spring insect is harmful to the Bulgarian pepper, but not as much as the white-tailed and other pests.
