At the bottom of many freshwater bodies - clean, fast streams and overgrown ponds - you can find amazing creatures that live in tubular houses that they construct from various small particles lying at the bottom. Depending on what small objects lie at the bottom, and depending on the type of insect, houses can be built from different materials. For some it is a structure made of large grains of sand, for others it is made of pebbles or shells of small mollusks, often it is a tube consisting of small fragments of twigs or dead parts aquatic plants, etc. The “building material” is firmly held together by spider threads. These houses are built by caddisfly larvae.
Adult caddisflies are rather delicate insects, similar to hairy moths (Fig. 310). The easiest way to distinguish a caddisfly from a butterfly is by its wings - butterflies have wings covered with scales, while caddisflies have hairs. When at rest, their dark-colored wings are folded like a roof on their back. The head is quite large with compound eyes and usually with 3 simple ocelli between them.
The antennae are long, thread-like, the oral organs are reduced, in particular there are no mandibles at all, and the remaining oral parts are transformed into a short proboscis with a tongue. Adult caddisflies do not feed, but can drink water. The legs, ending in 5-segmented tarsi, are quite slender.
These generally inconspicuous, inconspicuous insects fly reluctantly and sluggishly. After mating, female caddisflies lay gelatinous lumps of eggs called “spawn” in the water. The eggs hatch into larvae, which in most species immediately begin to build an arachnoid sheath from a silk thread secreted by modified salivary glands. The cover is inlaid with suitable small particles , lying on the bottom and accessible to the larva. Including hard objects in the case makes it stronger and stronger. A necessary for caddisfly larvae. The fact is that it never leaves the water and breathes through the entire surface of the skin of the entire elongated abdominal section of the body. The abdomen of caddisfly larvae not only has very thin, easily permeable (and if so, easily vulnerable) integument, but often also bears numerous even more delicate gill outgrowths, increasing the surface of gas exchange with water. Bundles of gills are also found on the posterior parts of the chest.
If everything around is calm, the larva crawls along the bottom, carrying the cover on itself. When moving, the larva protrudes its head and thoracic region from its case, on which there are 3 pairs of rather long and tenacious legs extended forward. However, the front legs are often shorter than the rest, and some caddisfly larvae have only two pairs of legs. The head and thoracic segments protruding from the cap have dense coverings. The head of caddisfly larvae is amazing - there are no antennae on it. In larvae different insects with complete transformation, the antennae are of different lengths, but rarely they are reduced to such an extent that they become completely indistinguishable, as happens in caddisfly larvae. The eyes of the larvae look like dark spots and consist of several simple ocelli (no more than 6 on each side of the head). The oral apparatus of larvae, in contrast to adult caddis flies, is well developed and gnawing. The larvae also feed on plant foods, scraping soft fabrics jagged jaws, and animalistic. The cap serves the caddisfly larva not only as a permanent armor that protects the abdomen, but also as a refuge: in case of danger, the entire larva is drawn into the “house”, the entrance hole of which is closed with its dense and durable smooth head capsule. The posterior end of the body of the caddisfly larva is held in the case by a pair of powerful hook-shaped processes directed forward. Therefore, the larva can quickly hide in the cover. Holding the house with hooks, the larva drags it along with it, without losing it and only completing construction as it grows.
What caddisfly larvae are easy to find in our reservoirs?
In fast streams with cool water and a rocky bottom, tube houses are easy to spot under rocks stenophile(Stenophylax stellatus), constructed from large grains of sand neatly attached to each other (Fig. 311, 1). The larva easily lifts its house, the front edge of which hangs like a hood over the larva’s head, making it invisible to fish swimming from above. If the larva's cover is damaged, it immediately tries to repair it, picking up grains of sand of the required size with its front legs. She fits them to the damaged edge of the cover, discards those that fit less tightly, testing and selecting the most suitable ones. The larva glues the grains of sand with saliva that hardens into a silky thread, wraps them repeatedly with threads, binding the grains of sand to each other, as a result of which the case turns out to be very durable. After repairing the walls of the house, the larva carefully lines its inner surface with several layers of silk cobwebs. If the larva is carefully removed from the case and placed in a vessel, on the bottom of which beads are placed instead of sand, it will make itself a house of small bright beads. Stenophila larvae feed on both plant and animal foods.
In lakes into which streams flow, larvae live in more open places at the bottom apathania(Apatania). Their houses are shaped like a horn (Fig. 311, 4). Larger grains of sand are embedded in the sides of the apatania house.
In shallow sandy places, larvae make their houses built from grains of sand. Molanna(Molanna angustata). Molanna's house, when viewed from above, is wide and flat. The central tubular part, in which the larva sits, is made of larger grains of sand, but attached to its sides are wings made of smaller grains of sand and the same hood. In general, the cover has the appearance of a rather large shield, its length is more than 2 cm (Fig. 311, 5). The molanna larva with its case moves in jerks.
Larvae live in dense thickets of plants freeganei(Phryganea), making their tubular houses from gnawed quadrangular pieces of plants, like short planks (Fig. 311, 5). Often such houses even retain their green color - pieces of aquatic plants in water remain viable for a long time. Freegans have a spacious and long house, the larva can run freely in it. The rear end of such a tube house is open, and if the larva is pushed out of the case, it will quickly run along its surface and deftly duck into it from the rear end. Friganea - large insect, the length of an adult larva is about 4 cm. Although the larvae of freegans, when making caps, bite off pieces of plants and, if necessary, especially in summer and autumn, sit mainly on a plant-based diet, they are not vegetarians. Freegan larvae are more likely to eat mosquito larvae and other small invertebrates.
Larvae are common at the bottom of overgrown ponds limnophiles(Limnophilus). The houses of some species of limnophiles are quite similar to each other. The larva builds a house from various solids. small items, lying on the bottom. There may be small swollen sunken sticks, small shells of mollusks, needles, and other plant remains, but pebbles and grains of sand are not used by limnophiles. If the limnophila larva is expelled from the house and the house is removed, it, releasing sticky spinning threads and spinning restlessly, first makes a temporary house out of anything, and then, feeling that the abdomen is somehow protected, begins to make a permanent house, carefully selecting durable particles and fitting them well together.
IN North America common snail caddisflies(family Helicopsychidae), making spirally convoluted cases for themselves, so similar to snail shells (Fig. 311, b) that even zoologists, before confidently saying whether they have encountered a shell or a caddisfly house, must take a very careful look.
Although caddisfly larvae are very well adapted to life in water, among the forms that build cases there are also those that left the aquatic environment and moved on to life on land. That's how land caddisfly(Enoicyla pusilla), living in beech forests Western Europe(Fig. 312). Interestingly, the females of this caddisfly are wingless. The larvae of land caddisfly live in the litter and among the moss covering tree trunks. This larva avoids water and, when the layer of fallen leaves becomes very wet after heavy rains, moves to tree trunks. The larva makes a house from small pieces of fallen leaves.
Although life in cases is typical for most caddisfly larvae, representatives of some families lead a different lifestyle, despite the fact that they have well-developed spinning glands. In shallow and slow-moving rivers, in thickets of pondweed and other aquatic plants, there are delicate, barely noticeable transparent tubes attached to aquatic plants (Fig. 313).
They oscillate in streams rhythmically flowing water. Usually there are many such tubes in one place - a whole cluster. They are made by larvae neuroclip(Neureclipsis bimaculata) from family polycentropidae(Polycentropidae). If these tubular formations are transferred to still water, for example placed in a bucket of water, they will collapse and become inconspicuous - the flow of water inflated and maintained the shape of these thin underwater nets. If you look at such a tube through a binocular, you can see that it is indeed a network - a network, remarkably woven, with small cells of the same type. These tubular networks are weaved by narrow, long larvae that live without a cover and do not have gills. The larvae (Fig. 314) build themselves in flowing water not houses, but nets - trapping nets, into which small crustaceans, mayfly larvae and other animals carried by the current fall, becoming prey for the neureclipse. In the water, the predatory larva of this caddisfly catches prey in the same way as web spiders do on land!
In large lowland rivers - in the waters of the Volga, Don, Dniester - many caddis flies develop hydropsychides(family Hydropsychidae). The larvae of hydropsychids make a snare with rectangular cells, and they themselves sit nearby in a light cover made of thin threads (Fig. 315).
As soon as a small crustacean or insect gets caught in the snare, the predatory larvae (their sizes reach about 2 cm) jump out of the shelter and grab the prey with their strong jaws!
Larvae make trapping nets in the form of bags (Fig. 316). plectronemia(Plectrocnemia). It is interesting that such specialized hunters of aquatic prey as hydropsychidae and plectronemia can also go to land. These larvae were found at a distance of tens of meters from streams in the forest floor, where they lived, of course, without making any trapping nets.
However, some caddisfly larvae (family Rhyacophilidae) do not make complex structures in water. Beautiful greenish-blue larvae crawling along the rocky bottom of clean, cold streams riacophile(Rhyacophila nubila), (Fig. 311, 7), reaching a length of 2.5 cm, only release a thread that keeps the larva from being carried away by water. These predators cling to the bottom and to the thread they secrete with their legs and attachment hooks at the rear end of the abdomen and wait for prey. The rapid grasping of prey by rhyacophila larvae is helped by the fact that their strong jaws are directed straight forward, like the predatory larvae of ground beetles.
The development of caddisflies usually lasts 1 year, but in large northern species it lasts 2-3 years.
Familiarization with even a few representatives of caddisfly larvae shows how diverse their habits and characteristics are. But adult caddisflies do not feed, they only reproduce, and they all lead a similar lifestyle. Therefore, it is clear that it is relatively easy to recognize caddisfly larvae (not only the lifestyle of different species is different, but also the structure of individual parts of the body is different), and the species of adult caddisflies can only be recognized by entomologists who specifically study them.
Acquaintance with caddis flies also shows that not only the study of the structure of different parts of the animal’s body makes it possible to distinguish and recognize them well, but also behavior (expressed, for example, in the construction of covers of one form or another) can be used by taxonomists as a reliable sign. The founder of comparative zoopsychology, Russian zoologist V. A. Wagner, first drew attention to this.
There is a lot of peculiarity in the life and development of caddisflies. In most insects with complete metamorphosis, the pupa is almost motionless and, if the larva and the adult insect live in different environments, the larva before pupation makes it easier for the adult insect to find favorable conditions for it, for example: larvae adapted to life in water, such as the larvae of swimming beetles, Before pupation, they emerge from the water and burrow into the ground. Caddisflies behave differently. Their pupa begins its life in a case constructed while still in the larval stage, then it lives freely in the water column for some time, and the last stage of the pupa’s life, before its transformation into an adult insect, occurs in the air.
The pupa of caddisflies is free (Fig. 317). This is generally the same stage adapted to life in water as the larva. The life of a pupa can easily be traced using the example of a stenophila, from whose consideration the acquaintance with caddisfly larvae began. Before pupation, the larva selects a calmer area of the reservoir and, attaching the cap to a stone, braids its ends so that each has a hole for free access of water. When the larva pupates, the pupa inside the cap makes oscillatory movements all the time, resting against the wall of the cap with an outgrowth at the base of the abdomen. To clean the holes, pupae have strong bristles on the upper lip and cleaning processes at the rear end of the body. By the time of maturation, the pupa breaks through the front end of the cap with its powerful serrated jaws (unlike the larval ones, and even more so the practically absent jaws of adult caddis flies) and, emerging from it, begins to quickly swim on its back, like smooth bugs, making rowing movements long, equipped swimming hairs of the middle legs. Having reached a stone, shore or plant, the pupa clings to it and crawls out of the water. It is difficult to call a caddis fly pupa a “resting stage”, as insect pupae are often called!
In the air, the pupa begins to move its abdomen regularly, its spiracles open, its body swells, and the final molt occurs—an adult winged caddisfly emerges through a longitudinal slit on the dorsal side of the chest and head. Those caddis flies whose larvae do not live in covers build themselves covers before pupation. The lifestyle of the pupae is quite similar.
Hello friends! Today I want to continue the conversation about insects that are of great interest to anglers and I want to talk about such a popular insect among anglers as the caddisfly.
Probably many people remember from their childhood how they caught fish in clear water crawling houses, and the caddisfly reminds many of us of this very house, and few people at this moment imagine a butterfly that is usually small in size and not brightly colored, similar to night moths.
However, a caddisfly is such a butterfly, and crawling houses are caddisfly larvae that always live in water.
Caddisfly – (lat. Trichoptera) a detachment of insects with complete metamorphosis (transformation).
The life cycle of a caddisfly, unlike a mayfly, is complete and can be described by the following scheme: egg - larva (larva) - pupa (pupa) - adult insect.
The difference between the caddisfly and many butterflies is that its body and especially the front wings are covered with hairs, and not scales like those of butterflies. Hence the name Trichoptera: thrix - hair and pteron - wing.
Let's look at the development of the caddisfly in order. The female lays eggs in the water slightly differently depending on the species. Basically, females descend into the water from the shore or dive to the bottom and lay eggs there, but some species can do this on the surface of the water or plant, but in any case, caddis eggs fall to the bottom of the reservoir and larvae (larvae) emerge from them. 
The larvae of many caddisfly species live in houses that are built from sand, small pebbles, plant remains and other materials. These caddis flies are known to many anglers. Often such larvae are collected and fish are successfully caught with them, both in winter and summer. Few people know that some species of caddisflies build shelters among stones from silk threads secreted by special glands. And some species of caddisflies do not build any houses, but simply crawl between the stones.
And so we figured out that all caddisflies are divided into three groups: those that build houses, those that live freely and those that weave nets from silk threads, building shelters for themselves. In this regard, the features of their life and place of residence may differ.
I will not describe the life features of various caddisfly larvae so as not to clutter your brain; for those who are very interested in these features, you can find a lot of such information in works on entomology.
Regardless of the type of caddisfly, in order for a larva to develop into an adult insect, it must go through the pupal stage (pupa). Those larvas that had houses attach them to stationary objects in the water and plug the holes, and those that did not have houses have to build themselves shelters from sand and small pebbles.
After the caddisfly larva has taken refuge in its shelter, it begins to weave a silk cocoon. Then this cocoon hardens and inside it the larva transforms into an adult insect.
At this stage of metamorphosis, the larva grows wings and the body shape changes, as well as legs and antennae (antennae).
After an adult insect has formed in the cocoon, the caddis fly chews the cocoon and rushes to the surface of the water. At this moment, the caddisfly is still in a transparent shell, which bursts when it reaches the surface. In this state, the insect is very vulnerable and is eaten in large quantities by fish.
The emerging adult caddisfly insect rushes to the shore to a safe place.
An adult insect has two pairs of wings, which are covered with small hairs, as is the whole body. When the caddisfly is resting, the back pair of wings are located under the front ones, and the front ones are folded on the sides of the insect and cover it from above in the form of a house.
The antennae of the caddisfly are long and usually exceed the length of the body.
The caddisfly feeds on the nectar of plants on the shore, but every day they fly to the reservoir to drink water, where they fall into the mouth of a voracious fish.
The silhouette of all types of caddisflies is similar and usually has a brown color with various shades. Fly fishermen have long learned to copy the silhouette of an adult caddisfly, and the variety of flies is simply enormous.
Among them there are flies that are very popular, such as “ELK HAIR CADDIS”. I fished very successfully with this fly last season.
There is also a large number of flies that imitate all stages of caddisfly development, and not just the adult insect. Imitation of caddis fly is also successfully used in ice fishing.
, herbaceous plants (flowers) of ponds and swamps, aquatic invertebrates, freshwater and migratory fish, amphibians and reptiles
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pocket field determinant, including: inhabitants of reservoirs
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methodological benefits, among which 10 manuals are devoted to aquatic ecology and hydrobiology, and 40
educational and methodological films By methods carrying out research work in nature (in the field).
Caddis flies and their larvae
Caddis flies (Trichoptera) constitute a special order of insects. In the USSR there are currently more than 600 species, comprising 16 families.
Adult insects resemble moths in appearance. They are most often painted in different shades brown or gray and have a generally rather inconspicuous appearance. They fly little, often sitting on coastal plants. They usually stay near bodies of water, but sometimes fly quite far from them. When at rest, they fold their wings along their back at an acute angle, like the roof of a house. They have the ability to run quite deftly on the surface of the water. Like butterflies, they feed on flower sap. Many people do not eat any food as adults.
Adult caddisfly Glyphotaelius punctatolmeatus). Eating. led
Many of these insects have a characteristic, rather bad smell, depending on the secretion of skin glands, which is especially noticeable if you hold an adult specimen in your fingers. It is possible that this smell plays the role of a deterrent against the enemies of caddis flies, for example, birds.
Less common are larvae that do not have caps - most of the so-called campodeoid larvae, which differ from the previous ones in many features of their structure.
Cases of various caddisflies. (According to A.F. Wintergalter.)
1 - agrypnia (Agrypnia pagetana); 2 - large caddisfly (Phryganea grandis); 3 - Grammotaulius nitidus); 4, 5 - Glyphotaelius pellucidus; 6 - Platypteryx brevipennis; 7 - Limnophilus stigma; 8-18 - Limnophilus rhombicus and L. flavicornis; 19 - anabolia (Anabolia nervosa); 20 - Stenophylax stellatus; 21 - Stenophylax rotundipennis; 22 - quiver (Limnophilus vitattus); 23 - molanna (Molanna angustata); 24 - goera (Goera pilosa). Eating. led
Caddisfly larvae lead an aquatic lifestyle. They are found everywhere in large numbers - in rivers, ponds, lakes, streams, not excluding even the smallest bodies of water, such as never-drying ditches and puddles. These larvae are very interesting for their diverse biological characteristics and at the same time are easily observed in natural conditions at the bottom of reservoirs, are easily caught with a net, and live well in aquariums. Because of this, caddis flies are among the most important excursion objects, both for a quick acquaintance with them on excursions, and for long-term systematic observations of them in a laboratory setting.
Most larvae live in special cases - covers, which they build from a wide variety of materials. Both in shape and material, the covers are very diverse and in themselves can already serve as an object of excursion acquaintance.
The simplest form of covers is a reed tube into which the larva crawls using a ready-made room (Agrypnia pagetana Curt., 1).
A more complex structure is a tubular case made of individual pieces of leaves, which the larva gnaws and arranges in a spiral line (great caddisfly - Phryganea grandis L; 2). Sometimes the building material is arranged in a tile-like manner, and they are either pieces of reed (3, Grammotaulius), or pieces of leaves and fragments of bark (4, 5, Glyphotalius). Less commonly, plant remains are placed across the cover (Limnophilus stigma Curt., 7).
How diverse the building material of covers is is shown by the buildings of the most commonly found caddisfly species in our country - the rhombic caddisfly (Limnophilus rhombicus L.) and the yellow-whiskered caddisfly (Limnophilus flavicornis F.). For construction they use moss (8), and various blades of grass (9), and pieces of dead wood (10), and fresh wood twigs (11), and pine needles (12), and horsetail stems mixed with other plant debris (13 ); they attach small shells (13), sunflower husks (14), etc. to their home. Sometimes representatives of these species build their tubes not from plant remains, but from small shells, for example, peas (15), small coils , young meadows and other mollusks (16, 17, 18).
From this it can be seen that it is possible to identify larvae by the material of buildings only to a certain extent. Great importance has an architectural shape of the cap, which is very typical in some genera (Phryganea, Molanna), but it gives only an approximate idea of what species the observer is dealing with.
Species of caddisflies that live in fast-flowing waters build cases from large and small grains of sand (Stenophylax, 20 and 21). Sometimes these mosaic buildings have the shape of a wide flat shield, over the surface of which water slides freely without turning the cover over or tearing it out of place (Molanna, 23). The anabolia larva (Anabolia, 19) attaches heavy twigs and sticks to the sand tube, which in fast-flowing water most likely play the role of a kind of anchor. The goer larva (24) attaches 2-3 pebbles to a sandy flattened tube.
Two types of caddisfly larvae. Natural vel. 1 - large caddisfly (Phryganea grand), the gills of the larvae are depicted in an elevated state - in a living larva they are pressed to the body; 2 - larva that does not build caps, campodeoid in shape (Holocentropus diiblus).
It is clear that the case is wonderful protective device for larvae. He gives them a safe, strong shelter. In addition, this shelter, built from materials from the surrounding environment, is well camouflaged among other underwater objects. It’s remarkable that some forms of covers seem to copy underwater objects. Thus, the cap of the caddisfly Limnophilus stigma strikingly resembles an alder fruit that has fallen into the water. Such protection is all the more necessary for caddisflies because their larvae serve as tasty food for many predators and are especially readily eaten by fish. This has long been known to fishermen, who use these larvae for baiting hooks.
At first glance, the cover appears to be a bulky, unconvenient structure. However, a closer look reveals that this is not the case. One should not lose sight of the fact that the cover, according to Archimedes’ law, weighs very little under water, and in cases where the building material is close to specific gravity water, the cover is completely weightless. Thanks to reliable web fastenings, the walls of the case are very strong, which is easy to see for anyone who tries to tear it. The heterogeneous material from which the walls of the covers are made are fitted to each other with remarkable skill. All this makes caddisfly larvae one of the first-class builders in the insect world. The basis of the structure is very strong silk threads, with the help of which caddis flies bind and connect various building materials. These arachnoid threads are spun by the larvae from the secretions of a pair of long arachnoid glands, which open through a common duct on the lower lip and are built in exactly the same way as in caterpillars. The inside of the tube is completely covered with a delicate arachnoid lining.
As you grow the larva builds up the anterior edge of its cap, making it wider; the rear end, which has already become narrow, gradually breaks off or is nibbled by the larva.
If you take the larva out of its case (in an aquarium), it looks extremely helpless, tries to hide under various objects, and after a while begins to build itself a new case. Not finding the usual material, the larva also uses building particles that are new to it. So, for example, you can force larvae, removed from cases that were made from plant debris, to build new homes from scraps of colored paper, sawdust, eggshells, even staniol, etc. For larvae that build cases from grains of sand, we tried with It is successful to offer small beads, crushed glass, crushed bricks, and metal filings.
Let us now follow the movements of the larva, choosing for this some close-up view, for example, the large caddis flies we often encounter - large or striped (P. grandis and P. striata).
The larva captured by the net during fishing hides in its case and lies completely motionless, so that when analyzing the contents of the net it is easy to view it, mixed with the stems of aquatic plants. Place the caught larva in a flat vessel (plate with water). Here she will soon expose the front end of her body from the case and begin to crawl along the bottom of the vessel, dragging her home behind her. At the same time, you can see that the head, the first segment of the chest, covered with a hard shell, and three pairs of long legs protrude from the cover. If you expose the larva to some stems or sticks, you can see how tenacious its limbs are: it can crawl in a variety of positions on both the top and bottom sides of underwater objects.
Caddisfly larvae removed from their cases. Eating. led 1 - Phryganea; 2 - Odontocerum alblcorne; 3 - Helicopsyche sperata.
Let's try to remove the larva from its shelter. It is easy to see that it offers great resistance: if you pull it out of the tube, holding it by the front end of the body, it is easier to tear it than to free it from the cover. Meanwhile, the case seems quite spacious in comparison with the size of the larva’s body, and at first glance, the force with which it lingers in its tube is incomprehensible.
To show what’s the matter, let’s try to expel the larva from the cap in another way: we insert a thin stick or straw through the rear hole of the cap and disturb the larva from the rear end of the abdomen. This technique makes her crawl out.
When examining, first of all, you should pay attention to the difference in the density of the cover that covers the protected (case) and unprotected part of the larva’s body. Under the cover of the cap there is an abdomen, consisting of ten segments, and a posterior (third) thoracic segment. These parts are covered with soft skin. On the contrary, the first two segments of the thorax, which the larva exposes from the cap when crawling, are highly chitinized and have a much darker color. The significance of this phenomenon is completely understandable, especially if we recall a similar difference between the protected and unprotected part of the body in other animals, the classic example of which is the famous hermit crab.
The devices with which the larva is firmly held in its shelter when attempts are made to extract it by the head end are instructive. At the posterior end of the abdomen it has a pair of appendages, which are equipped with strong sharp hooks, the tips of which are directed in opposite directions. With the help of these hooks, the larva hooks onto the inner walls of the case, acting like a pair of hooks. In addition, on the third segment of the chest, which is adjacent to the outer edge of the cap, there are three warty projections. The latter can protrude strongly and, in turn, resting against the walls of the case, prevent the larva from falling out of its shelter.
Campodeoid-shaped larvae, which do not build caps, have a completely different body shape than those described above. Their body is laterally compressed and does not have a pair of hooks at the rear end.
Breath. Already a cursory examination of the naked larva reveals that its round, oblong, caterpillar-like body is covered with whitish thread-like outgrowths. These are nothing more than the gills of a larva, which is protected by a cap. The gill apparatus requires a constant change of water. This is achieved by the fact that the larva sitting in the cover makes peculiar movements with its abdomen, thanks to which a constant flow of water is established through the cover. Hence the meaning of the second hole at the rear end of the cover, through which water is pushed out during breathing, is also clear. The writhing of the abdomen can also be observed on a naked larva if you put it in a vessel with water. Similar movements are also produced by larvae of the campodeoid type, which do not build a cap.
Eating caddisfly larvae mainly by plant matter, such as leaves of aquatic plants.
Larvae belonging to the families of phryganeids and limnophilids are herbivorous forms: They are quite voracious and can eat an amount of food per day equal to their own body weight or even slightly more (in young larvae). Larvae from the molannid family are predators that feed on daphnia, chironomid larvae, etc. (Kolenkina, 1951). However, there have been cases where the larvae of large caddis flies attacked water donkeys, frog tadpoles, and even each other. In aquariums, caddisfly larvae can be successfully fed with lettuce leaves.
Campodeoid-shaped larvae for the most part lead a predatory lifestyle and build special trapping nets woven from thin spider threads to catch prey. Such nets, shaped like funnels, are placed with a wide opening against the current and are attached motionless to aquatic plants, stones and other underwater objects. This is a kind of device for catching mayfly larvae, small crustaceans and similar living prey.
Reproduction and development. Along with the crawling larvae, on an excursion you can often find caps, which caddis flies are sealed with sieve-like caps at both ends (Fig. on the right). These are pupated caddis flies that weave the openings of their cases with cobwebs, leaving a free passage for water, but protecting themselves from predators. Typically, pupation occurs in the larvae in the spring, in our latitudes in May (large caddisfly) or June (larvae with sandy caps). Adult insects emerge in about a month.
If you were able to find such a sealed case during the excursion, you can open it to examine the pupa enclosed inside, if it has already formed. The pupa is completely different from the larva and has a very unique appearance (Fig. 240). She has the rudiments of wings, very long antennae, big eyes and huge mandibles, with the help of which she leaves further development its shelter, destroys the lid of the case. Thin thread-like gills are visible on the abdomen.
Limnophilus caddis fly pupa. Eating. led
The pupa is equipped with long swimming legs. At the rear end of the pupa's body there are long bristles, with which it cleans the hole in the sieve-like cap, which is easily clogged with silt, and thereby provides access to fresh water. The opening of the anterior sieve lid is cleaned with the help of bristles sitting on the upper lip, and also, perhaps, with the help of elongated jaws.
Using this apparatus, the doll makes rhythmic pendulum-like movements inside the case. The mature pupa leaves its shelter, gnawing through the cover. It is remarkable that within a few minutes after being released from the cap, it floats freely on the surface of the water. Here it sheds its skin and turns into an adult caddisfly, which soon rises into the air.
It should be noted that the interesting phenomenon of short-term swimming of the pupa, as well as the process of hatching of an adult insect, can be observed extremely rarely on excursions. This phenomenon requires close, aquarium observations. But relatively often you have to catch it with a net from waters of the dead completely mature pupae without a case. This is explained by the fact that the pupa emerging from the case quickly dies if it does not find a way out of the water. In addition, pupal skins are often found floating on the surface of the water. 
Eggs of various caddisflies: spiral, ring-shaped and finger-shaped (Triaenodes, Phryganea, Glyphotaelius). Eating. led
Caddis flies (lat. Trichoptera) are a detachment of insects with complete transformation, with exclusively aquatic larvae. The order Trichoptera includes 13,574 species, grouped into 45 families and about 600 genera, widely distributed on all continents except Antarctica and on many oceanic islands. It is estimated that the world's fauna may contain up to 50 thousand species of caddisflies.
Adult insects resemble small, dimly colored moths, but their body and especially the front wings are covered with hairs. In some species, females go underwater to lay eggs. They are usually found in the vicinity of water bodies where their larval stages live. The transformation is complete. The larvae and pupae of the vast majority of species live in water or live in the thickness of the bottom of reservoirs; in rare cases, they constantly live outside the water or live near the coast in sea water.
Caddis flies are easily recognized by a number of characteristics. The oral apparatus of adults is reduced, with the mandibles (upper jaws) non-functional or vestigial, but the maxillary (mandibular) and labial (labial) palps may be visible. In addition, adult insects have a well-developed proboscis, used by some species to absorb liquids.
The antennae are thread-like, usually comparable in length to the fore wings, sometimes noticeably shorter or much longer.
The wings are membranous, developed on the mesothorax and metathorax. The front ones are longer than the rear ones. Like the body, they are covered with hairs; sometimes areas of the wings may be covered with bristles. Along the edges of the wings, a marginal fringe of hairs or hair-like scales is developed; the size of this fringe is small species may be more than 2 times the width of the hind wing.
The larval stages of caddisflies are aquatic, found in lakes, rivers and streams around the world and are essential components of food chains in these freshwater ecosystems. Adult caddis flies, unlike larvae, are terrestrial, eat almost no food, and their lifespan is limited to one to two weeks. Many of these insects have a characteristic unpleasant odor caused by the secretions of specific glands. This scent can serve as a repellent to caddisfly enemies, such as birds.
After fertilization, the female caddisfly lays eggs glued together with a mucous mass, attaching them to underwater rocks or plants. The larvae emerge from the eggs after three weeks. Like most fully metamorphosed insect larvae, they have well-developed mandibles and well-developed thoracic legs, but abdominal limbs are usually absent (except for a pair on the last abdominal segment, each leg may bear a strong "anal claw"). The transformation of a larva into an adult insect occurs through the pupal stage.
Almost all Trichoptera larvae build a case or house. The simplest form of covers is a reed tube. A more complex structure is a tubular case made of individual pieces of leaves, which the larva gnaws out and arranges in a spiral line. Depending on the type of caddisfly construction material may vary. Sometimes the building material is arranged in a tile-like manner, and they are either pieces of reeds, or pieces of leaves and fragments of bark.
To build their cases, caddisflies use moss, blades of grass, pieces of dead wood, fresh wood twigs, pine needles, horsetail stems mixed with other plant debris; they attach small shells and sunflower husks to their home. Sometimes the buildings may not be made from plant remains, but from small shells, for example, peas, small coils, young meadows and other mollusks. In case of danger, the larvae climb into their house and plug the entrance to it with their heads, covered with chitin armor.
Less common are larvae that do not have caps - the so-called campodeoid larvae. Such larvae are mainly predators, building special trapping nets from thin cobweb threads. Such nets, shaped like funnels, are placed with a wide opening against the current and are attached motionless to aquatic plants, stones and other underwater objects.
The larva pupates underwater in a case constructed by it. The pupa has the rudiments of wings, very long antennae, large eyes and huge mandibles, with the help of which it destroys the cap. Thin thread-like gills are visible on the abdomen. The pupa may be equipped with long swimming legs. At the rear end of the pupa's body there are long bristles, with which it cleans the hole in the sieve-like cap, which is easily clogged with silt, and thereby provides access to fresh water. The opening of the anterior sieve lid is cleaned with the help of bristles sitting on the upper lip, and also, perhaps, with the help of elongated jaws. To exit the imago, the pupa floats to the surface, rowing its middle legs like oars. Adult insects emerge in about a month.
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Fishermen call caddis flies the larvae of numerous butterflies that live in the floodplains of rivers and lakes, according to the “fishing” literature. But let's be clear.
The larvae, which are attributed to being related to butterflies, Lepidoptera, Glossata (third order of insects), actually belong to the lacewings, Neuroptera (fifth order of insects). It is worth saying a little more about this interesting order of insects, at least with quotes from Bram. So, according to Bram, “retinoptera are those insects that can withstand complete metamorphosis, have biting mouthparts, a free prothorax, and uniform leathery fore and hind wings.” Bram notes that representatives of this small order are difficult to distinguish not only from each other, but also from representatives of the order Orthoptera (sixth order, Gymnognatha, Orthoptera).
Of particular interest to us are individuals of the family of midges and brooms (Phryganeodea). The wings of these insects are covered with hairs, scales, or simply mesh. Their mouth parts are reduced. These spring “flies” are similar to each other, in basic features, in their lifestyle, and most importantly, in their development pattern. In May–June, adult insects fly directly near water bodies. They move mainly in the dark. IN daytime adult insects prefer to sit out on aquatic plants, on boards, coastal alluvial debris, and more often - behind the flaps of old bark on logs. Insect larvae almost always live in aquatic environment in cocoons or “houses” they themselves built. The name Shitiki appeared by analogy with Diptera, the dorsal part of which (three knees) is called the dorsal shield.
To build shelters, larvae use a wide variety of materials: just sand, the “remains” of plants, quite large pebbles, pieces of shells of small shells, small twigs and last year’s rotted leaves. It has been noticed that larvae of different species build their homes in the same natural conditions from similar materials. The main material, depending on the area, can even be plant seeds. Each type builds, regardless of source material, a cocoon of the same shape.
The larvae in their “fortresses” survive winter and spring, attaching themselves together with the house to the threads of aquatic plants, closing the inlet and outlet holes (in stagnant cold water bodies this also happens in the middle of summer).
After several weeks have passed after the water warms up, a nymph emerges from the larva, and after a while an adult winged insect appears.
Caddis flies, which are of interest to anglers as insect larvae, usually have a two-year development cycle before becoming an adult insect. Therefore, they can be found at any time of the year. It should only be taken into account that at the end of August, with the beginning of the night cooling of the water, the larvae move to a depth of 1.5–2 m. This significantly complicates their extraction, but the game is worth the candle, since it is with the descent into depth that the larvae become more accessible to large fish, and therefore, more important as bait.
Literary advice regarding the effectiveness of using caddis flies in winter seems very doubtful to me personally. Repeatedly on the reservoirs of the Novgorod and Tver regions, I observed local “masters” hunting caddisflies with the help of spears and brooms, but in a conversation with them it turned out that their goal was not caddisflies, but amphipod jigs. However, based on my own fishing experience, I can safely say that using caddisfly as bait invariably leads to positive results when catching almost all types of fish - both in those reservoirs where caddisfly is found, and in those reservoirs where it has never been possible to catch it .
WITH childhood Having read the then few “fishing” publications, I repeatedly tried to put into practice the advice on ways to preserve caddisfly larvae. If this is interesting, then I inform you that I have not met a more capricious animal bait than the caddisfly. I think the whole problem with storing caddis flies is temperature. Firstly, larvae cannot be stored directly in water. The realistic amount you can store bait in is approximately 100-300 ml (g) of water. In order to maintain the necessary isothermal conditions in such a quantity of liquid, you need to have at least a liquid thermostat with adjustment to the second class of accuracy, which, alas, is not very realistic in our everyday practice. Theoretically, this is, of course, possible, but practically... However, try it. There is another option - to introduce the larvae into a state close to suspended animation, that is, try to keep them at a temperature of about 4 °C (taking into account temperature depression). But then you will inevitably come into conflict with your loved ones who want to take out of the home refrigerator in the morning not your bait, but butter and sausage, ready for immediate consumption.
For summer fishing, it is best to stock up on caddis flies for a day, storing the remainder in damp cloth somewhere in the shade. In winter, I simply don’t bother with caddis flies, since the time spent catching them significantly exceeds the time spent on fishing itself. The caddis is one of those reliable baits whose actual use turns fishing into bait fishing. The principle is that every vegetable has its time and every bait has its own fish. in this case is being fully implemented.
The only place where I always and in any conditions use caddisfly as bait is all the reservoirs around the city of Valdai, in the Novgorod region.
By the way, it has been noticed that if the caddisfly stays at a depth of up to a meter, then large fish also go to the upper shore edge to feed, and if the larvae can only be caught at depth, then there is no way to fish in places where the depth is less than 3–4 m sense.
Now a few words about what size and color of caddis fly it is best to use as bait. I found the final answer to this question by analyzing the results of my numerous fishing trips on the lakes of the Valdai Upland. Regardless of the size and type of fish you intend to catch (be it roach weighing from 20 to 300 g, ide weighing from 70 g to 3 kg, bream weighing from 50 g to 1,600 kg, crucian carp weighing from 200 to 300 g, perch weighing from 15 g to 2 kg), it is preferable to use the largest larvae as bait. As for color, preference is given to caddis flies of greenish and brownish shades. This is obvious because the larvae of the indicated shades are the most common.
