At the bottom of many fresh water bodies - clean, fast streams and overgrown ponds - you can find amazing creatures that live in tubular houses, built by them from various small particles lying on 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, this structure is 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 of aquatic plants, etc. The “building material” is firmly fastened with cobweb threads. These houses are built by caddisfly larvae.
Adult caddisflies are rather delicate insects that look like hairy moths (Fig. 310). It is easiest to distinguish a caddisfly from a butterfly by its wings - in butterflies, the wings are covered with scales, and in caddis flies, with hairs. At rest, their dark-colored wings are folded roof-like on their backs. The head is rather large with compound eyes and usually with 3 simple ocelli between them.
The antennae are long, filiform, the mouth organs are reduced, in particular, there are no mandibles at all, and the rest of the mouth 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 rather slender. These generally inconspicuous nondescript insects fly reluctantly and sluggishly.
After mating, the female caddisflies lay gelatinous lumps of eggs - "caviar" - in the water. The eggs hatch into larvae, which, in most species, right off the bat begin to build themselves a cobweb cover from a silk thread secreted by modified salivary glands. The case is encrusted with suitable small particles lying on the bottom and accessible to the larva. The inclusion of hard objects in the case makes it stronger and stronger. And reliable protection is necessary for the caddis larva. The fact is that she never leaves the water and breathes with the entire surface of the skin of the entire elongated abdominal part of the body. The abdomen of caddisfly larvae has not only very thin, easily permeable (and if so, easily vulnerable) integuments, but often also has numerous even more delicate gill outgrowths that increase the surface of gas exchange with water. Bunches of gills are also on the back of the chest.
If everything is calm around, the larva crawls along the bottom, carrying a little house on itself. When moving, the larva protrudes its head and thoracic region from its sheath, on which there are 3 pairs of rather long and tenacious legs protruding 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 covers. The head of caddisfly larvae is amazing - it has no antennae. In larvae of different insects with complete metamorphosis, the antennae are of different lengths, but rarely they are reduced to such an extent that they become completely indistinguishable, as is the case with 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 mouth apparatus of the larvae, in contrast to the adult caddis flies, is well developed, it is gnawing. The larvae feed on both plant food, scraping off soft tissues with serrated jaws, and animal food. The sheath serves the caddisfly larva not only as a permanent armor protecting the abdomen, but also as a refuge: in case of danger, the larva is all drawn into the “house”, the inlet to which closes 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 a case. Holding the house with hooks, the larva drags it along without losing it and only completing it as it grows.
What larvae of caddis flies are easy to meet in our reservoirs?
In fast streams with cool water and a rocky bottom under the stones, it is easy to find tubular houses. stenophile(Stenophylax stellatus), constructed from large grains of sand neatly attached to each other (Fig. 311, 1). The larva easily raises its house, the front edge of which hangs like a hood over the head of the larva, making it invisible to the fish swimming from above. If the cover of the larva is damaged, it immediately tries to fix it, picking up grains of sand of the required size with its front legs. She adjusts them to the damaged edge of the case, discards those that are less tight, trying and selecting the most suitable ones. The larva glues the grains of sand with saliva that solidifies into a silky thread, repeatedly covers them with threads, connecting the grains of sand with 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 thrown instead of sand, it will make a house for itself from small bright beads. The larvae of stenophila feed on both plant and animal food.
In lakes into which streams flow, larvae live on the bottom in more open places. apathy(Apatania). Their houses are shaped like a horn (Fig. 311, 4). Larger grains of sand are embedded on the sides of the apatania house.
In shallow sandy places, the larvae make their houses built from grains of sand. molanny(Molanna angustata). The molanna has a house, when viewed from above, wide and flat. The central tubular part, in which the larva sits, is made of larger grains of sand, but wings of smaller grains of sand and the same hood are attached to it on the sides. On the whole, the cap looks like a rather large shield, its length is more than 2 cm (Fig. 311, 5). The mollanna larva moves with its cap in jerks.
Larvae are kept in dense thickets of plants freeganey(Phryganea), making their tubular houses from gnawed quadrangular, like short planks, pieces of plants (Fig. 311, 5). Often such houses even retain their green color - pieces of aquatic plants in the 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 house-tube is open, and if the larva is pushed out of the case, it will quickly run over its surface and deftly dart into it from the rear end. Freeganea is a large insect, the length of an adult larva is about 4 cm. Although the larvae of freegans, 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 solid small objects lying on the bottom. There may be small swollen sunken sticks, and small shells of mollusks, and needles, and other plant remains, but pebbles and grains of sand are not used by limnophiles. If the limnophila larva is driven out of the house and the house is removed, it, releasing sticky spinning threads and twirling 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 choosing strong particles and fitting them well together.
Common in North America snail caddis flies(family Helicopsychidae), making spirally twisted cases for themselves, so similar to snail shells (Fig. 311, b) that even zoologists, before confidently saying what they met - a shell or a caddis house, should look very carefully.
Although the larvae of caddisflies are very well adapted to life in water, nevertheless, among the forms that build caps, there are those that left the aquatic environment and switched to life on land. Such land caddisfly(Enoicyla pusilla), living in the beech forests of Western Europe (Fig. 312). Interestingly, the females of this caddisfly are wingless. The larvae of the land caddisfly live in the litter and among the moss that covers 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 caps is characteristic of 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 rivers, in thickets of pondweeds and other aquatic plants, there are delicate, barely noticeable transparent tubules attached to aquatic plants (Fig. 313).
They oscillate with streams of measuredly flowing water. Usually there are many such tubes in one place - a whole cluster. Make their larvae neuroclip(Neureclipsis bimaculata) from family polycentropids(Polycentropidae). If you transfer these tubular formations to stagnant water, for example, place them 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 really is a network - a network remarkably woven, with small cells of the same type. These tubular nets are weaved by narrow, long larvae that live without a sheath and do not have gills. Larvae (Fig. 314) build themselves not houses in flowing water, but nets - trapping nets, into which small crustaceans, mayfly larvae and other animals carried by the current, fall prey to the neuroclips. In the water, the predatory larva of this caddisfly catches prey in the same way as web spiders do on land!
In large flat rivers - in the waters of the Volga, Don, Dniester - many caddis flies develop hydropsychide(family Hydropsychidae). Hydropsychid larvae make a net with rectangular cells, while they themselves sit side by side in a light case made of thin threads (Fig. 315).
As soon as a small crustacean or an insect gets into the net, predatory larvae (their size reaches about 2 cm) jump out of the shelter and grab the prey with their strong jaws!
In the form of bags (Fig. 316), trapping nets of the larvae are made plectrocnemia(Plectrocnemia). Interestingly, such specialized catchers of aquatic prey as hydropsychids and plectronemias can also go on land. At a distance of tens of meters from streams, these larvae were found 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 even in water. Beautiful greenish-blue larvae crawling along the rocky bottom of clear cold streams riacophilus(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 feet and attachment hooks at the posterior end of the abdomen and wait for prey. The fact that larvae of riacophiles have strong jaws directed straight ahead helps the larvae to grasp prey quickly, like in 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. And adult caddis flies do not feed, only multiply, and all lead a similar lifestyle. Therefore, it is clear that it is relatively easy to recognize caddisfly larvae (not only the way of life is different for different species, but also the structure of individual parts of the body is not the same), and only entomologists who specifically study them can recognize species of adult caddisflies.
Acquaintance with caddisflies also shows that not only the study of the structure of different parts of the body of animals makes it possible to distinguish and recognize them well, but also behavior (which is expressed, for example, in the construction of covers of one form or another) can be used by taxonomists as a reliable feature. This was first noticed by the founder of comparative zoopsychology, the Russian zoologist V. A. Wagner.
There are many peculiar things in the life and development of caddis flies. In most insects with complete metamorphosis, the pupa is almost immobile, and if the larva and the adult insect live in different environments, the larva, before pupation, makes it easier for the adult insect to get into favorable conditions for it, for example: such larvae adapted to life in water as the larvae of swimming beetles, before pupation, they emerge from the water and burrow into the ground. Otherwise, caddisflies behave. With them, the pupa begins its life in a case built 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 turning into an adult insect, takes place in the air.
The pupa of caddisflies is free (Fig. 317). In general, this is the same stage adapted to life in water as the larva. The life of the pupa can be easily traced by the example of the stenophile, from which the acquaintance with caddisfly larvae began. Before pupation, the larva chooses a quieter part of the reservoir and, attaching the cap to the 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 all the time oscillatory movements, resting against the wall of the cap with an outgrowth on the base of the abdomen. To clean the holes, the pupa has strong bristles on the upper lip and cleansing processes at the posterior end of the body. By the time of maturation, the pupa breaks through with its powerful toothed jaws (not similar to the larval, and even more so to the practically absent jaws of adult caddisflies) the front end of the cap and, leaving it, begins to swim quickly on its back, like smooth bugs, making rowing movements long, equipped with swimming hairs on middle legs. Having reached a stone, shore or plant, the chrysalis clings to it and crawls out of the water. It's hard to call a caddis pupa a "resting stage" as insect pupae are often called!
In the air, the pupa begins to gradually move its abdomen, its spiracles open, the body swells and the last molt occurs - an adult winged caddis flies emerges through a longitudinal slit on the dorsal side of the chest and head. Those caddisflies, whose larvae do not live in caps, construct caps for themselves before pupation. The way of life of pupae is quite the same.
The bottom of many clean fresh water reservoirs is covered with insects resembling a night one. They belong to a special order of insects and are called caddisflies.
Adult caddisflies bear a striking resemblance to the nocturnal moth. Scientists have long been interested in these strange creatures. They described more than a thousand of their species, which were divided into dozens of families and hundreds of genera, and spread over the entire earth's surface, with the exception of the cold climatic conditions of Antarctica and some oceanic islands.
Features and habitat of the caddisfly
An adult caddisfly in all its external features resembles a night butterfly with a soft gray and brown color. On the front wings of this insect there are small hairs, it is thanks to them that the caddis flies differ from.
Butterflies have scales on their wings instead of hairs. On the photo caddisfly and also in real life absolutely nothing attractive. Its wings in a calm state are roof-like folded on the back.
A rather large head with eyes and rather long whiskers, similar to threads, stands out well against this background. Special attention should be paid to the eyes of this creature. He has more of them than the usual norm for everyone - 2 compound eyes on the sides of the head and 2-3 auxiliary ones, which are located at the top or in front of the head.
Instead of a mouth caddis insect a proboscis with a tongue was formed. The whole head is covered with warts, which do not create a very pleasant sight. Their paws are slender and not very strong.
They can be seen anywhere and everywhere. Your name fly caddisfly received because he prefers to live in shallow and clean water bodies. They are comfortable in streams, ponds, lakes, and in some cases in swamps, but not too polluted. A clean environment is very important for squad of caddisflies.
Mating process of caddisflies
Caddisfly larvae very reminiscent of children of mayflies and the fact that, during their development, they are also forced to live in water. In order to make it convenient for them to live there, they build houses for themselves, which are practically one with their body.
This cocoon is firmly attached to the insect larva. They have to move around with this house on themselves. Anyone who has tried to extract a larva from its hiding place knows that this is a difficult task.
And at the same time, it is impossible to maintain its integrity at all. But there is a secret how to lure him out of there. It is enough just to fit it from behind with something sharp and thin. In order to build a house for the larva, a variety of building materials are used, even broken glass.
An unusual experiment was carried out. They took a caddisfly larva, placed it in a clean pond, where, apart from the larva, clean water and broken glass, there was nothing. The larva had no choice but to build a glass house for itself.
Pictured is a caddis larva in a cocoon
Learned an original, creative and comfortable home. Such a transparent house made it possible to observe how water constantly passes through the gills of the larva. Gills in the form of white threads are located on the back and side of this interesting creature. Whatever the dwelling of the larva of this insect, it always has the shape of a tube.
There is a variety of dwellings in the form of a horn or a spiral. Caddisfly larvae slowly move along the bottom of the reservoir along with their house, sticking their heads out of it to see everything around.
And at the slightest danger, the head hides in the house and the movement stops. The house itself is made of materials that simply merge with the bottom and become completely invisible. Every living being needs oxygen. How does the caddis larva solve this problem? Everything is very simple and at the same time clever.
They build their houses from plants in which the process of photosynthesis is constantly taking place and thus, merging in work with their house, provide themselves with the oxygen that is so necessary for their life.
Mormyshka caddisfly is the lightest and most common bait among many fishermen. It is versatile and easy to obtain. Good caddis fly fishing falls between mid-May and mid-June.
This is when the larvae are the largest. After this time, the larvae turn into pupae, and later into "butterflies", which are called caddis fly. In winter, getting a caddisfly from the bottom of a reservoir is a little more difficult.
It is necessary to drill a hole and lower a broom of birch twigs into it, onto which all the caddis larvae will crawl. They are stored for a long time in an ordinary jar of clean water.
The nature and lifestyle of the caddis
Adult caddisflies live in reeds and grass on the banks of water bodies. In the evenings they create massive flocks and fly out to mate. These flights are rather large and take them a long distance from their place of permanent residence. The distance can be a kilometer or more.
Adult individuals, when the slightest danger arises, emit an unpleasant fetid odor, with which they try to scare away and protect themselves from possible danger. This smell can be heard even if you just pick them up.
Types of caddis
On the earthly planet, there is simply a huge number of different types of caddis flies. They differ in their external data, habitat, character and even nutrition.
For example, not all caddisflies are as harmless as they seem. There are also those who, in search of food, can envelop a large body of water with their silk patch, into which not only small insects, but also other inhabitants of the underwater world come across.
Each species has its favorite place of residence. Some people like quiet clean backwaters, others like the bottom of a fast-flowing mountain river. Accordingly, their size and color are completely different.
Caddisfly nutrition
Most of all, caddisflies eat the green pulp of aquatic plants. Those predatory caddis flies who, in order to get their own food, use the help of their web, love various small insects, and. These caddisflies have a very well developed jaw, which helps them cope with prey.
Reproduction and life span of the caddis
The life of an adult insect is not long. It lasts one or two weeks. The life cycle of the caddisfly is divided into four stages. Its development begins with an egg, which turns into a laurel. It passes into the navel and into the limbs into a mature caddisfly.
Fertilized females lay their eggs in a variety of ways, depending on their species and habitat. Most often, eggs are laid on the surface of aquatic plants that originate at the bottom of water bodies.
Over time, thanks to dew and raindrops, they gradually sink to the very bottom, and after 21 days, caddisfly larvae form from these eggs. The sticky gel protects the eggs from all environmental factors. They gradually swell and turn into laurels, which outwardly resemble thin and elongated worms.
Gradually laurels grow and turn into pupae. After 30 days, adult caddis flies emerge from the pupae. Caddisflies are useful not only because they serve as excellent bait for fishing. These beneficial insects feed on most freshwater fish.
At the bottom of many fresh water bodies - clean, fast streams and overgrown ponds - you can find amazing creatures that live in tubular houses, built by them from various small particles lying on 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, this structure is 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 of aquatic plants, etc. The “building material” is firmly fastened with cobweb threads. These houses are built by caddisfly larvae.
Adult caddisflies are rather delicate insects that look like hairy moths (Fig. 310). It is easiest to distinguish a caddisfly from a butterfly by its wings - in butterflies, the wings are covered with scales, and in caddis flies, with hairs. At rest, their dark-colored wings are folded roof-like on their backs. The head is rather large with compound eyes and usually with 3 simple ocelli between them.
The antennae are long, filiform, the mouth organs are reduced, in particular, there are no mandibles at all, and the rest of the mouth 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 rather slender. These generally inconspicuous nondescript insects fly reluctantly and sluggishly.
After mating, the female caddisflies lay gelatinous lumps of eggs - "caviar" - in the water. The eggs hatch into larvae, which, in most species, right off the bat begin to build themselves a cobweb cover from a silk thread secreted by modified salivary glands. The case is encrusted with suitable small particles lying on the bottom and accessible to the larva. The inclusion of hard objects in the case makes it stronger and stronger. And reliable protection is necessary for the caddis larva. The fact is that she never leaves the water and breathes with the entire surface of the skin of the entire elongated abdominal part of the body. The abdomen of caddisfly larvae has not only very thin, easily permeable (and if so, easily vulnerable) integuments, but often also has numerous even more delicate gill outgrowths that increase the surface of gas exchange with water. Bunches of gills are also on the back of the chest.
If everything is calm around, the larva crawls along the bottom, carrying a little house on itself. When moving, the larva protrudes its head and thoracic region from its sheath, on which there are 3 pairs of rather long and tenacious legs protruding 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 covers. The head of caddisfly larvae is amazing - it has no antennae. In larvae of different insects with complete metamorphosis, the antennae are of different lengths, but rarely they are reduced to such an extent that they become completely indistinguishable, as is the case with 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 mouth apparatus of the larvae, in contrast to the adult caddis flies, is well developed, it is gnawing. The larvae feed on both plant food, scraping off soft tissues with serrated jaws, and animal food. The sheath serves the caddisfly larva not only as a permanent armor protecting the abdomen, but also as a refuge: in case of danger, the larva is all drawn into the “house”, the inlet to which closes 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 a case. Holding the house with hooks, the larva drags it along without losing it and only completing it as it grows.
What larvae of caddis flies are easy to meet in our reservoirs?
In fast streams with cool water and a rocky bottom under the stones, it is easy to find tubular houses. stenophile(Stenophylax stellatus), constructed from large grains of sand neatly attached to each other (Fig. 311, 1). The larva easily raises its house, the front edge of which hangs like a hood over the head of the larva, making it invisible to the fish swimming from above. If the cover of the larva is damaged, it immediately tries to fix it, picking up grains of sand of the required size with its front legs. She adjusts them to the damaged edge of the case, discards those that are less tight, trying and selecting the most suitable ones. The larva glues the grains of sand with saliva that solidifies into a silky thread, repeatedly covers them with threads, connecting the grains of sand with 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 thrown instead of sand, it will make a house for itself from small bright beads. The larvae of stenophila feed on both plant and animal food.
In lakes into which streams flow, larvae live on the bottom in more open places. apathy(Apatania). Their houses are shaped like a horn (Fig. 311, 4). Larger grains of sand are embedded on the sides of the apatania house.
In shallow sandy places, the larvae make their houses built from grains of sand. molanny(Molanna angustata). The molanna has a house, when viewed from above, wide and flat. The central tubular part, in which the larva sits, is made of larger grains of sand, but wings of smaller grains of sand and the same hood are attached to it on the sides. On the whole, the cap looks like a rather large shield, its length is more than 2 cm (Fig. 311, 5). The mollanna larva moves with its cap in jerks.
Larvae are kept in dense thickets of plants freeganey(Phryganea), making their tubular houses from gnawed quadrangular, like short planks, pieces of plants (Fig. 311, 5). Often such houses even retain their green color - pieces of aquatic plants in the 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 house-tube is open, and if the larva is pushed out of the case, it will quickly run over its surface and deftly dart into it from the rear end. Freeganea is a large insect, the length of an adult larva is about 4 cm. Although the larvae of freegans, 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 solid small objects lying on the bottom. There may be small swollen sunken sticks, and small shells of mollusks, and needles, and other plant remains, but pebbles and grains of sand are not used by limnophiles. If the limnophila larva is driven out of the house and the house is removed, it, releasing sticky spinning threads and twirling 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 choosing strong particles and fitting them well together.
Common in North America snail caddis flies(family Helicopsychidae), making spirally twisted cases for themselves, so similar to snail shells (Fig. 311, b) that even zoologists, before confidently saying what they met - a shell or a caddis house, should look very carefully.
Although the larvae of caddisflies are very well adapted to life in water, nevertheless, among the forms that build caps, there are those that left the aquatic environment and switched to life on land. Such land caddisfly(Enoicyla pusilla), living in the beech forests of Western Europe (Fig. 312). Interestingly, the females of this caddisfly are wingless. The larvae of the land caddisfly live in the litter and among the moss that covers 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 caps is characteristic of 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 rivers, in thickets of pondweeds and other aquatic plants, there are delicate, barely noticeable transparent tubules attached to aquatic plants (Fig. 313).
They oscillate with streams of measuredly flowing water. Usually there are many such tubes in one place - a whole cluster. Make their larvae neuroclip(Neureclipsis bimaculata) from family polycentropids(Polycentropidae). If you transfer these tubular formations to stagnant water, for example, place them 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 really is a network - a network remarkably woven, with small cells of the same type. These tubular nets are weaved by narrow, long larvae that live without a sheath and do not have gills. Larvae (Fig. 314) build themselves not houses in flowing water, but nets - trapping nets, into which small crustaceans, mayfly larvae and other animals carried by the current, fall prey to the neuroclips. In the water, the predatory larva of this caddisfly catches prey in the same way as web spiders do on land!
In large flat rivers - in the waters of the Volga, Don, Dniester - many caddis flies develop hydropsychide(family Hydropsychidae). Hydropsychid larvae make a net with rectangular cells, while they themselves sit side by side in a light case made of thin threads (Fig. 315).
As soon as a small crustacean or an insect gets into the net, predatory larvae (their size reaches about 2 cm) jump out of the shelter and grab the prey with their strong jaws!
In the form of bags (Fig. 316), trapping nets of the larvae are made plectrocnemia(Plectrocnemia). Interestingly, such specialized catchers of aquatic prey as hydropsychids and plectronemias can also go on land. At a distance of tens of meters from streams, these larvae were found 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 even in water. Beautiful greenish-blue larvae crawling along the rocky bottom of clear cold streams riacophilus(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 feet and attachment hooks at the posterior end of the abdomen and wait for prey. The fact that larvae of riacophiles have strong jaws directed straight ahead helps the larvae to grasp prey quickly, like in 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. And adult caddis flies do not feed, only multiply, and all lead a similar lifestyle. Therefore, it is clear that it is relatively easy to recognize caddisfly larvae (not only the way of life is different for different species, but also the structure of individual parts of the body is not the same), and only entomologists who specifically study them can recognize species of adult caddisflies.
Acquaintance with caddisflies also shows that not only the study of the structure of different parts of the body of animals makes it possible to distinguish and recognize them well, but also behavior (which is expressed, for example, in the construction of covers of one form or another) can be used by taxonomists as a reliable feature. This was first noticed by the founder of comparative zoopsychology, the Russian zoologist V. A. Wagner.
There are many peculiar things in the life and development of caddis flies. In most insects with complete metamorphosis, the pupa is almost immobile, and if the larva and the adult insect live in different environments, the larva, before pupation, makes it easier for the adult insect to get into favorable conditions for it, for example: such larvae adapted to life in water as the larvae of swimming beetles, before pupation, they emerge from the water and burrow into the ground. Otherwise, caddisflies behave. With them, the pupa begins its life in a case built 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 turning into an adult insect, takes place in the air.
The pupa of caddisflies is free (Fig. 317). In general, this is the same stage adapted to life in water as the larva. The life of the pupa can be easily traced by the example of the stenophile, from which the acquaintance with caddisfly larvae began. Before pupation, the larva chooses a quieter part of the reservoir and, attaching the cap to the 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 all the time oscillatory movements, resting against the wall of the cap with an outgrowth on the base of the abdomen. To clean the holes, the pupa has strong bristles on the upper lip and cleansing processes at the posterior end of the body. By the time of maturation, the pupa breaks through with its powerful toothed jaws (not similar to the larval, and even more so to the practically absent jaws of adult caddisflies) the front end of the cap and, leaving it, begins to swim quickly on its back, like smooth bugs, making rowing movements long, equipped with swimming hairs on middle legs. Having reached a stone, shore or plant, the chrysalis clings to it and crawls out of the water. It's hard to call a caddis pupa a "resting stage" as insect pupae are often called!
In the air, the pupa begins to gradually move its abdomen, its spiracles open, the body swells and the last molt occurs - an adult winged caddis flies emerges through a longitudinal slit on the dorsal side of the chest and head. Those caddisflies, whose larvae do not live in caps, construct caps for themselves before pupation. The way of life of pupae is quite the same.
About 3000 species of caddis flies are known; they are distributed mainly in non-hot areas. About 600 species have been recorded in the USSR.
According to the system of a major connoisseur of these insects A.V. Martynov, caddisflies are divided into 2 suborders. Suborder whole-palp(lntegrilpia.) so named because in adult insects the last segment of the jaw palps is simple, not divided into rings, this suborder includes caddisflies, mainly making houses for themselves. Suborder Annelids(Annulipalpia) is named after its ringed jaw palps and includes, in particular, the non-house-forming hydropsychids and riacophylls.
In total, within the order, different entomologists distinguish from 13 others 16 families.
Caddisflies are undoubtedly a useful group of insects; commercial fish of our rivers feed on their larvae. In mountain streams, trout feed on stenophile larvae, eating them, despite strong sandy houses.
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- - a detachment of insects that look like butterflies. Length 0.5 - 3 cm, wingspan up to 7 cm, covered with hairs. Over 3000 species, widely distributed ...
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"Squad of Caddisflies (Trichoptera)" in books
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Order Chiroptera
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author Akimushkin Igor IvanovichDragonflies, mayflies, stoneflies and caddis flies
From the book Animal World. Volume 5 [Insect Tales] author Akimushkin Igor IvanovichDragonflies, mayflies, stoneflies and caddisflies Dragonflies, mayflies, stoneflies and caddisflies are different orders. Not all taxonomists place them in the classification of insects close to each other and to dragonflies, too. But certain similarities and a certain closeness to the ancient
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From the book The Last Emperor of China. Pu Yi author Usov Viktor Nikolaevich16. Detachment No. 731 On the basis of a secret order received from Tokyo, in 1936, a secret Detachment No. 731 was created and deployed in Harbin. However, later it was withdrawn outside the crowded Harbin, where there were quite a lot of unnecessary "eyes", in the face of spies and scouts
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From the book String and Chandelier author Krapivin VladislavCaddisflies(Fig. 99A) - these are inconspicuous, non-showy, brown or brown insects, 2-24 mm long, found near water bodies where their larvae develop, hence their name. There are over 15,000 species of caddisflies in the order.
Lifestyle
Adult insects are inactive during the day, sitting hiding in the coastal grass or bushes, and even frightened take off reluctantly. Seated caddisflies are easy to recognize: their long, thread-like antennae are joined together and stretched forward, and their wings are folded on their backs like a roof. The mouth organs of caddisflies are underdeveloped, so they do not feed at all, they are limited to licking moisture. They do not live long, usually about a week.
They begin to fly at dusk, before sunset, often above the very surface of the water, sometimes even glide on the water. Small caddisflies sometimes swarm over coastal bushes.
Life cycle
Larva
Caddisfly larvae inhabit various water bodies with both stagnant and flowing water.
House (case). They are easily recognizable by the little houses they make themselves. Larvae of different species build various houses, sticking together grains of sand, small pebbles, fragments of shells, pieces of plants with the secret of the spinning glands. The houses also differ in shape and laying of the components. Caddisfly species are easier to distinguish by their house covers than by body structure. As the larva grows, it builds a little house-case in front.
Motion. To move, the larva protrudes its head and chest with three pairs of tenacious legs out of the house and clumsily crawls along the bottom, dragging a case behind it. So she is looking for food and building material for the superstructure of the house. material from the site
Nutrition. Herbivorous larvae predominate, scraping off the soft tissues of aquatic plants, but there are also omnivorous and predatory larvae.
Role (value). Caddisfly larvae, in turn, constitute an important part of the food of various fish and some
The caddisfly larva lives in water and carries out a full cycle of transformation. The insect is in a house of small pebbles and the remains of shells. The larva is used in fishing as bait and put on a hook, previously removed from its home.
Description
A characteristic representative of the superorder Covered-winged is the caddisfly. Adults look like with a soft color. They are small in size. The anterior part of the wings is covered with hairs. The name of the insect - Trichoptera - comes from the Greek words for "wing" and "hair".
The caddisfly and its larvae develop best in close proximity to water. Habitat - neighborhoods of water bodies. Serves as food for underwater inhabitants and a key link in the food chain. It is found in rivers, reservoirs, streams and lakes.
The life cycle of an insect consists of an egg, larva, pupa and butterfly. In the second stage, it is most of life. The time interval between pupation of the egg and turning into an insect is 2 years. Interesting as fish food at every stage. It is more difficult to find a pupa, as well as to put it on a hook, so fishermen deal with larvae. This applies to caddisflies that create a house around themselves, since there are individuals living without it.
By the way, not only the caddisfly is used for fishing - the dragonfly larva also serves as bait, like the formed insect, but there are some nuances. For example, fish living in the upper layers of water bodies peck at an adult dragonfly, while all the rest are successfully caught on a larva.
reproduction
The female caddis flies lay their eggs directly in the plants. The deep parts of the reservoir are preferred, since there is less danger. There are also varieties that breed on land. Caviar has a slimy consistency, and the testicles are inside. This is a favorable environment for the development of larvae. As it grows, the shell is washed out or removed from the caddis. The shape of the eggs and their clusters depends on the species. In most cases, this is an oblong or spherical lump of mucus. There are cords that look like bagels or round plates. The eggs are spirally arranged.
Development
The caddis larva molts and grows, along the way completing the construction of its house in the form of a tube, making it more spacious. After sheathing the dwelling, the insect carries it along, moving along the bottom. The chest, head and 2-3 legs are exposed outside. In case of danger, the larva hides in a case, like a turtle. The head is blocking the entrance. Ascent for breathing is not required: oxygen comes from the water through the abdominal cover and nourishes the blood. The larvae have tracheal gills, outgrowths on the abdomen of a bushy type. As a weighting agent, the insect attaches pebbles or shells of small mollusks to the house (empty or together with the inhabitant).
A complete transformation of the insect is carried out. Pupae and larvae are at the bottom or in the water, near the shore. As a result, the larva is reborn into an insect, the head of which is round, and the mouth is directed downwards. located on both sides. Above and in front there are no more than 3 dark eyes, which are distinguished by a rather complex structure. The direction of the optical lenses is in different directions. There is an eye on the forehead between the antennae. An insect flies using wings.
Habitat
The movement of these insects into the grass occurs in the middle of summer. The water is better heated by the sun in the shallow water zone and there is more food available. The larva of the caddisfly will be on almost every bunch of grass pulled out onto land. Plants are full of this type of bait. The house of the caddis larva looks like a cover. As a binding material, the insect uses silk, which it itself secretes. This process uses blades of grass, fallen leaves, debris, sticks, sand, shell fragments and small pebbles. In the dwelling, the insect holds firmly, so it is difficult to get it out of there without damaging it. Caddisfly, whose larva serves as an excellent bait, is eaten by fish along with the cover. It is the “dressed” version that is more familiar to underwater inhabitants, therefore the cleaned individuals, which are much tastier, cause an instant stir. In this case, the caddisfly larva brings a larger catch, and in use it is more effective than a maggot or a worm. Perch, roach, pike, bream and other species are caught in this way.
Varieties
The caddisfly and its larvae have several species. Their description and way of life are somewhat different. So, some individuals live at the bottom, while others float to the water surface (the houses are made of light material - grass containing air). Their food is the pulp of algae. This causes a large number of insects in plants.
Allocate predatory species of caddis flies. They do not weave a cover and are very mobile. With the help of a thin thread, insects cling to stones and shells at the bottom, resist the current, and build a network of cobwebs that looks like a funnel. Food source - mosquito larvae, small crustaceans and mayflies. Such a larva has a strong jaw - this helps to quickly cope with prey. Such individuals are of little interest to fishermen, since their search and storage is difficult. Shitiki are preferable - larvae living in the house. They are assembled by hand. There are a lot of them in the grass in summer. Plants for this are considered very carefully - it is not easy to immediately notice the camouflage of the larva.
Mining
The larva is easily removed, especially if the fisherman has experience in this matter. In case of danger, the caddisfly is completely immersed in the shell. The back end of the tube is compressed. On the other side, the head protrudes. It is gently picked up and pulled to extract the entire body. The insect has jaws and does not look the most pleasant way, but this should not be an obstacle. A knowledgeable fisherman acts confidently and without hesitation. You can be absolutely sure: the finger of the caddis is not able to bite through. The bait is taken out of the shelter by pressing on the walls - the larva remains intact. Naiad (dragonfly larva) is harvested in the same way.
Caddisfly is used as bait in all seasons. The methods of extraction in winter are different from those in summer. They are more complicated, as are harvesting methods. However, if desired, everything is possible. This tradition comes from Karelia, where special preliminary measures for bait breeding were traditionally welcomed. For example, before freezing, a place was chosen on a river or stream, and the bottom was laid with bath brooms and stones holding them. Before the start of fishing, the brooms were taken out, and when the fisherman began to shake them, the larvae fell onto the ice. By the next time, new insects stuck to the products. The broom became a shelter and refuge for the caddisfly, especially when the object was sprinkled with flour or something edible (lard, bread) was attached.
Bait storage
Serious and experienced fishermen know how to save caddis larvae. To do this, use a damp cloth, a plastic box, and also use strips of wet foam rubber. Outside the house, individuals quickly die. Long-term storage is possible when the bait is laid out in a row and tightly wrapped so that the insect does not leave the home.
At a cool temperature, the caddisfly will live for another month. To make the larva mobile before fishing, use a cloth bag placed in the water. On polyethylene, the assembled houses are laid in one layer at a small distance from each other, otherwise damage may occur during thawing. Put a second layer on top and place in the freezer.
Acting carefully and scrupulously, the fishermen provide themselves with bait for the next fishing trip: they cut off the right amount with scissors, and put the rest in a box. On the way to the reservoir, thawing occurs, so subsequently it is easily placed on the tip of the hook. Previously, the larva is released from the house, if it can be done. Otherwise, the cover is broken or the back of the insect is pierced with a pin.
Usage
In the process of fishing, the larva is put on a hook and a float is used. In conditions of a strong current, the bite is good: the float deviates to the side or quickly goes down and the wait lasts for several moments. The fish swallows the caddisfly, and then the cutting is done and the fishing line is quickly wound up.
The target, meanwhile, is trying to swim away into the thicket. So that it does not break, the rod is held perpendicular to the shore, directing the prey to the center of the river. The current is added to the strength of the escaping fish, which causes difficulties. However, acting decisively, fishermen get a solid catch.
Having tried to use this bait, people are convinced of its effectiveness in comparison with worms and maggots, so they use it constantly.
