Are water striders a pest? Why doesn t it fall into the water?

Water Strider. It's a beneficial insect. Because it does not interfere with human life, and it usually floats on the surface of the pond. Water striders are aquatic hemiptera.

Insect-like insects, inhabiting still water or slow streams. The body is slender and very light; The forefoot is short and can be used to catch prey; The middle and hind feet are elongated and have fine hairs with an oily texture, which is waterproof.

Why is it that the water strider is an insect that is able to walk on the surface of the water without falling into the water?

Because the weight of the water strider is very light, a water strider is only about 30 milligrams, and there is a membrane-like substance on the water surface, so the light water strider is not easy to fall into the water. The second most critical part is the legs of the water strider, although the legs of the water strider are very slender, bending at about 90 degrees to the sides, which prevents the water strider's feet from destroying the water film. In addition, there are some small mysteries about the legs of the water strider, if you catch a water strider, put it in a magnifying glass.

If you look below, you can see that the legs of the water strider are covered with villi, which are hydrophobic.

In this way, when the water strider moves on the surface of the water, there is no need to worry about the feet getting soaked in the water and falling into the water. It is precisely because of these particularities of water strider that water strider has also become an important symbol for testing the degree of water pollution.

Water striders are not pests. Because it weighs so lightly and its legs are so long that it can support it on the water.

Water striders like to move on the surface of the water, and although they look like mosquitoes, they are not pests, they are beneficial insects, and they can be said to be "cleaners" on the surface of the water. This is because water striders mainly feed on things like other insects, insect carcasses, or debris of other animals that fall on the water. Due to the action of hydrogen bonds between water molecules, the surface tension of extremely pure water is very high, so the water strider is able to stand on the surface of the water.

No. This is "Horseshoe Crab".

Horseshoe crab (Triops spp.)) belongs to branchiopoda, notostrace, triopsidae, and triops are freshwater crustaceans. At present, there are 9 species of horseshoe crabs recorded in the world [1], and three species have been found in Japan, namely the American horseshoe crab (Triops longicaudatus (Leconte)), the Asian horseshoe crab (Triops granarius (LACES) and the European horseshoe crab (Triops cancrifomais (BOSC)).

Chinese name horseshoe crab.

Looks like a three-eyed dinosaur shrimp.

Water striders don't die if they fall into the water. Water striders are aquatic hemiptera insects that inhabit still water or slow streams. The body is slender and very light; The forefoot is short and can be used to catch prey; The middle and hind feet are slender, have oily fine hairs, are waterproof, have a black-brown body color, and are about 22 mm long, and can also live on land for a period of time.

Water striders feed on the body fluids of small insects, dead fish or insects that fall into the water. Through the very sensitive organs of their legs, they can feel the struggle of insects falling into the water. By sliding a pair of legs in the middle of them they can move on the water, reaching speeds of meters and seconds, in addition they can do 30-40 centimeter high and far jumps.

When eating, the mouth is in a tube shape. The habitat generally lives in still water, often gathering in groups on the surface of the water, and can be seen in parts of southern China for many years. Some species also live exclusively in running water.

Sea strider insects mostly live on the coast, but there are also some insects that live in the ocean and lay their eggs on floating objects.

It is caused by the surface tension of the liquid.

Water striders are very lightweight, with slender feet that bend to the sides, so that their weight can be effectively dispersed and can be better supported by the surface tension of the water.

More importantly, water striders have a special structure of the legs. The legs of the water strider have thousands of multiple layers of bristles arranged in the same direction, which can adsorb air in the gaps of the bristles, forming a stable air film on the surface of the bristles, hindering the infiltration of water droplets. The joints of the feet are lined with rows of non-watery hairs, so that the part of the water that comes into contact with the foot is concave, and the toes of the feet do not break through the surface tension of the water, so that their bodies are completely above the surface of the water, and they can run as fast as they can fly almost without resistance.

The water strider has 4 legs, and we take one of the legs as the research object, and press the leg on the water surface, and the water surface must be concave. In the case of legs, the legs have their own gravity (downwards) and the support force given to the legs by the surface of the water (perpendicular to the liquid surface).

In this case, we consider the surface tension of the liquid, so it is necessary to analyze the liquid level. The contact part, under the pressure of the leg, its resultant force is downward, and the magnitude is gravity g. and the surface tension t of the liquid.

According to the equilibrium relation, the tension t=g 2sin can be obtained. Obviously, the dead weight of the water strider is not to such an extent that it can break the surface tension.

The structure of the water strider leg is by no means a bare rod. There are many, many hairs on it, which prevents the intrusion of liquid water and thus does not break the surface tension. The image below shows the structure of leg hair captured by researchers using scanning electron microscopy. So much hair, so that the force point is greatly dispersed.

Because the mass is relatively light. More buoyancy.

Because the mass of its body is very light, much less than buoyancy.

Because it is lighter in weight and less than buoyancy.

Because they are very light in their bodies, they are very suitable for such an environment.

Because their body structure is suitable for swimming in the water.

Because their bodies are very light and light.

Because there is a bit of a peculiarity in his body structure.

Because he has special devices on his paws.

Because its own gravity cancels each other out with whose buoyancy.

Because it experiences a buoyant force greater than its own gravitational force.

Water flies are the larvae of dragonflies before they emerge.

Water bug (chài) is a general term for the larvae of insects of the order Dragonflies. The body color is generally dark brown or dark green, similar in appearance to its adult, wingless, and not sexually mature. Lurking in the muddy bottom of the stream or under the stump of branches and leaves, carnivorous, ferocious, like to prey on small water insects and their larvae, large water flies, and can even prey on small fish and tadpoles.

Depending on the species, the period varies from 2-3 months to 1 to 3 years for the common species, and 7-8 years for the longest to fully mature, during which it takes about 8-14 peels before crawling out of the water and becoming an adult dragonfly.

The color of the water fly varies depending on the habitat in which it lives. The water fly that likes to inhabit the yellow soil is yellow, and the surrounding environment is black, such as the blue dragonfly and the feast fly, depending on the surrounding environment and aquatic plants. Usually lurking in the mud bottom of the stream pond reservoir or under the dead branches and leaves, some like to perch and lie in ambush in dense places of aquatic weeds, waiting for the arrival of prey, such as feast flies.

The time and distribution area of dragonflies:

Dragonflies generally appear from April to September, and live in still water such as ponds, lakes, and swamps at low altitudes, and the time of appearance varies depending on the species. For example, the black-veined dragonfly can be seen from May to August in North China and Liaoning in the Northeast; In South China, it can be seen from March to October.

Common dragonflies such as blue-faced dragonflies are mostly distributed in Zhejiang, Sichuan, Guizhou and other provinces; The long mole green fly is distributed in North China; Yellow dragonflies are distributed in many provinces, municipalities and autonomous regions across the country; The jade-banded dragonfly is only found in China, mainly in Beijing, Jiangsu, Fujian and other provinces, municipalities and autonomous regions.

The scientific name for the larvae of the dragonfly is "water baton" (or water scorpion), and "fish eater" is the common name for it, and it lives in the water. Dragonfly larvae spend at least one year in the water, and longer ones have to endure seven or eight years of ordeal before they become adults. Dragonflies only live one-tenth the lifespan of a stinging snake, and they only live for about one to eight months.

However, it has a long lifespan in insects. Dragonfly larvae (larvae) develop in water, where they breathe through the rectum, trachea, and gills. Generally, it takes more than 2 years to molt more than 11 times, crawl out of the water along the aquatic weeds, and finally molt and emerge into an adult.

In the water, young insects can prey on the larvae of mosquitoes or other small animals, and sometimes the same animals will devour each other.

There are many insects that will die when they encounter water, first of all, refute Mumu's point of view - cockroaches are the most resilient insects among insects, and can still survive in the water for up to 24 hours, while most flying insects will quickly drown in the water due to their wings without waterproof substances, such as moths (including larvae), flies (including larvae), cicadas (including larvae), bees, grasshoppers, beetles (including larvae), praying mantises, etc., common insects that are not afraid of water at home - midges, cockroaches, cockroaches, swishing, etc., And the common water-sensitive insects in the home - clothes moths, houseflies, mosquitoes, spiders, snakes, centipedes, fish clothes.

It is worth mentioning that insects in the wild, such as dragonflies, mosquitoes, damselflies, and adults whose larvae live in the water are also afraid of water, and water striders and water spiders that can float on the water surface will drown if they fall into the water, while dragon lice, water beetles, and turtles are not only not afraid of water, but also can prey on other insects and even small fish and shrimp in the water.

Correct: The one behind the water beetle mentioned above is not a turtle but a turtle.

As long as insects encounter water, they will die, because of lack of oxygen, but some insects have unique skills to keep themselves from hypoxia, some have pubescence on their bodies to isolate water, some are very light, some have wax on their bodies and can swim, like cockroaches, which are hundreds of millions of years ago, needless to say, they are gods.