Insects are the largest group in the animal kingdom, and they all play a very important role in biodiversity in terms of the number of individuals, organisms, species and genes. The relationship between insects and humans is complex and close. Some insects have caused serious disasters to mankind, and some species have provided abundant resources to mankind.
Insecta Insecta is the largest class in the animal kingdom. In Chinese, one of the meanings of Kun is "numerous" and "huge"; The word "worm" refers to a wide range. Liu An and Dong Zhongshu's "Five Insects Theory" and "Insects" in "The Core Monument of Dai Li's Life" are the floorboards of all animals. 1890, Rick Fang classified 2 19 kinds of small animals in the five categories of "feather, fur, Kun, scale and ostrich" as "insects", and the word "insects" had a modern concept.
In western languages, "insects" (entoma and sect, the former from Greek and the latter from Latin) included a wide range at the earliest. In 1602, the "insects" in Deanimbus Inserts written by U.Aldrovandi include arthropods, annelids and echinoderms. 1758 Karl von Linne (or Carolus Linnaeus) named in his masterpiece "System a Nature"10 edition also includes arthropods such as arachnids and lipopoda. 1825, P.A.Latreille established hexapod, that is, hexapod, and then standardized "insect" into hexapod with body, chest and abdomen separated.
insecta
Insecta is not only the largest class of arthropods, but also the largest class of animals. There are more than 1 0.5 million known animal species in the world, of which insects are more than10.5 million (that is, 2/3). There are about 335,000 known species of plants (including bacteria), only 1/3 of insects. It is difficult to know the exact number of insect species because taxonomists are still describing new species. For example, according to Imms statistics, the number of LEPIDOPTERA insects (moths and butterflies) increased from 80,000 in 193 1 to 1934 and 1944. The largest order of Insecta is COLEOPTERA, with more than 250,000 species, including as many as 60,000 species of weevil.
There are not only many kinds of insects, but also an amazing number of individuals in the same species. An ant colony can have as many as 500 thousand individuals. It is estimated that the total number of ants may exceed the total number of all other insects. There are as many as 25.92 million wheat midges in an acre. A tree can have 654.38 million+aphids. There are 6,543,800 springtails per square meter of soil in broad-leaved forest.
Insects are widely distributed, and no animal can compare with them, almost all over the earth. Insects exist from the equator to the poles, from oceans and rivers to deserts, as high as Mount Everest, the roof of the world, and as deep as several meters in the soil. Such a wide distribution shows that insects have amazing adaptability and are also the ecological basis of a wide variety of insects.
Reasons for the prosperity and development of Insecta
First of all, insects are the only group of invertebrates with wings. Flying brings great benefits to insects in foraging, courtship, avoiding enemies and expanding distribution.
Second, insects are generally smaller. A small body needs only a small amount of food to develop. For example, a cabbage leaf can feed thousands of aphids, and a grain of rice can feed several rice elephants. It is precisely because of its small size that food can become its hiding place, thus gaining the benefits of moistening and avoiding the enemy.
Thirdly, the differentiation of insect mouthparts, especially from eating solid food to eating liquid food, greatly expands the scope of food and improves the relationship with the host-generally speaking, the host will not die because of losing some juice, nor will it adversely affect the survival of insects.
Fourth, insects have amazing reproductive ability. This is related to small size and rapid development (that is, more generations can be completed in a unit time), which has also become an important condition for insects to have a very high reproduction rate. Therefore, under the natural conditions of changeable environment and numerous natural enemies, insects can maintain a certain population level even if the natural mortality rate reaches over 90%.
When tracing the origin of insects, people found the oldest insect fossils, which were found in rocks of Middle Devonian. In other words, insects have existed on the earth for at least 350 million years. The appearance of human beings was probably in the recent Paleogene, but it was only one million years ago. Therefore, before human beings appeared, insects and all the animals and plants in their habitats had established a long historical relationship.
The reason why insects become the most prosperous animal group
1. You can fly with wings
Insects are the only invertebrate group with wings and the earliest animal group with wings. The acquisition of flying ability has brought great benefits to insects in foraging, courtship, avoiding enemies and spreading.
2. Strong fertility
Insects have amazing reproductive ability. Most insects lay hundreds of eggs, and social and parthenogenetic insects are more fertile. If necessary, 65,438+0 bees can lay millions of eggs in their lifetime. It is estimated that if all the offspring of 1 parthenogenetic aphid survive and continue to reproduce, the total number of aphids will reach about 600 million in half a year. Strong reproductive potential is the foundation of population prosperity;
3. Small size advantage
Most insects are small in size, which can not only meet the nutritional needs of their growth and reproduction with a small amount of food, but also give them many advantages in living space, flexibility, avoiding enemies, reducing harm and moving with the wind.
4. Diversity of feeding organs
Different groups of insects have different types of mouthparts, which on the one hand avoids the competition for food, but also improves the relationship between insects and feeding objects to some extent;
5. It has metamorphosis and development stages.
Most insects are completely metamorphosed, and there are great differences between larvae and adults in habitat and feeding habits, thus avoiding the contradiction between the needs of the same or similar insects in space and food;
6. Strong adaptability
From the characteristics of wide distribution, many species, large quantity and long history, it can be inferred that insects have strong adaptability to temperature, hunger, drought, chemical substances and other insects, and their life cycle is short, so it is easier to preserve mutations beneficial to the population. For periodic or long-term adverse environmental conditions, insects can also sleep or diapause, and some species can diapause in the soil for several years, more than ten years or longer to maintain the continuation of their populations.
Nomenclature and type specimens of organisms
Scientists give a Latin scientific name to every creature they have studied but have not recorded, including two Latin words, a generic name and a species name, which is called binomial method, which was initiated by Swedish scientist Linnaeus in 1758. The specimens on which the naming is based are called type specimens, one of which is designated as the normal mode and the other as the auxiliary mode.
The relationship between insects and humans
Since there have been people on the earth, it is inevitable that people will compete with insects for resources because they want to obtain survival materials from nature and transform nature. On the other hand, insects also provide resources for human beings. Therefore, people have a close relationship with insects.
The relationship between insects and human beings is very complex, and one of the main factors that constitute the complex relationship is that insects have an unusually wide range of feeding habits. According to previous estimates, 48.2% of insects are phytophagous; 28% are carnivores, preying on other insects and small animals; 2.4% is parasitic, parasitic in other insects and animals, 17.3% eats decaying biological organisms and animal excreta. This outlines the advantages and disadvantages of insects for us. But this is only a natural phenomenon, and people's views on benefits and harms are based on people's economic interests, so it is much more complicated. The following are the harmful and beneficial aspects of insects to human beings.
How to identify insects?
Speaking of insects, maybe we are already familiar with them. Colorful butterflies, bees visiting flowers to make honey, silkworm babies spinning cocoons, cicadas singing loudly, competitive crickets, fireflies shining with stars, dragonflies with superb skills resembling airplanes, simple and lovely ladybugs, mantis with a big knife in hand, annoying flies, mosquitoes, cockroaches and so on. So, what do insects have? Are spinning spiders and spiny scorpions insects? What about Ma Lu and centipede? You may not be able to answer all these questions. Now let's see what kind of insect is an insect.
Insects, like other organisms, have their own special taxonomic status. It belongs to Insecta of Arthropoda in the animal kingdom. Its main features are as follows (imitation color map):
(1) Body links are grouped into three body segments: head, chest and abdomen, but they are not divided.
(2) The head is the center of sensation and feeding, with mouthparts (mouth) and 1 pair of antennae, usually with compound eyes and monocular eyes;
(3) The chest is the sports center, with 3 pairs of feet and generally 2 pairs of wings;
(4) The abdomen is the center of reproduction and metabolism, which contains genitals and most internal organs;
(5) In the process of growth and development, insects have to undergo a series of internal and external morphological changes before they can be transformed into adults. This change in posture is called metamorphosis.
(6) The chirping insect is male, but the female can't sing.
Therefore, the basic characteristics of insects can be summarized as follows: "the body has three sections: head, chest and abdomen, two pairs of wings and six feet;" 1 The pair of antennae are born in the head and the bones are wrapped in the body; There are many changes in life forms all over the world. "
With the concept of insects, you already know the answer to the last question: spiders and scorpions are not insects, because they have head, chest and abdomen and eight legs. Centipede and Ma Lu have more legs, and almost every link (body segment) has 1 ~ 2 pairs of feet, not to mention insects.
The largest and smallest insects
In terms of weight, the heaviest insect in the world is the giant rhinoceros beetle (COLEOPTERA rhinoceros) in tropical America. This kind of rhinoceros beetle protrudes from the head to the end of the abdomen 155 mm and its body is 100 mm, which is larger than the largest goose egg. Its weight is about100g, which is equivalent to the weight of two eggs. In addition, a longicorn beetle (Coleoptera Cerambycidae) produced in Brazil also has a body length of more than 150 mm, but in terms of body length, the longest insect is a stick insect living in the Malay Peninsula, with a body length of 270 mm, which is longer than a pencil.
The smallest and lightest insect in the world is the magnolia bee, which is an egg bee of Hymenoptera. Its body length is only 0.2 1 mm, and its weight is extremely light, only 0.005 mg. Converted, 200,000 is less than 1 g, and100,000 is as heavy as an egg.
How many kinds of insects are there in the world?
Recent research shows that there may be 654.38+00 billion species of insects in the world, accounting for about half of all biological species on earth. However, at present, there are only 6.5438+0 million species of insects with surnames, accounting for 2/3- 3/4 of the known species in the animal kingdom. It can be seen that 90% of the insect species in the world are unknown to us; According to the most conservative estimate, there are at least 3 million species of insects in the world, and there are still 2 million species of insects to be discovered, described and named. At present, about 1000 new species of insects are published every year in the world and are included in Zoology. Therefore, this magazine is a retrieval tool that researchers engaged in animal classification must consult.
Among the named insects, there are as many as 350,000 species of COLEOPTERA (Beetle), among which there are more than 60,000 species of weevil, which is 10 times that of mammals. Lepidoptera (butterflies and moths) comes next, with about 200,000 species. There are about 6.5438+0.5 million species of Hymenoptera (bees and ants) and Diptera (mosquitoes and flies).
There are not only many kinds of insects, but also many individuals of the same kind, some of whom are surprisingly large. An ant colony can have as many as 500 thousand individuals. A tree can have 654.38 million+aphids. In the forest, there are 654.38+ ten thousand jumping insects per square meter. When locusts broke out, the number of individuals could reach 70 ~1.200 million, the total weight was about1.250 ~ 3,000 tons, and the area covered by swarms could reach 500 ~ 1.200 hectares, which can be said to be a day's canopy coverage.
How many kinds of insects are known in China?
China has a vast territory and complex natural conditions. It is the only country in the world that spans two animal geographical regions, so it is one of the countries with the largest number of insect species in the world. Generally speaking, the insect species in China account for110 of the world's species. There are 1 10,000 species of named insects in the world, and there should be about 1 10,000 species of named insects in China. However, there are only over 50,000 species of named insects in China at present, and there is still a long way to go to catch up with the current world level. Besides, there should be 300 million ~100000 species of insects in the world, so there should be 300 million ~100000 species of insects in China. It can be seen that there are too many new insect species in China waiting for friends who are interested in studying insects to discover, name and describe them.
Where do insects live?
With so many kinds of insects, their lifestyles and living places are bound to be varied, and the expression of some insects' lifestyles and life instincts is of great research value. It can be said that insects are everywhere from the ends of the earth to the ends of the earth, from mountains to abyss, from equator to poles, from oceans, rivers to deserts, from grasslands to forests, from the wild to indoors, from the sky to the soil. However, according to the most suitable activity places of the main insect States, they can be roughly divided into five categories.
(1) Insects living in the air: Most of these insects are active in the daytime, and they have developed wings and usually have developed mouthparts, so adults have a long life. Such as bees, wasps, dragonflies, flies, mosquitoes, fireflies, butterflies and so on. During aerial activities, insects mainly migrate and spread, looking for food, mating and choosing spawning grounds.
(2) Insects living on the surface of the earth: These insects have no wings, or they have wings but are no longer good at flying, or they can only crawl and jump. Some flying insects also live on the ground in the larval and pupal stages. Some parasitic insects and insects that feed on decaying animals and plants (including insects that live indoors with humans) are also mostly active on the surface. Insects active on the ground account for the vast majority of all insect species, because the ground is the location and habitat of insect food. This kind of common insects are walking insects (fart insects) and cockroaches.
(3) Insects living in the soil: These insects feed on the roots of plants and humus in the soil. Because of their activities in the soil and their consumption of plant roots, they have become a great harm to agriculture, fruit trees and seedlings. These insects are most afraid of light, and most species have poor mobility and migration ability. They rarely go underground during the day, and the most suitable time for their activities is at night and rainy days. This kind of common insects are mole crickets, cutworms (larvae of Noctuidae) and cicada larvae.
(4) Insects living in water: Some insects live in water all their lives, such as salamanders, soft-shelled turtles, salamanders, the female offspring of Hemiptera, COLEOPTERA lice, water turtles and so on. Some insects, such as dragonflies, stone moths, ephemera, etc. , just living in the water larvae (especially called larvae). The common characteristics of aquatic insects are: the valves on the body side are degenerated, while the valves on both ends of the body are developed or special tracheal gills are used to replace the valves for breathing; Most species have flat hairy swimming feet, which play the role of paddling.
(5) Parasitic insects: These insects are relatively small and have poor mobility. Most species of larvae have no feet or can no longer walk, and their vision is impaired. Some parasitic insects, such as fleas and lice, live on the surface of mammals all their lives. Others are parasitic in animals, such as horse stomach flies. Other insects are parasitic on other insects, which is beneficial to human beings. They can be used to control pests, which is called biological control. These insects mainly include wasps, wasps, cocoon bees and flies. Among parasitic insects, there is another phenomenon called heavy parasitism. That is, when a parasitic bee or fly is parasitic on a herbivorous insect, another parasitic insect is parasitic on the previous parasitic insect. Some species can also carry out double or triple parasitism. For insects, these phenomena are just an instinct for survival and competition.
Edible insect
When insects are mentioned, people will think of ants, crickets, dragonflies, grasshoppers, cicadas, caterpillars and other grotesque animals. These small animals are ok to catch and play with, but if they are eaten as food, many people may find it hard to imagine, and maybe they will feel sick and vomit. In fact, insects have a long history as human food, and many countries and regions in the world have the habit of eating insects. According to incomplete statistics, there are dozens of insects eaten as food in various parts of China.
Insects are not only rich in organic matter, such as protein, fat, carbohydrates, salts and other inorganic substances, but also rich in potassium, sodium, phosphorus, iron, calcium and free amino acids needed by human body. According to data analysis, every 100 ml of human plasma contains 24.4-34.4 mg of free amino acids, which is much higher than human plasma. The content of protein in insects is also extremely high. Cicada contains 72% protein, wasp contains 865,438+0% protein, and protein is higher than beef among termites. 100g of termites can generate 500 calories, while100g of cattle net can only generate 30 calories.
In addition to the above advantages, insects as food also have the characteristics of short generation, fast reproduction and easy acquisition. Therefore, insects are often the first choice food for people in distress in the wild. The author himself has eaten more than a dozen in the wild and feels that the taste is not bad. In order to let outdoor lovers know something about edible insects, the author lists some edible insects that are easy to get in the wild in China and have a good taste, as well as the methods of catching them, for the reference of "brave people" who are interested in eating insects. Insect names marked with "*" are the first choice for edible insects. When eating insects, you can choose different eating methods according to your own conditions at that time, such as roasting, burning, frying, boiling and frying.
Grasshoppers eat their adults or larvae, and all kinds of locusts, including grasshoppers, can eat them. Beat with branches with leaves, or spread plastic film on the ground to drive locusts to the film, because the film is smooth, locusts can't escape and are easy to catch.
Grunts eat their adults, catch them with their bare hands, or lure them with lights at night.
Crickets eat adults, scratch them with their bare hands or beat them with branches.
The catch, also known as slugs, is similar to that of crickets.
Silkworm and tussah mainly eat pupae, which are domestic insects and are not easy to meet in the wild.
Moths include moths, spiny moths, moths and moths. Because their larvae have long hair and ugly appearance, they usually choose to eat pupae.
Butterflies can be eaten by various pupae. Compared with moth larvae, most species are hairless and edible.
Termites eat adults and eggs and find nests to dig. Termites can be divided into two types: those living in trees and those living in soil. The termites sacrificed by trees are pure white and have no peculiar smell. The termites on the ground are mostly brown, which tastes a little strange.
Ants feed on adults, larvae, pupae and eggs, looking for nests to dig, or trapping with food. When eating ants, we should pay special attention to the species of Formicidae in ants, which are poisonous and inedible. Stinky ants are small in size, with upturned tails and peculiar smell, which are easy to distinguish from other ants.
Cicada eats adults, whips them with branches or sticks them with glue sticks. In southern Shan Ye, cicadas that died after drinking water can sometimes be seen gathering in large numbers and can be collected.
Dragonfly adults and larvae can be eaten. Adults can be whipped by branches, stuck or entangled in nets. Larvae fish with nets in the water.
The smelly bug, a female child, eats adults and catches them in the water with a net.
Silkworms eat larvae, which live in streams. Several stones were glued together with silk to form a sacrificial place, and the silkworm's stone nest was picked up in the water with bare hands to catch larvae.
Long-horned beetles eat larvae, which live in wood and live on wood. Choose dead branches with many insect eyes and cut them open to find larvae.
Mantis eats adults and larvae and grabs them directly with its hands. Mantis eggs can also be eaten.
Both adults and larvae of lice can be caught and eaten with nets in ponds and rivers.
Bees include wasps, wasps, bees, edible adults, larvae and pupae. Find the hive and burn the adults.
After that, larvae and pupae can be collected. Collecting bees is even in danger of being stung by fire. You should choose to go in at night, prepare more torches that suddenly catch fire, and protect your head and hands with thick clothes or other items.
Earthworms, spiders, crabs and shrimps are often used as food in outdoor activities, but they are not among insects, so I won't mention them here.