What positive effects do insects have on human health?

Arthropod whose body is divided into three parts: chest and abdomen. The chest has three pairs of feet and usually two pairs of wings, about 1 10,000 species, which is the largest class in the animal kingdom. Water, land, mountains and poles are all distributed. Complex structure and great changes in living habits are closely related to human beings. Common such as locusts, mosquitoes, flies, moths, butterflies, bees, silkworms and so on. The body is obviously divided into three parts: head, chest and abdomen, and each part is composed of several body segments. The cephalic segment is completely healed, with compound eyes, single eyes, 1 pair of antennae. The chest is divided into three sections: the front chest, the middle chest and the back chest, each with 1 pair. Most adults have two pairs of wings, which are located on the back of the middle chest and the back chest. Insect wings vary according to different species, such as hymenoptera (bee), COLEOPTERA (scarab), Hemiptera (stinkbug), compound wing (locust), scale wing (moth, vegetable) and so on. The hind wing of the housefly degenerated badly and became a balance pole. The digestive tract is divided into foregut, midgut and hindgut. The excretory organ is the malpighian duct, which opens at the junction of the midgut and the hindgut. Respiratory organs are valves and trachea. The circulatory system is an open pipe, and there are dorsal blood vessels on the back of the digestive tract, which are divided into two parts: the heart and the aorta. The nervous system is chain-shaped. Sensory organs are developed, and there are various receptors for feeling touch, taste, smell, vision and hearing. It is dioecious, with diverse reproduction methods and strong reproduction ability. In the development process, it can be divided into two categories: no metamorphosis and metamorphosis, and the latter can be divided into gradual metamorphosis, semi-metamorphosis and complete metamorphosis. Generally divided into 2 subclasses and 33 orders. The important categories are: ladybird belongs to COLEOPTERA. The body is oval and arched, and the back is smooth and hairless. The head is black. Compound eye black oval. Feeding on various aphids such as bean aphid, peach aphid and locust aphid. In China, it is distributed in Beijing, Hebei, Henan, Shandong, Shanxi, Xinjiang, Jiangsu, Jiangxi, Hunan, Zhejiang, Fujian, Yunnan and Sichuan. India is also distributed. Bee belongs to HYMENOPTERA. The front end of female head is narrow. The body is light yellow. Distributed in all parts of China. Chilo suppressalis belongs to LEPIDOPTERA. The female moth has yellow front wings, white rear wings and yellow outer edges, and there are bundles of yellow-brown scales at the end of her abdomen. The head, chest and front wings of the male moth are grayish brown. Mainly distributed in Southeast Asia. In China, it has been found in Jiangsu, Zhejiang, Hunan, Anhui, Jiangxi, Hubei, Henan, Shaanxi, Sichuan, Guizhou, Fujian, Taiwan Province, Guangdong, Guangxi, Yunnan and other provinces, which is harmful to rice. Papilio belongs to Lepidoptera, with black body, white hair on the head and chest and white wing veins, which mainly harms plants of Cruciferae, Leguminosae and Rosaceae. Distributed in the north and south of China. New termites belong to Isoptera. The head of winged adults is square and round. The front lip base is short and wide, and the boundary between the back lip base and the head is not obvious. One eye is big and the compound eye is round. The head is orange, and the chest and abdomen are orange. Live in groups in wooden houses, cross tunnels and feed on sawdust. Distributed in Taiwan Province, Fujian, Guangdong, Hainan, Yunnan and other provinces in China. Buildings that endanger wood and wood structures. Insects are very adaptable to the environment. For example, locusts are green on crops and yellow on hay. Insects such as butterflies live in a wide range, not only on land and in the air, but also in water. Its distribution range is related to temperature, humidity, light and other conditions. Ants and bees are social, cooperative and social insects. Bees also have social habits of strict division of labor. Insects have a wide range of feeding habits. There are herbivores (feeding on plants), carnivores (feeding on animals), saprophagous (feeding on plant debris, feces, etc.) and so on. ), oligotrophic (cabbage caterpillar larvae eat cruciferous vegetables), monophagic (Chilo suppressalis only eats rice), and polyphagous (corn borer eats a variety of crops). Economic significance: beneficial aspects: ① providing industrial raw materials, such as silkworms and tussahs, Bai La secreted by male white-film worms, tannic acid contained in gallnut gall, and so on; (2) Drugs, such as turnips in Mylabris, can be used as foaming agent during operation, diuretic and stimulate organs when taken orally, and bee stings can treat arthritis. (3) Honey and royal jelly are good tonics for food (such as silkworm chrysalis and mature larvae of bean paste) and breeding (such as Tenebrio molitor); (4) it is beneficial to pollinate insect-borne flowers and promote crop yield increase; ⑤ Use natural enemy insects to eliminate pests. Harmful aspects: Many of them are important pests of agricultural and forestry plants and warehouses. Such as East Asian flying earthworm, armyworm, rice planthopper, rice leaf roller, etc. , harmful to cereal crops; Cotton pests, such as cotton aphid and cotton bollworm; Pieris rapae and Plutella xylostella harmful to vegetables; Dendrolimus punctatus, Monochamus alternatus, etc. Endangering forests; Store pests such as rice weevil and broad bean weevil. In addition, termites seriously harm buildings, dams, bridges, sleepers and so on. There are also many insects that endanger the health of people and livestock. Two thirds of human infectious diseases, such as plague and typhus, are spread by insects. Mosquitoes, fleas, lice, gadflies and spiny flies are all blood-sucking insects. Stable flies can suck the blood of cattle and horses and spread diseases.