What subject do spiders belong to?

According to documents, it is estimated that there are more than 30,000 species of spiders in the world, belonging to 66 families, and there are about 3,000 species in 39 families living in China. The largest spider is 9 cm long, and the smallest is only 1 mm. The bird-catching spider we have here is nearly 10 cm long, and is known as the "king of poisonous spiders in the world".

In China ancient books, spiders have many different names. For example, networms, flat beads and round beads are recorded in Compendium of Materia Medica written by Li Shizhen: "Spiders are elegant and earthy, and there are nets in the soil".

Spiders have both advantages and disadvantages for human beings, but as far as their contribution is concerned, they are mainly beneficial insects. For example, in farmland, spiders prey on pests of crops. At the same time, spiders are recorded in many Chinese medicines, so it is of great significance to protect and utilize spiders. In particular, the protection of spiders in rice fields has three advantages: first, it can effectively stabilize the balance of biological populations; Secondly, reduce the residue of chemical pesticides in rice to ensure the safety of people and animals; Third, reducing production costs can increase production and income. Therefore, in the prevention and control of crop diseases and insect pests, it is advocated to use high-efficiency and low-toxicity pesticides to carry out biological control and protect natural enemies.

There are many kinds of spiders, which are widely distributed and adaptable. They can live on the soil surface, soil, trees, grasslands, rocks, caves, watersides, low-lying areas, bushes, mosses, houses or make webs, or inhabit fresh water (such as water spiders) and coastal lakes (such as lake spiders). In short, there are traces of spiders in water, land and air.

Spiders, in animal taxonomy, belong to Arthropoda, Arachnida and Arachnida. Arachnida is a small or medium-sized arthropod, with 14 orders and 5 orders extinct. 66 families of 7 orders of Araneae have been found in China. For example, Taraxaceae, Crab Spider, Araneae, Araneae, Araneae. ...