CATDOLL : CATDOLL: Why don’t some spiders weave webs?

1. Why don’t some spiders weave webs?

In nature, spiders can be roughly divided into two categories: web-building spiders and nomadic spiders. Since nomadic spiders hunt and prey everywhere, they have no fixed residence, and webs are no longer of much use to them. Therefore, in the long-term evolutionary process of adapting to the environment, they gradually lost the ability to build webs and became spiders that do not build webs.

Li Shizhen, a great medical scientist in the Ming Dynasty, described spiders in his Compendium of Materia Medica: "This insect sets up a web, and kills anything that touches it. It knows how to kill unjust people, so it is called a spider." This shows that spiders' habit of weaving webs was already known in ancient my country. But the flycatcher, a common spider that preys on flies indoors, never weaves a web. Why is that?

We know that spiders have three pairs of spinning protuberances on their abdomens, which are connected to the silk glands in their bodies and form the spinning organs. There are many small tube openings of different sizes on the surface of the spinning protuberances, which are connected to various silk glands respectively. The secretions of the silk glands are discharged through these tubes and solidify into spider silk when they encounter air.

Spiders have many types of silk glands, 8 of which are known. The spider silk secreted by each silk gland has different properties and uses, and a spider often only has a few of them. So although spiders can spin silk, their uses are not the same. Some spiders can spin silk to make webs, while others spin silk but do not make webs.

In nature, spiders can be roughly divided into two categories: web-building and hunting.

Orb-weaving spiders are a common type of web-building spider. They often weave large, round webs on the eaves and corners of houses, waiting for all kinds of flying insects to fall into their traps. Orb-weaving spiders have five types of silk glands, among which the silk secreted by the spherical glands is used as the radial threads when weaving webs, and the spiral silk secreted by the dendritic glands is the surrounding threads that make up the web. Due to differences in living environments, the webs made by different web-building spiders are also different, some are simple, some are complex; there are circular webs, triangular webs, basin webs, funnel webs, etc.

The web-building spiders’ method of waiting for flying insects to fall into their traps and waiting for prey is somewhat accidental after all, and sometimes they may have to endure hunger. However, roaming around and taking the initiative may allow them to catch more prey, so in the process of evolution, some spiders gradually evolved from web-building to hunting. At this time, the types of silk glands in their bodies also changed. The silk glands that secrete silk for web-building gradually degenerated, and the number of silk glands suitable for hunting life increased, so the use of spider silk also changed.

The flycatcher is a hunting spider that is an expert at catching flies. When it finds a fly, it quietly climbs 4 to 5 cm above the fly, attaches itself to a point on the wall with spider silk as a "safety belt", and then jumps on the fly from a high position to kill it. Even if it misses, it will not fall to the ground and get hurt, because it is firmly held by the "safety belt" and can crawl back to its original position along this "safety belt".

Wolf spiders, which are active in fields and bushes, often lurk in caves and lay a little spider silk in the passage near the cave entrance. When insects, centipedes and other small animals accidentally step on this "clue", they quickly rush out of the cave and quickly chase the prey. The dusk six-eyed spider can quickly spray a large amount of sticky silk to wrap the target it finds, and then go to eat the food.

Since nomadic spiders hunt and prey everywhere, they do not have a fixed residence, and webs are of little use to them. Therefore, in the long process of evolution to adapt to the environment, they gradually lost the ability to make webs and became spiders that do not make webs.

2. Why do sites that spiders visit every day never update snapshots or indexes?

The first scrolling picture has a dead link and is removed. The second scrolling picture has a scrolling text description added below it, or the picture and text are written in code and kept in an external link. Wait for a few days and update 100%

3. What is spider code?

This question is not very comprehensive. The so-called spider code refers to the code that the spider crawls on your website. If you upload the network log, you can see the pages crawled by the spider by viewing the log. Ask the space provider to upload the spider crawling log to the space, and download it to see it!

4. My website has changed its space, but the spider has not updated it. What should I do? The spider has also found a dead link. What should I do?

Maybe the IP address of your new space was blocked by someone else, so your site will be affected.

It is recommended to change the space again.

5. About Spiders

You should ask yourself why you are afraid. Is it because you have watched similar horror movies or been influenced by someone who said spiders are scary? The solution is that you need to get in touch with them more often. They are not scary. Most spiders are non-toxic and there is nothing to be afraid of. It is just your mind playing tricks on you. But you can watch them, but don't move your hands. If you get bit, you deserve it... It feels a bit like obsessive-compulsive disorder... You should know that it is impossible to completely eliminate spiders in your home, so you can only work hard to eliminate your delusions about spiders. Uh~ But I can't help you do this. I suggest you go to a psychologist. Ask another person around you who is not afraid of spiders to catch a spider and put it in an empty glass bottle, and then put it in front of you, of course, the bottle cap should be buckled. Just look at it. Until you don't get goose bumps. Only you can help yourself to overcome such fear!

6. Baidu spider?

Take your time. If this is the case, then your structure may not be done well. Or make a site map and put it on the homepage.