Meteor hammer spiders can attract male moths by imitating the smell of pheromones secreted by female moths when they are in heat. When the male moths arrive, they dance "meteor hammers"—actually, a small ball of slime hanging from spider silk—and throw them at their prey.
——[United States] Matt Simon's "Crazy Evolution"
Most of the animals we know, including humans, have only one pair of eyes, but some animals have 8 eyes. There is a riddle about it: "Zhu Geliang of Nanyang, sitting alone in the middle of the army tent, setting up a gossip array, specializing in catching flying generals." This eight-eyed animal is a spider.
Spiders are a class of ancient creatures. In 2012, archaeologists discovered an amber in Myanmar that perfectly documents a Cretaceous accident: As a spider was about to pounce on a wasp trapped in its web, a drop of resin fell from the sky and hit it. Buried in the ground for more than 100 million years, the drop of resin was petrified under pressure and heat to form amber. This extinct spider is thus fixed in the wonderful amber.
spiders are not insects
Some people think that spiders are insects, which of course is wrong. However, laypeople are justifiable for this fallacy: spiders do resemble insects—both with tough exoskeletons and segmented bodies and appendages. Even Fabre's great book "Insects" has a dedicated chapter on spiders (Fabre doesn't care about spiders' taxonomic status at all).
The advent of exoskeletons and segmentation is a remarkable event in evolutionary history. Exoskeletons are relative to the bones of vertebrates such as birds and animals. The bones of vertebrates grow inside the body, and the exoskeletons of insects and spiders grow outside the body, but their functions are similar, both supporting, protecting and moving. The exoskeleton is like wearing armor and protective clothing outside the body, which provides more direct protection and support to the body, and can also reduce the loss of water in the body. Therefore, scientists have been developing mechanical exoskeletons, trying to give professionals an "Iron Man"-like power suit, or to help the elderly and disabled walk and go up and down stairs. However, exoskeletons also have shortcomings, that is, they cannot grow up with the body, which is a constraint on growth. Therefore, creatures with exoskeletons need to molt during growth and development. Molting is not only troublesome, but dangerous.
Another common feature of insects and spiders is segmentation. Segmentation is the beginning of the physiological division of labor and enhances motor function. The segmented appendages are like three-segmented sticks, soft and hard. With segmented appendages, insects and spiders are more mobile and better suited for ingesting food and evading predators on land. For this reason, insects and spiders etc. are called arthropods. Arthropods are therefore higher and more widely distributed than snails, earthworms and many other invertebrates, and are more suitable for survival on land.
So, what is the difference between insects and spiders? Insects have antennae, spiders do not, many insects have wings, and spiders do not. The body of insects is divided into three parts: head, thorax, and abdomen, while the head and thorax of spiders are one. What's more, insects have 3 pairs of legs in their thorax, while spiders have 8 legs in their cephalothorax. In addition, the front of the spider's cephalothorax has a pair of tentacles and a pair of chelicerae with venom glands. The reason why spiders can "become full of flying insects and fat like gourds" lies in their "beaks and poisonous stings that are beneficial to cones".
Insects such as locusts and crickets are good at jumping because they have developed muscles in their legs. Spider legs may seem weak, but the Florida jumping spider can leap six times its own body length. Why is this? It turned out that there is a very unusual "blood" in the spider's legs, like a hydraulic transmission device, which uses liquid pressure to convert energy to help the spider move. People have imitated spider legs to develop a "walking machine", and they have also tried to apply the blood pressure regulation principle of spider legs to medical treatment to treat diseases such as hypertension.
In the animal kingdom, insects are the most diverse and widely distributed, and no other animal can compare with them, and spiders are no exception. There are about 50,000 species of spiders in the world, which is not comparable to the coleopteran weevil family of insects (more than 60,000 known species of weevil). Although there are few species of spiders, none of them are vegetarians, and they are all natural mortal enemies of insects.
Spider prey on insects is not flesh and blood. In fact, it is not insects that are really related to spiders, but the ancient blue-blooded animals - horseshoe crabs. Both spiders and horseshoe crabs have cephalothorax and abdomen, and both have chelicerae without antennae and wings. It is only because there are few species of horseshoe crabs, they are large, and they live in the ocean, people will not associate spiders with horseshoe crabs.
Spiders don't all make webs
When it comes to spiders, people will immediately think of spider webs. It seems that spider webs are the "standard" of spiders. Mei Yaochen said that spiders "wrap a foot of web a day", but this is not the case. While all spiders are talented "weaver girls," only half of them are excellent web weavers.
Webbing spiders are the most eye-catching and well-known spiders and the oldest "web workers". The use of silk by other spiders is relatively simple: either weave a simple shelter, or set up a sensing device, or act as a rope when hunting, or as a seat belt when leaping... Web-making spiders can weave in different places Heavenly nets are used as hunting grounds, such as pan spiders, round web spiders, Chinese vortex spiders, chest-spotted spiders and so on. The orb-web spider is the most common and most elaborate web spider. The web of the orbweb spider is a beautiful work of art made by nature, which fully reflects the creativity of the spider. "The corners of the house are under the shade of bamboos and trees. It is pitiful to use up a lot of ingenuity." Yang Wanli was talking about the orb-web spider, whose living place is the most inconspicuous eaves, fences or corners of the garden.
Tough cobwebs are not only hunting grounds for webbing spiders to obtain food, but also marriage and love places to find love. However, the spider's marriage life is not romantic, but a hidden murder. The spider's lover is always smaller, and he is always afraid of female spider beauties. During the breeding season, the lover approached the beauty's net happily, but timidly stopped at the corner of the net. The lover plucked the mesh with her feet like playing the piano, while the beauties reservedly guarded the center of the net, savoring whether the lover's signal contained the sweetness of love. If the beautiful woman is not happy, she will rush over like a hungry tiger, and the net will vibrate violently. On the contrary, if the beauty listens to the beautiful piano sound quietly and even responds gently with a unique rhythm, the lover will know that the beauty is secretly promised, so he continues to play the net as if he is attentive, while cautiously approaching the beauty. Even so, once the bridal night is over, the groom must slip away, otherwise, the bride will unceremoniously treat the groom as a delicious meal to ensure that the future spider babies have sufficient nutrition.
The black widow spider is the most famous of these spiders, why is it called the black widow? This may be related to the black body color, but also because the female spider has a dark heart and will eat the male spider without hesitation after mating, willing to become a widow. Therefore, for the spider groom, marriage is not only the tomb of love, but the end of life. Of course, if the groom is well prepared and brings the bride a rich "bride gift" - a fly or other insect, that's another matter.
Cave spiders also weave webs, but the webs are not sticky. They rely purely on the vibrations of the web and the ground to sense the range of their prey and then attack. In fact, spiders are among the most vibration-sensitive animals in the world, and hungry spiders are especially acute.
Cave spiders are accustomed to hiding in sand piles or burrows and waiting for their prey to arrive, such as tarantulas, cast spiders, and Sydney funnel-web spiders. The Amazon giant tarantula is really the "giant" of the spider family, with a foot span of up to 30 centimeters, 10 times that of the orb-web spider, and about 700 times the size of the spider. In its recipe, in addition to insects, there are frogs, lizards and birds. All spiders are venomous (spider venom has important medicinal properties), but the Sydney funnel-web spider is the most venomous spider in the world, and its venom contains atracotoxin (a neurotoxin), A single sting can easily kill an adult. They not only hunt insects, but also larger frogs and lizards. The burrowing tarantula is very special. It builds a burrow but does not bother to build a web. Relying on the highly poisonous chelicerae, it directly attacks its prey violently. Tarantulas have a fierce temperament, but they treat their children with tenderness.
Safari spiders live in no fixed place and forage for food, such as jumping spiders, cat spiders, crab spiders, flat-bellied spiders, etc. Crab spiders do not build webs, and often lie in the flowers and grasses waiting for passing insects. Flat-bellied spiders are intelligent and strategic, and do not rely on brute force to win. When it preys, it always cautiously approaches prey such as cockroaches, secretly releases silk threads to entangle the prey, and then finds an opportunity to strike the neck of the prey with a fatal blow. In addition, the Nepenthes flower spider will use the spider silk as a "safety belt" or "airbag" to steal the prey captured in the pitcher's bottle (for details, please refer to "Encyclopedia Knowledge" 2016.02A "Nepenthes and Small Animals" "The Convenience Store of Flower Spider").
Of course, spiders don't strictly adhere to three distinct lifestyles: netting, burrowing, or hunting. For example, males and females of the meteor hammer spider hunt very differently. Really worthy of the title of the meteor hammer spider is the female spider. Female spiders make a "meteor hammer" out of silk and mucus and lure moths with their scent. When the moth gets close, it moves the meteor hammer frantically until it sticks its prey. The male spider is a "pocket man", can't dance the "meteor hammer", and can't catch big moths, it simply doesn't bother to make tools, just lurks among the leaves, directly catching small flies with its furry appendages .
A mimetic spider does not build its own web, it feeds on other webbing spiders. It first invades the prey spider's web, and then gently tugs the spider silk to send out deceiving signals, disguising itself as a smaller intruder, to lure the web owner to come. When the prey comes into attack range, the mimetic spider touches the prey very gently, numbing the prey with the venom in its chelicerae when it is unsuspecting.
Many misunderstandings about spiders
In ancient times, some people regarded spiders as auspicious signs and called them "happy spiders". "Xijing Miscellaneous Notes" said: "The spider gathers and the Pepsi is good." This refers to the annual custom of "happy spiders should be clever". This custom may have originated in the Northern and Southern Dynasties. At that time, the famous scholar Zong Yi's "Jing Chu Sui Shi Ji" has a relevant account: "On the evening, Chen Guaguo was in the court to beg for skill. If you had a xizi net on the melon, it was considered a match. "On the night of Qixi Festival, people put melons, peanuts, red dates, etc. in the fruit bowl, and girls in new dresses begged for wisdom from Vega in the courtyard. Whoever is lucky. "Xiko" is a spider, a small long-legged spider. In an empty courtyard, at night, spiders release their silks to prepare their webs. If the spider silk does not attach to anything, and it happens to encounter an upward air current, the light spiders will rise into the air and fly with the wind. It happens to fall in the fruit bowl, that is, joy falls from the sky.
"Butterflies dance with powdered flowers, and spider webs add silk to the corner of the house." Butterflies dance in the flowers, deliberately exposing their pink wings to the sun, and spiders are busy around the corner of the house, carefully adding silk and weaving while the sky is sunny. cobweb. Song Dynasty writer Zhang Lei showed a leisurely mood through "Butterfly drying powder" and "Spider web adding silk", comparing spiders and beautiful butterflies, and writing their activities with great interest.
However, there are not many people who like spiders like Zhang Lei. In books, movies, and TV shows, spiders are often a symbol of horror. Many people not only judge "spiders" by their appearance, and think that spiders are indecent, but also disdain and even dislike the stunt of spiders for spinning their webs. They think that spider webs affect cleanliness and are not beneficial to humans. More people are afraid of the poison of spiders, and the fear of spiders is even more than that of scorpions and other poisons. Zheng Qingzhi of the Southern Song Dynasty called the spider "full of poison as big as a scorpion". In fact, although spiders are poisonous, most of them are not that scary. Most spiders are not very venomous, and their stingers do not easily penetrate human skin. Therefore, deadly threatening spiders are rare. Even if bitten by this spider, most of the conditions can be cured with existing medical conditions.
Poets have compared spiders to silkworms, which also spin silk, and seem to be making a judgment call. Meng Jiao criticized the spider: "Silk is the clothes, and Ru silk is the snare. It's almost useless to help things, and the harmful things are too many days." Su Zheng also accused: "The spring silkworms spit out silk, which has made great contributions to the world. Blood is gathered. Silk is patented, and silk is sinful.” Yang Liluo, a singer-songwriter of the late Tang Dynasty, also used spiders to ridicule the fat monk Yun Bian: “I have eaten my stomach, and I am thinking about going around the temple. "
However, what must be justified for spiders is that their "harms", "blood gathering" and "killing all beings" actually eliminate a large number of agricultural and forestry pests for human beings. One arthropod scientist even said: "If spiders disappear, human beings will face famine." We actually know very little about the 8-eyed, 8-legged, and unpopular creatures like spiders. As a natural "netizen", the skill of spiders has attracted the attention of many people. Spiders know how to survive and are the perfect combination of weakness and strength. Spiders are indeed worth studying, and the more you study, the more you discover the sparkle in them.