”Now think about an animal you never want to kiss!”, this is the last verse of the riddle of the sphinx in the labyrinth. For Harry Potter the solution is clear. He never wants to kiss a spider and with this emotion he is not alone. A lot of people don’t like spiders and find them disgusting and dangerous. Of course with their eight legs, 4 pairs of eyes and the sharp teeth of the jawbone they really look a bit gruesome, but in general the lest of the 45.000 kinds of spiders in the world could be dangerous for humans. Especially in the western industrial countries there are no very dangerous types. But in these nations live the most people with fears of spiders. In other parts of the world people tolerate spiders much more, because they keep mosquitos away from their houses. In parts of West-Africa the spider “Anansi” is worshipped as a god. It should be the origin of all knowledge, the inventor of farming and the god of rain and the weather. On the other hand bird spiders are a delicacy in Cambodia. There they become fried and are sold as street food.
But now, let’s have a clearer look at these animals. Spiders are no insects. They belong to the family of the arachnids. Since around 400 million years they exist on our earth and the most of them are less than 1centimetre small. Bird spiders have with up to 12 centimetres the biggest body.
Although spiders have many eyes, but they can see very bad. For orientation, they mostly use the small hairs at their legs. With them they can feel sound waves and weak breezes as well as vibrations. Also, spiders smell with their hairs at legs and mouth. In contrast to insects the body of spiders is only divided into two parts, the front abdomen and the tail. Spiders mostly hunt at night. So usually they have a dark colour. Spiders hunting at the day are more colourful or have white stripes.
Spiders are eating insects. Some kinds jump on their victims but the majority build spiderwebs to catch their food. Very popular is the spiderweb in the figure of a wheel. It includes five different types of spider silk. First the spider builds the frame of the web with a very tear proof material. The middle of the web is made of different kinds of silk, which are more elastic and sticky. After an insect was caught at the web the spider is going to kill it. A spider has two different kinds of toxin. With the first bite the spider paralyses its victim. With the second one it injects a toxin which dissolves the inner organs of the insect. When the insect has more the consistency of paste the spider drinks it.
Today spider silk is very interesting for scientists. In the modern medicine spider silk can help to close sores and is useful to heal burnings or destroyed nerves. A filament has a diameter of 0,002 millimetre. It is very strong, elastic, antibacterial, heat-stable till 200 degree and biodegradable. Because of these characteristics’ spider silk is going to be the new biological material of the future. It is very difficult to take spider silk, because spiders producing a low-quality material when they are kept in captivity. Also, they are cannibals. So it is not easy to hold a lot of them together. Currently scientists are researching in the area of synthetic spider silk. This product is based on bacteria and should be used in the fields of medicine as well as cosmetic.
– by Linda M. –
Sources:
http://www.biospektrum.de/blatt/d_bs_pdf&_id=981493
https://www.swr.de/swr2/programm/sendungen/wissen/spinnenseide/-/id=660374/did=16631110/nid=660374/1vurhn3/index.html
https://www.wasistwas.de/archiv-natur-tiere-details/wieso-sind-spinnen-keine-insekten.html
http://www.lernspass-fuer-kinder.de/aktuell/tier-des-monats-spinnen/