why do spiders spin webs at night
To create the initial base line, the spider uses
the wind to carry its initial sticky thread. The
silk is released from its spinnerets and carried by
the wind to a suitable surface. When it sticks to a
surface the spider will carefully walk over the
thread and strengthen it with a second thread. This
process is repeated until the primary thread is
strong enough to support the rest of the netting. After strengthening the first thread, the spider
will continue to make a Y shaped netting. The first
three radials of the web are now constructed. More
radials are added making sure that the distance
between each radial is small enough to cross. This
means that the number of radials in a web directly
depends on the size of the spider plus the size of
After the radials are complete the spider will
strengthen the centre of the web with about five
circular threads. Then a spiral of non-sticky,
evenly spaced, circular threads are made for the
spider to easily move around its own web during
construction. Then, beginning from the outside in,
the spider will methodically create the adhesive
spiral threads. It will use the initial radiating
lines as well as the non-sticky spirals as guide
lines. The spaces between each spiral will be
directly proportional to the distance from the tip
of its back legs to its spinners. The spider uses
its own body as a measuring/spacing device.
the sticky spirals are formed, the non-adhesive
spirals are removed as they are not needed any more. After the spider has completed its web, it will chew
off the initial three centre spiral threads then sit
and wait with its head down, in the web for its prey
to come along. If the web is broken without any
structural damage during the construction, the
spider does not try to remake it as this would use
up too much energy and it will probably be taken
down in the morning or repaired the next night.
Spider webs are a masterpiece of structural engineering. Whether you re looking at the strength, the architectural organization, or even the make-up of the webbing itself, it s hard not to be impressed by the construction abilities of spiders.
But how do they decide where to build? In response to seeing this genuinely impressive use by a spider of a rock as a counterweight pillar to anchor a web (seriously, a discussion began about another seemingly clever engineering decision that commenter had noticed among the spiders at her house. I have a healthy respect for spider ingenuity. One summer, these penny sized spiders kept making huge webs in the evening on the front porch that we kept walking into when we came out of the house. But, after about a week, the spiders moved their webs up and to the right about a foot, just enough to let a human pass by without hitting it.
On the plus side, it was surprisingly considerate of them. On the minus side, the spiders are LEARNING. I have some spiders around my house that do this. They build their webs about 3 inches taller than I am, regularly. It can t be an accident that they all do it, every time. They re learning, and possibly communicating about it? Well, a lot of spiders rebuild their webs every day, so it makes sense that they d have some way of adjusting its positioning to avoid continual problems. Still, pretty impressive work for things that barely weigh anything at all, especially with how precise they d make it to avoid humans. It turns out spiders do, indeed, have a method for determining the position of the next day s web, and (alas! ) it has very little to do with polite spiders trying to keep their webbing (literally) out of your hair.
We already know that there are many different kinds of spiders and, therefore, many different kinds of webs, but even within a single web there are different kinds of threads. One of the most important structural parts of a web is a thread called a bridge line. it also serves as a web to a more stable point (a wall, or a tree, for instance. ) While the spider may not leave its whole web up overnight, if the bridge thread has survived the day (i. e. by not being pulled down by a passing person), the spider will often leave just a bridge thread up to build the next day s web.
- Autor: HellenHarwell
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