Spiders make lots of kinds of webs. The webs
serve at least 2 purposes - catching the prey
and protecting the spider from getting eaten.
Orb webs are probably the most famous type of
spider web. They certainly have spaces big enough
for insects to fly through, but they have 2
features that are good for catching the prey and
protecting the spider. The spiral part of the
orb web is made of "capture silk," and it's
sticky, so the insects stick to the capture
silk. Also, when part of the web wiggles, the
spider can feel the movement, wherever it is on
the web, which alerts the spider to either food
for it or a predator wanting to eat the spider.
The capture silk spiral is attached to another
type of silk related to dragline silk. It's
stronger than capture silk but not sticky, and it
forms the spokes of the wheel-like orb web.
Other spider webs have closer spaced silk
strands and would seem to have better geometries
for trapping insects by having them get tangled in
Some of these webs are sheet webs and frame webs.
One type of spider, Agelenidae, weaves a dense
sheet of web with a funnel-shaped hole at one end
where the spider can hide until it senses prey and
comes out to eat it. I've seen these webs in tall
grass, where they're near the ground. They're
easier to see in the early morning when they have
dew on them.
Another spider type, Linyphiidae, builds
sheet-like webs that can be nearly 2 ft across!
The dense sheet-like webs are held up by many silk
strands related to dragline silk, and the insects
hit those silk strands and then drop down onto the
I got some of this information from a book
called "Biology of Spiders" by Rainer Foelix.
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