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Most spiders' eyes can detect little more than brightness and motion, so vision plays only a minor role in behaviour. However some species, such as jumping spiders, wolf spiders, and deinopids, have more developed eyes which they use in hunting and courtship. [2]
Spiders do not have compound eyes, but instead have several pairs of simple eyes with each pair adapted for a specific task or tasks. The principal and secondary eyes in spiders are arranged in four, or occasionally fewer, pairs. Only the principal eyes have moveable retinas. The secondary eyes have a reflector at the back of the eyes.
Spiders also have several adaptations that distinguish them from other arachnids. All spiders are capable of producing silk of various types, which many species use to build webs to ensnare prey. Most spiders possess venom, which is injected into prey (or defensively, when the spider feels threatened) through the fangs of the chelicerae. Male ...
In web-building spiders, all these mechanical and chemical sensors are more important than the eyes, while the eyes are most important to spiders that hunt actively. [ 13 ] Like most arthropods, spiders lack balance and acceleration sensors and rely on their eyes to tell them which way is up.
Caponiidae are unusual in the degree to which the eye number varies. In this they surpass even the family Cybaeidae in which some species have two eyes, some six, and some eight. In some species of the Caponiidae paired eyes meet in the midline, giving the spider in effect, an odd number of eyes. The following genera have eyes as follows:
The "factoid" is definitely eye-catching — but it's also improbable. A spider could do this only a few ways, like using its silk to float and land in a sleeping person's mouth.
Spiders could, theoretically, eat every single human on earth within one year. It gets worse. Those humans consume about 400 million tons of meat and fish each year, so ultimately, the tiny ...
Forest Spiders of South East Asia: With a Revision of the Sac and Ground Spiders. Brill Publishers. ISBN 978-9004119598. Eaton, Eric R.; Kaufman, Kenn (2007). Kaufman Field Guide to Insects of North America. Houghton Mifflin Harcourt. ISBN 978-0618153107. Filmer, Martin R. (1991). Southern African Spiders: An Identification Guide. Random House.