Did You Know About Spiders .

The spider , also called spiders , are jointed - book kind of animal ( an arthropod ) with two body segments , four pairs of legs , no wings and do not have a mouth chewers . All types of spiders are classified into the order Araneae , and along with scorpions , scorpion , eight-legged mite - all - put in the class Arachnida . Field study of spiders called arachnologi .
Spiders are predators ( carnivores ) , sometimes even cannibals . Its main prey are insects . Almost all types of spiders , with the exception of about 150 species of the tribe Uloboridae and Holarchaeidae , and suborder Mesothelae , be able to inject through a pair of fangs to the enemy or prey . Nevertheless , tens of thousands of species that exist , only about 200 species that can harm human bite .
Not all spiders make webs to catch prey , but all of them are capable of producing silk yarn - the strands of protein fibers are thin but strong - of the gland ( called spinnerets ) located on the back of his body . The silk fiber is very useful to help the movement of the spider , swinging from one place to another , entrap prey , making egg sacs , protecting the nest hole , and others .

Morphology .

Anatomy of a spider :

( 1 ) four pairs of legs
( 2 ) cephalothorax
( 3 ) opisthosoma
Unlike insects have three body parts , spiders only have two . Front segment called the cephalothorax or prosoma , which actually is a combination of head and chest ( thorax ) . While the rear segment called abdominal ( stomach ) or opisthosoma . Between the cephalothorax and abdomen are thin connective called pedicle or pedicellus .
In four pairs of legs attached to the cephalothorax , and one to four pairs of eyes . In addition to a pair of large fanged jaws ( called chelicera ) , there are also a pair of mouth or some similar hand tools called pedipalps . In some types of spiders , the pedipalps adult males enlarged and changed function as a tool in marriage .
Spiders do not have mouth or teeth to chew . In return , the mouth of a spider vacuum to suck the prey 's body fluids .

Senses .

Eye on spiders generally a single currency ( single lens eye ) , and not like the compound eyes of insects . Most spiders have eyesight is not so good , can not distinguish colors , or just on dark and light sensitive . Spider cave dwellers have even blind . There are exceptions in some kind of spider hunters who have sharp eyesight and good , including in recognizing colors .
To mark the presence of prey on spiders generally rely on vibrations , both in silk nets or on land , water , or place its host . There is also a spider that is capable tasted the difference in air pressure . The sense of touch a spider located at the hairs on his legs .

Predation .

Most spiders is indeed a predator ( predator ) interceptor , which is waiting for prey to pass nearby while hiding behind a leaf , petal layers , rock crevice , or a hole in the ground that was covered in camouflage . Some types have color patterns that disguise herself on the ground , rocks or tree pepagan , so no need to hide .
Weaver spider ( eg tribal members Araneidae ) make silk nets approximately spherical shape in the air , among the leaves and twigs , on the face of the rock fractures , in the corners of the building , between the telephone wire , etc. . These nets are attached , to catch flying insects that become prey . Once trapped insect webs , the spider promptly walked over and thrust its fangs to immobilize prey to simultaneously transmit and digestive enzymes into the prey 's body .
Slightly different , spider hunters ( such as members of the tribe Lycosidae ) are usually more active . Type of spider is common to explore the trees , grass sidelines , or the surface of the rocky wall to search for prey . This spider can jump to chase and pounce on its prey .
Can be injected through fangs spider is usually well digested and destroyed parts of the prey's body. Then slowly crushed organs and their bodily fluids in it is inhaled by the predator. For hours the spider suck up the liquid that dries prey carcasses. Spiders have jaws (chelicera) stronger, get faster spend their food by damaging the body and crush prey with the jaws and fangs. Live the rest of the little balls that are crushed prey body had shrunk.
Some weaver spiders have the ability to wrap the body of its prey by winding threads of silk . This capability is very useful especially if the prey has a self defense tool that is dangerous , sting like a bee that has , or if the spider wants to save some time while waiting for their prey when preferred to enjoy it later .

The diversity of type. 

Until now, approximately 40,000 spider species have been described, and graded into 111 parts. However, given that these animals are so diverse, many of which are very small stature, often hidden in nature, and even many specimens in the museum are not in the description well, it is believed that the possibility of a variety of types of spiders can reach 200,000 species entirely.

Order spider is further divided into three major categories at the level of the suborder , namely :

Mesothelae. 

which is a primitive spider was venomous , with the segments of the body are clearly visible ; shows a closer genetic relationship with the ancestral arthropod jointed .

Mygalomorphae or Orthognatha. 

was to a group of spiders that make burrows hiding , and also makes a hole in the ground trap . Many large -bodied species , such as tarantulas and also lancah maung .

Araneomorphae is a group of spiders ' modern '. 

Most spiders that we encountered included in this suborder , given that its members consist of 95 parts and covers approximately 94 % of the number of spider species . Fangs of this group leads slightly tilted forward ( and not upright like the tarantula group ) and moved in the opposite direction as the claw biting prey .
A new study says that every pair of eyes eight spiders have special functions . It is known through the study of jumping spider .
Jumping spiders is a group of spiders that actively hunt prey . They do not use webs to trap prey .
A study of spiders reveals that the eye or eye at the center of the main pair of eyes can see in good detail . While a pair of eyes that is beside the function gives a warning when something is approaching .
These responses similar to those seen in humans who ducked when he saw the ball coming toward his face . However , human enough to avoid the use of two eyes and see the detail of the ball , while the spiders use four eyes for the same task .
" We found such a division of labor within the visual system , " says researcher and doctoral student at the University Skye Long to Live Science .
The researchers captured wild spider Phidippus audax is a species of jumping spider . They mark each pair of eyes that spider eyes with green and orange paint instead of a blindfold. 16 spiders covered his main eye , eyes covered 14 secondary tail called the anterior lateral .
Then use the iPod touch , the researchers examined the response of the spider . On the iPod touch screen has appeared a black spot will swell rapidly when researchers hit the play button . If able to detect motion , then the spider who saw it responds by moving backwards or lift the front legs .
Spiders secondary closed eyes did not show any reaction when the test is done . Meanwhile, according to Long , " spider eyes closed primarily move like a spider whose eyes were not covered . "

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Thank you for reading this article . Written and posted by Bambang Sunarno.
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DatePublished: February 15, 2014 at 10:23

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Tag ; Did You Know About Spiders, spider.