THE MARVEL OF SPIDERS

If you have ever taken an interest in spiders, you will definitely observe that these are some of the most amazing animals on earth. From a lot of observations and studies about spiders, they are wonderful creatures blessed with skills, and they deserve our attention.

We are going to be taking a look at some of the mind-boggling and indeed interesting features of spiders.

EYES

eyes of jumping spider
 

Spiders have two true eyes and six eye spots, that is eight parts that look like eyes with only two actually used for sight. Spiders do not see very clearly, so they have other features that make them move freely without hitting things unnecessarily. But what significant purpose do their true eyes serve?

Research shows that the Jumping spider, like many other spiders, can catch insects for food in one jump. To do this, those same eyes with faint sight are needed.

The Jumping spider have a retina (the part of the eye that sends message to the brain about what it receives as light and still changes the brains message to the things we see as objects) in each of their true eyes that have multiple layers. One layer receives green light and is seen as an image that is not clear in another layer. As another layer receives light, the image becomes larger as other layers see the image of the target. This method helps a spider to understand how far a prey is from it and to know how far and fast to jump in order to catch it. It is like trying to adjust a camera as you increase the size of the object you want to snap. The more you zoom in on the image, the more details about it you will get.

SILK (WEB)

photographic (above) and diagram (below) renditions of drag-line web

When we think of spider’s web, we often imagine something confusing that is designed naturally by spiders and that are soft and easy to pull off our walls with brooms. But have you ever thought of cobwebs that are strong enough to stop a bullet?! That seems impossible, and truly many spider webs cannot do that. But some are able to. Consider the spider web of drag-line silk produced by orb-weaving spiders.

This is the strongest spider silk so far discovered. It is stronger than steel. It is also far stronger than Kevlar, the material used to make a lot of bullet proof vests.

While Kevlar is produced under very strong heat, this type of spider silk is produced inside the spider and obviously at far much lower temperature.

The materials used by orb-weaving spiders to produce drag-line silk are not known, and the strength of this type of silk is not fully understood. But if drag-line web is made as large as a football field, it will catch a big jet flying at high speed! Just imagine that!

LEGS

Spiders have eight legs that are amazing. The movements of these legs to carry spiders about as well as their features make them worthy of consideration. In fact, think of spiders’ legs as ears, tongue and nose too.

a ballooning spider floating on air

Spiders have very light weight. As such, they rely on breeze to make them run faster or even float on air. This is done by keeping the four middle legs on the ground and lifting up the two front legs and two back legs so that they can be easily pushed faster by the wind. This method of movement is called ballooning. This is a reason why spiders walk as if they are dancing or gliding through the ground.

The legs of spiders are also full of hairs called setae. These hairs act like foam to prevent a spider’s footsteps from being heard as they move to catch their prey.

Have you ever wondered why spiders are not caught in their own web? Do they have immunity over the stickiness of their web? The answers also lie in their legs and in something about their web.

satae and claws of spider legs

Some of the silk produced by spiders to make their web are not sticky, and spiders are fully aware of which parts of their webs are sticky and which parts are not. They also make sure of not stumbling on the sticky sides by walking in a very confident manner, firmly grasping the non-sticky silks as they walk. They also make sure they don’t get stuck to sticky silk by holding unto each silk firmly with their claws. So, as to whether spiders are immune to the stickiness of their web, the answer is No! But skills and intelligence enable them escape. 

Spiders do not also have ears and nose. But can they hear and smell? Yes! How? The secret also lies in their hairs.

Spider hairs are connected to tiny points called nerve endings that connect very tiny parts like thread called nerves to the brain of spiders. When air flows, the hairs sense them as sound more clearly than we feel cold wind over our bare body at night.

Not long ago, it was also discovered that spiders can sense air movements (sound) using their webs. These webs are so light that they can also respond to very tiny sound (as low as 10Hz) lower than what humans can hear (20Hz). So spiders can feel the vibrations on the web when they are on top of it. The spider webs serve as giant “ears.”

Finally, the special organs found on their legs and pedipalps (swollen male organ for pushing sperm into female spiders) enable spiders to both taste and smell as make use of chemical detected in the air, such as olfactory chemicals or scents called pheromones that they sense in order find their mate. As for tasting, this is not totally verified. But since most chemical combinations of taste are actually those of smell, it is believed that spiders can also detect taste.