5 facts about spiders - scary but very useful creatures

1. Some spiders feed their offspring with milk

Everyone knows that animals produce milk. Some may also know that some birds - certain species of pigeons, parrots, flamingos and penguins - can develop so-called goiter milk. What do you think of...a mammalian spider?

Researchers from the Chinese Academy of Sciences discoveredthat some species of jumping spiders, in particular Toxeus magnus, feed their young with a milk analogue. Previously, it was believed that this level of care for offspring was not characteristic of arthropods.

The spider produces "baby food" for her brood, containing almost four times more protein than cow's milk, as well as sugar and fat.

First, the female lays from 2 to 36 eggs. And when the babies hatch, she secretes droplets from her epigastric groove. This is the hole in the abdomen from which the eggs emerge. The offspring feed on this milk for about 20 days. However, even after children grow up and begin to hunt, they continue to supplement their diet with mother's milk for another 20 days.

The spider feeds its offspring with unfertilized eggs. Video: Science News / YouTube.com

Researchers suggest that this milk consists of liquid spider eggs - some animals also feed their young in this way. For example, frogs and bees.

2. The web can be very strong

It would seem that a web is something fragile and ephemeral. But in fact, fiber built from protein is one of the strongest materials in nature. In terms of tensile strength, spider silk can be compare with alloy steel, but at the same time it is also plastic - capable of stretching five times.

This allows arachnids create incredible designs. For example, the Madagascar Darwin spider (Caerostris darwini), whose silk is 10 times stronger than Kevlar, builds giant networks up to 28 m². For such a megaproject, these creatures gather in groups and work together on their trap, which then feeds the entire population.

Can you imagine how many flies can fly in there?

And this material can be made even stronger. Scientists from the University of Trento in Italy came up with Spray spiders of the species Pholcidae with water containing graphene particles, and the arthropods began to produce silk reinforced with carbon nanotubes.

Dress made of undyed spider silk. Video: On Demand News / YouTube.com

You can even make clothes from spider silk, but it costs a pretty penny. So, in 2012, fashion designers presented a golden cloak made from the silk of 1.2 million Madagascar spiders. The fabric was a natural yellowish color and it took 8 years to collect enough webs.

3. Spiders can fly using electricity and walk on water

People who afraid of spiders, console themselves with the thought that these creatures cannot fly. And therefore, they don’t land on their heads. Now, that's not true. Spiders fly. Live with it now.

Of course, a huge furry tarantula will not open its wings and migrate from the jungle to the urban areas of the middle zone by air. But small species of spiders travel quite well in the sky. They release a thread of silk from their abdomen, which works much like a sail or paraglider, and take off. Some people manage to overcome this distances more than 1,600 km, rising to a height of up to 5 km.

One study showsthat spiders do not use the wind to create lift. Their threads accumulate a static charge, which interacts with natural electric fields in the atmosphere. And the spiders literally levitate. And then, having reached higher layers of the atmosphere, arthropods travel around the world using air currents.

This ability is very useful for expanding the range of spiders.

Moreover, arthropods that practice flight also you worked has the useful ability... to walk on water. This comes in handy when you land before reaching the shore.

The spider quickly drops its parachute so that it does not drag it to the bottom, and runs along the water surface with a messianic gait thanks to the hydrophobic surface at the tips of its paws. At the same time, the arthropod is able to survive waves up to one and a half meters in height and adapts to both fresh and salt water.

4. Spiders have a very difficult sex life

At all, intimate life spiders are much more complex than one might imagine. Thus, males do not copulate with females in the usual sense. Instead, the spider spins a small cocoon, spews sperm inside, and then grabs it with its pedipalps (forelimbs that serve as jaws) and inserts it into the female's genitals.

You got it right: the spider transfers its genetic material to its girlfriend with its own mouth.

By the way, there are no nerves in the clawed tips of the pedialps, so few people manage to get where they need to go the first time.

Many people have also heard that female spiders eat their partners after mating. Some individuals actually do this, but not always. Even the famous black widow eats her lover only if she is hungry and he is running slowly.

But still, before the female allows her boyfriend to enter her body, he has to go through a thorny path. Some males, for example, perform complex mating dances in front of their chosen one. This is necessary to let her know that he is not food.

A peacock spider performs a mating dance. Video: Dario Trovato Videomaker / YouTube.com

Other species resort to more sophisticated courtship. Yes, pisauras bring give his ladies a treat before the meeting to prevent aggression on her part. Particularly inventive individuals wrap something inedible in a cocoon, and while the female is busy unpacking the gift, they quickly complete their business and leave without saying goodbye.

And some males, for example Latrodectus hasselti, lose so much strength during ejaculation that they soon die from exhaustion themselves. And they literally forcefully climb in between the jaws of the female so that she eats them, even if she is not hungry. Well, so that his death would not be in vain and the extra calories would go to feeding the eggs.

5. Spiders eat more than people

Once, ecologists from the University of Basel in Switzerland calculated how much spiders eat. And this is the data they received. Humanity consumes on average 400 million tons of fish and meat every year. The blue whale keeps pace with humans, consuming between 280 and 500 million tons of plankton. But all this is nonsense compared to what spiders eat - they consume up to 800 million tons insects annually.

How was this calculated? Well, scientists have added up average biomass values ​​from a number of different terrestrial biomes, including forests, grasslands, croplands and other areas. And they came to the conclusion that there are now about 25 million tons of spiders on Earth. And then ecologists figured it out, how much one individual eats, and multiplied the values.

Yes, 25 million tons of spiders on our unfortunate planet devour 800 million tons of insects every year.

And although arachnophobes will shudder at the thought of such numbers, it is good that there are so many spiders and that they are so voracious.

The fact is that these arthropods devour a huge number of pests - among their victims aphid, caterpillars and weevils that destroy every year one fifth of the world's crops. If spiders became extinct, humanity would face a famine the likes of which the world has never seen.

Employees of Hubei University in China tried to purposefully breed spiders in cotton fields, and arachnids allowed reduce the use of pesticides by as much as 80%, exterminating pests much more effectively than chemicals. So eight-eyed, eight-legged monsters can be of great benefit.