The Water Spider – although very small and harmless in appearance, is poisonous. It is notable for the fact that it lives underwater, for which it constructs a dome with air. Small droplets of water on its hairs, refracting through the air of the dome, shine in the sun and create a silvery glow.
Origin of the Species
Arachnids arose a very long time ago – the oldest fossil species are known in the Devonian sediments, and this is 400 million years BC. It was they who came out on land first, then their main distinguishing feature – the spiderweb apparatus, took shape, and according to the assumptions of some scientists, it could even have arisen in the water. The degree of development of the spider, its place on the evolutionary ladder is largely determined by the use of the web – the most primitive species use it only for cocoons, just as their most distant ancestors did. As spiders developed, they learned to use the web in other ways: to make nests, networks, signaling systems out of it.
According to paleontologists, it was the invention of the trapping web by the spiders of the Jurassic period, along with the appearance of flowering plants, that made the insects acquire wings and rise into the air – they sought to escape from the abundance of nets spread by spiders. Spiders turned out to be very tenacious and during all five big extinctions, when most of the species disappeared from the face of the Earth, they managed not only to survive but also to change relatively little. Nevertheless, modern species of spiders, including the Water Spider, originated relatively recently: most of them are from 5 to 35 million years old, some even less.
Gradually, the spiders developed, so their initially segmental organs began to function as a whole over time, the abdomen also ceased to be segmented, the coordination of movements, and the speed of reactions increased. But the evolution of most of the genera and species of spiders has not yet been studied in detail, this process continues. This also applies to the Water Spider – it is not yet known for certain when they originated, as well as from whom. It is almost definitely established that they became an example of the return to the sea of land arachnids. This species was described by Karl Alexander Clerk in 1757, received the name Argyroneta Aquatica and was the only one in the genus.
Interesting fact: Spiders are incredibly tenacious creatures – so, after the eruption of the Krakatoa volcano, when, as it seemed, lava destroyed all living things, having arrived on the island, people were the first to meet a spider that spun a web the middle of the lifeless desert.
Appearance and Features
In structure, it differs little from ordinary spiders living on land: it has four jaws, eight eyes, and eight legs. The longest of the paws are located at the edges: the front ones are adapted for grabbing food, the rear ones for swimming – and the Water Spider is good at doing this. At only 12-16 mm long, females tend to be closer to the lower end of the range and males to the upper. They also differ in the shape of the abdomen: the female is rounded, and the male is much more elongated.
For breathing, the Water Spider forms an air-filled bubble around itself. When the air comes to an end, it floats for a new one. Also, to breathe, the spider has one more device – the hairs on the abdomen lubricated with a waterproof substance. With their help, a lot of air is also retained, and when the spider floats up for a new bubble, it at the same time replenishes the supply of air retained by the hairs. Thanks to this, it feels great in the water, although it is necessary to float to the surface dozens of times a day.
The color of the Water Spider can be either yellow-gray or yellow-brown. In any case, a young spider has a light shade, and the older it gets, the more it darkens. At the end of his life he turns out to be almost completely black – so it is very easy to roughly establish his age.
Habitat
Water Spider prefers a temperate climate and lives in the territories of Europe and Asia located in it – from the Atlantic Ocean to the Pacific. The spider prefers to live in stagnant water, but the water that will flow, but slowly, is also suitable, which means that its main habitats are rivers, lakes, and ponds. He especially loves abandoned, quiet places, preferably with clean water.
It is also desirable that the reservoir is abundantly overgrown with vegetation – the more there is, the higher the chance that Water Spider lives in it, and if there are, then most often there are many of them at once, although everyone arranges for himself a separate nest. Outwardly, a spider’s dwelling can either resemble a thimble or a small bell – it is woven from a web and is attached to the stones at the bottom.
It is very difficult to spot the spider as it is almost transparent. Also, it does not allow air to pass through. The spider spends most of the time in its underwater nest, especially for females – it is reliable and safe, because signal threads stretch from it in all directions, and if there is a living creature nearby, the spider will immediately know about it.
Sometimes the spider builds several nests of different shapes. These spiders can be kept as pets. This is quite rare, but it happens, because they can be interesting for their nests and silver glow. One spider can be kept in a small container, and several will need a full aquarium. They do not conflict with each other, but if they are undernourished, they can enter into a fight, after which the winner will eat the loser. They adapt well in captivity, but they need to arrange an environment of aquatic plants, and so that some of them appear on the surface (or throw branches) – this is necessary for the spiders to get out for air.
Although spiders are poisonous, they do not tend to attack humans, this is only possible if the spider is defending itself – such situations can arise when the Water Spider is caught along with the fish, and the spider thinks that it has been attacked. Usually, he tries to escape from people.
Food
The spider’s diet includes small animals that live in the water, these are:
- aquatic insects;
- larvae;
- water donkeys;
- flies;
- bloodworm;
- small crustaceans;
- fish fry.
When attacking, the spider entangles the victim with a web to restrain its movements, plunges chelicera into it, and injects poison. After the prey dies and ceases to resist, it introduces a digestive secret – with its help, the tissues liquefy, and it becomes easy for the Water Spider to suck out all the nutrients from them.
In addition to hunting, they drag away and digest already dead insects floating on the surface of the reservoir – flies, mosquitoes, and so on. Most often, in captivity, the water spider is fed with them, it can also feed on cockroaches. It drags prey with the help of a web into its dome and eats it already there. To do this, he lies on his back and processes the food with a digestive enzyme, and when it softens enough it sucks into itself, then what turned out to be inedible is removed from the nest – it is kept clean.
In the ecosystem, these spiders are useful in that they destroy the larvae of many harmful insects, for example, mosquitoes, preventing them from over-breeding. But they can also be harmful because they hunt fish. However, the weakest become their prey, so that they do not do much harm to the fish population.
Interesting fact: Although the Water Spider has many eyes, most of all during the hunt he relies not on them, but his web, with the help of which he can feel every movement of the victim.
Features of Character and Lifestyle
The Water Spider goes hunting at night, resting most of the day. Females rarely get out of the nest except to replenish their air supply – except for hunting. But even she is often led passively, barely leaning out of the nest, and waiting until some prey is nearby.
Males are much more active and can move away from the nest to a distance of up to ten meters in search of food. Although most often they also remain within a meter or two, under the protection of their networks, ready to respond to signals emanating from them at any time.
They can hibernate either in cocoons, which they weave themselves, or in empty shells of mollusks. Spiders prepare the shells of mollusks for wintering in a very interesting way: they drag the air inside until they float, then attach them to the duckweed and crawl inside the shell. When the shell is ready, you can hibernate – the inside will be warm enough for the Water Spider to survive even in the most severe cold. Such floating shells can be seen in the autumn months – this is a sure sign that the spider lives in the reservoir because shells rarely float without their help.
When winter comes, the duckweed falls off, and the shell goes to the bottom with it, but thanks to the dense web, the water does not flood it, so the spider hibernates successfully. In the spring, the plant emerges, and with it the shell, feeling the warmth, the spider wakes up and gets out. If the summer is dry and the reservoir is dry, then the Water Spider simply make cocoons and hide in them from the heat, waiting until they find themselves in the water again. Or they may fly away on the cobweb in search of a larger, still-dry reservoir. In any case, they are not threatened with death in such situations.
Social Structure and Reproduction
They settle in groups, although each individual lives in its own nest at a short distance from the others. They do not conflict with each other, but in rare cases, cases of cannibalism are known. This is also possible when kept in captivity if there are too many Water Spiders living in one aquarium. Both individuals of the same sex and different ones can live nearby since the females of the Water Spider are not inclined to eat males. Spiders often live in pairs, placing nests near each other. Females breed in the nest.
At the onset of a warm spring, a female carrying eggs makes a clutch in her nest: usually, there are about 30-40 eggs in it, sometimes much moreover one and a half-hundred. She separates the masonry from the rest of the nest with a partition and then protects it from intrusions, practically without leaving. After a few weeks, spiders appear from the eggs – they are developed in the same way as adults, only less. The spider mother continues to take care of them until they leave her – this happens quickly, the spiders grow in just two to three weeks. After that, they build their own nest, most often in the same reservoir. Although sometimes they can travel, for example, if there are already many spiders where they were born. They climb a plant, launch a thread, and fly along with it in the wind until they reach another body of water.
Interesting fact: When keeping small spiders in captivity, it is necessary to resettle, because otherwise there will be too little space in it, and they may even be eaten by their own mother. This does not happen under natural conditions.
Natural Enemies of Water Spiders
Although they themselves are dexterous and dangerous predators for small aquatic animals, they also have many enemies. There are almost no threats in the nest, but getting out for hunting they themselves risk becoming prey – sometimes this happens, and the nest loses its owner. Among the dangerous enemies:
- birds;
- snakes;
- frogs;
- lizards;
- fish;
- dragonflies and other predatory aquatic insects.
Nevertheless, they face much less danger than ordinary spiders, primarily because they live in water. Here, numerous land predators cannot reach them, but fish can eat them – and this threat should not be underestimated, because even the nest does not always protect from it.
And yet this is reliable protection in many cases, the system of threads stretching from it is no less important – thanks to them, the Water Spider not only hunts but also learns about the threat promptly. Therefore, the main chance for predators to take by surprise and catch this spider is when he hunts himself, at these moments he is most defenseless. Often frogs use just this, and nevertheless, not to say that so many Water Spiders end their lives in the teeth of predators – usually, their life is relatively calm.
Interesting fact: The poison of the Water Spider is quite toxic, but it is not dangerous for humans – usually there is redness or swelling at the site of the bite and nothing else. A child or a person with a weakened immune system may feel dizzy, feel worse, and develop nausea. In any case, everything will pass in a day or two.
Population and Status of the Species
These spiders inhabit the vast expanses of Eurasia, and they can be found in almost every body of water, often in rather large numbers. As a result, this species is classified as one of the least threatened – so far, it clearly does not have any problems with the size of the population, although no calculations are being made.
Of course, the deterioration of the ecology in many reservoirs could not but affect all the living creatures living in them, however, Water Spiders suffer from this least of all. To a lesser extent, but this can also be attributed to their prey, due to the disappearance of which they could also be forced to leave their habitats. 
Thus, we can conclude that of all highly organized living organisms, extinction threatens most spiders, including Water Spiders, almost least of all – these are perfectly adapted creatures that can survive even in extreme conditions.
Interesting fact: Water Spiders are sometimes brought up in houses because they are interesting to watch: they can cleverly use their webs, showing peculiar “tricks”, and at the same time are active most of the day – although this applies mainly to males, females are much calmer.
