Common Spider Species
How Spiders Hunt
Spiders are one of the most fascinating predatory species that can be commonly observed in everyday life, and have evolved very specialized ways of hunting for their prey. However what many people don't know is that there are actually many different ways which spiders use to hunt, which aren't always limited to the use of a web.
Spiders tend to be put into one of two categories dependent on the way that they hunt, although there are also those which use a mixture of both methods. The two categories used are either hunting spiders, which actively look for their prey, or web spinning spiders, who tend to lie in wait for their prey to come to them. Although the web sinning spiders are thought by many to be the most common type, they are in fact probably equal in terms of numbers, Web spinning spiders only appear to be more plentiful due to the fact that they are more visible.
Hunting spiders are categorized by the fact that they actively seek out their prey rather than building a web, and are generally more robust than web spinning spiders. Hunting spiders do not lack the ability to produce silk, however they more commonly use it to line their burrows rather than for use with catching prey. Wolf or zebra spiders are good examples of hunting spiders, both of which are common in most parts of the world.
Most hunting spiders hunt by simply rushing their prey and inflicting a poisonous and usually fatal bite. If the prey is large, then the spider may retreat and give the venom time to weaken it before they attack it further, decreasing the risk of them being injured trying to subdue it. If the prey is small enough, then a spider will often simply hold on to it until it is killed, and very often eats it then and there.
Web spinning spiders are what most people tend to think of when spiders are mentioned, although this is by no means the only method that spiders use for hunting. There are two distinct types of webs that different species of spider make, the first is the typical orb shaped web. These can be identified by the fact that the strands are spread fairly far apart, and they are also sticky, trapping things that land on them.they are most commonly seen in gardens, and need two surfaces as starting points.
The second type of web that many other spiders produce is more of a finely woven sheet, which although isn't sticky, has loose strands, making the feet of the prey fall through. Because these kinds of webs are easier to escape from for larger prey, most often the spider is alerted to the presence of prey through the vibrations of the web being moved. The spider can then rush out and attack the prey before it escapes. This behavior is also exhibited in sticky web producing spiders, although they will also sometimes simply leave prey to die to starvation or exhaustion at times.
As well as the conventional means of catching their prey, many spiders specialize further, and have a hunting method unique only to their particular sub species. The bolas spider is a good example of this, which uses a blob of sticky web material on the end of a single thread to catch its prey. When suitable prey comes close enough, the spider swings the bolas at it, sticking it together and allowing the spider ample time to bite and subdue it. Because of its odd method of hunting, this spider is also often called the fisherman spider, or angler spider.
There are also some kinds of unusual spiders that act as parasites on the webs of larger spiders, stealing the smaller kills that the larger spider might not notice, or might not be concerned with. Other species are light enough to skate on the surface f a pond or lake, eating insects that fall into the water and send vibrations through the water to it. They can often be seen sitting on Lilly pads with their two front legs touching the water surface to detect these tiny movements.
One of the more famous spiders that have a unique hunting method is the trapdoor spiders that can be found in many warmer parts of the world. These spiders construct a burrow with a trapdoor surface and silken tripwires running from the entrance in several directions. When something trips over one of the strands, the spider quickly emerges from the camouflaged trapdoor and attacks the prey before retreating back inside again.
The zebra spider is one of the most common spiders in the world, and is probably the best known among the jumping spider family. It can be found in almost every climate and is a common sight in warm weather in and around the home. However there are many traits and behaviors exhibited by the zebra spider, which set it apart from most spiders and make it a most fascinating species to study.
Zebra spiders (Salticus scenicus) are so named because of their black and white stripes, similar to that of a zebra. The black and white camouflage in this case is useful because it helps to hide the spider against dark backgrounds and also to predators makes it look like a bird dropping from above. Mainly this is useful because the zebra spider stalks and then jumps on its prey, and so needs to get fairly close to it.
The prey of zebra spiders ranges from ants to mosquitoes, and pretty much everything in between. Although because they must physically subdue their prey they cannot take anything much larger or stronger than themselves, as they are unaided by webs to trap their prey before attacking it. Their usual method of hunting is to get close to prey on the ground by sneaking up to it on an adjacent vertical surface. From there they can pounce and kill their prey very quickly.
Unlike most spiders zebra spiders also have excellent eyesight and because of this aren't immediately alarmed when they encounter a human. If you were to approach one on a wall rather then fleeing as their first response they are quite happy to observe you unless you actually try to attack or eat them. This is because their eyes perceive things faster then ours, or in fact many animals do. For example if they were to watch TV the images would be too slow for them to perceive as a moving image, giving it the appearance of a slide show.
Compared to most spiders the zebra spider has short legs and a stocky body, which allow it to leap very powerfully and to run extremely fast as well. It is so powerfully built in fact that it can leap up a vertical surface, which is something that few other species can do. This build also means that it is comparatively strong for its size, allowing it to overpower as well as surprise its prey. Many spiders by comparison have to either be a lot larger or rely on the aid of a web to kill their prey.
Normally towards the end of summer some spiders will make their way into the home, mainly because of the warmth. Zebra spiders will rarely make their way inside buildings in the same manner though, as they usually die by the end of the summer. Also the smaller prey species that they usually like to feed on don't tend to be found inside the home either, and tend to die off at the end of the summer themselves.
Another interesting behavior that zebra spiders exhibit is that they will readily feed on other spiders. Most web-building spiders have very poor vision, and rely on the vibrations of their web to locate their prey. Because of this the zebra and indeed other jumping spiders, can sneak as close as they need to before striking. Zebra spiders have also been known to purposely touch other spiders webs to entice them over before attacking, which is something that only a few spiders have shown.
Despite their speed and jumping prowess there are still several other insects that will make a meal of the zebra spider on occasion. Centipedes and other larger hunting spiders will on occasion eat zebra spiders, as will ants who happen to catch them on the ground. This isn't generally a regular occurrence however, because among invertebrates they are one of the fastest and certainly have better eyesight than most.
Wolf spiders, belonging to the family Lycosidae are one of the most common types of hunting spider in the world today, being found on every inhabited continent. They are also misunderstood by many people, who might be frightened of their appearance or speed. Many people also assume them to be dangerous because some of them can reach large sizes, although this isn't the case either.
Wolf spiders are so named because they ferociously hunt their prey, similarly to a wolf. Most species roam around at ground level until they find something appetizing, and then quickly attack and subdue it. This differs from many spiders, which make webs and then passively wait for their prey to come to them. Because they don't have the safe haven of a web to rest on, most wolf spiders live in crevices or burrows in or low to the ground. It is common to find them sheltering under rocks or when disturbing leaf litter.
Because wolf spiders spend their lives in among the leaf litter where there are many more species than in the air, they have had to become hardier than many types of spider. This is why they are often able to attack and eat web-building spiders even of their own size. Of the wolf spiders that live several years, many will hibernate during the colder winter months either in a burrow or under a rock. Those that live under rocks tend not to hibernate fully, which would be very dangerous, but rather just become sluggish and only move if they have to.
Because wolf spiders don't build webs to catch their prey it was thought for many years that they were unable to produce silk. More recent research has found this to be untrue, indeed the white covering that their eggs are encased in is made from silk. They will often spin silk inside their burrows as well to protect them from the cold and even to keep inquisitive insects away by completely encasing themselves.
Wolf spiders unlike many other types of spider carry their egg sac around with them attached to their abdomens. The reason being that many species live more then a single year and can therefore protect their young better. Web building spiders tend to fasten their egg sacs in a quiet, dark place and die soon afterwards. But wolf spiders will carry their eggs around until they hatch and then carry the young on their backs until they are ready to fend for themselves.
This method of protecting their young has its benefits and of course its downsides. On the one hand the mother protecting the eggs in this way means that more of them will likely hatch and reach an age where they can protect themselves. On the downside of course if the mother is killed whilst carrying the sac, then all of the young are lost. This is how many people identify wolf spiders and differentiate them from other types. It is a common sight to see female wolf spiders in fact sitting in the sun to warm their eggs, which helps them to develop and hatch faster.
A good way to identify wolf spiders is that they have very good eyes, and two much larger then the others in the center of their heads. Most spiders having all their eyes the same size, and not being able to see very well, or perceive color at all. This is why when you disturb a wolf spider it will bolt immediately, but when approaching a web with a spider sitting in the middle it will usually not move or even notice that you are there.
Far from being things to be feared as many people do, wolf spiders are in fact useful to have in either the home or garden. The reason being that they are voracious predators and will readily eat much more troublesome insects such as recluse spiders or ants. Contrary to popular belief they are also not aggressive as many think. In fact when encountered they will usually try to get away from humans as quickly as they can, having as most spiders do, an intense fear of anything larger then themselves.</p>
The common house spider (Parasteatoda tepidariorum) is probably the most common spider in the world, and due to its love of hiding in human dwellings, is the most encountered by people as well. Although many millions of people are scared of house spiders, they are usually very timid, and wont expose themselves to humans intentionally.
Although house spiders might have a fearsome appearance, they are in fact harmless. They tend to always run rather than bite when faced with a larger adversary, and are more scared of humans than we are of them. Only the larger of the species could even pierce the human skin with their fangs, and their bite, although perhaps painful would not do any lasting damage.
House spiders webs are non sticky, usually sheet like and old webs are what forms cobwebs in the home. The reason that they can trap other invertebrates in their webs is that they are tightly woven, so that anything walking over the surface loses its footing and falls through. This also alerts the waiting spider who can feel the vibrations of the struggling prey. The spider itself is usually to be found inside a silken tube attached to the main web but out of sight.
Because they are one of the larger spiders in most of their habitats, they tend to rely on their webs and fangs to do the work of catching their prey rather than venom. Web spinning spiders that are large usually target smaller prey, and so unlike hunting spiders, don't need to have a powerful venom to finish the job. Also they are usually stationary in their webs, and only tend to roam around for mating purposes in the late summer.
The house spiders that tend to get themselves stuck either in the bathtub, or can be seen scuttling across the floor when you turn the lights on suddenly are male spiders. They are usually looking for a mate, which is why this encounter is most common in late summer. the reason that they also tend to run across the center of rooms rather than sneaking around the edges is simply because they are looking to find a mate as quickly as they can.
Although spiders tend to be towards the top of their food chains, there are still a few species that will feed on house spiders. Smaller animals such as rats and birds will sometimes catch and eat spiders, although for the most part the spiders tend to stay hidden.
Also if their web is too easily accessible to close to the ground, ants will readily raid a spiders funnel and eat anything that they find. Lastly when on the rare occasions a house spider strays onto the ground, there are many species that will make a meal out of it. these include everything from centipedes and beetles, to household pets such as dogs and cats.
A little known fact about house spiders that most people don't know is that there are actually two distinct species, the other being the giant house spider (Tegenaria duellica). The giant house spider is found only in the United kingdom, the north of France and a select few parts of the united States, which it was accidentally introduced to. It is basically the same as the regular house spider except that it has acquired the trait of gigantism over time, being the largest spider species in its native country.
Both species of house spider are known to actually have benefits beyond the fact that they will eat garden pests. The giant house spider in particular is known to kill and sometimes eat hobo and brown recluse spiders, both of which are dangerous and potentially fatal to humans. In fact because these spiders all inhabit the same niche in the food chain, wherever giant house spiders are found, recluse and hobo spider populations fall sharply, as do humans being bitten.
In different parts of the world there are many different species that are sometimes referred to as a house spider. However the most commonly referred to spiders are the barn funnel weaver spider (Tegenaria domestica), giant house spider (Tegenaria duellica) and the common house spider (Parasteatoda tepidariorum). All three species are harmless, and the differences between them are mainly concerned with their size and web structures.
The barn funnel weaver is roughly the same size as the common house spider (7-12mm), and its web is usually a tangled mess, which is usually roughly spherical in shape. The giant house spider is much larger then the other two species (18-30mm), and its web is a flat tightly woven sheet connected to a funnel. this is similar to the common house spiders web also, although the funnel is not always connected to the main web directly in the case of the common house spider.
Cellar spiders belong to the group of spiders known as the Pholcids, and are among the most numerous in the world. They also go by several different names depending on where you are in the world, often being referred to as daddy longlegs in the United States for example. They are actually only one of three species known as daddy longlegs, with the harvestmen and crane fly being the other two.
The crane fly is called the daddy long legs in the United Kingdom, and the Harvestman goes by the same name in Australia. The cellar spider having taken the name in the United States, although in actual fact the three species aren't very similar at all. The crane fly is a large clumsy flying insect that looks like a giant mosquito although it doesn't actually have any mouth-parts and cant feed. The Harvestman is an arachnid, although not a spider, and doesn't make a web either.
The confusion probably happened because all three species have long thin legs and was at some point confused as being each other by travelers. But knowing the difference between the three species is important when studying cellar spiders. Cellar spiders are as with all spiders exclusively predatory, and are commonly encountered by man because they live close by. Their bite however is harmless, and they are shy to the point of retreat when encountering humans.
Cellar spiders are usually found inside the home, and in fact usually live exclusively in human dwellings. In appearance they have long bodies compared to many spiders, and have very long thin legs, which are up to three times the length of their bodies. It is because of their frailty that they probably prefer secluded areas such as houses rather than the outdoors. They vary greatly in size, but at their largest can reach sizes of 40mm (leg span).
Typically cellar spiders make large webs that hang in messy clumps, trapping their prey through it being tangled rather than stuck. That is to say that their webs aren't sticky as with many web making species, but instead are finely woven making them easy to get caught in. This is why they often hang both horizontally and vertically and don't appear to conform to regular patterns.
Another trait of Pholcids is that many of them target other spider species as their prey, including the dangerous Red back, Hobo spider and Huntsman spiders. In fact they are often thought to be beneficial to households because they are harmless to humans and pets, but will keep more dangerous spider populations down.
As well as being good for keeping pests away, cellar spiders are also unlikely to disturb humans by running across the ground, as they generally stay in their webs and tend not to roam onto the ground very often. They also prefer to live close to their mates rather than only briefly meeting as most arachnids do.
Curiously, cellar spiders aren't affected by other spider populations very much, other than giant house spiders found in the United Kingdom and parts of Europe. Typically spider populations depend largely on competition from other species in the area. So for example populations of hunting spiders such as wolf spiders, often lower the populations of web making spiders in the immediate area. This isn't as prevalent in outdoor areas because of the higher numbers of flying prey, but indoors this effect can be numerically significant.
The most common prey for cellar spiders is usually small flies, mosquitoes and other spiders, although tat they can they will eat anything that they can easily overpower. They are also known to let larger, more powerful prey escape rather than try to tackle it. Things such as wasps, hornets etc, will often then eventually escape of their own accord.
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