All of our friends live in the garden, so spide going on right next to you may not actually seem like much of a threat. If a spider is too near for you to comfortably handle, don’t worry about it. Spiders are actually one of our friends and an unavoidable part of nature that has given us many benefits!
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Role of Spiders as Biological Control Agents
Spiders hate insects and they’re both predators, so they serve a very important role in keeping populations of pests in check.
There are only four species that have been known to bite humans and only two of them cause bad reactions.
Most spiders are small, as you can see, but they are harmless. They help keep the levels of insect population down while hunting their prey – which includes fish and other tiny critters!
Basic Spider Biology
Spiders are arachnids, not insects; however both belong to the largest group of animals on earth the arthropods. These are animals with hard external skeletons and jointed limbs. Arthropods come from the Greek author meaning joint and pods meaning footed. So what’s the difference between spiders and insects, you ask?
Simply put, spiders have two main body parts (a cephalothoraxes, which is the fused head and thorax, and an abdomen on which the tip has a group of small spinnerets that produce silk) whereas insects have three body parts (head, thorax and abdomen).
Spiders have eight walking legs and insects have six. Spiders have six or eight simple eyes and insects eyes are compound.
Spiders have a piercing jaw and fangs (the jaw-like structures are called chelicerae, each of which ends in a hollow fang through which venom can be ejected) and insects simply chew. Spiders can’t fly, but many insects can. Spiders come in unusual body shapes and colors, which are helpful to deceive and ambush prey, as well as to attract mates. The spider size is somewhat limited as their respiratory systems become less efficient as their size increases.
Yet there are spiders that are quite tiny and found in hidden areas such as damp, cool forest leaf litter and moss. This is because their small bodies will lose water quickly in dryer habitats. On the other hand, some spiders grow so large that their legs can span a dinner plate. These spiders usually take more than a decade to reach full maturity.
Spiders lay their eggs in a silken, egg-shaped sac. The egg sac can be hidden in a web, attached to a surface, or carried by several of the female species (wolf, cellar and nursery web spiders). Spiders may produce several egg sacs, each containing up to several hundred eggs. Young spiders, known as spider lings, emerge from the egg sac and disperse.
Many climb to the top of a nearby object, produce long filaments of silk (known as gossamer) and are carried by the wind. This method of dispersal is known as ballooning. Young spiders (spider lings) resemble adults except for their smaller size and coloration. A spider grows by shedding its skin between four to twelve times before maturity. Adult male spiders are smaller than females, sometimes dramatically so.
Males are identified by an enlarged pair of pulps (mouthparts), which have been compared to miniature boxing gloves or a fifth pair of legs. These pulps are used to transfer sperm. Male spiders are often found in homes as they tend to wander during the mating season in search of females or during the early fall when cooler outdoor temperatures force them to find shelter.
Though some species of spiders (widows and some wolf spiders) may live for a few years, most only survive for a season. However, tarantulas will often survive a decade or more. Another thing that sets spiders apart from all but a few insects is their ability to spin silk. All spiders produce silk, which is secreted as a liquid through their spinnerets and hardens on air contact.
Spiders use silk for a variety of purposes, such as making egg sacs, capturing and holding prey, making shelters or retreats and transferring sperm during mating. Spider silk is necessary to some species of birds for nest building; for example, hummingbirds steal spider webs and use them to bind their nests. The venom of most species is not particularly toxic to humans, usually resulting in no more than a slight inflammation or itching sensation.
Most spiders’ fangs are too small or weak to puncture human skin. Spiders usually will not attempt to bite unless accidentally trapped against the skin or grasped, although some species actively guard their egg sacs or young.
The black widow spider (Latrodectus Hesperus), the brown recluse (Loxosceles recluse), the hobo spider (Tegenaria arrests) and the sac spider (Cheiracanthium tracheas) are the quarrelsome quartet in the US.As previously stated, some spiders actively search for their prey such as jumping spiders, nursery web spiders and wolf spiders.
Any webs they construct are used solely as resting areas. You will only see these spiders when they are in search for food. Passive hunters are spiders that lay in wait for their target rather than searching for it. When their quarry approaches, they may jump or pounce to seize it. Crab spiders are purely passive hunters, though tarantulas and other spiders use this technique. Many spiders use webbing to ensnare their prey.
Their web designs vary and may or may not be elaborate. Web building spiders include cellar spiders, cobweb spiders, funnel web spiders and orb weaver spiders. All spiders produce venom that is poisonous to their food source and once this venom is injected, it immobilizes their victim and then begins the digestion process.
One other group of spiders are the spitting spiders (Synods). A spitting spider has long, spindly, banded legs and a spotted pattern on its raised cephalothoraxes’, the front body region. Spitting spiders are slow-moving, common in window sills and considered harmless.
The class Arachnidan includes spiders and some other arthropods that are closely related to them. Close relatives of spiders are scorpions, pseudo scorpions, mites, ticks and daddy-long-legs (also called harvestmen).
Daddy-long-legs are very commonly confused with spiders due to their general appearance and eight legs, but these brown creatures belong to the order Opinions and are not spiders.
Influence of Spiders on Human History & Mythology
Science, history and literature are some of the amazing things that have inspired storytellers to tell us stories about spiders.But it’s not just the genre of story that has spiders in it. King Saul pursued David, he hid in a cave near Jerusalem.
As he entered, a spider made its web across the cave’s entrance and his life was saved because there were no signs of any other human presence around him. In Japanese mythology, warriors Yoritomo, with six of his most faithful followers found refuge inside a giant hollow tree.
After his enemies had left believing Yoritomo dead because of a silvery web found nearby, but it wasn’t true! Spider tried again and again to reach its goal (a place where they could be hidden), but failed every time until one day they succeeded!
On the seventh try, these tiny insects managed to weave their way into their new home. The spider is somehow connected to their success and this motto lives on through history today with Robert Bruce’s full commitment to fighting process: “six times I fought against the English and failed.”
History of Spiders
Spiders have a long and interesting history. They’ve been around for longer than we can imagine. They’re fascinating because they continue to fascinate us today.
Insectivores evolved 240 million years ago during the Silurian Period, while spiders emerged 390 million years later during the Devonian Period.
Experts think insects served as some sort of predator of arachnids in the early Carboniferous Period. During this period, they were probably ground-bound as well, living among giant club mosses and ferns with slaters and millipedes as their prey.
Here is some evidence on spiders. Many species are very beneficial to our well-being, stopping insect pests in their tracks.