Spiders

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This presentation gives a detailed insight into spiders, including what they are, how they live, how they hunt, how they defend themselves etc. Please do enjoy!

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Spiders

  1. 1. A detailed insight into spiders
  2. 2. Many people think of spiders as these small, fastand deadly creatures that hide in our baths andlurk in dark corners, waiting to pounce. In fact,what I have just described is entirely wrong, andwhilst they are often found in our baths and oftenin our houses and gardens, they are, in fact, morescared of us they we are of them!Many people see spiders as these eight-eyedmonstrosities with sharp fangs that deliver avenomous bite. Yet you may be surprised to knowthat there are only about 30 kinds of spider thatare dangerous to people, and only a few of theselive in the United Kingdom.Spiders are actually more amazing than scary. They have many different andfascinating ways to catch their prey, such as hunting, jumping, fishing and evenspitting! There are even spiders that look like crabs, ants and wasps! Thispresentation provides a detailed insight into spiders, and hopefully, by the end ofit, you will be in awe of these great little critters, rather than absolutely paranoidabout them!
  3. 3. The spider’s eight legs are joined to the cephalothorax.Spiders are often confused with insects, whenin fact they belong to a completely differentgroup, known as Arachnids (these are alsoscorpions, ticks, harvestmen and mites). Youcan differentiate between a spider and aninsect through a few key differences:• A spider has eight legs, but an insectonly has six. The rear part of the spider is called Spiders use a• A spider’s body is made of only two parts pair of furry the abdomen. It is not covered by the(cephalothorax and abdomen) whilst an “feelers” called palps exoskeleton, andinsect’s is made of three parts (head, for holding instead by a soft, stretchy skin. their food.thorax and abdomen).• A spider typically has eight eyes (some The front part of a spider is The spider’s jaws, orhave six) whilst insects usually have two fangs (officially known called the cephalothorax – basically it’s head andeyes. as chelicerae) are used to bite and crush their chest. The body is covered by a tough, hard skin called• Many insects have wings and antennae, prey. Each ends in a an exoskeleton. fang that injectsbut spiders do not. poison.
  4. 4. Ok, so it is fair to say that I am trying to convince you that spiders really are not asbad as many people think, but there is no denying it – some spiders are HUGE!The biggest spider in the world, the Giant Huntsman, is as big as a dinner plate!However, others are miniscule, perhaps the size of a pinhead. Apart from size,spiders also vary greatly in appearance. Fair enough; many spiders are yourtypical dull brown or grey colour, but others are a striking combination of yellows,reds and oranges. Some spiders have short, wide bodies, while others are long,thin and skinny. There are round spiders, flat spiders and spiders with spines,warts and horns. Spiders really are wonderful creatures! ()You may look at this strange little creature in the picture and thinkto yourself “what in the name of all that’s holy is that?”It is in fact, the aptly named Kite spider (Gasteracantha). Thisstrange spider is found in Central and North America, as far northas California and as far south as Jamaica, in gardens and parks.Only the females have the striking colours, and are also muchbigger than the males, typically around 8 mm in length, and 12mm wide. They have six sharp spines protruding from theirabdomen that look a lot like horns. No one knows quite what thesestrange spines are for, but they may make it difficult for predatorsto hold or swallow the spider.
  5. 5. The following picture is not an attempt to scaremonger. I ammerely trying to demonstrate to you the pure beauty of the WolfSpider – AKA The Master Hunter.If you are terrified of spiders...... (if you are then I don’t reallyknow why you are viewing this presentation) then double clickthe screen now (and obviously look away whilst doing so)........
  6. 6. Despite possessing the dull brown or greycolouration I mentioned earlier, please do not befooled by the colouration of this spider, as itactually acts in their favour, as camouflage! Theeloquently named Wolf spider is a mean nocturnalhunter, and possesses all the characteristics thatmake it so.• They are robust, agile hunters• They don’t have time to spin little pathetic webs!They’re not wusses! No, they CHASE after theirprey!• They are capable of defensive bites that are suited The wolf spider has The strongto their hunting but are generally not harmful to eight eyes – 2 big Two large exoskeletonhumans eyes, 2 medium eyes chelicerae (fangs) gives the and 4 small eyes. means the spider spider a This gives the spider can hunt large goodTo get a further insight into Wolf Spiders, click the good vision as it prey defence hunts during the against itslink below for a short video... night predatorshttp://www.youtube.com/watch?v=v6M_84t3oa4
  7. 7. Spiders, among other things, are renown fortheir rapid speed. However, these are oftenquick bursts of speed as spiders are soon outof breath. This is perhaps the main methodof movement for a spider.Spiders can walk, run, jump, skate, climband hang upside down. Each spider’s legshave seven separate sections, powered bysets of muscles and blood pressure. At theend of each leg are two or three sharp, The fishing spider (Dolomedestoothed claws for gripping surfaces. fimbriatus) floats on the surface of water to catch it’s prey of fishSpiders that spin webs have a special, and frogs. It’s long legs spread itshooked claw to help them hold on to their weight over the surface so that itwebs. Hunting spiders have furry tufts of does not sink.hair between the claws for gripping smoothsurfaces and for holding prey.
  8. 8. Aren’t they just the cutest thing? Awwwwwww.You may say that the most remarkable thingabout this innocent jumping spider is it’s sweetlittle eyes...... and, to be fair, it sort of is.However, another very commendable thingabout this spider is it’s hunting technique – ittraverses across leaves by jumping! It is alsohow it catches it’s prey. Jumping spiders are active hunters, which means that they do not rely on a web to catch their prey, which is usually insects. They use their clever camouflage to blend in with the surroundings, and lie in wait for their prey, ready to pounce. They use their superior eyesight to spot their prey, then they pounce and deliver a venomous bite. The venom acts very quickly, giving it’s prey little time to react. To get a further insight into Jumping Spiders, click the link below: http://www.youtube.com/watch?v=Xwmgg7GDWJ4&feature=fvst
  9. 9. Whilst all spiders produce silk, not allspiders spin webs. A few spiders go fishingfor their food instead. The net-castingspider throws a strong, stretchy net overit’s prey. The bolas spider is very unusualin that it traps insects by swinging a thinline of silk with a sticky ball on the end,like the fishing hook on the end of a line.Spitting spiders are even more cunning.They fire a poisonous “glue”-like substanceto pin their prey to the ground. This female golden orb weaver is not only known for her size, but for the intricacy of her orb-shaped web. The spider’s body alone grows up to 2 inches, but the size of it’s actual web is drastic – perhaps even three times bigger than it’s maker!
  10. 10. No matter how many times you look at pictures ofthis unique spider, you always feel creeped out atit’s ominous face and it’s long, spindly legs.Nevertheless, the hunting method of this creatureis something to admire. The spider builds a small,round-like web that it suspends in mid-airbetween it’s front legs. It usually positions itself inmid-air above a leaf or a branch, waiting topounce. When prey approaches, the spider will stretch the net to two or three times its normal size and pounce onto the prey from above, entangling it in the web. Their excellent night-vision is provided by two large eyes. These eyes are so large in comparison to the other six eyes that the spider seems to have only two eyes. To see a video on a net-casting spider catching it’s prey, click the link below: http://www.youtube.com/watch?v=-AjFHPy3cx8
  11. 11. Some spiders do not spin webs, nor dothey go out hunting for food. Thesespiders prefer to build and wait insideunderground burrows or tubes of silk andwait for prey to approach and pass by. Silkthreads placed carefully around theentrance to the burrow vibrate when aninsect or other small creature such as amouse passes over them. Inside theburrow, the spider is waiting, concealed ina shadow of darkness. The spider feelsthis vibration on the silk threads, giving itthe indication that it’s prey is nearby. Thisgives it the opportunity to rush out of itsburrow and pounce of the prey before itcan escape. It then drags its prey back intothe burrow, where it is killed and laterdevoured. How pleasant.
  12. 12. The trapdoor spider is the master ofdisguise, the artist of deception, thecreator of craftiness. It is thedesigner of..... well you get thepicture.Whatever you call it, this spider is onemean brute. This spider does not spina web, nor does it hunt. Instead, itbuilds a crafty burrow with atrapdoor, and places silken threadsaround it’s burrow which act as triplines. These detect the movements ofa passing insect or creature, and gives Trapdoor spiders remain fiercely loyal to their burrows, and live in them for up to 20 years!the trapdoor spider it’s opportunity to To get a further insight into Trapdoor spiders,pounce, rushing out of it’s burrow to click the link below:grab the prey with it’s jaws and drag http://www.youtube.com/watch?v=7yJgPVxS5aIit back down.
  13. 13. I can imagine that by this time you haveviewed most of my presentation and theidea of spiders being AWESOME is prettymuch now ingrained into your brain.But I can also understand that yourgetting a little bit tired. Not to worry! Thisslide will liven things up a bit!No doubt the forefront of your mindsthroughout this presentation has beenthat of a spider’s venomous bite.Nearly all spiders use poison to kill or paralyse their prey and for defence. There aretwo main kinds of venom that can have serious effects on humans – one isneurotoxin, which acts as a nerve poison which attacks the nervous system,paralysing victims quickly. This type of venom is produced by the widow spiders,most notably the black widow spider (Lactrodectus). The other kind of venomworks more slowly, destroying tissues and causing necrosis, ulcers and gangrene.This is produced by the recluse spiders, most notably the brown recluse spider(Loxosceles). Both of these spiders are found in the United Kingdom, so be afraid!
  14. 14. You may look at this spider and be fooled into thinking that itlooks terrifying. Well, the truth is.... your right; it doesn’t justlook terrifying, the way in which it lives is terrifying!This is the Brazilian Wandering Spider, the master of cunning,the creator of..... ok I’m not starting this again.This spider is a large hunting spider that, according to theGuinness Book of Records, produces the most toxic of all spidervenoms. It is also notoriously aggressive. If disturbed, it raisesit’s front legs above it’s head to expose it’s threatening jaws.Then what? Does it run? No. Even if this spider is confronted bya foe much bigger than itself, it will CHASE AFTER the foe untilit flees. Luckily for most people, the Brazilian Wandering Spiderroams the Amazon Jungle in...... Brazil (Yep....go figure), sopeople in the UK can go to bed at night knowing you’ll be safe. Ifyou live in Brazil, then you’ll more than likely know about thisspider, seeing as it’s accountable for around half of all recordeddeaths as a result of spider bites in Brazil each year.To get a further insight into Brazilian Wandering Spiders, clickon the link below:http://www.youtube.com/watch?v=noLn2gK3fzY
  15. 15. Judging by the last slide, you would thinkthat the need for a spider to defend itselfis quite pointless. Truth is, not all spidersare massive, powerful hunters like Mr.Wanderer of the previous slide.Spiders are typically small, with softbodies that make a tasty snack for manypredators. To avoid predators, such asother spiders, hunting wasps, lizards andfrogs, many spiders hide. Other spidersconceal themselves by being beautifullycamouflaged to blend in with theirsurroundings. In complete contrast,some spiders copy the bright colours of This is the seven-spined crab spiderdangerous predators, such as wasps. This (Epicadus heterogaster). The fleshytricks predators into leaving the spider lobes on it’s abdomen imitate the whitealone. Spiders will even play dead, since flowers of the plant it dwells on. Thispredators prefer to eat live prey. helps it to blend in with its surroundings and avoid detection by predators.
  16. 16. I know I’ve covered some pretty insanespiders in this presentation, but there is nodenying the ingenious way in which thisspider avoids predation.This is the aptly named Golden WheelSpider, a spider that lives on the sand dunesof the Namib Desert in Africa. You may thinkthat it’s gold colour helps it blend in with it’ssurroundings, but this spider has anothermethod of escaping from its predators.If caught out in the open, however, the spider rears up to make itself look larger and morefrightening to enemies. If that doesn’t work, then it has another remarkable way ofescaping. The spider throws itself sideways, pulls in its legs and rolls itself into a ball. Itthen cartwheels rapidly away down the dunes, escaping from it’s prey.To see a video on this great escape, click on the link below:http://www.youtube.com/watch?v=ozn31QBOHtk
  17. 17. For me, it’s been a long day of creating presentations, for you, a long day ofviewing them. So, I’ll keep this short and sweet.SPIDERS ARE COOL! STOP BEING COWARDS! THEY ARE A VALID PART OFOUR ECO-SYSTEM AND WITHOUT THEM IT WOULD FALL APART.THIS VIDEO MAY HAVE BEEN HUMOUROUS, BUT IT IS ALSO HERE TOEDUCATE. PLEASE, THE NEXT TIME YOU SEE A SPIDER, THINK BEFOREYOU ACT!LET IT SEE THE LIGHT OF DAY AND THE FEELING OF THE LIGHT BREEZERATHER THAN THE UNDERSIDE OF YOUR BOOT AND A POOL OF IT’SOWN BLOOD TO DROWN IN.TREAT IT WITH RESPECT, AND DON’T SCREAM, COS THEN IT WILL JUSTBITE YOU. YOUR FAULT REALLY. HA. HAHA. HAHAHA.Anyway, that’s it really. A short conclusion outlying the main point of mypresentation.

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