a Mud Puddles to Meteors mini-lesson

Transcription

1 spiders a Mud Puddles to Meteors mini-lesson

2 spiders Although many people think of spiders as being a type of insect, they are actually their own animal, so to speak. In other words, despite having many insect-like characteristics, spiders are not insects at all. Spiders are arachnids, a type of arthropod. Spiders have two body parts, eight legs, and produce silk for purposes such as web construction or even making parachutes. Most spiders have four sets of eyes, although there are some with fewer (including a small number with no eyes at all). Most spiders are venemous, and use fangs to inject their venom into prey. For the most part, this venom isn t dangerous to humans (although there are some notable exceptions!). Spiders are only able to digest liquid food, so they employ various techniques, including specialized enzymes, to liquify their prey before eating it. This is why you often find insect bodies in the form of empty husks when looking at a spider web. About half of all spiders make webs to capture their prey, while the rest use a variety of other techniques including active hunting. But webs are an excellent way to explore spider silk, which is one of the most interesting and remarkable features these arachnids have to offer. In the pages that follow, we will take a closer look at webs, their construction, and their uses.

3 what about webs? For many of us, webs are the first thing we think of when we talk about spiders. And rightfully so. The webs that they weave are one of the most remarkable features of our arachnid friends. Coming in a variety of shapes and sizes and designed with purposeful precision, spider webs are natural works of art. Let s take a closer look. types of spider webs There are five basic types of webs that spiders make, and that we will consider more in depth. They are: orb triangle funnel sheet tangle An orb web is the type perhaps most commonly associated with spiders and most people recognize them as spider webs when they run accross them. orb webs Orb webs are undeniably the most recognizable of spider webs. The is not only because their spoked, spiral design (and the fact that their creator can often be seen right in the center of the web), but also because they have become a part of classic holiday decorations around Halloween time. To create an orb web, a spider begins by laying out frame and radius (spoke) threads to create the base of the web. These threads are not sticky, and provide the spider with threads to walk on without getting caught in their own web. The spider then lays a round of nonstick threads to form the first spiral. After that comes the sticky spiral characteristic of orb webs. A triangle web looks like an incomplete orb web and has just just three main spokes.

4 Funnel webs don t have the same neat and tidy appearance that an orb webs does, but provide excellent means for spiders to hide from both predators and prey. funnel webs Funnel webs have a hole (or funnel) that creates a little lair for the spider. The spider uses the hole to hide out from predators or to launch attacks on potential prety. sheet webs Sheet webs are webs that extend out across a flat area like a sheet. The spider can be seen on top of the web, hiding underneath, or in the case of a funnel sheet web, right in the entrance to the funnel.

5 tangle webs Tangle webs are messy webs made up of lots of crossed lines of silk. These are usually found close to the ground or high up in the corner of a room. web walking Have you ever wondered why spiders don t get caught in their own webs? It is because they make different kinds of silk for different spidery jobs. A web begins as a liquid gel inside the spider s body. As it passes through the spider s spinnerets, the tension exerted by the spider pulling it out makes the web material harden. Different glands inside the spider create different types of silk as well. The kind a spider walks on, which makes up the spokes of an orb web, is not sticky. The silk that catches prey, which makes up the spiral design on an orb web, is sticky. Spiders also employ different types of silk for draglines, to wrap up prey, and to create an egg sac.

6 hunt for spider and their webs! tips for hunting for spider and their webs - Early morning, while the dew still clings to the webs, is a great time to get a closer looks at web designs. - If you want to take a picture of a web, try to get something dark in the background, even a tree or some grass will help make the web show up better in the photo. - Ask some questions about the webs you find: Where do you think the spider waits? Why did it build its web here? What do you think it might catch? - This is also a good time to talk about the insects in the area; which ones would make good spider food and how spiders help us keep insects under control. - If a spider is not in the middle of its web, in the classic orb weaver style, look along the framework of the web. Spiders often hide off to one side with a line attached to the web (allowing it to feel for vibrations). - If you find a funnel web look at the entrance to the funnel, or even down inside, to find the spider. A flashlight can be handy for this. - It may be a little more difficult to find the master builder of a sheet web. Look all around the web, including underneath if you can, and in the surrounding grass or leaves. - Don t worry too much about getting up close; spiders are little and you are big, chances are good they will retreat to their lair or hiding spot once you get too close for their comfort. - Remember that not all spiders build webs: wolf spiders, jumping spiders, and crab spiders are all active hunters. So be on the lookout for these small, hidden arachnids who are waiting to pounce on an unsuspecting flier under a flower or leaf, and are sometimes even disguised as the flower itself.

7 draw your own web You have learned a bit about spiders and how they build their webs. You have even gone on a web hunt! Now imagine life as a spider. What would you look like? What would you eat? (While spiders are widely known for their habits as meat eaters there is one spider, out of over 40,000, that is a vegetarian, so don t rule out any food source!) What type of web would you build? How would you use your silk? Get creative and have fun! draw your web here