Oh what wicked -- but useful -- webs spiders weave

It's October and Halloween is fast approaching, so I thought I would do a seasonal piece on spider webs. In order to brush up on some details I decided to glean some knowledge off of the all-powerful internet. I chose "spider webbing" as my search. What a great search phrase! I can now … with fair confidence … state where my neighbors purchased the lovely Halloween spider webbing that now dominates their landscaping and makes a charming statement about neighborhood. (And I can confirm that these bags of spun polypropylene don't come with instructions or decorating tips.) (But I can not tell you why some of it comes in purple and orange or why some display gigantic spider webs made out of rope.) Like bats, spiders have found their way into our contemporary Halloween decorations for one simple reason -- they are different than us ... quite different. Spiders have way too many legs and too many eyes, as well. They have evil-looking bodies, with a relatively tiny head (cephalothorax) and a ginormous abdomen. Oh, and they have fangs and venom, which is sometimes even deadly to us. Yep, it wasn't difficult for spiders to make the Halloween "list." But let's try to turn their obvious differences into something less spooky, and a bit more like amazing. To do this, let's turn to their bulbous backends (abdomens), and what comes out of them. (And by this, I don't mean spider poop!) On the inside of a spider's abdomen are all of the normal "animal" parts, but also some really special organs called spinneret glands. These glands produce the protein-laden material we call spider webbing, sometimes called spider silk. On demand, this material shoots out of an assigned nozzle called a spinneret. There are several different spinneret glands. Some produce sticky webbing. Some durable webbing. Some elastic webbing. (But isn't it always sticky and durable when it floats onto your face.) Depending upon the species, spiders may only have a few, or a wide variety, of spinneret glands. Different glands, different threads, different uses and a spider can select which type of webbing they need at any time. Here is an overview of the names of different spinneret glands, and the type of web they produce (from spiderknowledge.com.) Major Ampullate Glands: durable dragline silk for web framework and safety lines. Flagelliform Glands: elastic silk that makes up the capture spiral. Tubuliform Glands: robust silk used in egg sac construction. Aciniform Glands: silk used for wrapping and immobilizing prey. Piriform Glands: attachment disc silk, which anchors threads securely to surfaces. Aggregate Glands: glue-like silk droplets that are added to the capture spiral. Cylindrical Glands: female glands specialize in creating silk for egg sacs. Again, not all spiders have all of these web-producing glands. The well-known jumping spider, for example, only has ampullate and tubuliform glands. Being an active hunter, they don't build sticky webs, but they can jump off stuff with the confidence that they are always attached to a safety line of their own making. So, that brings us to web types and there are several. Most spider webs are used to capture prey. Sometimes they ensnare a meal, and sometimes they provide clever concealment for ambushing prey. Here's a short list of web types, and how they work. The best-known web is the orb web. This web contains two basic types of silk. The first is the framework silk from the spider's ampullate gland. To start its web, orb-weaving spiders need to attach a few strands between two or more objects. To do this downward, they just lower themselves on a dragline. To do this sideways, they need to either jump or send out some silk in the hopes that a breeze allows it to hit and attach to something. Once a dozen or so framework lines are set up, the orb weaver starts the spiraling portion of the web. Here it switches to its flagelliform glands. The spider uses its hind-most legs to grab this silk as it is produced and to systematically attach it to its web frame. This process may take hours to complete, and it likely needs to be repaired or replaced daily. This type of spider may add stickiness to this spiral using its aggregate glands. Sheet webs are flat messes usually on top of plants like yews and boxwoods and sometimes the blades of grass in your lawn. They possess less architecture than an orb web but serve the same general purpose. Funnel webs are shaped like -- you guessed it -- a funnel. The contracting spider hides at the bottom of the funnel and waits for some unexpecting meal to pass closely by. These webs also offer reasonable protection for the spiders themselves. The last one I will cover here is the tangle web. This web is a mess and makes no sense, but it is deadly effective. The mess that you see is a framework not too dissimilar to an open ceiling configuration that exists above your head in a large retail store except the spider's version completely lacks symmetry. Added to this framework are sticky and elastic downlines formed by the spider's flagelliform glands. These are attached things below the framework with piriform silk discs. Just for good measure, the spider adds some aggregate gland stickiness to the bottom of these lines. If prey contacts these lines, the lines break free, and their elasticity lifts the victim helplessly upward. The spider races in and immobilizes the prey with a bite and then adds more elastic downlines which raises the now paralyzed prey further upward. The effectiveness of this system allows a spider to take prey many times its own size. And the scariest thing is that the spider itself just might be a black widow. So, there's the real science and ingenuity of spider webs. Pretty cool, huh? There's so much more to this topic, but I have to go now. It's nearly dark and I have to spray some adhesive on my giant rope web outside. I wonder what I will catch tonight.