01/31/2017 | The Five W’s of Spider Webs
Whether you’re amazed or repulsed by spider webs, you have to admit they’re interesting. Spider webs have the tensile strength of steel while retaining high elasticity and low density. They can absorb more energy without breaking than a Kevlar vest. And they’re made with a material that basically comes out of spider’s butts. Like we said, interesting.
You probably know that most spiders use their webs to catch prey, but there’s a lot more to know than that. If you get to know where and why spiders weave their webs, it could actually help you figure out how pests get into your property! That’s why Assured Environments pooled our collective knowledge and answered the classic “five ‘W’s and an ‘H’” on webs. Well, and because we just think spiders and their webs are pretty cool. Yeah, yeah: we’re nerds. You’re reading this too, you know.
All spiders have the ability to extrude silk from their spinneret glands, located on the abdomen. Different spiders produce different kinds of silk and use it for different things. Webs are the most common use for spider’s silk, but some spiders don’t build webs. These spiders use their silk for other things instead. There are even spiders that have the ability to produce multiple different kinds of silk on their own, which they can use for different tasks.
The spiders that build webs feed on insects such as flies. By catching their prey in their webs, they don’t need to spend the excessive energy and time it would take to ambush or catch it. They can also stay in one location and maintain a consistent food source. Basically, the spiders making webs in your home or business are opportunists, looking for a nice setup where they can relax and let food come to them. The most common web-building spiders are members of the Araneidae, or “orb-weaver” family of spiders. An incomplete list of spider species established in New York may be found here.
What (and How)
Spider webs are made of a special kind of silk produced naturally by spiders. Spider silk is a protein fiber made primarily from sequences of the amino acids alanine and glycine. Creating this silk is an energy- and resource-intensive process, which is why spiders need a consistent and plentiful source of protein.
The silk actually starts as a liquid when it’s first created within the spider’s body. When the process for creating silk begins, this protein liquid begins flowing toward the spider’s spinneret gland through a series of ducts. As the liquid moves through the ducts, the spider’s cells draw water out of it. When the liquid reaches the spinneret gland, hydrogen is introduced from a different part of the duct. This combination creates an acid bath within the gland that solidifies the protein into a gel. This gel is pulled out through a tiny opening in the spider’s abdomen, where it hardens into a solid fiber when exposed to the air.
Spider webs are made of various types of silk, secreted by as many as seven different spinneret glands. Each gland produces a different silk, each of which serves a different purpose. Most webs use sticky and non-sticky silk. Spiders use non-sticky silk to create footholds, which they use to navigate without getting stuck in the web. A web’s complexity occurs in part because spiders have to thread their footholds strategically, so they can move around without compromising the web’s prey catching surface area. There are also types of silk used for structural integrity, protecting eggs, immobilizing prey, and even bonding separate threads of webbing together.
Spiders are at their most vulnerable during web-building. Not only do they lack the defensive properties and maneuverability the web provides, the process of weaving the web requires all of the spider’s attention. This makes it easier for prey to ambush and eat or kill spiders. Any prey that sees the spider building will also, obviously, avoid the area where the web is built.
For both of these reasons, spiders, especially the common orb-weaving spiders, wait until night to build their nests. The cover of darkness makes it harder for prey and predator alike to see the spider while it’s working. Remember: as far as the spider is concerned, you are a particularly large and dangerous predator, so these rules apply to you, too! Spiders in your business or your home will usually hide until everyone has gone to bed and they feel safe to commit to building their webs.
Most spiders build webs in order to catch their food. Flies and other insects unfortunate enough to pass through the web get stuck on the sticky silk. As they struggle, the prey further entangles itself, until escape is impossible. Some spiders facilitate this entrapment by rolling their captured prey up in another kind of silk. Other spiders use their prey’s surprise as an opportunity to infect them with venom.
Spider webs have many uses other than prey-capturing, too. Some spiders use webs in their reproduction. Male spiders create ‘sperm webs’ which can fertilize eggs laid on them. Once spiders are born, webs serve as a nest for protecting the young spiders and giving them a food source. Many spiders will eat their own unused webbing as a means of recycling resources.
Spiders can even use their webs to extend their sensory awareness. Some spider silk conducts vibration very effectively. When motion vibrates these threads, the spider becomes alerted to the presence of whatever stimulated the vibration. These vibrations are used both for hunting and escaping from predators. Think of it as a spider’s natural alarm system. Webbing combined with pheromones can also help spiders find their way back home, or attract mates to their webs. Webs are integral to spiders’ survival and procreation.
A spider chooses where to build its web based on several considerations. First: logistics. In order to build a web, a spider must attach seven “guy lines” to nearby surfaces that can support them. In the picture above, you can clearly see all seven guy lines that connect the web to the surrounding twigs! These guy lines are the structural foundation of the web.
Orb weaver spiders’ webs are orb-shaped (hence the name), so the surfaces to which guy lines are attached must allow the spider to build a vaguely circular web within them. Guy lines are the only part of a spider’s web that actually touches the web’s surroundings. They can be attached to just about any surface, including sheer walls and glass, they’re hard to see, and they’re very thin. Spiders can also extend their guy lines along a surprisingly large area, so it’s very difficult to totally web-proof your property.
Luckily, building logistics aren’t the only consideration that goes into where spiders make their webs. Spiders use their webs to hunt, so logically they need to build in places where they’re likely to catch prey. We can use this to our advantage! Spiders are really good at finding the routes pests like flies and fleas use to get around. That means if you find a cobweb in your home or business, it’s very likely that the area where the cobweb was built is also where other pests are getting into your home. It’s like Harry Potter and the Chamber of Secrets: If you’re having trouble finding the source of your pest infestations, follow the spiders!
Webs are pretty cool, but we don’t blame you for not wanting them in your office. If you have a spider problem, give us a call today and we’ll take care of it for you. Assured Environments has learned an awful lot about spiders (obviously) in our 100+ years of operation, and we’re more than willing bring all that wisdom to bear on the spiders unlucky enough to choose your business for their home. They won’t know what hit them.
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