Today’s spider is the labyrinth spider (Agelena labyrinthica). Just as last week’s spider, it belongs to the family of the funnel-web spiders. Certain spiders build webs that are hardly noticeable until you walk in to one (eeks!). Not these spiders. They may very well be the architect among the spiders. Their webs are most often build on top of hedges or other vegetation and consists of 3 parts:
- A horizontal sheet web spread across a good-sized area
- A funnel / system of funnels in which the spider hides
- A 3D network of threads above the sheet web to catch (flying) insects
Usually the spider sits in the opening of the funnel keeping an eye out to the sheet web and the outside world. The 3D network of threads are made of non-sticky silk threads and is used to stop flying insects. Unsuspected insects fall on the sheet web beneath them and the labyrinth spider wastes no time to fetch their prey. The prey is paralyzed or killed by the spider’s bite and dragged to the hide-out place in the funnel for later consumption. If the spider is the one being preyed upon, it escapes through the funnel. Depending on the location, the funnel is part of a larger system of funnels and corridors where the egg sac is safely kept. This system can be quite intricate and it’s the reason why the spider is named ‘labyrinth spider’.
Not only its web-building skills are impressive, the spider itself has some cool features that distinguishes it from other spiders. All funnel-web spiders have relatively large spinnerets, but these spinnerets are even larger in the labyrinth spiders. With these spinnerets, they are able to build their complex webs and capture any prey that fall into the web. To locate the prey, labyrinth spiders have different sensory organs. Around 25 trichobothria ( = sensory hairs) cover each leg and with these organs the spider detects minute vibrations of insects trapped in the web even when these vibration occur far away. Labyrinth spiders are also excellent navigators, even in complete darkness. They use regular visual stimuli, but can also detect polarized light for orientation purposes (humans can barely detect this without any tools).
If it is time to mate, which is often in July or August, a male will visit a female’s web and gently taps on it to announce himself. When the female is ready, she remains in the opening of the funnel and the two of them mate. Later on, the egg sac is formed and hanged in the labyrinth of funnels and corridors. The young spiderlings survive the winter period by living off the egg yolk. Sounds like a simple and efficient way of reproducing, without the need to be good at dancing and gift giving or afraid of being eaten by the object of your affection!
For this blog, I kept an eye out on two labyrinth spiders. One is located in a corner close to the house and the other one on a patch of vegetation right outside the garden. I saw some more further down the block of houses in my area. I did notice that some are very shy and retreated down the funnel even when I was quite a distance away, whereas others let me come very close (maybe they knew about this series of blogs and wanted a moment of fame?). As I was observing the one close to my house, I wanted to test her reaction when something got in the web. The only thing I had in my hands was a corn-based snack. So I dropped a little piece of it in the web. She hesitated at first, but then attacked the piece and dragged it towards the funnel. Never thought that the spider would be fooled by that, but she seemed to enjoy it.