Ever since a Banded Garden Spider (Banded Argiope) hung its web in our garden many years ago, it has been one of my favorites. Now is the time of the year to watch for webs and to find this and other spiders. Many spiders mature in late summer and the early morning dews highlight webs that we might otherwise miss.
Earlier this week I spotted this Banded Garden Spider in Eliza Howell Park while I was walking through the wild flowers.
These spiders wait in the middle of the vertical orb web, in an inverted position, and hold their legs together so that, at first glance, it looks like they have only four legs instead of eight. They can feel when an insect is caught in the web and hurry to subdue it and wrap it in silk for eating later.
Many other spiders hide at the edge of their webs. The fact that Banded Garden Spiders position themselves at the center of the web, together with their practice of remaining on the web for much of the day, contributes to my observation pleasure. It has poor vision so one can come close without disturbing it, as long as they cannot detect an intruder with their other senses. It tends to drop down when there is contact with the web or with the branches that support it.
The web is large and basically circular. Banded Garden Spiders are among the spiders known as orbweavers and the webs are called orb webs. These spiders are large, but note how small they look in the center of the full web.
The spider in the middle here (difficult to see) looks different from the one in the first picture, but it is the same one. Since it is on a vertical web, it is possible to view both its top side and its underside. We are now looking at the underside.
Located on the underside, near the rear end of the abdomen, are the spinnerets, the external ends of the silk glands.
Large orb webs, especially when visible with dew drops, provide an opportunity to note the different threads. The radii threads (spokes) that go from the outside toward the center of the web are not sticky, but the spiral threads are – and are the ones that capture and hold the prey.
This orb web, made by another orbweaver, not a Banded Garden Spider, shows the typical orb web shape.
In the next picture, a close-up of a Banded Garden Spider and part of its web, one can see that the sticky threads do not touch the center, where the spider waits. When an insect is caught, the spider travels to it on the radii to subdue it.
Not all orbweavers incorporate the zig-zag looking arrangement near the hub (“stabilimentum”) in their webs, but Banded Garden Spiders do. The stabilimentum was visible in the pictures above and is shown again here.
The function of the stabilimentum is not fully understood. While areneologists (spider experts) seek to learn more about this part of the web, the rest of us might notice it and wonder what the spider knows that we do not.
I am very far from being an areneologist, but my appreciation of the world of spiders is greatly increased by having access to some of their work, including this 2018 book.
There are other types of spiders and other kinds of webs present now in Eliza Howell Park. This is the best time of the year for web watching – from now until the fall frost.