The rain has returned the Pacific Northwest, and on our afternoon strolls my wife has noticed something odd: webs. Dozens of circular webs with brownish spiders perched on them. The spiders are back! Hanging from trees, bushes, and walkways, and ensnaring joggers and walkers on nature trails and sidewalks all over the region, it seems like they are everywhere. But what are these arachnids and why are they out now?
A European Transplant
After some careful research I found that the majority of the spiders we saw were the cross orbweaver (Araneus diadematus) which are in the family of orb-web spiders. They are so named for the pattern of whites spots in cross-like pattern that appears on the abdomen. The cross orbweavers are known as the European Garden Spider, as it was originally native to Europe and parts of Asia. It is now also commonly found in the northern third of the United States and southern parts of Canada.
The cross orbweavers’ primary mission is to capture small insects, and their very geometrical webs are well suited for this. They spin an orb shaped web daily, and the spider usually sits head-down near the hub or center of their creation. The webs are aligned so that the spider can swiftly run down the web towards its prey. The part of the web nearer to the center or hub is covered in gluey globules to help catch its meals. The cross orbweaver sits on one side of their web, holding onto a “signal thread” so it can monitor the entire area. This spider, like others of its type, will also use its legs to aggressively oscillate its web when it feels threatened and to fend off other impending predators. As with most spiders, the Cross Orbweaver does not immediately eat its catch, but can wrap it in silk to consume later. The webs are often placed at chest height, which explains why we run into so many. The spiders are also fond of placing their webs close to human houses and habitation where they can land flying insects flying insects fascinated by any of our lights.
The cross orbweavers’ webs are usually eaten by the spider before they make another one. Cross orbs do this every night and it only takes them a couple of minutes to ingest the entire web sometimes with small insects inside it. The next morning a new web is spun and ready for trapping food. It is the females who spin most of the webs we see, as they continue to make more webs as they reach adulthood, while the males go off to search for mates.
The cross orbweaver is not harmful to humans, are considered rather docile as spiders go, and it is very hard to provoke them to bite us. We may have seen so many of these spiders because September and autumn is usually their breeding month. The females get larger and eventually generate egg sacs, which they place in crannies and underneath leaves. After they are done laying, the spiders die, but come springtime hundreds of small golden spider babies will then appear.
Eli Madrone is a freelance writer who lives in the Pacific Northwest. He learned about spiders from the Phoenix RV park, hosting rv in salem, oregon.