June 13th, 2006
inside the nursery
Several months ago, I wrote about watchful spiders that guard their egg cases. On Sunday, while hiking at Murphys Point Provincial Park, I found another nice example of a maternal spider that constructs it nursery shelter in the upper leaves of Common Milkweed plants. As you can see in the above photo, the leaves are gathered together to form a chamber. You can just see the upper side of the spider’s abdomen through the little “window” in the chamber (click on image to see larger view).
Taking care not to damage the chambers, I peered inside a couple and shot a few photos. A dense network of spider silk fastens the leaves together with the spider and its egg case sheltered deeply within the structure. All of the chambers were occupied by the same species, the Nursery Web Spider (Pisaurina mira) — a large, two-toned brown spider which is known for the maternal guarding of its egg case. It will remain inside the chamber with its case until the young spiderlings have hatched out.
Above is a photo of a spider which seemed to have just begun the process of fastening the top leaves of a milkweed together with silk. I’m guessing that she is beginning to prepare a chamber similar to the others which I found. This species of spider is recognized by the dark brown band with wavy pale borders that runs across the top of the abdomen from front to back. As you can see from the photo, it’s quite a handsome and goodly-sized spider with very long legs.
EDIT: I’m moving an excerpt of this comment from a previous post on spiders up to a place where it will be seen by more readers of this blog. I urge anyone with more than as passing interest in spiders to check out The Canadian Arachnologist website, the Nearctic Spider Database, and the Nearctic Arachnologists’ Forum (all of which can be accessed from the main page). Here is a little bit of info about the database written by David Shorthouse who maintains the site:
If I may shamelessly plug the Nearctic Spider Database for folks like yourself with an interest in spiders, bear with me.
This has been a labour of love for the past ~year and content is really starting to develop. One of the goals I had at the very start was to accommodate casual observations that might not have ever reached print. These sorts of general natural history comments in my mind are just as important as published species descriptions. So, on this front, I just configured a “leave a comment” icon and link for each of the ~4,400 Nearctic spider species pages. Eventually, visitor comments will be integrated into the species page proper if these are of sufficient quality and reach a general consensus. I may eventually permit image uploads, but first I’d have to cluster the server and move it out of my basement ;)~ In the meantime, I welcome (as will many others like me) comments in the individual species pages.
Keep up the great work Bev!
David P. Shorthouse
Dep’t of Biological Sciences
University of Alberta
Edmonton, AB
Tags: Nursery Web Spider, Pisaurina mira, Common Milkweed, Murphys Point Provincial Park