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grass spider - Agelenopsis pennsylvanica - female

grass spider - Agelenopsis pennsylvanica - Female
Puyallup, Pierce County, Washington, USA
October 29, 2009
Size: 12 mm
It looks like my choices are pennsylvanica, potteri, actuosa, oregonensis & utahana.

Images of this individual: tag all
grass spider - Agelenopsis pennsylvanica - female grass spider ventral view - Agelenopsis pennsylvanica - female grass spider epigynum - Agelenopsis pennsylvanica - female grass spider 1st egg sac - Agelenopsis pennsylvanica grass spider 2nd egg sac - Agelenopsis pennsylvanica - female spiderling - Agelenopsis pennsylvanica

Interesting development - 2nd egg sac
So, though I posted no images, this spider created a first egg sac on Oct. 30th. I was surprised to see that it just created a second egg sac today. How many egg sacs can a female spider create after mating once with a male? Can a spider create an egg sac if it never mates?

Also interesting, just as she has created this second egg sac, the spiders from the first egg sac are beginning to emerge. I guess I'll have to create a second container? How the heck to you feed spiderlings?

I got this from Jay, but I can't find his comment right now. I'm raising a couple of small jumpers and I needed food. He suggested taking a wide-mouthed container (I use something close to a plastic pitcher) and lay it down on the tall grass and then quickly slide it along mouth first. As is goes trawling through the grass bugs are knocked into the containter. Mostly it ends up full of springtails.

Good idea!
I'll have to try that next summer.

Another thing I've found that often works is to squish a fresh fly or cricket and put it in the web. In many cases the spiderlings will scavenge on the corpse and eat their fill. I also dip the corpse in water before putting it in the web, so the spiderlings get some water at the same time.

Thanks guys
I'll try those and I have added images of the egg sacs now.

To follow up on my first comm
To follow up on my first comment, RC certainly has additional experience to draw upon -- he knows what can be seen in the various species and what to look for -- but when I look at Chamberlin & Ivie's drawings (1941), I can't help but wonder, how, based only on these images, one can exclude A. actuosa, for example, which is a northwestern species. Even A. kastoni and A. potteri seem like they would be awfully similar, if you have nothing more than these (BG) images to view.

Looking at Kaston, as well as Paquin & Dupérré, I begin to wonder just how good the C&I drawings are, but even with seemingly better drawings (when available), what good are they, if you can't see the detail in the specimen?

I suspect that to really pin these down, the epigyne needs to be dissected.

To answer Drew's question (or rather the question behind the question): To get at the species you will at the very least need as good an image of the epigyne as that which is shown here. But in all honesty, I suspect that most of the specimens in this genus will have to be left at "Agelenopsis sp.".


I have examined the epigyne u
I have examined the epigyne under a microscope but I really don't have any resources that will get down to species, only the genus. And because I don't have the proper camera or equipment to get such a close photograph to send anyone, I think I will have to leave it at Agelenopsis sp. I think I need to invest in a nice camera and some better taxonomic keys!

Hi Drew-

I understand your situation only too well. :-) BTW, check your mailbox.


No problem
I've kept the specimen for Rod to ID. I may have jumped the gun moving it first, but if it turns out to be wrong I'll move it back. Thanks for all your info! I'll look for a new surface for photography. What do you use? I'm using a stone baking dish :). I like it because it's fairly neutral and it doesn't reflect any of the flash, and of course it has nice steep sides that impedes the spider from escaping...though of course many of the spiders can easily climb the sides.

Glad to hear -- I'm looking f
Glad to hear -- I'm looking forward to hear what he says. If we can slowly build up a small known collection, these should become somewhat easier with time.

As to background, yes I also like to use a dish. It's not perfect, but I've been using a white porcelain bowel that we happen to have. Of course, reflections are then sometimes a problem (a stone baking dish never occurred to me). You could try laying a sheet of paper in your dish -- white, grey, anything relatively neutral.


Great images, great collecting and sleuthing, as always. My only nit to pick -- you've picked up a bad habit (IMO) of RC's of using a non-neutral background. This makes it impossible to determine trueness of color (or do any accurate color correction) as there is no (relatively) neutral grey in the image that can serve as a reference. Of course, even if the background were tiger-striped, I'd still be happy to see images from RC -- and you. :-)

I find this genus difficult -- without being able to see images of other species (or have them under the microscope) it's difficult to know which features of the epigyne are more significant and which less so.


From Rod Crawford:
I think it's Agelenopsis pennsylvanica! Which is pretty uncommon in Washington. I don't even have any from Pierce County.

I just found a very similar l
I just found a very similar looking Agelenopsis in Maryland. The epigynum looks almost exactly the same as this spider, but I have no idea the distribution of the 13 US species. The Common Spiders of Maryland book I have says that both A. pennsylvanica and A. emertoni are both common in the state, but the size of my spider (12-13 mm) seems to match closer to A. pennsylvanica. Do you know the distribution of the genus or have any suggestions on where I would be able to find it?

A. pennsylvanica
is in your area. However, I don't know the other species in the northeast that may look very similar.

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