Spider Cairn? - Rhysodromus alascensis

Reference and many images

I found a reference for the cairn-building behavior
“At least one species, Philodromus alascensis, places its egg sac in a small, rocky recess, where it is covered with grains of sand, wood flakes, and other debris.”

Field Guide to the Spiders of California and the Pacific Coast States
Text by R. J. Adams Illustrations by Tim D. Manolis”
University of California Press 2014

Rhysodromus alascensis on Olympic Natural History, 45 slides

… Stephen Hart, 9 June, 2018 - 6:49pm

Moved

Moved from Unidentified Spider Egg Sacs.

… Charley Eiseman, 8 October, 2011 - 5:36pm

Moved

Moved from Spiders.

… Charley Eiseman, 6 June, 2009 - 11:10pm

The reason I was asking...

I posted this photo a few months ago with a phidippus jumping spider standing by a group of stones--all glued together. I wonder if it also contains an insect. Very interesting!
[thumb:#204549]

… Carol Davis, 17 September, 2008 - 5:12pm

Thumb

I think you meant:

… Stephen Hart, 17 September, 2008 - 5:18pm

Cairn 2

More photos of another cairn, dissected:

… Stephen Hart, 16 September, 2008 - 9:26pm

Huh?

I hate to appear stupid, but what do you mean by a spider cairn?

… Carol Davis, 15 September, 2008 - 2:13pm

Spider Cairn

According to http://www.merriam-webster.com/dictionary/cairn a cairn is "a heap of stones piled up as a memorial or as a landmark".

In this case the person was suggesting that this cairn (pile of rocks) was built by a spider (as it was held together with webbing.

… apgarm, 15 September, 2008 - 2:32pm

Silk and stones....

I would be hesitant to assign this object to a spider, though it certainly could be. You didn't take one apart to see what was inside? Don't know that any conclusion can be drawn then.

… Eric R. Eaton, 15 September, 2008 - 3:29pm

Right

I didn't dissect one. It could be an insect as well, I suppose, maybe a caterpillar?
I used "cairn" fancifully.

… Stephen Hart, 15 September, 2008 - 4:33pm

Cairn

There is, in fact, a spider that builds a 'cairn' of pebbles--Zodarion rubidum (which is native to Europe, and in North America so far has only been found in Colorado and Pennsylvania)--but the 'cairn' is only a few millimeters across, and is hidden on the underside of rocks. My guess would be that this was built by a caterpillar as a structure in which to pupate, but it would be good to take one apart and investigate if you come across these again.

… Charley Eiseman, 15 September, 2008 - 7:48pm

I can go back

I can go back to this location, but not until Friday. The road is closed for construction M-Th for a month.

… Stephen Hart, 15 September, 2008 - 8:14pm