Philodromus - Rhysodromus alascensis

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Home » Guide » Arthropods (Arthropoda) » Chelicerates (Chelicerata) » Arachnids (Arachnida) » Spiders (Araneae) » True Spiders (Araneomorphae) » Entelegynae » Running Crab Spiders (Philodromidae) » Rhysodromus » Rhysodromus alascensis

Photo#801955

Copyright © 2013 Stephen Hart

Philodromus - Rhysodromus alascensis -

Hurricane Ridge, Olympic National Park, Clallam County, Washington, USA
July 8, 2013

I'm focussing on the male in this set, because it's the first time I've observed one, let alone photographed it. I'm going out on a limb and assigning an ID based on association with the female. (Of course, I'm willing to stand corrected.)
Both the male and the female were running around on a rock outcrop maybe 6 feet in diameter on a scree slope. We observed them for some 15 minutes. There was what I took to be a cairn from last year on the rock, but no new web.
At one point, shown in these photos, the male was on the top edge of the outcrop. He was stilting noticeably, and spraying silk. He also waved his forelegs, or maybe manipulated the silk. Finally, he ran off.
Meanwhile, the female, who looks much fatter than all others I've seen--I guess she hasn't laid yet--was running around the face of the rock, pausing occasionally. I never saw the two interact directly.

Female here:

Images of this individual: tag all

Philodromus - Rhysodromus alascensis - male

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Contributed by Stephen Hart on 10 July, 2013 - 6:36pm
Last updated 11 July, 2013 - 9:39am

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 - 6:43pm

Very nice

I unlinked your two specimens since linking is supposed to be only for one specimen. Instead I thumbnailed the other sex in your comments.

… Lynette Elliott, 11 July, 2013 - 9:42am

unllinked

Thanks. So should males and females only be on the same page if they're actually mating?

… Stephen Hart, 11 July, 2013 - 9:49am

Yes

If they are mating it's okay to keep the images together. However even then it's best to separate the male from the female when they are in individual frames. The rules become a little muddy when dealing with mating pairs though, so I think doing it either way would be OK.

… Lynette Elliott, 11 July, 2013 - 9:58am

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