Monday, October 12, 2015

12-Oct-2015 Shoreline, Washington

Site location map. Click to enlarge.
Finding only a juvenile Ozyptila in Lynnwood last week was very unsatisfying.  I couldn't be sure whether it was my target species O. praticola (Thomisidae), or something else.  So with a few hours free today and the rain in abeyance, I headed back to the same general area and see if I could find any mature specimens.

Sample site
Driving northwest on Ballinger Way (WSR 104) from O. praticola's northern-most known location in Washington (Lake Forest Park), I spotted numerous pines near the Shoreline-Mountlake Terrace town line.  After finding several potential sites to be cone-free, I found my collection site in the parking lot of a business: a pair of western white pines (Pinus monticola) growing in a small planting bed surrounded entirely by asphalt.  The fallen cones were laying on needle litter or in the groundcover, which was comprised of English ivy (Hedera helix) and a ground-hugging variety of juniper (Juniperus sp.).

Fallen cone microhabitat
Tachygyna vancouverana female
I tapped 50 cones and collected 42 spiders and 2-3 species.  Sixteen of the spiders appeared* to be female Tachygyna vancouverana (Linyphiidae).  How refreshing to find a native species proliferating in Seattle-area fallen cones!

The other identifiable species was my target species, the introduced crab spider O. praticola (see photos below).  So, the nexus of Ballinger Way, 15th Ave NE and 244th St SW in Shoreline now marks the northern-most known location of Ozyptila praticola in Washington.  The search continues.

*As always, thank you to Rod Crawford for helping me with IDs.
Ozyptila praticola female, ventral view
Ozyptila praticola female, dorsal view.

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