8-Aug-2017 Bainbridge Island, Washington

Site location map. Yellow pin marks Harborview Drive site.
Click to enlarge.

Smoke from wildfires in British Columbia precluded a trip to the gridspace of interest to Rod, so I took a solo trip to Bainbridge Island (Kitsap County) to continue my search for the introduced European thomisid Ozyptila praticola. So far I haven't found any O. praticola on the nearby Kitsap Peninsula, but it is present on Vashon Island five miles to the south of Bainbridge Island. Both islands are connected by frequent ferry traffic to Seattle, where O. praticola is now common.

Sampling site on Harborview Dr.

The fallen cone microhabitat

Almost immediately after disembarking from the ferry, I found a nice cache of fallen cones to tap on Harborview Drive. The cones were a jumble of Douglas-fir (Pseudotsuga menziesii) and black pine (Pinus nigra) cones intermingled with Douglas-fir and madrone (Arbutus menziesii) litter.

Juvenile Ozyptila (?praticola?)

O. praticola in western WA. Blue,
yellow & red pins indicate adult, juvenile
or no O. praticola found, respectively.

I tapped 100 cones and collected 26 spiders. Most were Cryptachaea blattea (Theridiidae), but two were juvenile Ozyptila. They look like O. praticola to me, but unfortunately I can't definitively identify the species from juvenile specimens, so a return trip with litter sifting equipment in tow will be required.

The other four Bainbridge Island sites I sampled produced more C. blattea as well as juvenile specimens of Tegenaria, Tenuiphantes, Philodromus, and Phrurotimpus. In all, very typical for fallen cones in urban western Washington.

Seattle skyline seen through the milky haze of wildfire smoke from the
deck of the M/V Tacoma.