9-Jul-2011 Chiwawa River Valley, Washington

Site locations

Wanting to tap as many pine cones as possible before moving to Massachusetts in August, I decided to squeeze in a day of solo collecting in the Chiwawa River Valley, located north of Lake Wenatchee, the day before a planned collecting trip with Rod Crawford to the southeast side of Mt. Rainier.

My plan was to start at the highest-elevation site in Chiwawa River Valley where I could find either ponderosa pine (Pinus ponderosa) or western white pine (P. monticola) easily accessible, then work my way back down the valley towards its confluence with the Wenatchee River.

Site 1. Schaefer Creek
Campground.

Schaefer Creek Campground, located about 15 miles upstream from confluence of the Chiwawa and Wenatchee rivers, served as my up-valley starting point.  The site was nearly devoid of people, but there were plenty of western white pine cones laying in and around the dusty campsites.  Tapping 63 cones got me 11 spiders from 2 species.  Seven were Euryopis formosa (Theridiidae), including males, females and juveniles.

Site 2. NF-62 SE of Chikamin Creek

Site 2 was a selectively cut ponderosa pine forest located just south of the Chikamin Creek crossing, which is about 6 miles down the valley road from Schaefer Creek Campground.

Site 2. Cones and buried sign

I didn't see the half-buried "No Trespassing" sign until I was nearly done sampling, but perhaps the spiders had; fifty tapped cones produced only 1 spider, a juvenile Tarentula sp. (Lycosidae).

Site 3. N of Huckleberry Ford
Campground

What a difference a small distance can make in forest characteristics!  Less than a mile further down the valley road from Site 2, the roadside forest where I established Site 3 was again a dense, mixed-species assemblage containing white pine.  In contrast to Site 2, where fallen cones were highly exposed to solar radiation, the forest floor at Site 3 was only "sun dappled".  Tapping 50 white pine cones resulted in 13 spiders and 1 species, amaurobiids and agelenids being the most common.

Site 4. Alder Creek

Site 4. Ant mimic Micaria sp. (L)
and crab spider Ozyptila sp. (R)

Site 4, located near Alder Creek, provided me with another opportunity to tap ponderosa pine cones.  Unlike the exposed working ponderosa forest at Site 2, however, Site 4 was in a dense, mixed-species forest.  Tapping 50 ponderosa pine cones at Site 4 produced 12 spiders and 2 species including the rare crab spider Ozyptila yosemetica (Thomisidae).  Also of interest were several juvenile ant mimics, Micaria sp. (Gnaphosidae).  Euryopis formosa was again the most numerous species present.

Site 5. Near E end of Lake Wenatchee

Site 5. Thanatus formicinus
in ponderosa cone

My fifth and final stop was in an area of open ponderosa pine forest located near the east end of Lake Wenatchee.  Sixty tapped cones produced only 3 spiders, but each was identifiable to species.  Besides the two most common "pine cone spiders", E. formosa and Pholcophora americana (Pholcidae), also present was a female Thanatus formicinus (Thomisidae).  Her size and coloration made her quite visible even before I expelled her from the cone.

Thanatus formicinus female expelled from a Site 5 ponderosa pine cone