Monday, May 21, 2018

7-May-2018 Alpha, Washington

Site location map. Chehalis locality not shown.
Rod Crawford was really pining for a field day in Lewis County, which meant a lot of driving for me. But the weather was favorable and the daylight hours long, so I agreed. After all, how could I resist a destination called Alpha? Our primary sampling sites were working forests west of Alpha on Centralia-Alpha Road, including a recent clearcut in a Douglas-fir (Pseudotsuga menziesii) and alder (Alnus sp.) woods and a second-growth woods dominated by western hemlock (Tsuga heterophylla).

The underside of a dew-bejeweled
agelenid web
Tiny linyphiid web in mud
crack
Morning dew was still very heavy on roadside vegetation, making it easy to spot the webs of certain agelenids and linyphiids. But where the sun hit dry ground, lycosids did abound! After an initial perusal of the dewy and the dry, I spent most of my day sifting moss gathered from tree trunks in the two forest types. I was, of course, most interested in seeing which species of Ozyptila was present. I only found juveniles, but they didn't appear to be O. praticola. Rod collected the only mature Ozyptila for the day, a male O. pacifica from leaf litter.

Neighbor's tree generously
provided...
...fallen cones full of surprises.
It wasn't until we moved on to the Alpha Cemetery that we found any cones for me to tap. A set of 50 Douglas-fir cones lying in landscaping debris just outside the cemetery's back fence produced zero spiders, but I had more luck with the 25 black pine (Pinus nigra) cones that had fallen into the cemetery from the neighbor's tree. They only contained two spiders, but both were the introduced species Zodarion rubidum (Zodariidae)! I first discovered this species in Washington in 2015. And oddly, with the exception of a few specimens found by another collector recently in tree litter and rotten wood near Husum, all of our Zodarion specimens in Washington have been found by me in fallen conifer cones (see map below).

A long line of shore pine ringed the
shuttered building
Cones were as vacant as the
building they surrounded
We made a final stop in Chehalis at a shuttered business near the airport so that I could have one more crack at tapping fallen cones. Here, finally, was a plentiful deposit of cones! And they were the native shore pine (Pinus contorta var contorta), too. But 50 cones produced only one juvenile dictynid. Still, having found Zodarion at the cemetery, I couldn't be too disappointed in the cone-tapping aspect of the day.

Be sure to read Rod's account of the day, too!

Location of Zodarion rubidum found in Washington state. Blue and yellow
pins indicate mature and juvenile specimens, respectively

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