Saturday, October 10, 2015

8-Oct-2015 Mukilteo and Lynnwood, Washington

Site location map. Click to enlarge.
My plan was to visit the campuses of community colleges in Everett and Edmonds, where I knew pine trees were growing, to continue exploring western Washington pine cone spiders (most of my data is from eastern Wash.) while also gaining insight into the local distribution of the introduced crab spider Ozyptila praticola.

No cones at Everett CC!
Of course my plan relied on the presence of open fallen cones beneath trees that I had legal access to.  As it turned out, those basic requirements were hard to fulfill.  For starters, the groundskeepers at Everett Community College had fastidiously removed the undergrowth and plant litter from their planting beds.  So had Everett city park crews, as I found while looking for cones beneath pines along Marine View Drive (red pins on map).  I was delighted to see that the ground layer habitat was largely intact at Edmonds Community College, but sadly the scales on the fallen cones were closed there as well as at two other sites (blue pins on map).  The two towering pines on Bothell's Main Street were fenced off due to construction (yellow pin on map).

SW of Paine Field, Mukilteo

Fallen cones at site SW of Paine Field
A pine grows in an industrial park
But persistence paid off!  Cruising south down Mukilteo Speedway, I spied a western white pine (Pinus monticola) growing behind Adpro Litho.  And laying beneath it on a bed of pine needles were about 150 open cones!  The folks in Adpro's office cheerfully gave me permission to collect spiders ("take them all!"), so I was finally in business.  Note that this site is labeled "SW of Paine Field" on the map above.

Juvenile Tegenaria in retreat in cone
Tiny salticids, 2.5 mm long
I tapped 100 cones and collected 30 spiders and 4 species, as well as 7 harvestmen.  Half of the spiders were juvenile Tegenaria sp. (Agelenidae).  The second-most common spider was a salticid*.  Most of the remaining spiders were linyphiids.
*Update (17-Nov-2015): The salticid was Pseudeuophrys lanigera, a European species.  Read more here.

*Update (25-Jan-2018): You can read our subsequent paper about P. lanigera in Washington state here or here.

East of Scriber Lake, Lynnwood

A tiny green island in a sea of
pavement and razor wire.
Urban cones in Lynnwood
"Accidental" pine trees growing in neglected places seemed to be the theme of the day.  My second collecting site was another western white pine growing next to a pungent dumpster behind Lynnwood Square, a shopping center in Lynnwood.

"Toothy" Erigone sp. male.
Click to enlarge
I was only able to find 25 fallen cones to tap, but they produced 6 spiders and 2 species.  One was a very "toothy" microspider Erigone male (Linyphiidae), which sported numerous denticles on the palpal femur as well as on the edge of the carapace.

I also collected a juvenile Ozyptila sp. which had the same patterning and coloring as O. praticola.  It was a tantalizing find because it indicates that the species is probably in the area, but doesn't prove it.

Western white pine (Pinus monticola) terminal bud

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