25-Oct-2015 Nooksack Cemetery, Everson, Washington

Sample site. Click to enlarge.

Wanting to get in at least one more field day before the rain switch gets flipped and Washington's wet season begins in earnest, Rod Crawford and I headed up to Everson in Whatcom County.  We spent most of the day collecting spiders in and around the Nooksack Cemetery and neighboring Nooksack Elementary School before tapping a round of pine cones in Everson on our way home (interesting area history here).

Nooksack Cemetery

Juvenile Xysticus sp. on a headstone

The cemetery and school sit atop the end of a tongue of elevated land bordered by a wooded Breckenridge Creek and the highly cultivated Sumas River floodplain.  While Rod dove headlong into his search for productive leaf litter at the foot of the bluff, I began searching the headstones and grave markers for eight-legged life.

Zygiella atrica in a retreat
on a headstone

Araniella displicata on headstone

Orb-weavers, crab spiders, linyphiids and the jumping spider Salticus scenicus (Salticidae) made up the bulk of my "rock collection".  Rod pointed out that most were common forest spiders, which led him to suspect that they had ballooned their way into the cemetery. 

Philodromus spectabilis on a headstone

Zygiella atrica on school window sill

Ready for new frontiers and, frankly, a bathroom, I eventually ambled next door to the Nooksack Elementary School's row of playing field Honey Buckets and then collected spiders from the exterior of the school building.  Luckily it was Sunday, so nobody was present to be concerned about the middle-aged woman with the "butterfly net" staring at brick walls, downspouts and door frames.  Where introduced Araneus diadematus (Araneidae) reigned supreme on the cemetery shrubbery and buildings, introduced Zygiella atrica and Z. x-notata (Araneidae) were the most common orb-weavers I found on the school building.

Zygiella x-notata removed from
retreat on school building

Ponderosa cone site in Everson

Since the cemetery had no pines, on our return trip through Everson we knocked on a few doors of homes where pines had been planted in the yard.  A pair of mature ponderosa pines (Pinus ponderosa) in one kind woman's side yard supplied me with a fallen cone sample of 43 cones.

The tapped cones yielded 11 spiders and 4 species, plus 7 adult harvestmen.  As I've found in other cone samples in western Washington, many of the spiders present and all of the harvestmen were introduced species.  However, Ozyptila praticola (Thomisidae), which we have found in great abundance in the Seattle area, was not among them.  Further, we didn't find it in any of the other microhabitats we sampled in the area, and Rod hasn't collected any from other sites he's sampled in Whatcom County.  If the species has spread south from the Vancouver area, its presumed point of introduction in British Columbia, we have yet to detect it in northern Washington state.

Read Rod's account of the day here.

Philodromus spectabilis on a headstone in Nooksack Cemetery

22-Oct-2015 Marysville and Arlington, Washington

Site location map. Click to enlarge.

Last week I looked for but did not find the introduced crab spider Ozyptila praticola (Thomisidae) at two sites on the south end of Tulalip and Marysville.  But spiders are patchy even in microhabitats they're known to frequent, so a few negative results could mean that the species isn't present in the area, but not necessarily.  It could also mean that the sampling wasn't intensive or extensive enough to detect them.  With these possibilities in mind, I returned to Marysville for another cone sample and then headed further north to Arlington to continue my search for O. praticola.

Marysville

Marysville collection site

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My first stop was the parking lot behind the Marysville Municipal Court, which features a dumpster corral flanked by cypresses and backed by black pines (Pinus nigra).  Several hundred cones lay on a bed of pine needles.  I tapped 100, most of them lying near or under the drip line of the cypresses.  The result was 13 spiders and 3 species, plus 7 harvestmen.

Tegenaria sp. in black pine cone

Pelegrina sp. juvenile

The introduced linyphiid Tenuiphantes tenuis was the most abundant species present, with Tegenaria sp. (Agelenidae) coming in a close second.  The most spectacular spider both in life and in my wet vial was a penultimate male Pelegrina sp. (Salticidae), which turned bright red in alcohol.  I found no O. praticola.

Arlington

Haller Park cone source

Pine cone microhabitat in Haller Park

Next I headed north to Arlington.  My first stop was Haller Park, situated at the confluence of the north and south forks of the Stillaguamish rivers.  A youngish western white pine (Pinus monticola) growing along the Centennial Trail, an old railroad right-of-way bisecting the park, had dropped cones on the steep grassy embankment.  I could find only 13 cones to tap, and they produced two juvenile spiders: a penultimate female Clubiona sp. (Clubionidae) and a Tegenaria sp. (Agelenidae).  No O. praticola.

Pines at Snohomish Co. District Court

Fallen cone microhabitat at the
SnoCo District Court in Arlington

Not satisfied with the measly 13 cones I found at the park, I cruised through town until I spotted this row of Scots pines (Pinus sylvestris) planted behind the Snohomish County District Court building.  Tapping 50 cones I collected 6 juvenile spiders, all apparently of the same species: Enoplognatha probably ovata (Theridiidae).  No O. praticola.

Clubiona sp. from Haller Park cone

Returning to Seattle, I tapped 15 P. nigra cones from the same accumulation I described in May.  Mainly it was to verify that adult O. praticola were still "on the hoof".  Indeed they were.  That small number of cones produced 4 O. praticola in total: 1 female, 1 male, and 2 juveniles.  So I can't attribute to seasonality my not (yet?) finding any O. praticola north of Everett and the Snohomish River.

View up South Fork Stillaguamish River from the Centennial Trail in Arlington

20-Oct-2015 Blackpine Horse Camp, Washington

Site location map. Click to enlarge.

After several weeks of looking for Ozyptila praticola in the concrete jungle of the Seattle-area urban corridor, I was delighted to accompany Rod Crawford on a collecting trip to the very peaceful Blackpine Horse Camp located in Wenatchee National Forest.  We had scouted out this location last June when we drove up the Icicle Creek road to collect a sample in the neighboring Icicle Gorge gridspace.  We came away two species short of a full sample that day, so this day's goal was to collect a full sample at the horse camp, then pick up at least two additional species in the incomplete gridspace.

Pinus monticola (center)

Cones were found on mixed
conifer-deciduous litter

I knew from our previous visit here that Blackpine Horse Camp was missing the ponderosa pines (Pinus ponderosa) I found in the neighboring Icicle Gorge gridspace, but there were a few western white pines (P. monticola) dotted about.  I was able to find three trees in the camp for a total of 45 fallen cones to tap.  Accessing some of the cones required maneuvering through dense wet underbrush, but the effort was worth it for the interesting array of spiders they held.  The 45 tapped cones yielded 41 spiders from 6 families and 9 to 10 species, plus both Neobisiid and Chthoniid pseudoscorpions.  This was an unusually species-rich cone sample!

Cryphoeca in a retreat under a
riverside stone

Female Cicurina sp. #1 tapped
from a cone. Photo
copyright Rod Crawford

Not too surprisingly, I tapped more individuals of the common spider Cryphoeca exlineae (Agelenidae) from the cones than any other species.  I also collected it under riverside rocks, and Rod found it in litter.  Most of the 5+ linyphiid species present were microspiders, so ID determination will have to wait until the specimens cure.  But Rod was able to quickly identify another spider as the undescribed dictynid Cicurina sp. #1, an uncommon spider in Washington.

Gray jays

A few cars drove past during the course of the day, but as for the horse camp itself, Rod and I had it to ourselves.  Consequently I could enjoy the sights and sounds of nature, including a snowshoe hare (Lepus americanus) starting to put on its white winter coat, coyotes (Canis latrans) calling (Rod and I agreed they were literally howling...with laughter at how we blundered through the underbrush that they so easily glide through) and a pair of gray jays (Perisoreus canadensis) that followed me around the camp.

By the way, whoever named the camps and trails in this forest sure did like compound names: Blackpine, Jackpine, Blackjack ...

Brilliant fall foliage

We had hardly an hour of daylight left by the time we left the horse camp and moved back down the valley into the Icicle Gorge gridspace to complete our June sample.  Although Rod swept grass and I beat shrubs, there weren't many spiders present and Rod was skeptical that we'd added any new species to the gridspace list.  Luckily Rod found a deposit of cottonwood litter to sift as twilight set in.  The final specimens were collected by flashlight as the air temperature slipped into the low 40s.  Our reward for working so hard was the sight of a buck and several does on the forest road as we departed.

Be sure to read Rod's take on the day here!

Moonlit spider sampling - we must be getting close to Halloween!

14-Oct-2015 Everett, Tulalip, and Marysville, Washington

Site location map. Click to enlarge

I continued my search for the introduced crab spider Ozyptila praticola (Thomisidae) by traveling north along the I-5 urban corridor.  I stopped first in south Everett, then crossed the Snohomish River and sampled in Tulalip and Marysville.

Everett

Everett site, P. sylvestris in center.

Having found that commercial areas are among the easiest places to find accessible fallen cones, I cruised the Everett Mall area and quickly found a fencerow of conifers that included Scots pine (Pinus sylvestris). 

P. sylvestris cones are tiny

The day was still cloudy and cold when I began collecting.  I enjoyed listening to the chirping of a Pacific tree frog (Pseudacris regilla) while I loaded my net with 50 cones, then retreated to the warm car to tap them.  From those cones I collected 10 spiders and 3 species.  As with my previous sample from Shoreline, the most common species present were O. praticola (another mark on the WA distribution map!) and Tachygyna vancouverana (Linyphiidae).

Snail & friends

Among the non-spider inhabitants of these cones was this diminutive snail, less than 5 mm in diameter.  It immediately began exploring my net while some even tinier creatures began to explore it.

Can you spot the female O. praticola?

Speaking of tiny things, plenty of the spiders that I collect grow to a maximum of 1-2 mm in length.  Adult O. praticola are larger than that (3-4 mm long), but have the habit of curling up and 'playing dead' when in the net.  Unless they start to move about, it takes some skill to distinguish them from the brown bits of detritus in the net.  Fortunately they have a recognizable silhouette, which helps.  I've circled an adult female in orange in the photo to the right.

Tulalip

Tulalip site

P. monticola cones in Tulalip

Having found the cones so quickly in Everett, I had plenty of time left to proceed north to Tulalip and neighboring Marysville for further sampling.  In Tulalip I was once again able to very quickly find fallen pine cones.  Cones beneath an eastern white pine (Pinus monticola) growing next to a McDonald's had miraculously escaped the chopping blades of lawn mowers.

Grammonota kincaidi females

I tapped 50 of these cones and collected 10 spiders and 2 species.  The most common spider looked like Grammonota kincaidi, a linyphiid found on conifer foliage in western Washington.  No O. praticola, though, so I crossed under I-5 and into Marysville to look for another collection site.

Marysville

P. nigra cones in Marysville

Marysville site

Marysville really knows how to welcome pine cone spider collectors!  Greeting visitors entering the city from northbound I-5 is a mini park with the city's sign and a small grove of black pines (Pinus nigra).  And, unlike many of my recent experiences with P. nigra cones south of Marysville, the scales of the fallen P. nigra cones here were open.  From 50 tapped cones I collected 7 spiders and 2 species of linyphiid microspiders.  But the most numerous denizens of these cones were juvenile Enoplognatha, probably ovata (Theridiidae).  I've tapped them from every set of cones I've sampled this year in the Puget Sound area of Washington.

I found no O. praticola in Marysville.  At present, then, the northern-most known location of Ozyptila praticola in Washington state is the 9800 block of 3rd Ave SE in Everett.

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.

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