Our Pine Cone Spider Paper Gets An Honorable Mention

The paper that Rod Crawford and I co-wrote, "A survey of spiders found in fallen pine cones in eastern Washington State", has received honorable mention in Western North American Naturalist's ranking of outstanding natural history papers for 2014.

"The Western North American Naturalist (WNAN) is pleased to announce the award for the outstanding natural history paper of 2014.  This annual award was instituted to celebrate our authors' achievements in creative and meaningful research, insightful interpretation, and articulate writing.  Finalists were selected from the 41 regular articles published in Volume 74, and the WNAN Editorial Board members selected the outstanding paper and honorable mention papers by vote."

21-Nov-2015 Fidalgo Head, Washington

Site location. Click to enlarge.

The same sunny dry spell that made it possible for me to tap pine cones in Federal Way the day before gave Rod Crawford and me an opportunity to collect another full fall sample at one of Rod's unsampled gridspaces.  Our original plan had been to head south and collect near Matlock on the Olympic peninsula, but predicted temperatures were slightly higher for Anacortes on Fidalgo Island, so we headed north instead.

Douglas-fir & juniper on Fidalgo Head

Looking across Burrows Bay towards
Sugarloaf (left) and Mt Erie (right)

Our sampling site was a rocky prominence called Fidalgo Head, located on the northwestern point of the island.  The trail was slippery with moist red clay and caused us each to "sit unexpectedly", as Rod put it, but otherwise little effort was required to access this lovely spot.  Near to the precipitous face of the head, the dense inland forest opened to a few small grassy meadows growing on a very thin veneer of soil over bedrock.  The meadows were punctuated by Douglas-fir (Psuedotsuga menziesii), Pacific madrone (Arbutus menziesii) and tree-sized coastal junipers (Juniperus scopulorum), and featured large pockets of reindeer lichen.

Future fallen cone microhabitat:
Douglas-fir cones still on tree

Fallen Douglas-fir cones were often
near deer scat at this site.

Although I swept the meadow grass (2 species) and searched for ground-active spiders (to no avail) and spiders in webs (nothing not found elsewhere), I spent much of my time tapping Douglas-fir cones.  Since the scales on most cones were only partially opened, I adopted the method I've used with mountain hemlock cones (described here).  It is a more time-consuming procedure than conventional pine cone tapping, but worth the effort.  Tapping 50 cones got me only 7 spiders (all linyphiids) but 4 species not collected by other means, plus 20 pseudoscorpions from the family Chthoniidae.  In all, about 1 in 6 species we collected at Fidalgo Head came from my tapped cones.

As dusk loomed, I searched webs on a boulder while Rod finished sifting moss.  A couple hiking past asked if I was collecting moths, and was I a biologist.  They were interested to learn that I was looking for spiders, asked to see some, and said they were excited to get back to camp and tell their kids that they'd met a real biologist on the trail.  Now that made my day!

Read Rod's trip narrative here and view his photo album here.

Spider collectors cast long shadows!

Sunset over the San Juan Islands

20-Nov-2015 Federal Way, Washington

Site map. Click to enlarge.

Continuing dry conditions made it possible for me to continue my search for the introduced crab spider Ozyptila praticola (Thomisidae).  My current theory is that the spider is present in the entire Seattle-Tacoma conurbation.  This area stretches from Everett in the north to DuPont in the south, and is bounded by the Snohomish River estuary and Nisqually River delta, two formidable natural barriers to the spread of Ozyptila praticola if the species isn't a strong ballooner and isn't getting an unwitting travel assist from humans (Those are two big "ifs" which I still need to research.).  Having found the species in Kent a few days prior, I jumped about 6 miles southwest to Federal Way for the present sample.

Lugubrious sample site

The fallen pine cone microhabitat

Black pines (Pinus nigra) planted along the southern and northern borders of a senior housing complex provided me with plenty of partially opened cones to sample.  I tapped 55 cones and collected 14 spiders and 4-5 species, plus some harvestmen.  Among the spider species present were "the usuals" I've been finding in this urban corridor: Tachygyna vancouverana (Linyphiidae), Cryptachaea blattea (Theridiidae), and yes, Ozyptila praticola!

O. praticola tapped from fallen pine
cones in Federal Way, Washington

While I was collecting, a steady stream of people walked by me on the narrow, unofficial path that ran between the fence and the senior apartment building.  One man asked what I was looking for, and upon hearing my answer was eager to show me an ugly sore on his leg that he insisted was from a spider bite.  He attributed it to the brown recluse, which I assured him doesn't live in our region.  Not surprisingly, people don't like hearing that they or their doctor may have made a mistaken diagnosis, and frequently stick to their opinion even though they never actually saw what bit them.  Much to this man's credit, he was willing to hear about alternate possibilities.

Mount Rainier was radiant in the distance

First Record of Pseudeuophrys lanigera (Salticidae) in North America

Pseudeuophrys lanigera tapped from
fallen pine cones in Mukilteo,
Washington, USA on 8-OCT-2015

Early in October 2015 I tapped several salticids, including one male, from 100 fallen Pinus monticola cones I found in a light industrial area of Mukilteo, Washington.  Rod Crawford has identified the male as Pseudeuophrys lanigera, a species endemic to Europe and found as far east as the Caucasus and as far north as Scotland and Denmark.  As far as we can ascertain, this constitutes the first record of the species in North America.

Photo of male showing left palp

In Europe, the species is frequently synanthropic, often found in and on buildings.  In contrast, I collected my specimens from pine cones that were lying on the ground over 100 feet from the nearest building.  The area between my collection site and nearby buildings was paved with asphalt or other impervious materials.  The only structures immediately bordering my collection area were the trunk of the pine tree, stacks of wooden pallets and other industrial debris, and a cyclone fence.  A few writers in Europe have also mentioned finding P. lanigera outdoors under stones and boards, and on tree bark.  Eugène Simon, the French entomologist who described the species in 1871, wrote that it was common in the south of France on sun-exposed rock walls and arid places.

Location of Mukilteo, Washington

More sampling will be required to determine whether my specimens represent a naturalized, self-sustaining population.  But we can say now and with certainty that pine cone tapping has once again revealed the presence of a spider species in Washington state not previously detected by more conventional methods of sampling.

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

Fallen cones containing P. lanigera
were lying in an industrial yard.

16-Nov-2015 Yangzhou Park, Kent, Washington

Site location (click to enlarge)

A few hours lull in the rain allowed me to make my first foray south of Seattle in search of the introduced crab spider Ozyptila praticola (Thomisidae).  My destination was Kent, a small city about 10 miles south of Seattle's Beer Sheva Park, the southern-most place in Washington where I've documented the presence of O. praticola.  I headed first to Kent's branch of the King County Library because Google Street View had revealed numerous pines in its parking lot.  Disappointingly, all cones had been removed by groundskeepers.  But from there I was able to spot the pine that was to be my sampling site.

Most of the fallen cone microhabitat
was on the railroad side of the fence

A lovely setting for cone tapping

Across the railroad tracks from the library sits Yangzhou Park, which features a lovely little friendship pagoda from Kent's sister city Yangshou, China, and a pine tree that had dropped over 100 cones.  Although the scales on most of the cones were barely open, I decided they were worth tapping since I've found that O. praticola can be found in such tight places, and because most of the cones were resting on pine needle and broadleaf litter, a substrate amenable to my target species.

O. praticola juveniles tapped from cones
in Yangzhou Park in Kent, Washington

I tapped 95 cones and collected 5 juvenile Ozyptila that were colored and patterned like praticola, and 1 harvestman.  This is the first time that I've tapped only one species of spider from a set of cones in western Washington.  I was especially surprised by this result given that I had tapped almost twice the number of cones that I consider a full sample (50).  The poorly-opened scales could perhaps explain the absence of other species, but it hasn't been a barrier before, especially not to juvenile linyphiids.

I returned to the safe side of the fence before each train roared by.

12-Nov-2015 Issaquah, Washington

Known distribution of Ozyptila praticola
in Washington (so far)

After finding juvenile Ozyptila that were colored and patterned like praticola almost everywhere I looked in Seattle's eastern suburbs, I was convinced that the introduced thomisid was present east of Lake Washington.  But I lacked an adult specimen to prove it.  Until now, that is!

I returned to my previous sampling location in Issaquah, knowing that there were some untapped cones there dropped by "weeping" white pines (probably Pinus monticola 'Pendula').  This being late autumn, and judging from my recent experiences, I knew the likelihood of finding an adult Ozyptila praticola in any particular cone was not high.  But I also knew that the likelihood would increase with each cone I tapped.

My cone source was three ornamental
'weeping' pines

The strong winds predicted for the day had already begun to gust by the time I reached Issaquah.  This complicated the sorting of my tapping samples, but at least I didn't get rained on!  Once I started rooting around for P. monticola cones, I was pleasantly surprised to find 65 of them to tap.  The high count wasn't obvious at first because so many were hidden in and under the juniper bushes growing around the pines.

Fallen cones on shrubs, needle litter
and pavement.

Despite the bounty of cones, this was not a very productive set.  I only tapped 7 spiders from them -- a very low density of 0.11 spiders per cone when compared to the density of 1.43 I found a week earlier in nearby Woodinville.  However, one of those spiders was an adult female O. praticola!

Weather may force me to suspend further eastward sampling until spring.  Until then, I will probably refocus my search southward, towards Tacoma.

The star of the show, a female Ozyptila praticola from Issaquah, WA

3-Nov-2015 DeYoung Park, Woodinville, Washington

Site location map. Click to enlarge.

The weather wasn't dry enough for a regular field trip with Rod Crawford, but it was just fine for tapping pine cones.  I chose Woodinville's shopping area for my destination and quickly spotted a huge western white pine (Pinus monticola) growing in tiny DeYoung Park (only 0.6 acres!).  The park is surrounded by parking lots and businesses and, like most urban parks, is kept clear of "tree trash".  However, I did manage to scare up 23 cones, many of which had escaped the groundskeeper's rake by falling into the Spiraea shrubs that were growing around the pine tree.

Huge pine tree in tiny park

Cones and needles accumulated
in Spiraea

I tapped 33 spiders from those 23 cones!  That averages 1.43 spiders per cone, which is the highest density I've collected so far this year in western Washington.  Twenty-one of them were juvenile Ozyptila (Thomisidae) colored and patterned like praticola.  And as usual I collected several juvenile Enoplognatha (Theridiidae) that look like ovata. A male theridiid still awaits identification.

Female Cryptachaea blattea tapped
from pine cone

What a stately pine

I also found several Cryptachaea blattea (Theridiidae) in this cone sample.  I've tapped this cosmopolitan species before from cones at other sites in the Seattle conurbation, but until now I hadn't gotten around to identifying it.

UPDATE [19-Aug-2017]: I again tapped fallen western white pine cones in DeYoung Park. Thirty-nine tapped cones produced 64 spiders, including a female O. praticola. This sample confirms the presence of O. praticola at this location.

A sprig of Spiraea still in bloom!

27-28 Oct 2015 Southeast Of Lake Sammamish, Washington

Sample site locations. Click to enlarge.

My family and I have been systematically hiking our way through the entire regional trail system in King County, Washington.  Since this activity has coincided with my effort to discover the local distribution of the introduced crab spider Ozyptila praticola (Thomisidae), I had my net and vials with me on 27 October when we hiked the lower end of the East Lake Sammamish Trail and happened to find pine trees that had dropped open cones in an accessible spot.  Finding accessible pine cones had been difficult along this particular trail, since virtually every parcel along it is privately owned and most trailside pines had dropped their cones on the private side of the ubiquitous fences.

27 Oct: Southeast Lake Sammamish

SE Lake Sammamish sampling site

Fallen P. monticola cone in
salal (Gaultheria shallon)

Two huge old western white pines (Pinus monticola) growing close to the trail had dropped numerous cones, many of which had been pressed into the mud by vehicles.  But I was able to find 15 intact cones to tap, and those cones produced 21 spiders and 2 identifiable species as well as some harvestmen.

Microneta viaria epigynum

The introduced linyphiids Tenuiphantes tenuis, Microneta viaria and Enoplognatha sp. (probably ovata) accounted for half of the spiders present.  As for Ozyptila, I collected one juvenile specimen.  It had praticola coloration and patterning, so I'm pretty sure that the species exists east of Lake Sammamish.  However, I cannot prove it with this specimen.

28 Oct: Issaquah

Issaquah sampling site

Fallen P. nigra cones under
juniper shrubs

The following day, I decided to return to the same general area and see if I could find any adult O. praticola specimens.  If the adult season for the local population is the same as it is for its British population, then the odds were quickly decreasing that I'd find many more adult specimens before spring.  However, with the rainy season already having begun, I couldn't pass up the opportunity that this not-entirely-soggy day presented to make one last effort.

Black pine (P. nigra) trees planted in front of a local business provided me with 45 tappable cones and 14 spiders.  Half of them were Ozyptila, but they were all juveniles, and all praticola in appearance.  The day before, I had thought that there was nothing more annoying than finding one juvenile Ozyptila probably-praticola, but I was wrong.  It was much more annoying to find seven of them!

A flock of cackling geese (Branta hutchinsii) in flight over Lake Sammamish