7-Mar-2016 U-W Campus, Washington

Site location map. Click to enlarge.

The day was dry and sunny but only about 50 degrees Fahrenheit, perfect weather to find insects and spiders on the sun-warmed sides of brick buildings.  So I decided to spend an hour on the University of Washington campus in Seattle attempting to find more of the introduced European jumping spider Pseudeuophrys lanigera.  I'm not quite satisfied with having documented only two populations in the area.

Oecobius navus on building exterior

Sitticus pubescens on building exterior

Spiders weren't as numerous on the buildings as I'd hoped, but I did find what was probably an Oecobius navus (Oecobiidae), and one female jumping spider.

Sitticus pubescens epigynum

As it turned out, the jumping spider wasn't a P. lanigera, but a different introduced European species, Sitticus pubescens!  This is only the second record of S. pubescens in Washington state.  The other was a male that Rod Crawford found a few years ago in Everett.

Eastern white pine

My search of building exteriors led me to the Communications Building, which has a huge eastern white pine (Pinus strobus) growing near its entrance.  Beneath the tree were hundreds of fallen cones, apparently undisturbed by groundskeepers.  How could I resist?!

Fallen pine cones on a sumptuous bed
of needle litter

I tapped 50 fallen cones and collected 7 spiders and two identifiable species: Ozyptila praticola (Thomisidae) and Diplostyla concolor (Linyphiidae), both also introduced European species.  I also tapped 6 harvestmen and countless sow bugs, snails and insects from these cones.

Tiny snails tapped from cones

I'm quite amused by how the search for one introduced species keeps leading to the discovery of another and yet another.  Last fall, while tapping cones in Mukilteo, Washington to determine the local range of the introduced species Ozyptila praticola, I discovered the presence of a different introduced species, Pseudeuophrys lanigera.  Then this day, when in search of more P. lanigera, I confirmed the presence yet another introduced species, Sitticus pubescens.  If I search for more S. pubescens elsewhere in the city, I wonder which "new" introduced species I'll find next.

Putting flies into perspective.

25-Feb-2016 Square Lake, Washington

Site location. Click to enlarge.

Considering that February is the heart of western Washington's rainy season, I have been pleasantly surprised at how much spidering I've been able to do this month.  And since this past week was essentially rain-free, Rod Crawford and I were able to squeeze in one additional field trip before the month draws to a close.

This white pine was conveniently located
in the middle of the trail!

The day's destination was the northeastern corner of Square Lake, which is located a few miles south of Port Orchard on the Kitsap Peninsula.  Note the ridges trending NNE-SSW on the site location map above.  They're relics of the Fraser glaciation. A very interesting topography!

When Rod sampled a nearby gridspace last year, he noted that western white pines (Pinus monticola) were present there.  Always a good enticement for me, even better that it turned out to be true for this site as well!  I was delighted to spot numerous pines next to the trail during the short hike to the lake, not to mention one growing smack dab in middle of the trail itself.  And fallen cones were plentiful.

Mossy pine cone

Despite no rain reported in the area several days prior to our visit, the cones were heavy with absorbed moisture and full of lots of organic debris.  As if to emphasize the moist fertility of the area, many cones even had moss growing on them.

I tapped my usual sample of 50 cones and collected 10 spiders and 57 (!) pseudoscorpions.  All but one of the spiders were from the family Linyphiidae (the other was an agelenid), while all but one of the pseudoscorpions were from the family Neobisiidae (the other was from Chthoniidae).  I later tapped an additional 10 cones which produced 2 more linyphiids and even more pseudoscorpions, the latter which I didn't have the heart to collect.

Female Wubana pacifica

A bit blurry, but this photo shows
Wubana's white "butt spot" (not
the technical term :)

Three spider species were identifiable in my cones sample: Frederickus coylei, Wubana pacifica and Lepthyphantes zelatus.  Although all three species are common in western Washington leaf litter, we didn't collect the first two in any other microhabitat at this site.  Once again, cone tapping saves the day!  Or at least, helps fill out the site species list.

Just a few of the dozens of pseudo-
scorpions I tapped from pine cones

Rod noted how rotund many of the pseudoscorpions were and wondered whether they were perhaps full of eggs.  Whatever the explanation, they sure seemed to be flourishing in these pine cones.  At an average of 1.14 pseudoscorpions per cone, this was by far the highest density I've tapped from fallen cones.  The next highest density was 0.56 that I tapped in October 2011 from ponderosa pine cones in Brooks Memorial State Park (Klickitat County).

Since western white pines are not the dominant forest tree species anywhere in Washington state, I've had to hone my pine-spotting skills in order to find them.  When I have a good line of sight into the forest canopy, I usually find them by spotting the tree's feathery foliage and large, pendant cones.  But when I'm inside a dense forest where the canopy is just a distant, indistinguishable mass of green, I simply search for fallen cones along the trail and look for the western white pine's unique bark pattern on nearby tree trunks.

Looking up the unusual pine
with the alder-appearing trunk

Mature western white pines have fairly smooth grey bark broken into flat rectangular scales.  It's often described as "checkered".  The pattern is always visible because pine bark is never obscured by epiphytes...or so I thought until we visited Square Lake!  Almost immediately upon hitting the trail I spotted the foliage and pendant cones of a nearby mature white pine.  But as my gaze slid down the trunk of the tree, I was surprised to see that it was entirely covered in epiphytes.  Had I not seen its crown, I would have been certain I was looking at an alder!  Alder (Alnus) bark is typically "painted" with accumulations of mosses, liverworts, lichens, and algae.  As the saying goes, to every rule there is an exception.

Tree trunk comparison. A. typical white pine, B. unusual alder-appearing white pine, C. typical alder

Read Rod's trip description here.

21-Feb-2016 Bellevue Highlands, Washington

Site location map. Click to enlarge.

Another sampling event in the catch-as-catch-can category, this time in the Highlands area of Bellevue.  Although I usually keep my nose to the grindstone on spider collecting ventures, especially short ones like this (I had only 2 hours, less if it started raining), I couldn't resist taking the time to stop at one of the area's numerous Indian grocery stores first to stock up on snacks.  What a treat!

Cone source: Pinus nigra trees

Cone microhabitat, scales hardly open

Not far from the grocery I found my cone source: eight black pines (Pinus nigra) planted along 140th Ave NE.  These trees had been heavy cone producers, but few of the cones had more than a few scales even partially open.  I see this repeatedly in P. nigra in western Washington, where this exotic tree species is widely planted.

Tenuiphantes tenuis in my net

Preserved Erigone male

With some diligent searching, however, I managed to scrounge up 50 of these barely-opened cones, and tapped 9 spiders from them.  Immediately identifiable were female Tenuiphantes tenuis and Tachygyna vancouverana, both from the family Linyphiidae and both species I tap frequently from cones in the greater Seattle area.  The other identifiable species was another linyphiid, an Erigone male.  I'll have to wait for the specimen to cure before I can identify it to species.  I've tapped an Erigone from cones only once before: a male E. aletris last October in Lynnwood.

Delicious!

18-Feb-2016 Mill Creek, Washington

Sample site location (red arrow) in
relation to nearby Ozyptila praticola
collection sites

There's nothing that beckons like a sun break in winter, especially when the thermometer hits 50 F!  And since business took me to Mill Creek, a town I hadn't collected spiders in previously, I made sure to find an hour to tap some pine cones while there.

The tree, the ivy

My cone source was a white pine tree.  Whether eastern white pine (Pinus strobus) or western (P. monticola) I couldn't be sure because the bark wasn't well enough developed to tell.  I've found both species planted in the urban landscapes of Pugetopolis.  Whichever species it was, it was growing in a typical urban setting: surrounded by pavement and with an understory of pure English ivy (Hedera helix).

A cone suspended in the ivy matrix

I usually curse English ivy because, like the exotic invasive it is, it entirely snuffs out native plant species.  But I must admit that it did serve several useful functions in this case.  First, the dozens of cones that had fallen onto/into it escaped removal by groundskeepers.  And second, the cones suspended in the ivy matrix, which was up to 2 feet thick in some places (!) were fairly dry even though it had rained the night before.  Not so the cones I found on the ground, which tended to be muddy.  So I can hardly complain about the presence of the ivy, at least under this particular tree.

The haul

I tapped 50 fallen cones and collected 4 spiders, all juveniles.  Two were likely Ozyptila praticola (Thomisidae), the introduced crab spider that I'm working to determine the local distribution of.  The others were a theridiid and a Philodromus sp. (Philodromidae).  Not an exciting catch, but it does serve as another point on the O. praticola map.  Or at least, a fuzzy point.

Beautiful pine foliage blowing in the wind

2-Feb-2016 Bay View, Washington

Sample sites. Click to enlarge.

Back in the field with Rod Crawford and Ben Diehl!  The focus of our spidering activities this day was the "census-designated area" of Bay View.  Bay View is situated on the southeastern shore of lovely Padilla Bay in Skagit County.  Our first stop in Bay View was the dike-top trail Padilla Bay Shore Trail. We then drove a mile or so north to the Bay View Cemetery.

Neriene digna penultimate
male in web on metal
garage wall

This south-facing corrugated
metal wall was loaded with
overwintering spiders.

We began our day's collecting in the trail's parking lot, which is surrounded by large maintenance or storage buildings and a scattering of old rusty equipment.  Collecting linyphiids from their webs on the building with corrugated metal sides was straight-forward, but it took me some time to find the orb weavers that had built webs on the old wooden structure.  I did finally find one by following its trip line to its hiding place - under a big curl of peeling paint!

Spider-hiding paint peel

Translocated spider microhabitat
(cones and pine needles)

Rod had spotted a few shore pines (Pinus contorta subsp. contorta) in photos of the trail head itself, so I had some small hope that I might find a few cones there to tap.  Unfortunately a groundskeeper had removed the cones and pine needles from beneath the pines.  I later found these materials dumped at the edge of the marsh.  Why do groundskeepers insist on doing this?  Cones and needles are not just spider habitat, they're ornamental!  Leave them be!

Tiny male Tachygyna ursina approaching
a sizable juvenile Philodromus rufus

Juvenile Philodromus rufus in "tiptoe"
pre-ballooning posture

After our productive day of spidering at the Nooksack Cemetery last October, I was looking forward to collecting at Bay View Cemetery.  But February isn't October, and in the end I found only two spiders on headstones in the entire cemetery.  Humorously enough, I didn't even see the tiny male Tachygyna ursina (Linyphiidae) until it approached the juvenile Philodromus rufus (Philodromidae) that I was busy photographing.  Apparently the ursina startled the rufus when the former tried to walk over the latter, because the rufus jerked the ursina off its leg and send him dangling by his drag line.  The thrills, the spills!

Douglas-fir trees and fallen cones

A fallen Douglas-fir cone = great
spider habitat!

I didn't spot any pine trees at the cemetery, but a stand of Douglas-firs (Pseudotsuga menziesii) next to the utility shed had a nice accumulation of open cones lying beneath it on needle littler. I tapped 50 of those cones and collected 11 spiders.  Most were juveniles of the introduced species Enoplognatha probably-ovata (Linyphiidae), but two native linyphiids were present as well: Tachygyna vancouverana and T. ursina.

Caterpillars were more common than
spiders on the grave monuments

Moss 'highlighted' monument messages

One of the delights of frequent spider collecting is that, in addition to gaining spider knowledge, I am able to observe the seasonal changes in weather, flora and fauna.  Something I noticed this week were pairs of birds in synchronous flight.  A pair of bald eagles (Haliaeetus leucocephalus) near the head of the Padilla Bay Shore Trail alternated short flights together with sitting in close proximity on treetop branches and chatter-calling.  [A pet peeve of mine is that movie makers always substitute the scream of the red-tailed hawk (Buteo jamaicensis) for the eagle's chatter call, probably because eagles sound like whiny seagulls.].  At Bay View Cemetery, I also saw a pair of ravens (Corvus corax) flying synchronously from tree to tree.  Looks like spring courtship has begun for these species.  Maybe this is why Valentine's Day is in February?

Read Rod's trip narrative here.

Sunset over Padilla Bay during low tide

20-Jan-2016 Second Population Of Pseudeuophrys lanigera (Salticidae) Found In Washington State

Pseudeuophrys lanigera collection sites
in Washington, USA

Last fall I discovered a male and several juvenile Pseudeuophrys lanigera jumping spiders in pine cones lying in an industrial back lot in Mukilteo, Washington.  Since mine was the first reported discovery of this European species in North America, I was eager to determine whether the species was naturalized in the area, or whether I had found a dead-end population.  But then winter weather set in, so I postponed follow-up sampling until spring.

As luck would have it, I didn't have to wait that long to revisit the P. lanigera question.  Betsy Bruemmer, Collections Manager at the Museum of History and Industry (MOHAI) in Seattle contacted Rod Crawford last week because she'd noticed several tiny spiders in the MOHAI Resource Center, MOHAI's administrative offices and storage facility located in Seattle's Georgetown neighborhood.  The photos she sent of some of the individuals she'd captured on sticky traps sure did look familiar - like P. lanigera!  Rod and I couldn't resist requesting a tour of the facility, and Betsy very kindly obliged.

Right P. lanigera palp,
ventral view. Spider
dead when collected.

Right Pseudeuophrys lanigera palp,
semi-lateral view. Spider dead when
collected.

Although we didn't find any live, free-ranging P. lanigera during our visit as we'd hoped, Betsy was able to give us a specimen that she'd recently captured live and preserved in alcohol.  She also pointed out another still-alive individual stuck to a sticky trap that Rod was able to extricate, and found a dead but intact individual on the floor.  Rod examined the live-captured specimens, while I examined the one that was already dead when collected.  They all turned out to be mature P. lanigera.

Dead & desiccated but still identifiable

Betsy had made several interesting observations about this population of P. lanigera.  First, all the specimens were captured in windowless storage rooms that are frequently dark.  Second, there is some suggestion that these animals may have used the walls to guide their movements since so many were intercepted by sticky traps, which were situated on the floor along walls.  In addition, Betsy found the specimen that I examined (and whose right palp is pictured here) dead on the floor next to the baseboards.  This is all in great contrast to the population I found in Mukilteo ("SW of Paine Field" on the map above), which were tapped from pine cones laying outside in an open lot.  However, both populations were found in areas of light industry and warehouses.

Considering that the Mukilteo and Seattle sites are 24 miles (39 km) apart, it seems likely that P. lanigera is resident in the greater Seattle area.

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

Rod and Betsy examine one of the (highly magnified!) jumping spiders captured in a sticky trap

6-Jan-2016 Discovery Park, Seattle, Washington

Site site location. Click to enlarge.

Daytime rain and overnight frost had been dissuading me from tapping cones for several weeks.  But with a few preceding nights above freezing and this day a sunny 48 F (~9 C), conditions were once again amenable to taking a winter cone spider sample.

Sample site

A western white pine (Pinus monticola) growing at the edge of a Douglas-fir (Pseudotsuga menziesii) woods in Seattle's Discovery Park was my cone source.  All of the cones I tapped were lying on needle-and-twig litter within the tree's drip line.

Fungus and a fallen cone

I tapped 50 cones and collected 20 spiders and 6 species.  Three were species I find commonly in Seattle-area fallen cones: juvenile Cryptachaea blattea (Theridiidae), juvenile Enoplognatha probably-ovata (Theridiidae), and female Tachygyna vancouverana (Linyphiidae).  However, the other 3 species in my sample were new to me.

Adult Blabomma californicum

Blabomma californicum epigynum

Almost half of the sample was comprised of Blabomma californicum (Dictynidae).  With females measuring 6 mm in length, this is by far the largest dictynid I've handled.  I'm more accustomed to the smaller dictynids found in webs at the apices of herbaceous plants, so finding (with the help of Rod Crawford - thanks Rod!) that these were dictynids was a surprise and learning experience for me.  Well, every cone sample is a learning experience, but some more than others.

I'm a linyphiid. Good luck IDing me.
Mwahahaha!

I have 2 more species of linyphiids still to identify, but that will have to wait for another day.

Although a merry sun was shining, the constant north wind kept me chilled.  But it was apparently fine weather for ballooning for numerous spiders in nearby Douglas-fir trees.  Glistening strands of silk 1-2 meters long were stretched horizontally on the wind from the ends of branches on the sun-soaked south side of the trees.  Unfortunately I was unable to intercept any of the attached spiders, so I don't know who was responsible for the eye-catching display.

Juvenile Blabomma californicum. Until I knew what these were, I was
calling them "tigers", for obvious reasons.  Beautiful spiders.