14-Dec-2017 Hunts Point & Bellevue, Washington

Site location map.
Blue: O. praticola confirmed via adult specimen.
Yellow: Juvenile O. ?praticola found.
Red: No O. praticola adults or ?praticola juveniles found.

With a few hours free on this, the final day in an extended dry spell, I decided to cross Lake Washington to look for Ozyptila praticola (Thomisidae) in the Bellevue area. I was sure that Bellevue lay solidly in the heart of O. praticola's local range. However, since I've done very little sampling there, I had no specimen to validate my assumption.

Hunts Point

Black pines at Hunts Point
Town Hall

I exited Hwy 520 at 84th Ave because I had seen, via Google Street View, that that street was lined with black pine (Pinus nigra) trees. This was indeed the case, but unfortunately their litter and fallen cones had been removed. So I proceeded to the next possibility, which was another row of black pines next to the Hunts Point Town Hall. The litter there was intact, but the fallen cones were poorly opened. Nevertheless, they harbored enough spiders to let me know I was on the right track; tapping 50 cones got me 3 spiders, two of which were O. praticola juveniles.

Cone scales poorly opened,
but needle-wood chip litter...

...produced several adult O. praticola.

Having had success sifting pine litter in a similar situation the other day in Kent, I decided that sifting another batch here, where I knew O. praticola was present, was probably a better use of my very limited time than looking for another cone deposit that might (or might not) produce a mature specimen. This turned out to be a good decision; the bag of litter (pine needles and wood chip mulch) I sifted contained 6 O. praticola, including 3 females and 1 male. Hunts Point is a tiny town of just 500 inhabitants. There are probably more O. praticola there than people.

Bellevue

Black pines on Bel-Red Road...

...had nice thick needle litter beneath.

I was still hoping to take a sample in Bellevue proper, but had no time to scout out a good cone source. So I made do with sifting litter from beneath yet another row of black pine trees with closed fallen cones, this time along Bel-Red Road. My luck wasn't as good at this site, as I found only one juvenile O. praticola and had no time to sift a second batch.

A pine peeks over the town hall of Hunts Point, where O. praticola
undoubtedly outnumbers the human inhabitants.

12-Dec-2017 West Seattle, Washington

I tapped cones dropped by both pines

The fallen cone microhabitat

An appointment today in Seattle's industrial district put me so close to West Seattle that I couldn't resist buzzing over there to take a sample. Driving south on 35th Ave., I very quickly spotted two western white pines (Pinus monticola) that had dropped open, accessible cones in front of neighboring houses. If only every sampling site were so easy to find!

Female O. praticola tapped from cones

Penultimate male Xysticus ?cristatus

I tapped 50 cones and collected 8 spiders and 3 identifiable species: An erigonine to be identified later, Tachygyna vancouverana (Linyphiidae), and Ozyptila praticola (Thomisidae). I'm not at all surprised to find O. praticola in West Seattle, but I'm quite happy to have found a specimen to verify its presence in that quadrant of the city. Also present in this sample was a penultimate male Xysticus probably-cristatus (Thomisidae), another introduced crab spider that's become established in western Washington.

Site location map. Click to enlarge. West Seattle site is circled.
Blue: O. praticola confirmed via adult specimen.
Yellow: Juvenile O. ?praticola found.
Red: No O. praticola adults or ?praticola juveniles found.

11-Dec-2017 Kent Redux & Covington, Washington

Site location map. Click to enlarge.

Last week, when I found all those juvenile Ozyptila praticola (Thomisidae) in fallen pine cones in Kent, I knew that I should continue the search for a mature specimen by sifting the pine needle litter near the cones. Wet litter and waning daylight eroded my immediate interest in doing so, however. Today, after a week of rain-free, litter-drying weather, and with the sun high in the sky, I returned to complete the task. And to great success!

One of three female O. praticola sifted
from pine needle litter.

An electrical box made a
convenient sifting table.

I sifted one sweep net full of black pine (Pinus nigra) litter and collected 18 spiders and 3 identifiable species: the linyphiids Tachygyna vancouverana and Tenuiphantes tenuis, and my quarry, Ozyptila praticola. This time, there were three females among the O. praticola in addition to several juveniles. Finally, I can verify the presence of the species in Kent!

Covington sampling site

Kent sampling site

I had time for one more sample before sunset (sunset at 4:30 pm really limits field work!), so proceeded east into Covington. Another row of black pines separating two parking lots was my cone source. Some cones had fully opened scales, others only partially, and they were lying on bare soil or a very thin layer of pine needles and maple leaves. I tapped 72 cones and collected only 5 spiders and 2 species: T. vancouverana and an Erigone to be identified to species later.

4-Dec-2017 Kent, Washington

Site location map. Click to enlarge.

Spider collectors in Europe report that male and female Ozyptila praticola (Thomisidae) can be found there every month of the year. It wouldn't surprise me if that were true here in Washington state was well, since I've collected adult O. praticola every month March through November. However, I have almost no O. praticola data for the months of December through February. A break in the wet winter weather this week gave me the opportunity to start remedying that.

My destination was the Kent - Covington - Maple Valley area in the southwestern corner of King County. I had collected juvenile O. praticola in Kent back in 2015, so I knew the species was in the area. On my way to my old collecting spot, I checked for fallen cones in the expansive business and industry parks on the north end of town. I found plenty of black pine (Pinus nigra) cones along the way, but none of them with open scales. As for my old collecting spot from 2015, groundskeepers had removed the cones.

First cone source: white pine

Erigone dentosa (bottom)
& Erigone TBD (top)

The same pattern continued until I got to the eastern edge of town, where I found a mature western white pine (P. monticola) growing next to a convenience store (the red pin on the map above). Many of its fallen cones had been run over by cars, but I was still able to find 20 intact ones to tap. They were wet and their scales were poorly opened, but they contained 7 spiders and 3 identifiable species of linyphiids: Tachygyna vancouverana, Erigone dentosa, and another Erigone species that I haven't identified yet. The sample was refreshingly free of introduced species. That doesn't happen often in the Seattle-Tacoma conurbation.

Second cone source: black pines

Ozyptila praticola juveniles

My next site was only about a mile further down the pike (the yellow pin on the map above) and consisted of a line of black pine trees growing behind a grocery store. The scales on these cones were also poorly opened, but that was no barrier to the spiders. I tapped 24 cones and collected 12 spiders and 2 identifiable species: T. vancouverana and O. praticola. At 10 spiders, O. praticola dominated the sample. However, they were, once again, all juveniles. Kent does not give up its mature O. praticola gladly!

With the sun setting, it was time to return home. Covington and Maple Valley will have to wait for another day.

1-Dec-2017 Mill Creek, Washington

Mill Creek collection site. Click to enlarge.

Almost two years ago, in February, 2016, I tapped cones dropped by an eastern white pine (Pinus strobus) tree growing in the parking lot of an office park in Mill Creek (Snohomish County). Among the spiders I collected that day were two juvenile Ozyptila praticola, the introduced thomisid that I've been studying. Finding myself back in Mill Creek this day, I decided to tap cones there again, in hopes of finding a mature O. praticola specimen. But though I tapped 65 cones this time around, I found no spiders in them at all!

Tree to the left: no spiders in cones!
Tree to the right: spiders few but worthy!

The fallen cone microhabitat

Undeterred, I crossed the driveway to tap a new set of cones that had fallen from a different P. strobus. The spiders weren't exactly plentiful; 100 tapped cones produced only 7 spiders, and none of them were O. praticola. However, four specimens were mature and therefore identifiable to species: two Tachygyna vancouverana (Linyphiidae) males, one Tenuiphantes tenuis (Linyphiidae) female, and one Cryptachaea blattea (Theridiidae) male. Better than nothing!