Tuesday, December 5, 2017

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.

Saturday, December 2, 2017

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!

Sunday, November 26, 2017

25-Nov-2017 Laurelhurst Neighborhood, Seattle, Washington

Site location map. Click to enlarge.
Seattle has about 150 public shoreline access points, called "shoreline street ends", where public roads end at a body of water (map). During a visit to one such street-end mini park in the Laurelhurst neighborhood this summer, I noticed an eastern white pine tree (Pinus strobus) nearby that had dropped numerous open cones. A short break in the rain this day gave me just enough time to go back and tap those cones.

Source tree, an eastern white pine
Fallen cone microhabitat
The tree turned out to have dropped hundreds of open cones, most laying on a thick bed of pine needles undisturbed by groundskeepers. What a gold mine! Since so many cones were available, I tapped a super-sized set of 150 (50 is my standard) and collected 22 spiders.

The sample contained quite a variety of theridiids, including CryptachaeaEnoplognatha, and Theridion, as well as the linyphiids Erigone, LepthyphantesTachygyna, and Tenuiphantes. The most numerous spider present was Ozyptila probably-praticola (Thomisidae), of which I collected four juveniles.
A newly-planted future grove of redwood trees (Sequoia sempervirens) in
nearby Laurelhurst Park.

Wednesday, November 15, 2017

10-Nov-2017 Bremerton & Southworth, Washington

Site location map. Click to enlarge.
When I tapped cones in Bremerton a few weeks ago in my ongoing search for the introduced thomisid Ozyptila praticola, I didn't manage to take any samples in the heart of the city south of the Port Washington Narrows. I returned this day to remedy that, as well as to take samples in Gorst, Port Orchard, and Southworth. Given that it had rained the day before, I knew the fallen cone microhabitat would be soggy. But it was now or never, since the long-range forecast indicated that this would be the only day in the foreseeable future with a low chance of rain.

Near Manette Bridge, Bremerton
Not entirely soaked
I had prepared a long list of potential collecting spots using Google street view, and was delighted to find numerous, accessible western white pine (Pinus monticola) cones at the site closest to the ferry dock: a hillside along Washington Street at the west end of the Manette Bridge. As anticipated, everything was wet from rain the day before. Cones under the trees' drip lines, however, were at least dry on their undersides. I tapped 50 cones and collected only 7 spiders, but 2 or 3 species: Grammonota kincaidi and one or two species of Erigone.

Hmm, maybe not.
Usually when potential collecting spots don't pan out it is because the tree is on private property posted with "no trespassing" signs, or the cone scales are not open. The latter frequently occurs with cones of the introduced black pine (Pinus nigra), but also cones of the native Douglas-fir (Pseudotsuga menziesii), which close their scales when wet. That means that during rainy weather, the most reliable tree to find open cones beneath is white pine. But accessing the cones of white pine trees, even those growing on public property, can still be a challenge. The magnificent white pine tree growing immediately south of Manette Bridge (left), for example, turned out to be inaccessible without a kayak or a rappelling rig. Well, at least it was a more scenic no-go tree than those growing along Route 3.

Across from Evergreen
Rotary Park, Bremerton
Soggy but fruitful
My second site consisted of a lone white pine in a grassy field across the street from Evergreen Rotary Park. I only found 32 cones to tap, but they produced a surprising 51 spiders and two more identifiable species: the introduced theridiid Cryptachaea blattea, and the native Phrurotimpus borealis (Phrurolithidae). The high overall number of spiders in this sample resulted in large part from the presence of 16 juvenile Enoplognatha probably-ovata, an introduced theridiid I often find in urban cones.

Park & Ride pines
Male (top) and female (bottom)
Phanias albeolus
I had absolutely no luck finding open, accessible cones in either Gorst or Port Orchard, so proceeded on to the last collecting site on my list, a Park & Ride lot in Southworth. Happily, dozens of at least partially open cones had accumulated under three white pines growing near the road. I tapped 65 cones and collected 34 spiders and 3 species, including a pair of mature Phanias albeolus (Salticidae). The P. albeolus were an unexpected find, since we usually find that species in conifer foliage and forest understory. I've never tapped if from fallen cones before.

As with my Bremerton-area samples from a few weeks ago, I found no Ozyptila praticola or even any juvenile Ozyptila in any sample this day. If it is present in the area, it is hyper-localized.

Perhaps this Pacific tree frog (Pseudacris regilla) was also searching for spiders

Saturday, November 4, 2017

28-Oct-2017 Bremerton & Silverdale, Washington

Site location map. Click to enlarge.
After recently finding the introduced crab spider Ozyptila praticola (Thomisidae) near the ferry terminal on Bainbridge Island, Bremerton became the next logical place to look for it. Accordingly, I hopped on a morning ferry from Seattle and tapped spiders from 8 sets of fallen conifer cones in the greater Bremerton area.

A typical black pine grouping,
this one in Silverdale.
The native western white pine (Pinus monticola) is a minor but common part of the forest in this part of Kitsap County, but I was unable to find any that were accessible; they tended to grow on the highway margins or in private back yards. However, there were lots of black pines (Pinus nigra) within reach. This is an introduced species commonly planted on commercial property in this region.

Kitsap Peninsula. Blue & red
pins show where I have and haven't
found O. praticola, respetively.
The long and the short of it is, I tapped a total of 357 fallen conifer cones and collected 33 spiders from 6 families. Five or six species were identifiable, including the native linyphiids Erigone dentosa, Grammonota kincaidi and Tachygyna vancouverana and the introduced theridiids Cryptachaea blattea and Theridion tinctum. All in all, it was a fairly typical set of cone spiders from central Pugetopolis, except that it didn't contain any Ozyptila praticola or even any juvenile Ozyptila of questionable identity. I have yet to find any O. praticola on the Kitsap Peninsula, despite having found it on neighboring Bainbridge Island and Vashon Island.

View from the ferry: Manette Bridge spans the Washington Narrows, linking
the two halves of Bremerton. The Olympic Range provides a scenic backdrop.


Thursday, October 19, 2017

Ozyptila praticola Catch-Up Post

Map 1. Sites sampled for Ozyptila praticola mid-August to 
mid-October, 2017.
The past two months have been a whirlwind. In addition to the usual collecting trips with Rod Crawford, I intensified my ongoing search for the introduced European crab spider Ozyptila praticola (Thomisidae). For the latter, I've tapped over 3,000 fallen conifer cones at 48 sampling sites (Map 1) since mid-August. I focused my search in areas that I suspected were on the periphery of or just beyond O. praticola's local range. I also re-sampled a few sites within its known range to confirm its presence with mature specimens where previously I'd collected only juveniles. Instead of blogging separately about each sampling day and site as I usually do, I'll summarize them together here.

Map 2. Ozyptila praticola confirmed during the mid-August
to mid-October, 2017, sampling period (blue pins)
I confirmed the presence of O. praticola at only three locations during this sampling period: Woodinville, Bainbridge Island and Mercer Island (Map 2). Only the Bainbridge Island sample represented an extension of the known range of the species.

Based on the data I've gathered to date (Map 3), the core range of O. praticola in Washington appears to be the urbanized western lowlands of King County and Snohomish County. In addition, there appears to be a small disjunct population in Bellingham (Whatcom County). The presence of O. praticola on Bainbridge Island signals the need for more sampling in Kitsap County, especially the Bremerton area. The search continues.

Map 3. Ozyptila praticola in Washington state.
Blue: O. praticola confirmed via adult specimen.
Yellow: Juvenile O. ?praticola found.
Red: No O. praticola adults or ?praticola juveniles found.
Purple: O. praticola confirmed in British Columbia, Canada by Bennett et al. (2017)

Wednesday, October 18, 2017

9-Oct-2017 South Fork Beaver Creek, Washington

Site location map. Click to enlarge.
Last year about this time, Rod Crawford and I sampled spiders in the gridspace covering the town of Plain and part of Little Chumstick Creek valley, both located in Chelan County. This day, since Stevens Pass was still free of snow, we decided to make what would likely be our last trip of the year over the pass, and sample an adjacent gridspace.

View down the "road".
As so often happens in field work, conditions on the ground were different than expected. Namely, the forest road paralleling South Fork Beaver Creek, which we had planned to take to our preferred sampling location, no longer existed! In fact, it hadn't existed for decades, judging from the volume of vegetation growing on its former bed. Luckily the main forest road was also in the gridspace, so Rod quickly returned to it to begin his sampling there.

One of several generations of markers
on the witness tree.
I didn't start sampling quite yet, since I was curious to follow a very narrow, almost hidden path along the former road that someone had pruned vegetation here and there to mark. And so I slogged on through the wet and slippery tangle, expecting to find a hunting blind. What I found was flagging hanging over the trail, which led me to notice a witness tree on the hillside directly above.

Male Spirembolus mundus
Female Pityohyphantes sp. #5
Curiosity satisfied, I beat conifer foliage as I worked my way slowly back to the main forest road. Interestingly, although the deciduous understory was quite wet, most of the conifer foliage was dry. Thanks to quite cool temperatures along the creek, many spiders were moving slowly enough to photograph, even in the dim light of the understory.

My main cone source
By the time I returned to the forest road, Rod had scouted the area and located a small grove of ponderosa pines (Pinus ponderosa) for me. Yay, cones to tap! Unfortunately the grove was fairly young and so I was only able to find 17 cones. However, after searching farther down the road, I found a pair of mature trees that had dropped hundreds of cones. It took a scramble up the steep roadside embankment to access them (going up is never the problem. It's getting down again...), but I was happy to get a good sample.

Lots of cones up the embankment!
From 100 cones I tapped 12 spiders from six families. Four species were identifiable, including typical denizens of eastside cones like Meioneta fillmorana (Linyphiidae) and Cryphoeca exlineae (Hahniidae). The surprise of the sample was an atypical female Pityohyphantes tacoma. Rod also found them in conifer foliage. They were atypical in the shape of their genitalia, but also in the sense that this was the first Pityohyphantes I'd tapped from a fallen cone.

You can read Rod's trip report here.

Fireweed (Chamaenerion angustifolium) and ocean-spray (Holodiscus discolor)