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 according to 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)


Monday, October 16, 2017

3-Oct-2017 La Center, Washington

Site location map. Click to enlarge.
Fall sampling has arrived! After barely making our species quotas in the dry heat of late summer, it's always exciting to collect in October. By then, days are cooler and autumn rains have begun, but there are enough consecutive dry days that collecting is still possible. And most importantly, we are usually able to collect many more species than our minimum daily target of twenty-one.

This day Rod Crawford and I headed south to La Center in Clark County, where a student's recent pitfall study in broccoli fields had provided Rod with interesting but incomplete samples from two adjacent gridspaces. Our goal was to raise the species total in each gridspace to at least twenty-one. Luckily, since we had a long drive to get there, accessible habitats in each gridspace were accessible within a few miles of the freeway.

Female Phidippus audax from shed
Our first stop was at a county reserve located at a convergence of agricultural land, forest and the East Fork Lewis River. I had little luck finding fallen open conifer cones to tap, but had some success sweeping riverside grass and collecting from the walls of a shed.

A formidable mantis...
The area was also good for some insect photo ops, including this European mantis (Mantis religiosa) that landed on me as I was walking down the road to the river. By its coloration, I'm guessing it had been spending most of its time on drying grass. Gardeners and farmers buy mantis egg cases and introduce these animals into their fields as pest predators. However, I am skeptical that they are effective since 1) they're generalist predators and so eat beneficial animals like bees and spiders as well as troublesome ones, and 2) like ladybirds, they have wings and don't stay put.
...and a decidedly unformidable woollybear

I also spotted my first woollybear (Pyrrharctia isabella) of the season, which was dashing headlong through the riparian grass.

Our second stop was at the Lake Rosannah Natural Area ("Mud Lake" on older maps) located at the lower end of the Allen Creek drainage. After collecting from gates and fences near the parking area, I walked the trail towards the lake and was happy to find open Douglas-fir (Pseudotsuga menziesii) cones next to the trail.

Female Comaroma mendocino
Cone tapping site by Lake Rosannah
Tapping 50 fallen cones produced only two spiders, a juvenile Phrurotimpus and a tiny, shiny dark-colored spider shaped like a theridiid. As it turns out, that tiny spider was a female Comaroma mendocino, a cobweb weaver currently placed in the family Anapidae. The species has only been reported twice before on the west coast of North America, in California and in British Columbia! If I had sampled more cones, perhaps I would have collected a male as well. But I was dissuaded by the poison oak (Toxicodendron diversilobum) growing through the forest litter, and didn't yet know I had found such a rarity.

Read Rod's account of the day here.

The lustrous leaves of poison oak.

Last blossoms of summer: Spiraea douglasii

Friday, August 18, 2017

16-Aug-2017 Mount Vernon and Bellingham, Washington

Site location map. Click to enlarge.
Ever since finding juvenile Ozyptila that were patterned like praticola at two sites in Bellingham last November, I've been wanting to return to search for adult specimens. I wanted to know conclusively whether this introduced thomisid was present in Whatcom County's biggest city. It seemed likely, given Bellingham's situation along Interstate 5 and its proximity to British Columbia's southern reaches, where O. praticola has also been found. This would be the day to find out! But first, on my way north from Seattle to Bellingham, I stopped in Mount Vernon and Bow to take a few more samples in Skagit County; I have yet to find O. praticola (or any Ozyptila) in fallen conifer cones in Skagit County.

Mount Vernon & Bow

Anderson Rd site
Lots of cones & litter under the shrubs
On past trips north I'd noticed a row of pines growing just east of the freeway near the Anderson Road exit. Upon closer inspection this day, I found that groundskeepers had removed all of the cones and needle litter from beneath them. But it didn't take long to find "greener pastures" on the other side of the freeway: black pines (Pinus nigra) planted along a parking lot perimeter. Groundskeepers had been busy there too, but hadn't gone so far as to remove cones and litter from beneath the shrubs.

Zodarion collection sites.  Blue = Zodarion rubidum adult;
Yellow = juvenile Zodarion 
I tapped 50 cones and collected 37 spiders from four families. Most were juvenile Steatoda (Theridiidae) and Philodromus (Philodromidae). The only identifiable species was Tenuiphantes tenuis (Linyphiidae). By far the most interesting spider in the sample was a juvenile Zodarion (Zodariidae), presumably Z. rubidum. This is the farthest north I've found this rapidly spreading introduced species. I also sifted pine needle litter, but didn't find anything new. I found no O. praticola in either microhabitat.

Bow Hill Rest Area
Bow Hill Rest Area along Interstate 5 provided another convenient spot to tap cones in Skagit County. The facility is situated in a fairly natural forest fragment dominated by western red-cedar (Thuja plicata) and Douglas-fir (Pseudotsuga menziesii). Nevertheless, the 50 Douglas-fir cones I tapped produced only two harvestmen and two juvenile linyphiids.

Bellingham

Lincoln St. site
Since I already knew that Ozyptila could be found at the two Bellingham sites I had sampled previously, I decided to intensively re-sample those sites before looking for new ones. My first stop was the western white pine (Pinus monticola) growing on Lincoln St. near the Interstate 5 underpass. Except for the need to wade through thorny Himalayan blackberry (Rubus armeniacus), I had no trouble finding 50 fully opened cones to tap.

Female Steatoda bipunctata
Those 50 cones produced an astounding 100 spiders, 64 of which were the introduced Steatoda bipunctata (Theridiidae). I also collected two female Eratigena agrestis (Agelenidae), commonly known as hobo spiders. Juvenile agelenids aren't uncommon in the fallen cone microhabitat, but this is the first time I've collected mature E. agrestis. I suspect the reason is that most cones that I tap don't provide large enough hiding places for Eratigena adults, which have body lengths of 11-15 mm (legs not included). As for O. praticola, I again found but one juvenile spider at the Lincoln St. site. My plan had been to sift litter if I didn't find an adult specimen in the cones, but I decided against it unless my second Bellingham site proved equally unhelpful. The reason was the poor dog on the other side of the fence that had been barking for the past hour and a half. I was sure that I, it and its neighbors would enjoy a reprieve.

This unassuming site on James St. ...
...harbored this male Ozyptila praticola
Moving on, I was pleased to find that the western white pine at the intersection of Whatcom Creek and James street also had numerous fully opened cones beneath it. I tapped 50 cones and collected 24 spiders from 5 families. Only two species were identifiable: T. tenuis and, O. praticola! So now we know with certainty; Ozyptila praticola is indeed present in Bellingham.
Status of Ozyptila praticola in western Washington. Blue, yellow, or red
indicate adult O. praticola, juvenile Ozyptila sp. or no Ozyptila found, respectively

Wednesday, August 9, 2017

8-Aug-2017 Bainbridge Island, Washington

Site location map. Yellow pin marks Harborview Drive site.
Click to enlarge.
Smoke from wildfires in British Columbia precluded a trip to the gridspace of interest to Rod, so I took a solo trip to Bainbridge Island (Kitsap County) to continue my search for the introduced European thomisid Ozyptila praticola. So far I haven't found any O. praticola on the nearby Kitsap Peninsula, but it is present on Vashon Island five miles to the south of Bainbridge Island. Both islands are connected by frequent ferry traffic to Seattle, where O. praticola is now common.

Sampling site on Harborview Dr.
The fallen cone microhabitat
Almost immediately after disembarking from the ferry, I found a nice cache of fallen cones to tap on Harborview Drive. The cones were a jumble of Douglas-fir (Pseudotsuga menziesii) and black pine (Pinus nigra) cones intermingled with Douglas-fir and madrone (Arbutus menziesii) litter.

Juvenile Ozyptila (?praticola?)
O. praticola in western WA. Blue,
yellow & red pins indicate adult, juvenile
or no O. praticola found, respectively.
I tapped 100 cones and collected 26 spiders. Most were Cryptachaea blattea (Theridiidae), but two were juvenile Ozyptila. They look like O. praticola to me, but unfortunately I can't definitively identify the species from juvenile specimens, so a return trip with litter sifting equipment in tow will be required.

The other four Bainbridge Island sites I sampled produced more C. blattea as well as juvenile specimens of Tegenaria, Tenuiphantes, Philodromus, and Phrurotimpus. In all, very typical for fallen cones in urban western Washington.

Seattle skyline seen through the milky haze of wildfire smoke from the
deck of the M/V Tacoma.


Saturday, August 5, 2017

30-July-2017 Ferbrache Unit, Washington

Site location map. Click to enlarge.
With choices of productive sampling sites dwindling rapidly due to summer heat and dryness, Rod Crawford and I returned to a favorite late-season region, Grays Harbor County. Our main collecting site had the interesting name Ferbrache Unit, which I kept confusing in my mind with Fibonacci, as in the mathematical sequence. The area consists of Chehalis River sloughs, forest remnants and agricultural fields managed for waterfowl. My source of fallen cones was the one and only Sitka spruce (Picea sitchensis) growing on the forested edge of one such grassy field.

Rod dwarfed by the Sitka spruce and
its encircling jungle.
Looking across grassy field
at the giant Sitka spruce.
The tree was a giant and sported a massive skirt of Himalayan blackberry (Rubus armeniacus) and coastal manroot (Marah oregana or M. oreganus). The latter resembles the edible cucumber and belongs to the same family (Cucurbitaceae), but is apparently not edible.

First set of tapped cones returned
to the grassy field
Numerous cones had fallen on the grassy field, so I tapped 57 of them while Rod beat the few reachable spruce branches and the tree's skirt of foliage. My efforts resulted in only one juvenile spider.

Fallen cones near tree base made up
the second set
By the time I was done with that first set of cones, Rod had made a big enough hole in the wall of green (a machete would have been useful!) for me to worm my way through to the trunk of the tree.

Inside the manroot tangle
I was pleased to find vast quantities of cones under the pleasantly green and less-dry tree canopy and manroot tangle. I tapped 100 cones from that cache and collected 11 spiders and a few neobisiid pseudoscorpions. Compared to the lone juvenile spider I'd tapped from the "field" cones just a few yards away, this was a bountiful result.

All eleven spiders were juvenile except for a male and female Ceratinella (Linyphiidae) which didn't immediately match any species Rod was familiar with. Two of the juveniles were Metallina (Tetragnathidae), a genus I'd never found in fallen cones before. In fact, I rarely find anything from the family Tetragnathidae in fallen cones. Rod also collected many juvenile Metallina in his Ferbrache Unit sweep samples.

Read Rod's account here.

A field of peas across the road from the Ferbrache Unit.

Monday, July 24, 2017

18-July-2017 North Mountain, Washington

Site location map. Click to enlarge.
Since habitats on the east side of the Cascades are now too dry to be productive, Rod Crawford and I decided to head north to North Mountain, a mid-elevation site near Darrington in Snohomish County. We collected in the area in May of 2016, but at lower elevations. I was excited to reach to fire lookout atop North Mountain and take in the views of Whitehorse Mountain, Mount Baker and perhaps even get a glimpse of Glacier Peak. Oh, and collect spiders there, too...

Rod on final approach to the
fire lookout.
Mt Baker as seen from the lookout. The
view was hazy due to moist marine air.
After some confusion as to which road was the one leading to the lookout, we arrived at the locked gate and continued the final 1.5 miles on foot. It was a hot and somewhat humid hike, but a refreshing breeze was blowing through the lookout, which was under renovation and therefore had no windows. The views were just as stunning as I'd hoped.

But to work! After feasting my eyes on the scenery, I came back down to earth and set about tapping Douglas-fir (Pseudotsuga menziesii) cones near the base of the lookout. Except for a few harvestmen, however, those cones were arachnid-free.

Female Orodrassus canadensis
guarding her egg sac.
Female Pardosa mackenziana with
egg sac
The renovation work on the lookout meant that there were pieces of wood scattered about, so I next began looking beneath them for spiders. I didn't find many, but what I found certainly made the effort worthwhile. One wooden post on a concrete slab was sheltering a male Cybaeus reticulatus (Cybaeidae) and a female Orodrassus canadensis (Gnaphosidae). When I rolled the post aside, the top of the Orodrassus' nest-refugium got pulled off. This left her and her egg sac visible for a nice photo. I also found a few female Pardosa mackenziana (Lycosidae) under stones in a roadside outcrop a few hundred feet below the lookout.

Male Misumena vatia stepping onto
draglines that led to...
...a female Misumena vatia eating
a fly.
Big swaths of goatsbeard (Aruncus dioicus) were in full and glorious bloom along the roadside, so while Rod searched for conifer litter to sift, I began examining goatsbeard inflorescences. Not surprisingly, everyone's favorite crab spider Misumena vatia (Thomisidae) was numerous therein and conspicuous. I spent quite some time observing a male traveling on draglines between two adjacent inflorescences. Each inflorescence had an actively-feeding penultimate female near its apex.

Clubiona pacifica nest in goatsbeard
leaflet
Opening the Clubiona pacifica nest
made in goatsbeard leaflet
As fun as it always is to watch Misumena vatia, the really exciting, novel observation of the day came as Rod and I began our walk back down to the car. As Rod was diligently sweeping roadside herbs, I was quite honestly just enjoying a leisurely downhill ramble while photographing the occasional bee or spider in the nearly endless stream of roadside goatsbeard. That's when I noticed that something had folded the end of a goatsbeard leaflet into a neat, triangular package.

Opened Clubiona pacifica
nest after removal of female.
Clubiona pacifica nest in alder leaf
Upon opening it, we discovered a female Clubiona pacifica (Clubionidae) and her egg sac inside! Water droplets on the inside of the silk-lined package indicated that this was perhaps a moisture-retention mechanism as well as a predator control device.

Clubiona pacifica juvenile in silken tube
Shortly thereafter I spotted another triangular C. pacifica nest, this time made from an alder (Alnus) leaf. I also found a third, albeit juvenile Clubiona in a tubular silken structure in a goatsbeard leaflet that had been folded in half lengthwise.

Lower Doug-fir cone site
Productive Doug-fir cones
Heading back down the mountain, we stopped in a stretch of mature Douglas-fir and red-cedar (Thuja plicata) forest where Rod spotted some old stumps and downed wood he wanted to tap. I decided to take another crack at tapping Doug-fir cones, and this time had some luck. I tapped 100 cones and collected 16 spiders from 3 families. At 7 individuals, Cryphoeca exlineae (Agelenidae) dominated the sample and was the only identifiable species present.

Read Rod's account here.

A female clodius parnassian (Parnassius clodius) near the
North Mountain lookout

View of Whitehorse Mountain as seen from a clearcut on North Mountain.
Fireweed (Chamaenerion angustifolium) in foreground.