Saturday, February 18, 2017

17-Feb-2017 Olympia & Lacey, Washington

Site location map. Click to enlarge.
The weather still wasn't dry enough for a full spidering trip with Rod Crawford, but it was just fine for tapping fallen conifer cones.  I decided to head to Thurston County to see what I could find.

I first tried looking for fallen pine cones in South Sound Center in Lacey, but had no luck. Like so many malls in western Washington, black pines (Pinus nigra) are a dominant feature in the landscaping there, but the needle litter and fallen cones had been removed by groundskeepers. In fact, a crew of groundskeepers was thus occupied while I was there.  Sadness.

Towering Jeffrey pine
Luckily I didn't have far to go to find my first cone source. I'd driven just a few hundred feet down Pacific Ave. when I spotted a magnificent Jeffrey pine (P. jeffreyi) towering over the realm. The native range of the Jeffrey pine is mainly the Sierra Nevada mountains in California, so it was a real surprise to find one growing in Olympia, Washington. But it was conveniently located at the edge of a parking lot in an area apparently untouched by groundskeepers, and it was gorgeous, so I was happy enough to come upon it.

My excitement faded, however, when I realized that this tree's fallen cones were poorly opened and few in number.  Still, I did collect a female Tachygyna ursina (Linyphiidae) from the 19 cones I tapped, a species not previously recorded in the gridspace. So at least there was that.

Double row of Douglas-firs
Fallen Douglas-fir cones
My second sampling site was located in St. Martin's Park in Lacey. A double row of Douglas-fir trees (Pseudotsuga menziesii) borders much of the park and had dropped a wealth of cones and needle litter undisturbed by groundskeepers. The scales on Douglas-fir cones usually close in damp weather, but not always entirely.  I was able to find plenty of cones with scales open far enough to harbor small spiders.

Grammonota kincaidi females
Tachygyna vancouverana
I tapped 50 cones and collected 14 spiders.  Nine of the 14 were Tachygyna vancouverana -- 8 females and 1 male. I often tap T. vancouverana from cones in western Washington, but usually it's just a few individuals per 50 cone set. However, I have tapped crowds of 16 or 17 of them a few times, so finding 9 was unusual but not exceptional.  I also collected 2 female Grammonota kincaidi from this batch of cones, another linyphiid that I've only tapped from fallen cones once before.

Wednesday, February 15, 2017

12-Feb-2017 Ferndale & Blaine, Washington

Site location map. Click to enlarge.
A lovely break in the winter weather gave me an opportunity to return to Whatcom County to continue my search for the European crab spider Ozyptila practicola (Thomisidae).  My destinations: Ferndale and Blaine.

Black pines bordering the Ferndale
Park and Ride lot.
The Ferndale Park and Ride lot was my first site.  A row of black pines (Pinus nigra) growing along the eastern property line had dropped plenty of cones. Most of them were poorly opened, but I managed to find 50 that were open enough for O. praticola, if present, to squeeze into. All I tapped from those 50 cones were three juvenile spiders: a linyphiid, a dictynid and a theridiid that was probably Platnickia tincta. Not a very auspicious start to my sampling day.

Mt Baker, as seen from the Haggen
parking lot
Heading into town I spotted another row of black pines, this time bordering the Haggen grocery store parking lot.  Although the cones were more open than at the previous site, I didn't find even one spider in the 50 that I tapped.  At least I had a nice view of Mt. Baker while getting skunked!

Black pines bordering picnic area
next to the Nooksack River
My third and final location in Ferndale was a pleasant picnic area overlooking the Nooksack River. The cone source was again a line of black pine trees bordering the parking area. The cones here were generally well opened, and lay on a thick, sumptuous bed of needle litter.

The fallen cone microhabitat
I tapped 100 cones and collected 15 spiders.  Eight of them were juvenile Enoplognatha probably-ovata (Linyphiidae).  Also present were a pair of penultimate male Xysticus probably-cristatus and another pair of Philodromus juveniles.  The only identifiable species, and perhaps also the only native species present, was Tachygyna ursina.

Black pines on C St.
in Blaine
The last two sampling sites of the day were in the border town of Blaine. The first site consisted of three black pines in a parking lot.  I found 91 cones to tap, all laying on thick needle litter.

Dictynid female from C St. cones
Those 91 cones produced 10 spiders, the most interesting of which was a female dictynid that I haven't yet identified.  I also tapped several female T. ursina and T. vancouverana from these cones, as well as juveniles from three of the more common introduced species.

Black pines at Blaine post office
My final cone source for the day was a row of black pine trees growing along the fence line of Blaine's main post office.  Tapping 50 cones, I collected 11 spiders and 4 to 5 species.  The only mature spider in the set was a male Erigone (Linyphiidae).  The rest were juvenile dictynids, Xysticus probably-cristatus and E. probably-ovata.

The mix of spiders I tapped from pine cones in Ferndale and Blaine was pretty typical of what I find in the urban Interstate 5 corridor.  But I was frankly surprised that I didn't find any O. praticola in cones in either city.  This is especially true of Blaine, which is only a few miles from locations in British Columbia where O. praticola has been collected.

Ozyptila praticola sampling sites in WA and B.C. Blue or purple: Confirmed with
adult specimen; Yellow: Juvenile likely O. praticola; Red: No O. praticola
found. Note: B.C. records via Bennett et. al 2014

Tuesday, November 8, 2016

6-Nov-2016 Bellingham, Washington

Site location map. Click to enlarge.
I was all set to drive to Olympia to look for the introduced crab spider Ozyptila praticola, happy at the thought that traffic on southbound Interstate 5 should be light since it was a Sunday morning. But right before leaving, just to be on the safe side, I decided to check the traffic conditions. Good thing I did! An accident in Tacoma was blocking all but one lane. But northbound traffic was still moving smoothly, so Bellingham became my last-minute destination for the day.

I hadn't found any O. praticola on a recent trip to the Burlington, the closest urban center south of Bellingham, but I still thought it likely to be present in Bellingham and the northwestern corner of the state, at least along the I-5 corridor.  This is because it's been collected just over the Canadian border near Vancouver, British Columbia (see map at end of post).  So although Bellingham wasn't my original destination for the day, I didn't mind traffic conditions diverting me there.

Bellingham has no shortage of pines, I found, but there was a distinct shortage of fallen cones beneath them due to groundskeeping practices. However, after searching diligently I eventually found two collection sites, each consisting of one western white pine (Pinus monticola) with fallen cones beneath.

Lincoln Street Underpass

Site on Lincoln Street near
I-5 underpass. Pine on left.
Lincoln St. cones were barely open
A pine tree dominated the space between the the sidewalk and someone's privacy fence, and had dropped numerous cones on a thick bed of needle litter with miscellaneous bits of trash mixed in. Most of the cones were only partially open and quite wet from recent rain. And in fact my net got wetter with each cone I tapped, to the extent that I was ruing the fact that I'd left my spare net at home.  But the result was worth it: I tapped 66 spiders and 6 identifiable species from those 50 cones!

Male Centromerita bicolor tapped
from a pine cone
Tachygyna vancouverana males
For the most part, the sample composition was typical of what I've found previously in Washington's I-5 corridor: lots of juvenile Philodromus and Enophlognatha, a few Tegenaria and some adult Tenuiphantes tenuis and Tachygyna vancouverana.  What was unusual, however, was that T. vancouverana made up over a third of the sample.  They were everywhere, both males (7) and females (24). In addition, this sample contained a novelty in terms of cone tapping: Centromerita bicolor, another introduced linyphiid.  It was first found in Washington in 1975 by Rod Crawford, in Seattle.  He collected it again in 1988 in Bellingham, just a mile or so from my Lincoln Street site.  Apparently it's naturalized in Bellingham.  And finally, I tapped from these cones one juvenile Ozyptila with praticola coloring and patterning.

James Street at Whatcom Creek

My James St. pine cone
source
The James St. fallen cone
microhabitat
My second site was only about a quarter of a mile (0.4 km) to the northwest of the first site, as the crow flies.  But with daylight rapidly fading (sunset at 4:40 p.m.!), I was just happy to have found another cone source.  It was another western white pine, this time standing in the grassy area between Whatcom Creek and a parking lot.  A tangle of Himalayan blackberry (Rubus armeniacus) growing at its base had recently been cut back, making the fallen pine cones beneath accessible to me.  I often grumble about groundskeepers, but in this case they'd inadvertently done me a good turn.

Juvenile Ozyptila from James St. site
As at the first site, the scales on the cones here were poorly opened, yet they were open far enough for many spiders to have entered.  I was only able to find 25 cones to tap, but they delivered 14 spiders and one identifiable species, Phrurotimpus boralis. The rest of the sample was very much like a subset of the Lincoln St. sample including, once again, one juvenile Ozyptila with praticola coloring and patterning. As the saying goes, "so close and yet so far".

Ozyptila praticola collection sites in WA and B.C.
Blue: Confirmed with adult specimen; Yellow: Juvenile possible O. praticola;
Red: No O. praticola found. Note: B.C. records via Bennett et. al 2014

The banks of Whatcom Creek are choked with invasive Himalayan
blackberry, which incidentally originated in Armenia and Iran, not the Himalayas.

Wednesday, November 2, 2016

25-Oct-2016 Burlington, Washington

Site location map. Click to enlarge.
A very rainy October slowed my hunt for the introduced crab spider Ozyptila praticola (Thomisidae), but I was finally able to get in one solid day of searching before turning the page on the calendar.  My destination was the Burlington metro area, which includes Mt. Vernon to the south and Sedro-Woolley to the northeast.

Fallen Pinus nigra cones
In total I tapped 52 spiders from 380 pine cones (Pinus nigra, P. sylvestris, P. strobus or monticola and P. ponderosa) across 7 sites.  As readers of this blog know, I usually describe the catch from each sampling site separately.  But the results were so unremarkable and typical of what I find in fallen cones in the Interstate 5 urban corridor that I'm just going to provide a combined summary this time.

The only thomisids I found in these cones were a few juvenile Xysticus.  Thus, no Ozyptila. Tenuiphantes tenuis and Tachygyna vancouverana were the most common identifiable species present, while juvenile Enoplognatha probably-ovata and Philodromus were numerous and widespread.  A mishmash of other juvenile linyphiids, theridiids and agelenids made up the rest of the combined sample.

Rain showers and sunshine created this beautiful rainbow in Sedro-Wooley

Monday, October 24, 2016

19-Oct-2016 Plain, Washington

Site location map. Click to enlarge.
It had been nearly three months since Rod Crawford and I were last able to align both of our schedules with the weather. Too long!  But finally all the pieces fell into place and we set out once again for another day of discovery.  Our destination: Plain, a small town on the east side of Stevens Pass, just southeast of Lake Wenatchee.  A dusting of snow on the upper reaches of Baring Mountain and Mount Index -- very unusual for this time of year -- was a visual reminder of the recent passage of Typhoon Songda through the area.

No room for spiders!
We made pine cone tapping the first order of the day's business, since vegetation and litter were still wet from rain or heavy dew the previous night.  With that in mind, we made our first stop on the unnamed forested pass between the Wenatchee River and Chumstick Creek valleys.  There were ponderosa pines galore (Pinus ponderosa) and plenty of cones, but for the most part the cones were still sealed.  They had apparently fallen from the trees prematurely.

Rod sweeping herbs under my pine
cone source in Plain.
We backtracked into Plain and drove through town in search of open, accessible cones.  The best cache of cones had been dropped into a shallow roadside ditch by a lone pine growing alongside the curiously named State Haul Road.

A typical fallen ponderosa
cone in Plain
Many of the fallen cones were dusty or muddy and fairly well decayed, and none had fully open scales.  And yet, a set of 50 tapped cones produced 19 spiders from 5 families.  Six species were identifiable, including Xysticus locuples (Thomisidae), Meioneta bucklei (Linyphiidae) and the undescribed Dictyna sp. #9 (Dictynidae), which we've mainly collected from fallen ponderosa cones or associated needle litter.  The most interesting spiders in this sample, however, were the three juvenile Zodarion, presumably Z. rubidum (Zodariidae).  We first confirmed the presence of this European species in Washington only this summer, from specimens collected in western Washington.  The present specimens are the first we've collected in eastern Washington.

Scots pine on a homestead in
Little Chumstick Creek valley
Fallen Scots pine cones
Our next collection site was located in the nearby Little Chumstick Creek valley.  A local homeowner gave us permission to collect on his property, which included an assortment of introduced tree species. Among them was a Scots pine (Pinus sylvestris), so naturally I tapped another round of fallen cones.  Many cones had been crushed by driveway traffic, but I was still able to find 30 undisturbed cones among the willow leaves and pine needles off to the side. I tapped 8 spiders and 4 species from those 30 little cones! Most were mature Tachygyna vancouverana (Linyphiidae), but a female Tenuiphantes tenuis (Linyphiidae) and a juvenile Enoplognatha ?ovata (Theridiidae) were also present. Together, these three species created a very familiar assemblage.  As Rod observed, this sample could have easily been tapped from cones in the Seattle conurbation in western Washington.

Read Rod's trip narrative here.
A female Helophora orinoma (Linyphiidae) tapped from a ponderosa cone
in Plain, Washington

Fall colors on the shore of the Wenatchee River near Plain, Washington
Rod sorting a sweep sample in the Little Chumstick Creek valley

Thursday, September 22, 2016

20-Sept-2016 Marysville, Arlington and Mt. Vernon, Washington

Site location map. Click to enlarge.
Time to re-draw the Ozyptila praticola (Thomisidae) range map again!  I returned to the field this week to continue my search for the northern edge of this introduced crab spider's range in western Washington.  I had previously sampled the urban corridor along Interstate 5 as far north as Arlington (as well as several non-urban sites well beyond there), but had not found any O. praticola beyond Granite Falls.

Although I sampled in Arlington in October 2015, I considered the city under-sampled since I had only tapped one full set (50 cones) and one partial set (13 cones) of cones there.  Further, the partial set of cones had been lying in tall grass, a situation that I've found to be unattractive to O. praticola in western Washington.  So I returned to Arlington in search of at least one more set of more suitably situated cones to tap.

Arlington Denny's

A welcome sight right off
the freeway
Fallen cones on pine needle litter: a
good place to look for O. praticola
Exiting I-5 onto eastbound Route 530, the first thing I saw was a Denny's restaurant with black pines (Pinus nigra) growing next to its parking lot.  How fortuitous!  Most of the 50 fallen cones I tapped had only partially opened scales and contained significant amounts of organic debris, but also 32 spiders from 6 families.  Forty percent of them (13) were juvenile Crustulina, presumably sticta (Theridiidae), a spider I have found in fallen cones before, but rarely.  Interestingly, all 13 were from a small number of neighboring cones.  The next most common spider present were juvenile Enoplognatha ?ovata (Theridiidae), a common spider in urban cones in western Washington.  As for O. praticola, it was a no-show until I tapped my 49th cone, which produced a mature female!

Mt. Vernon

An inviting spot south of Mt. Vernon
Lots of cones but few spiders
Next stop was Mt. Vernon, a lovely little city in the Skagit delta.  I searched downtown and the industrial zone to its south for pines, and found many.  But what I didn't find were cones.  Groundskeepers had swept them all away.  It wasn't until I hit the city's southern rural outskirts that I found an accumulation of accessible pine cones.  Black pine once again, this time planted along the fence at a plant nursery.  I tapped the usual 50 cones but only got 4 spiders: all juvenile Philodromus (Philodromidae). Oh well.

Marysville Public Works

How could I resist?!
Excellent fallen cone microhabitat
at Marysville Public Works
Heading home towards Seattle, I decided to take the scenic route from Mt. Vernon through Marysville before returning to the hurly-burly of the interstate.  I'm sure glad I did!  Just a few blocks before I had to get back on I-5, I spotted a delicious row of large black pines growing along the fence line of the Public Works.  Only one tree was accessible to me, but it had dropped plenty of cones that a) had escaped groundskeepers and b) had accumulated on pine needle litter.  I was in clover.

Male Crustulina sticta. Note the
Steatoda patterning on his dorsum.
The characteristic granulations were
visible on the sternum as well as carapace
So much so that I didn't pay attention to the time (6:30 p.m.) and almost got locked into that parking lot!  I had just captured the spiders from cones 41 through 45 in my dry vial when I heard the gate being dragged closed.  That sure snapped me out of my reverie!  The employee kindly held the gate for me while I jumped in my car and zipped by, one thumb still stoppering my dry vial.  As soon as I cleared the gate I had to pull over and transfer those spiders to my alcohol vial.  Although I had only managed to tap 45 cones, I collected a whopping 45 spiders!  Twenty-six of them were juvenile Philodromus, 7 were Tenuiphantes tenuis and 6 were O. praticola.  I also captured 3 more Crustulina sticta, including a mature male.

At present, Arlington is the northern edge of O. praticola's known range in western Washington.  The search will continue...

Evening sun illuminates the Marysville water tower.

Rich farmlands of the Skagit delta were just across the
street from my Mt. Vernon site.

Saturday, September 17, 2016

A Preliminary Look At The Phenology of Adult Ozyptila praticola (Thomisidae) in Western Washington

Whenever I take a break from collecting, I'm itching the whole time to resume field work as soon as I can.  But breaks do give me time to take an unhurried look at the data I've recently collected to see whether I've learned anything unexpected.  I've been doing this with my Ozyptila praticola project data.

The goal of the O. praticola project has been simply to determine the distribution of this introduced crab spider in Washington state, as found in the fallen conifer cone microhabitat.  But in the process of pursuing that goal, I've collected some interesting life history data on the species.  In this case, adult phenology.

The Spiders of Europe and British Arachnological Society's Spider Recording Scheme ("SRS") web pages for O. praticola both report that mature males and females have been collected every month of the year in their regions of coverage. Similarly, within their local range here in Washington, I have found adult O. praticola present every month that I've searched (February through November) except for February, a woefully under-sampled month represented so far by only one 50-cone sample.

Before graphing the monthly occurrence of females and males in my collection, I standardized numbers of specimens of each sex I collected each month by converting them to a per 100 cones tapped basis.  I did this because sampling effort -- defined here as numbers of cones tapped per month -- varied greatly from month to month (see chart, right).

The resulting chart shows that female O. praticola have been present in my samples in fairly consistent concentrations of about 1 to 2 spiders per 100 cones every month I've sampled (excluding February, as previously discussed).  In contrast, I found males in tapped cones only in spring (April & May) and fall (September & October), and at varying concentrations.

Adapted from British Arachnological Society's
Spider Recording Scheme
Although SRS reported O. praticola males present every month, it also showed a bimodal distribution with more males having been collected in May & June and, to a lesser degree, in September, than any other month (see chart, right).  Unfortunately, it is not possible to know whether this apparent similarity in patterns between my data and data reported by SRS is meaningful since it seems doubtful that the SRS data were standardized for sampling effort, as mine were.  The SRS results could be explained simply by more British spider collectors being active in spring and fall than other seasons.

Note that my phenology chart is based on preliminary data from a study not yet completed.  So far, I've tapped 268 O. praticola from 1,895 conifer cones.  Of those 268 O. praticola, 29 (11%) were female, 14 (5%) were male and 225 (84%) were juvenile.  That's not a lot of specimens to base any conclusions on.  Still, it's more data than we had a year ago, which was almost nil.  I am excited to know whether the patterns in my chart will change with the addition of more data.  And so, as usual, I am itching more than ever to get back out into the field.