Saturday, June 18, 2016

12-June-2016 Gig Harbor, Washington

Sample sites. Click to enlarge.
I had intended on searching for the introduced salticids Pseudeuophrys lanigera and Sitticus pubescens on building exteriors and stone walls in Gig Harbor on the same day I sampled on Vashon Island, but I ran out of time.  Gig Harbor was of interest because P. lanigera has been found recently in Bremerton, so that raised the possibility of wider dispersal on the Kitsap Peninsula.  Additionally, having collected a male Ozyptila praticola on Vashon, I also wanted to see if I could find any on the coast of the Kitsap Peninsula across Colvos Passage from Vashon Island.  I've not found O. praticola in other places I've sampled on the peninsula, including nearby Square Lake, but those previous sample sites were more or less natural areas.  So far, O. praticola appears to be synanthropic in western Washington, so it made sense to do some city sampling, and Gig Harbor again fit the bill.


A fallen white pine cone
Downtown cone source
My first cone source was a towering western white pine (Pinus monticola) on Judson Street.  Dozens of fallen cones lay on a bed of pine and red-cedar litter, sometimes under rhododendrons and other shrubs.  I tapped 55 cones and collected a bounteous 32 spiders and 3 identifiable species.  They were all species I find in cones in the Seattle conurbation: Tenuiphantes tenuis, Cryptachaea blattea and Philodromus dispar.

Lots of attractive stonework

This site was only a block from the harbor area, so I enjoyed the scenery as I scanned building exteriors and stone and brick walls for jumping spiders.  I found several Salticus scenicus, but nothing else.

High School

Gig Harbor High School
Female Platycryptus californicus
on school atrium pillar
My next stop was the Gig Harbor High School.  The building is huge and with a complex footprint, providing me with another excellent opportunity to look for wall-loving salticids.  I again found S. scenicus as well as a gorgeous female Platycryptus californicus.

Gig Harbor H.S. fallen cones
This dary-eyed junco (Junco hyemalis)
was my only company
A fairly dense mixed stand of trees grows between the street and the school's front driveway, with a dense salal understory.  I tapped 50 fallen Douglas-fir (Pseudotsuga menziesii) cones there and collected only 1 spider, a juvenile from the family Amaurobiidae.

West Harbor Heights

West Harbor Heights sampling site
My final cone-tapping spot for the day was a small grove of Douglas-firs growing between two parking lots. I tapped 50 cones and collected only 6 spiders, all linyphiids.  Only one spider was identifiable to species, a female Tenuiphantes tenuis.

I didn't find any of the three species of introduced spiders I was looking for in Gig Harbor.  Of course it is impossible to prove that something isn't present, but I think it likely that if O. praticola were in the city, odds are good that I would have detected it after tapping 50 cones in three places.  I base this on how frequently I find at least one O. praticola individual in samples taken in its known range in the Seattle conurbation.  As for the salticids, I have no idea how adequate my intensity of searching was to detect them if they're present.  All I can conclude is that if they are indeed present, they don't appear to be numerous or widespread.
Pleasure boats moored in the harbor

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