Arachnida (and Chelicerata) | Northwest Naturalist

June 1, 2017May 28, 2017 / RobNiese / Leave a comment

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Philodromus histrio “Theatrical Running Crab Spider” Philodromidae

Blue Mountain National Recreation Area, MT
May 16, 2016
Robert Niese

I have no idea why this species of running crab spider has been given the species epithet “histrio.” In Latin, histrio means “actor” or “player.” Perhaps the arachnid’s propensity for waving its arms about whenever a predator (or camera) approaches earned it this descriptor. Or perhaps some early entomologist first encountered it engaged in an impressive act of twig-impersonation. In fact, when I first stumbled upon this individual, its legs were perfectly aligned in the shape of an X and pressed flat against the underside of this Artemisia stem, perhaps hoping to be mistaken for plant matter. Regardless, these Philodromids are widespread, common, and relatively recognizable. Look for them in northern latitudes and in the Rockies anywhere you might find weedy Asteraceous plants like Artemisia, Tanacetum, Centaurea, or Senicio (yes, I know, that encompasses just about every habitat).

July 13, 2016July 18, 2020 / RobNiese / Leave a comment

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Oxyopes scalaris “Western Lynx Spider” Oxyopidae

Missoula, MT
May 6, 2016
Robert Niese

Lynx spiders are some of my favorite arachnids! They’re stealthy, fast, agile and ferocious predators, some of which specialize on other spiders! Oxyopes scalaris is virtually the only species of lynx found in the PNW, however. It can be found in just about any habitat from the coast to the Rockies and as far north as BC. One additional species, the Striped Lynx (O. salticus) can be found along the coast from California through Oregon and, rarely, in southern Washington.

July 22, 2015July 18, 2020 / RobNiese / Leave a comment

My spider photos and some of my natural history writings have been featured on the Oregonian’s website! I’m so excited to see my work getting out to the public!

Check it out!

May 25, 2015October 2, 2015 / RobNiese / Leave a comment

Paruroctonus boreus “Northern Scorpion” Vaejovidae (Scorpiones)

Ginkgo Petrified Forest State Park, WA
April 7, 2013
Robert Niese

Scorpions are a remarkably poorly studied clade of organisms. The Pacific Northwest is home to at least two described species (although there are likely others that remain undescribed): the Pacific Forest Scorpion (Uroctonus mordax) and the Northern Scorpion (Paruroctonus boreus). The Pacific Forest Scorpion, as its name would suggest, is most often found in dense coastal forests wherever it can find constant moisture (also found inland as well, west of the Cascades). The Northern Scorpion tends to prefer more open habitats than the Forest Scorpion and is typically the only species one will encounter east of the Cascades here in the PNW. They are quite abundant at the Ginkgo Petrified Forest State Park where they spend their days hiding from the sun under large rocks.

May 20, 2015October 2, 2015 / RobNiese / Leave a comment

Misumena vatia “Goldenrod Crab Spider” Thomisidae on
Cymopterus glaucus “Waxy Spring Parsley” Apiaceae

Lolo National Forest, Bitterroot Mountains, MT
May 10, 2015
Robert Niese

Goldenrod Crab Spiders are inordinately abundant in spring blooms all around the PNW. They can be differentiated from their cousins in the genus Misumenoides by the lack of a faint white ridge on their face between their lower eyes and their jaws. But far more interesting than this lurking ambush predator is the fact that this image of Cymopterus glaucus is the first to grace the internet. And all because I thought I was taking a picture of a cool spider. You can see more photos of this plant below. C. glaucus is endemic to Idaho and western Montana where it is locally common on sandy or gravely slopes in dry Ponderosa Pinelands. I’m so confounded by the lack of images of this plant online that I’ll be checking out the UM herbarium later to verify that this is indeed C. glaucus. Any suggestions to the contrary would be much appreciated.

April 20, 2015July 18, 2020 / RobNiese / Leave a comment

Platycryptus californicus Salticidae

Missoula, MT
June 5, 2014
Robert Niese

An extremely abundant, charismatic jumper commonly found on door frames and windowsills throughout the summer here in Missoula.

March 24, 2015July 18, 2020 / RobNiese / Leave a comment

Phidippus “clarus” Salticidae

Missoula, MT
September 17, 2014
Robert Niese

Phidippus jumpers are some of the largest jumping spiders in the world. Here in Montana, we have several red-backed species, all of which are about the size of a nickel. They are excellent house-guests and will rid your home of flies, roaches, and other mid-sized arthropods in a matter of days.

February 8, 2015October 2, 2015 / RobNiese / Leave a comment

Pardosa sp. “Thin-legged Wolf Spider” Lycosidae, with young

Olympic National Park, WA
June 8, 2013
Robert Niese

Female wolf spiders spin an egg sac and attach it to their spinnerets, carrying around their

precious cargo until the spiderlings hatch and crawl onto her back. There, the babies will stay until they’re old enough to venture out into the world on their own.

December 10, 2014July 18, 2020 / RobNiese / Leave a comment