April 13, 2015

So this spider walks into a pine cone...

By Rod Crawford

Euryopis formosa spider in pine cone, July 10, 2011,
Thunder Lake, Yakima County, Washington.
Photo: Laurel Ramseyer.
On a sunny day in late May 2008, I went on a spider collecting field trip to Swauk Prairie outside of Cle Elum, Washington, with Laurel Ramseyer, a friend and field volunteer. The weather forecast called for "breezy." We'd have called it downright windy!

It was difficult to collect spiders with the wind blowing away anything loose and exposed. I did manage to sift nine spider species from hawthorn leaf litter, but only swept six species from the rippling sea of grass. Laurel had similar troubles.

Then Laurel saw a spider run into a large fallen pine cone (probably to get out of the wind), so she picked up the pine cone and started to whack it inside her net in an attempt to collect the spider. It worked! We were in a Ponderosa pine woodland with a lot of pine cones so she continued whacking more cones and eventually added three good species to that site's spider list.

This small beginning led to a major obsession for Laurel and she began using this method at other sites. To date she has whacked nearly 7,000 pine cones inside a heavy-duty net held against her leg, looking for the pine cone spider fauna that she, in a sense, discovered. Laurel (with a little help from me) collected 1,060 spiders from 4,600 eastern Washington pine cones between 2008 and 2013. I identified the spiders and added them to the Burke's collection.

Laurel sorting a pine cone beat sample, May 18, 2011,
Moloy Road on Wenas Creek, Yakima County, Washington.
Photo: Rod Crawford.

As it turns out, no spider species were previously recorded as collected from pine cones. Discovering a new spider species is relatively common, but discovering a whole new spider habitat—that's really something!

Some spiders evidently live in pine cones long-term, while others just use them to molt, lay eggs and rest when not out hunting. Or they wander in at random like that first one Laurel saw back at Swauk Prairie.

Euryopis formosa spider on pine cone scale, June 4, 2011,
Teanaway Campground, Kittitas County, Washington.
Photo: Laurel Ramseyer.

The spider we most commonly found in Washington pine cones was Euryopis formosa, a beautiful creature with a dark heart shape inside a bright silver patch on the abdomen. Sampling pine cones more than quadrupled the number of E. formosa specimens in the Burke spider collection—it was found at 47% of sampling sites!

This was the first study to describe the spider fauna of fallen pine cones and now there are 89 species recorded in our published paper, including two species never found in Washington state before.

Spiders are everywhere—even in pine cones!

Pine cone with spider web, June 22, 2011,
Thirteenmile Creek, Ferry County, Washington.
Photo: Laurel Ramseyer.


To learn which spider species use fallen pine cones, read our study published in Western North American Naturalist (PDF). 

Interested in more about arachnids? Read other Burke blog posts by Rod or check out Rod's Spider Myths website for myths, misconceptions, and superstitions about spiders.