Sunday, January 25, 2015

23-Dec-2014: Documenting Dutch Cone Spiders

Sample site. Click photos to enlarge.
BREAKING: The Netherlands has cone spiders too!  I've long suspected that if spiders use the fallen cone microhabitat in the USA, they probably use it elsewhere, too.  Because why wouldn't they?  But it was just an untested assumption until a recent trip to the Netherlands, during which I was able to squeeze in a few hours of cone sampling.

Corsican pines dropping open cones on Waalsdorpervlakte
My sampling sites were a pair of neighboring groves of exotic Corsican pine (Pinus nigra var. maritimus), apparently planted mid-20th century.  I wasn't crazy about sampling cones of an introduced species, but these were the pines I had access to, so these were the pines I sampled.

The trees were located on the western boundary of Waalsdorpervlakte, located in Wassenaar, Netherlands (Lat. 52.112532, Long. 4.332721).  The Waalsdorpervlakte is part of the dune complex that lies between The Hague and the North Sea.  In the area where I sampled, the dunes have been stabilized by grass, oaks and poplars in addition to the pines.

The fallen cone microhabitat
The cones I sampled were situated on a thin layer of pine needles over fine sand or on grass topped with some combination of oak leaves, poplar leaves and pine needles.  I collected between 10:45 a.m. and 12:45 p.m. under partly sunny skies, air temp 11-12 C with 25 kph winds from the SSE gusting over 35 kph (The wind was making nearby radio antennae "sing".).

Two spiders from one cone. For scale, the inner diameter
of the vial is 8 mm.
Corsican pine cones may be tiny (~ 5 cm long), but they weren't too small for Dutch spiders!  I tapped 20 cones into an old pillow case (never leave home without your net...) and got 9 spiders.  Two cones contained two spiders each, five cones contained one spider each, and twelve cones contained no spiders.  Cones also often contained fine sand, tiny flying insects, mites, woodlice and the occasional beetle.

Not knowing the local regulations on collecting invertebrates, to say nothing about getting them past airport security and USA customs, I opted to just photo-document the specimens as best I could, then return the live animals to their cones.  This means that I can't be certain of their identities beyond noting the presence of crab spiders and what look like dictynids.  However, it was enough to confirm that there are cone spiders here.  I hope this discovery will inspire local spider enthusiasts to start tapping conifer cones!
Beware armed storks!

Incidentally, although I was collecting in a country where people don’t own guns for self-defense, gunfire serenaded my collecting adventure.  It turns out that there’s a shooting club just down the trail from my collecting site.  Other than that, passers-by were friendly and inquisitive and either understood and accepted my pidgin Dutch explanation of what I was doing, or tactfully retreated from the crazy lady.  Either way, nobody interfered with my work.

Dutch Keywords: spinnen, spin, krabspinnen, Den Haag, dennenboom, Nederland, dennenappel, Meijendel

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