I put forth the electrical interpretation. See Also: Lichtenberg Figures.

Lichtenberg figures are essentially bottled lightning. IE, they'reformed when a highly bombarded charged object catastrophically discharges electrically. Acrylic lichtenbergs are formed by bombarding acrylic blocks with particle accelerators or other methods of bombarding them with high velocity/energy electrons, which charge the acrylic. Lichtenbergs are formed when that charge is catastrophically discharged, this altering permanently the composition and structure of the acrylic block as the electrons escape the block.

I believe that "spiders" are formed in much the same way as a "charging" interaction between the sun and Mars along field aligned currents (See Also: Birkeland Currents). IE, the electrons are accelerated by the electric field of the birkeland currents and thus charge the pole that the current connects to. At some point, dielectric breakdown occurs and there is a massive electrical discharge, which creates a surface and or subsurface lichtenberg figure. I would not be surprised if we dug up portions of the spiders and found glass lightning (See Also: Fulgurites).

This allso easily explains why the figures congregate near the poles (that where the majority of the charge is acquired and the most massive dielectric breakdowns will occur). If you go to Nasa's Planetary Photojournal, you will see on several planets massive auroras around the poles where the Birkeland currents intersect the planetary magnetic field and covey charge from the sun via said currents. This can be seen on Saturn, Jupiter, Venus has a conventionall "unexplained" double-vortex at the both poles. This is all fairly hefty evidence of electrical charge transfer as outlined in Plasma Cosmology.

Spiders taken individually resemble lichtenberg configurations. Taken as groups they'll tend to clump but still be radially branching, and in areas of extreme discharge you'll get entire fields of overlapping lichtenbergs, to the point of Chaos Terrain. Sometimes you'll even get cratering in the central discharge point of Lichtenberg "spiders". This is not unexpected if a sufficently powerful arc machined the surface (See Also: EDM / Electrical Discharge Machining).

Nasa has also shown images of dust devils schorching the surface of the planet leaving long blackened trails behind them as they wander. They have also FINALLY "discovered" that dust devils display grand electrical characterization, emitting x-rays, the whole 9 yards. I'd say that "dust devils" at the poles would tend to move much less frequently since they're in a more direct discharge exchange pattern with the polar aurora that dust devils further out. So, the "geyser" photos may in fact be "dust devils" misinterpreted. The blackening streaks associated with the region may be due to Dust Devil activity. They seem to be often associated directly with "spiders," but NOT ALWAYS. Some black streaks don't appear to have a massive "spider" formation underneath them. This leads me to believe that the spiders are transiently associated with streaking, and not 100% associated. But the fact that "spiders" often occur overlapping streaks suggests to me that they may be an occasion where the dielectric breakdown moves from slow in the case of dust devils to catastrophic "lightning" discharge...

Well, that's my 2 cents on t he issue. I'm sure everyone has forgotten it by now, yeah?

Well, anyway, my page is at www.myspace.com/mgmirkin look me up. I've been writing a few "interesting" articles on electrical interactions on Earth and in space... I did a write up on the "spiders," or will soon have it finished anyway. It's mostly done.