Sunday, February 18, 2007

Does Whatever A Spider Can

After the post on most of the arachnids on the US List, I couldn’t help but look at the non-cave spider. I will get to your suggestions1, but I’m still trying to spread the love to all the taxa2.
Image from Animal Diversity Web
Image from Animal Diversity Web

The Spruce-fir Moss Spider (Microhexura montivaga) is a small (3-5 mm) member of the tarantula group. They live above 5,400 feet in the Appalachian Mountains in North Carolina and Tennessee, where it can get colder and snowier than many spiders mind to handle. The prominent vegetation of these areas (surprise, surprise) is Frasier fir and red spruce, and the spiders inhabit the mosses found in association with those trees.

Like most tarantulas, the moss spider is an ambush predator, feeding on arthropods smaller than itself. This does not mean they don’t make webs; they weave tunnel-shaped nests between the rock and the moss. After mating, the males make a run for it, since many female spiders find the male to be a readily available protein. Females stay with the egg sac until it hatches, and will carry it around if she’s disturbed. When the spiderlings3 hatch, they disperse to other areas by a process called ballooning4, where the babies extend a strand of silk to be caught by the wind.

They’re not terribly sure why the spruce-fir moss spider is endangered, though there are some good ideas. The primary suspect: the balsam wooly adelgid, an invasive insect that attacks fir trees, which mess up the spider’s habitat. There’s a possibility of throwing out the baby with the bathwater, as it’s possible that the insecticide used to kill these tree-borers could also be killing the spiders.

The Louisville Zoo is working on a breeding program, though there are no cute little spiderlings yet. I’m finding enough information that I know someone is worried about the species. Heck, someone even named a debugging program after it.

1I’m really looking forward to learning more about the antelope that looks like something out of Star Wars.
2There are two lichens that I might have to write something about to spread the love even further.
3This is the actual term for a baby spider. Another Cute Endangered Ugly Thing design?
4Popularized by the animated version of Charlotte’s Web.


Greg said...

LOL! Yes, it does kind of look like its from Star Wars.

Zoë B said...

thats a pretty BIG spider...
i am not that of a big spider fan