DESCRIPTION. BIOLOGY AND HABITAT:
The spruce-fir moss spider is one of the smallest members of the primitive
suborder of spiders that are popularly referred to as
"tarantulas." Adults of this species measure only 0.10 to 0.15 inch (about the size of a BB). Coloration of the spruce-fir moss
spider ranges from light brown to yellow-brown to a darker reddish brown, and there are no markings on its abdomen.
The spruce-fir moss spider is known only from mature Fraser fir and
red spruce forest communities of the highest elevations of
the Southern Appalachian Mountains in western North Carolina and eastern Tennessee. The typical habitat of this spider is
found in damp, but well-shaded situations within these forests. The moss mats cannot be too dry (the species is very sensitive to
desiccation) or too wet (large drops of water an also pose a treat to the spider). The spider constructs tube-shaped webs in the
interface between the moss mat and rock surface. There is no record of prey having been found in the webs of the spruce-fir
moss spider, nor has the species been observed taking prey in the wild, but the abundant springtails in the moss mats provide
the most likely source of food for the spider.
WHY IS THE SPRUCE-FIR MOSS SPIDER SO RARE?
The primary factor determining the rarity or the spruce-fir moss spider
is its rare habitat, which continues to decline in quality.
Most of its habitat has suffered extensive changes and declines in size and/or vigor during the past century as a result of a
number of factors, including past logging and burning practices, storm damage, and possibly atmosphere pollution. climates
changes, disease, insect damage, exposure shock, and other factors not yet fully understood. The portion of the spruce-fir
forests where the spruce-fir moss spider has been found are dominated by Fraser fir.
In recent years, Fraser fir forests throughout the Southern Appalachian
Mountains have suffered extensive mortality due to
infestation by the balsam wooly adelgid (Adelges piceae), a nonnative insect pest believe to have been introduced into the
United States from Europe. Most mature fraser firs are easily killed by the adelgid, with death occurring within 2 to 7 years of
the initial infestation. The remaining trees become more susceptible to exposure, wind, and storm damage. The death and
thinning of the forest canopy results in locally drastic changes in the microclimate, including increased temperatures and
decreased moisture, leading to the drying of the moss mats on which the spider depends for its survival. The spruce-fir moss
spider is very sensitive to desiccation and requires climates of high and constant humidity. As the mats dry out, so does the
WHY SHOULD WE BE CONCERNED ABOUT THE LOSS OF SPIDERS?
All living things are part of a complex and interconnected
network The removal of a single species can set off a chain reaction
that could affect many other species. Each extinction diminishes the diversity and complexity of life on earth.
Furthermore, wild plants and animals are important to the development
of new and improved medicines, agricultural crops, and
other industrial products. One-quarter of all the prescriptions written in the United States today contain chemicals that were
originally discovered in plants and animals. If these organisms had been destroyed before their values were known, their
secrets would have died with them. When a species is lost, the benefits it might have provided are gone forever.
Venom from spiders is being studied in connection with possible cures
for Alzheimer's and Parkinson's diseases and for
preventing brain damage in stroke patients. Also, studies are currently being conducted to produce commercial quantities of
spider silk. Spider silk is very elastic, twice as strong as steel, and stronger than Kevlar (a material used to make products like
bulletproof vests and knifeproof gloves). The silk has numerous potential industrial, medical, recreational, and defense uses.
WHAT YOU CAN DO TO HELP:
When hiking in the high mountains, tread lightly, stay on designated
trails, and avoid climbing vegetated rocky outcrops and
boulders. The spider and the moss mats it inhabits are very fragile and easily destroyed by human trampling. Only one relatively
stable population of the spruce-fir moss spider is known to survive. This population appears to be restricted to the moss mats
on a single rock outcrop and a few surrounding boulders. Destruction of the moss mats (or even a portion of the mats) or
damage to the surrounding vegetation shading the mats could result in the extinction of this species.
Wild land and the plant and animal life that inhabit unique natural
places are now dependent on us for survival. These natural
places, with their diversity of life, can be enjoyed by and benefit all of us; with our help, they can be there for future