Hobo Spider
Introduction
The common name comes from this spider's method of very rapidly expanding its distribution by hitching rides with humans along major highways in the Pacific Northwest.
It formerly was known as the aggressive house spider. Their webs are a nuisance but their bite is of medical importance to both humans and pets because it may result in a
slow-healing lesion. This species was introduced from Europe and first found a Seattle in the 1930's, and currently is common in the Pacific Northwest and British Columbia.
The hobo spider appears to be rapidly expanding its range, displacing many native spiders as it spreads.
Recognition
Adult female body length is about 7/16-5/8 inch including oblong abdomen. Male body length is about 5/16-7/16 inch; total size including legs about 1-3/4 inch in diameter. Color variable
with carapace light to medium brown, with dark stripe to either side of lighter midline stripe, dark stripe with lateral extensions in posterior half; abdomen with interrupted
light midline stripe with about five light colored triangular shaped loops on each side bordered by a dark background but usually first one or two and last two or three loops incomplete,
last two or three loops chevron-shaped with enlarged ends. White on darker dorsal coloration gradually changes to dark blotches on a lighter background on sides and venter; sternum
with light midline stripe and usually solid dark lateral stripe on each side; legs solid light brown, no bands. With eight eyes in two transverse lines/row, front row slightly
covered forward and rear row almost straight. Cephalothorax, abdomen, and legs with plumose hairs. Abdomen with longer posterior spinnerets extending beyond abdomen, visible
from above. Tarsi with three claws each.
Habits
Hobo spiders may be found in almost any habitat containing holes, cracks, or crevices, which can support tunnel formation. Because they are poor climbers, they rarely are
found above ground level. They frequent dark, moist areas, and are most often are found in basements, window wells, and crawl spaces. Common web sites include rock retaining walls,
soil and concrete cracks, the junction of foundations and tall grass, firewood and lumber piles, landscape timbers, stones and rocks partially raised above the ground, etc.
These spiders build funnel webs opening at both ends with one end expanding outward into a broad, slightly curved sheet. Vibrations from struggling prey ensnared on this
sheet alert the spider, which runs out of the funnel, bites the prey, and quickly carries it into the funnel. An escape tunnel commonly is built in the back of the web, which
leads to a deep crack or other protected area.
From late June to October, males extensively wander about seeking a female mate. It is not uncommon for several roving males to enter the ground level of a structure each
day. Immatures wander about in the spring in search of a web site. This wandering tends to bring them into contact with humans. They can be seen moving on floors or trapped
in various objects such as buckets, sinks, bathtubs, open jars, and children's toys. Immatures can be found year-round in basements and garages behind stored items, behind
furniture, under raised baseboard heaters, in closets, etc.
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