INTRODUCTION
The common names reflect the fact that this is usually the spider
most often encountered indoors. It is a nuisance pest, probably
more because of its webs than the spider itself. This spider is
found worldwide and is common throughout the United States and
Canada
RECOGNITION
Adult female body length about 3/16-5/16" (5-8 mm) including an
almost spherical abdomen, male body length about 1/8-3/16" (3.8-4.7
mm) including an elongated abdomen. Color highly variable with
carapace (cephalothorax dorsum) yellowish brown; abdomen dirty
white with a few dark spots (sometimes with a black triangular
spot in center of dorsum) to almost black, with several dark stripes
meeting at angle medially(=chevrons/"army sergeant stripes") above
tip of abdomen; legs orange in male but yellow in female, with
dusky ring at end of each segment (=banded). With 8 eyes, 2 lateral
pairs almost touching. Last tarsal segment of 4th pair of legs
with row/comb of serrated bristles on venter; all tarsi with 3
claws each.
SIMILAR
GROUPS
(1) Other Achaearanea spp. lack chevrons on abdomen. (2) Other
spiders lack comb of serrated bristles on last tarsal segment
of 4th pair of legs and 8 eyes with 2 lateral pairs almost touching.
BIOLOGY
Female house spiders lay about 250 eggs (range 132-442) in a silken
sac which is brownish, oval to flask-shaped, about 1-4-3/8" (6-9
mm) in diameter, and with a tough, papery cover. There may be
more than one sac in the web at a time; a female may produce up
to 17 sacs, containing over 3,760 eggs, in her lifetime. The sacs
are usually located in the center of the web but may be moved
to warmer or cooler sites as required. The eggs hatch in about
7-10 days but the 1st instar spiderlings remain in the sac until
they molt once. The 2nd instar spiderlings then emerge and balloon.
Females molt 7 times and males 6 to 7 times to reach maturity.
Adults may live for year or more.
HABITS
The house spider randomly selects its web sites. If a web does
not yield prey (food) it is abandoned, another site is selected,
and a new web built. Eventually, successful webs are constructed
where air currents bring in prey. Survival is low in modern homes
with low humidity and few insects, higher in garages, sheds, barns,
warehouses, etc. because of more prey and generally higher humidity,
and highest outdoors in protected places. Inside structures, house
spiders are most likely to be found in upper corners, under furniture,
in closets, angles of window frames, basements, garages, and crawl
spaces. In warehouses, they are common in corners near doors that
stay open. Outside, they are often around windows and under eaves
especially near light sources which attract prey. Because of their
web site selection by trial and error, many webs may be constructed
in several days. Dust collecting on these webs accentuates their
presence. This situation is unacceptable in most households, offices,
food processing plants, ect
CONTROL
Follow the standard control procedures for spiders as outlined
in the introductory section. Use a vacuum to remove adults, egg
sacs, and webs. If a broom is used, adults usually escape unless
they are first individually treated with a nonresidual contact
pesticide; this can leave marks or dirt/dust on the wall and ceiling
surfaces. |