EDITOR'S NOTE: Digital photos of black widow and brown 
recluse available from spalmer@clemson.edu.  Photos by 
Dr. Joe Culin.
 

DATE:     10/26/00
WRITER:   Dr. Joe Culin, Clemson Extension entomologist, 
          (864) 656-5041
EDITOR:   Giles Singleton, (864) 656-3876

Spiders, spiders everywhere

     CLEMSON -- At this time of year, spiders seem to appear 
out of nowhere.  We may find ourselves walking into their webs 
at night, and we often see spiders running across the ground, 
and sometimes on our floors. 
     The reason for this seemingly sudden increase in spiders 
is that many of he species in our area spend the winter as eggs, 
or as adults that will lay eggs early in the spring. That means 
most of our spiders are small in the spring, and usually go 
unnoticed.  
     Spiders spend their summer eating a lot of insects and 
growing. As a group, spiders probably consume more pest insects 
than any other group of predators. By early fall, spiders have 
become large adults; this is when we really begin to notice 
them.
     Besides simply being larger, several other factors contribute 
to their increased visibility. One is that adult spiders roam 
around in search of mates and places to lay their eggs, so they 
are more likely to be noticed than immature spiders.
     Two other factors contribute to the increased visibility 
of web-building spiders. One is that adult spiders build much 
larger webs than young spiders. The other is that on cool fall 
mornings dew and fog condense on the,increasing their 
visibility.
     Many people are intimidated by spiders, and some are afraid 
of them. One factor contributing to this is that almost all 
spiders produce venom they use to subdue their prey.
     However, there are only a very few species of spiders in 
South Carolina that can produce harmful bites. Two of these, 
the Writing Spider, or Black & Yellow Garden Spider (Argiope 
aurantia), and the Golden Silk Spider (Nephila clavipes) can 
inflict a painful bite simply because of their large size. 
Both  of these bite only if handled.
     We also have both the Black Widow (Lactrodectus mactans) and 
the Brown Recluse (Loxosceles reclusa).
     Female widow spiders are about 1 to 12 inch long. They are 
shiny black spiders with a red to yellow hourglass-shaped 
marking on the underside of their round abdomens. Some individuals 
also have a row of red dots along the upper surface of the 
abdomen. 
     They build a cob-web type web, usually in a protected area: 
a brush pile, under outdoor stairs, decks, or porches, or in 
a woodpile. Widow spiders are most likely to bite if there are 
eggs present in the web. The bite produces a sharp pain, followed 
by cramps in the large muscles of the legs, chest, and 
abdomen.  Although painful, widow bites are rarely fatal.
     The brown recluse is a small, light brown to yellow, 
harmless looking spider. Its slim body is about 3/8 inch long, 
but its long legs extend its length to more than one inch. 
Brown recluses have a dark brown fiddle-shaped mark on the 
upper surface of their heads. 
     The name "recluse" is fitting for these shy spiders, which 
hide in areas that are rarely disturbed, such as wall voids, 
attics, and the back of closets. They hunt for insect prey at 
night. The bite of the brown recluse is usually painless and 
not noticed until a slow-healing open sore appears. 
     Although recluse bites are not usually fatal, they can 
be disfiguring.
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     If you have gardening questions or comments, write to PSA 
Media Relations, A-101 Poole Agricultural Center, Clemson 
University, Clemson, S.C. 29634-0129. Find other Buds and 
Blooms columns under news releases, at: http://www.clemson.edu/psamedia.
                              END