Subject: Re: Spiders

From: Sharon Litton <[email-masked]>
Date: Mon, 16 Sep 1996 12:55:16 -0500

nrichard wrote:
> 
> Hi Brian,
> I saw the same type of spider in my backyard last week, but also have no
> clue as it its identity.  Please post if you find the answer, and I will
> do likewise.

I believe you are both describing the Black-and-Yellow garden spider 
(Arigope aurantia).  From a book, Fieldbook of Natural History, the 
following description:
  Large, black and yellow.  Male about 1/4" long.  Female about 1 in. 
long, with front legs as long as body.  Colored conspicuously, with rear 
of body black, and with bright orange or yellow spots that form a band 
along sides.  Rather closely related to silk spiders, from whose silk, 
cloth has been made.  About 120 American species.  Favors marshes, 
gardens, or tall plants protected from wind.  Webs sometimes found on 
shrubs.

Male and female build similar nests.  Male visits female's nest in fall; 
after mating, female lays eggs in paper cocoon size of hickory nut, 
which is firmly fastened to vegetation.  Eggs hatch in midwinter but 
young remain in cocoon until May.  Mature by midsummer, disappear by 
October.

Remarkable web, sometimes 10 ft across, with ladderlike structure near 
center and shelter web where adult hides.  May add secondary web near 
center.  Can kill large grasshoppers that land in web, by enmeshing in 
silk and then biting.  If frightened, drops to ground and hides in 
vegetation.  Web remarkably strong.

Probably usefule as insect destroyer.  Physics of web worth studying.  
New web usually made each night.  Not all portions of web are sticky, as 
may be discovered easily.  Spider is commonly parasitized by ichneumon 
flies, which may themselves be parasitized.

Additionally, from the National Audubon Society Field Guid to North 
American Insects & Spiders:
  Male 1/4 - 3/8" (5-9 mm), female 3/4 - 1 1/8" (19-28 mm).  
Cephalothorax has short silvery hair.  Leggs black with reddish or 
yellow bands near body.  Abdomen egg-shaped, conspicuously marked with 
yellow or orange on black.

**This is one of my favorite garden spiders, and we have shared gardens 
off and on for many years, in different parts of the US.  They earn 
their keep, have interesting nests, and are fun to watch when you throw 
a grasshopper into their webs!