Black and Yellow Garden Spiders

     Living throughout much of the United Sates, female black and yellow garden spiders are most prevalent and seen by most people in southeastern Pennsylvania during late summer and into autumn when they are grown up and large.  Their bodies alone are about an inch long and their legs make them look even larger.  And, not only are they large for spiders in this area, but also quite striking in color patterns.  They have rounded, black abdomens, marked with white and yellow, "furry", light-gray cephalothoraxes (head and thorax joined together) and black legs with red on each one near the cephalothorax.      
     During summer, female garden spiders in southeastern Pennsylvania make their circular, two-feet-across webs on tall plants and shrubbery in sunny, overgrown abandoned fields, roadsides and gardens, all human-made places where they are easily seen by many people, if those folks look for them a little.  Each web has a vertical, zig-zag line of denser silk down the middle of the main web.  That more obvious, wiggly line of silk may be there to warn birds and other creatures of the presence of the web so they don't crash into it and ruin it for the spider. 
     Each female garden spider occupies the middle of her web, head down, as she waits for invertebrates of various kinds to blunder into it and become snared.  When an insect becomes entangled in her web, the owner runs across the web and injects venom into the victim, which paralyzes it.  That venom is harmless to people, by the way.  Then the spider wraps the prey in more silk and preserves it for a future meal of sucking out the victim's bodily juices.  If, however, the spider is disturbed by an animal larger than she can handle, she drops from her web and hides among foliage until the potential danger is past.
     Male garden spiders' bodies are a quarter inch long.  Each one of them finds a female and makes his smaller web adjacent to or near the female's web.  The male courts his female, but always has a drop line of silk ready in case she tries to eat him.  If the courtship goes well, the spider pair mates and the male soon dies. 
     The female spider produces a few tough, one-inch egg sacs with hundreds of eggs in each one and adheres each sac to the middle of her web.  She defends those egg sacs as long as she can, but becomes weaker as the cold of fall increases.  Each female garden spider is killed by the first heavy frost of autumn, sometime in late October in this region.   
     The tiny young hatch in their sac, but remain in it through winter.  They next spring they exit their sac and venture into the world.  Some remain in nearby vegetation, but others spin a thin web that carries them away on the wind.  Eventually, some of them land in favorable areas, and grow and reproduce.  This species is spread rapidly by that method.
     Female black and yellow garden spiders are large, beautiful spiders that are harmless to us and consume some insects.  But I think their greatest value to us is in their striking black, white and yellow abdomens and just their mere intriguing presence in human-made habitats.  But remember, they are most visible to us late in summer and into fall.