Nursery Web Spiders (Pisauridae)
Spider Clip Art
Types of Spiders
The family Pisauridae, or Nursery Web spiders, get their name from their child rearing practices.
As the top picture shows, females initially carry their egg sac in their jaws. Prior to the birth of spiderlings, she builds a web nest in brushy areas in order to protect the egg sac and young spiderlings.
Three genera of Nursery Web spiders live in the United States: Dolomedes (more commonly called fishing spiders); Pisaurina and Tinus.
Fishing spiders, engineering marvels as well as a feared predators, rely on neither a ground nor a web based hunting strategy.
The six-spotted fishing spider (Dolomedes triton) in the picture two, sitting on a rock near a big puddle, for example, watches for appropriate prey (insects, minnows etc., al) either landing on the top of, or immediately below the water surface.
Once spotted, the spider darts out onto the water to grab the prey. They can literally swim, or as some prefer, walk on water, to reach it.
The spider's larger than average size, stripes and spots makes for easy field identification.
Different fishing spider species populate different regions of the United States.
The gray colored spider in picture three possibly shows another common fishing spider in the United States, dolomedes tenebrosus.
Pisauridae species often grow to a fairly large size, with the body reaching one inch in length, or more. The addition of the legs can add another inch or so to the spider's total length.
Nursery web spiders and wolf spiders often look similar, and their identification can be confusing. While females of both species carry egg sacs, the female wolf spider carries her egg sac on the back of the abdomen, attached to the spinnerets. When the spiderlings hatch they piggyback on the mother until they are ready to go it alone.
Thanks to JL in Ohio for the great picture of a species in the Pisaurina genus.
© 2005-2011 Patricia A. Michaels