Orb Weaver Identification

Asked December 6, 2017, 2:01 AM EST

Hello, I've found a species of orb weaver at my work in Virginia, MN. She has two pointed sections on the anterior plane of her abdomen and has a legspan of nearly two inches. I kept her in a vivarium since late October since she was right on the main doorway, and she's just laid an egg sac this morning. I was hoping to identify her and figure out how long it would take for her eggs to hatch so I can prepare smaller jars for the spiderlings to ensure as many as possible can be released when it warms in the spring. Would you be able to determine her species from the photos I have? I've included a dorsal, ventral, and silhouette.

St. Louis County Minnesota spider identification orb weaver spider

1 Response

Dear Client,

You are correct as to the family of spider; your spider is an orb weaver spider in the Family Araneidae and it is in the spider genus Araneus. It is most likely Araneus gemmoides more commonly known as a cat-faced orb spider. There is a lot of variability in coloration and in design on the top-side of the abdomen in this species. If you use your imagination, you can see a cat face (for some reason, I see a cougar) on the back of this spider in the center image. The two bumps on the back (the interface between the dark and light colored areas on the spiders back or topside of the abdomen) appear as the cougar's ears. To the right of the ears are two dark spots that appear as the cougar's eyes.

Normally, the female orb spider will lay those eggs in a sheltered area (protected by the cold winter temperatures). Often she will die long before the eggs hatch in the spring, due to starvation, desiccation or cold weather. It may be necessary that the eggs are exposed to outside fluctuations in weather so that the spider eggs are better synchronized with the warming temperatures in the spring; and equally important, synchronized with the emergence of other insects and spiders that can serve as the food source for the newly-hatched cat-faced orb spiderlings. When exposed to room temperatures the egg mass may hatch prematurely and the spiderlings turn towards cannibalization to survive.

Thank you for conserving these insect predators, and good luck in your rearing endeavors.