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How to Identify Yellow-and-Black Spiders

Yellow-and-black spiders in the United States are often referred to as argiopes and have the Latin name Argiope aurantia. Their striking coloration gives them an attractive appearance but also serves as a warning to predators that the spider can cause them harm. Argiopes don't possess dangerous venom but their bite will inflict mild pain on a human. Aside from the yellow-and-black argiope itself, the closely related banded-and-silver argiopes also exhibit some black-and-yellow coloring. Other orb web spiders that sport similar markings make identifying yellow-and-black argiopes more difficult than one might imagine.

Instructions

- 1
  Study the markings of the spider. Yellow-and-black argiopes are normally dominantly black in the center of the abdomen with bright yellow markings around the outside. The head in adults is usually a contrasting white and the curved, long legs red at the top and then black for the greater length. Immature spiders vary considerably, but often exhibit an abundance of yellow all over, which can merge into red. This makes immatures easy to confuse with other orb web spiders, such as neosconas.
- 2
  Consider the size of the creature. Yellow-and-black argiopes are one of the biggest species of spider in the eastern United States, with large females, which are more than twice the size of males, reaching up to an inch in body length. This considerable presence, coupled with their bright markings, make them a familiar garden spider, although they are far from the most common arachnid.
- 3
  Note your location. Yellow-and-black argiopes are most numerous in the eastern and central U.S. from north to south and are particularly uncommon in the Rocky Mountain range and the Great Basin Area of the western U.S. They are happiest in a habitat with leafy, sunny locations blessed with shrubs and tall trees. They are common in gardens. Argiopes in warmer climes may live several years longer than those in temperate areas.
- 4
  Consider the time of year. In temperate areas yellow-and-black argiope eggs hatch in the late summer or fall, but the spiders remain hidden in their egg sacks until late spring. The spiders are seen in their largest numbers during the daytime in spring and early summer, when thousands of young spiders emerge from their dormant state. Their large size means their numbers decrease as summer drags on due to predation from birds and lizards.
- 5
  Observe the spider's web. Argiopes spin nests that are round and flat, as do most orb weaver spiders. Their webs can be 2 feet across and the argiopes hang down in the center, ready to ambush passing aphids, flies and other insects. They can be observed holding their legs together to make it appear they only have four legs. Argiope webs sometimes consist of stabilimenta, which are white zig-zag portions. The reason for these remains unclear.

Insects & Science