Bug Blog

The Largest Jumping Spider In The Western US Is Frequently Found In Homes Where They Are Known For Inflicting Tremendously Painful And Potentially Dangerous Bites

Arizona is not the best state for an arachnophobe to call home, as there are well over 1,000 spider species in the southwest, more than 30 of which are tarantulas. While tarantulas may bite if they are mishandled or threatened, their venom is not harmful to humans, but their size and hairy appearance is enough to induce a severe anxiety attack in those who have a fear of arachnids. The western black widow and five recluse spider species (not including the brown recluse) are the only spider species in Arizona that medical professionals consider potentially dangerous, and possibly life-threatening. However, there exists some evidence that several other spider species found in Arizona, particularly yellow-sac spiders, may inflict bites that can lead to serious medical harm, or at the very least, long lasting and intense pain. One of these species, Phidippus johnsoni, is the largest jumping spider species in the western US, and it is known for frequently entering homes where their alluring appearance has been known to draw the attention of curious and handsy young children, leading to frequent bites.

Phidippus johnsoni, is more commonly known as the “Johnson jumping spider,” and the “redback jumping spider.” These spiders are often described as having an aesthetically pleasing appearance due to colorful bodies. The Johnson jumping spider adult is between .27 and half an inch in length, not including their leg span, and both males and females possess a bright red abdomen and iridescent chelicerae, which are arachnid mouthparts that include venom sacs and fangs. These spiders are known for readily biting humans within and around homes, though they are not considered as aggressive, and in most cases, medical intervention is necessary following a bite. Just like wolf spiders, Johnson jumping spiders travel constantly in order to locate insect prey, and they only build webs for storing their eggs. According to a survey of 37 documented Johnson jumping spider sightings, 14 occurred indoors, while the remaining 23 sightings occurred on residential properties. Just as their name suggests, these spiders can jump long distances, and their bites are reported as causing extreme pain that can last four or more days.

Have you ever witnessed a spider jump within your home?