Many people encounter spiders with distinctive markings and wonder about their identity. A common observation is a spider with a prominent white dot on its back. This article clarifies the identity of such spiders, focusing on their unique features and offering guidance on how to interpret their presence.
Spiders Commonly Identified by a White Dot
The spider most frequently identified by a distinctive white dot on its back is the Bold Jumper, scientifically known as Phidippus audax. This species, part of the jumping spider family (Salticidae), is common across North America, including the United States, Canada, and Mexico. Bold Jumpers are typically black with a stout, hairy body. Their characteristic marking is often a large, triangular white spot located centrally on the abdomen.
Phidippus audax often exhibits two smaller white spots positioned further back on the abdomen. While these spots are usually white in mature spiders, juveniles may display orange or yellowish markings that whiten as they age. Adult females range from 8 to 15 millimeters in body length, and males from 6 to 13 millimeters. The presence and arrangement of these white spots are key features for identifying this species.
Beyond the Dot: Other Identification Clues
Beyond the prominent white dot, several other characteristics aid in identifying the Bold Jumper. These spiders have a robust, compact body with a high, convex cephalothorax, typically larger than their oval-shaped abdomen. Their iridescent chelicerae (mouthparts) can appear metallic green, blue, pink, or purple. Their legs are often banded with white and appear somewhat fuzzy due to short hairs.
Bold Jumpers possess exceptional eyesight, crucial for their hunting style. They have eight eyes, with large, prominent forward-facing anterior median eyes providing excellent stereoscopic vision. Unlike many spiders, Bold Jumpers do not build webs to catch prey; instead, they are active diurnal hunters, stalking and pouncing on insects. They are often found in open areas like grasslands, gardens, and on vertical surfaces, actively searching for prey. They use silk as a safety line when jumping or for creating retreats for shelter or egg sacs.
Encountering These Spiders
When encountering a spider with a white dot, such as a Bold Jumper, remember that most spiders, including this species, are not aggressive towards humans. They are more likely to flee or jump away if approached rather than bite. If a bite does occur, perhaps from accidental mishandling, it is generally considered mildly painful, comparable to a bee sting, and not medically significant. Symptoms are typically limited to localized redness, itching, and swelling, which usually resolve within a day or two.
To relocate a spider from indoors to outdoors, simple, humane methods are effective. The “cup and paper” method involves placing a cup over the spider and then sliding a piece of stiff paper underneath to safely trap it. The spider can then be carried outside and released in a suitable location, such as a garden or shrubbery, where it can find food and shelter. Relocating a Bold Jumper to an outdoor setting is generally appropriate given its natural habitat.