Menemerus bivittatus (Gray Wall Jumper)

Summary

The "Gray Wall Jumper," Menemerus bivittatus, is native to the Old World tropics, but has ridden cargo to many other tropical and subtropical places around the globe. It is found from West Virginia south and west to Florida and southern California in the U.S. This species is “sexually dimorphic,” meaning males and females do not look much alike (see images). Look for these little spiders almost exclusively on the exterior walls of buildings here in the U.S. They are active hunters during the day and spend the night hidden away in crevices. They have sharp eyesight, as most jumping spiders do. Prey is mostly small flies that either bask on walls or are attracted to lights at night, but researchers have witnessed this species taking down moths that were easily twice the spider’s weight. They do not spin webs. Mature individuals are most commonly seen during spring and summer. Females of this species are sometimes mistaken for members of the widespread genus Platycryptus.