https://digital.tnconservationist.org/publication/?i=663361&article_id=3697028&view=articleBrowser The Tennessee Conservationist - Jul/Aug 2020 Jumping Spiders Jackson Gibson and Steve Murphree 2020-06-17 14:41:00 A closeup image of a species in the genus Pelegrinis A closeup image of a species in the genus Pelegrinis "Spiders that jump? Will they jump towards me?" The answer is "not likely" since these spiders will jump away using a dragline of silk if you get too close. If you disturb one at eye level, its jump to escape makes it look like a tiny, furry bungee jumper. Although most jumping spiders attempt to flee, some may display the intriguing behavior of turning to look at observers, even following our movement and coming closer for a better look. This is why these spiders are a favorite subject of close-up nature photographers. Jumping spiders are true spiders belonging to the family Salticidae. This name comes from the Latin "salto" meaning to jump or to dance with pantomimic gestures, the latter referring to their courtship dances. Salticidae is the most bio-diverse family of spiders, with nearly 6,000 species and just over 300 species known from North America north of Mexico. They are rather small critters (most are less than one half inch in length) with short, stout legs. We see these spiders quite often since, unlike most spiders, they are diurnal, or active during the day, and found in open areas where they are easily spotted. These spiders occur in such abundance and variety that many of the photos with this article were taken in one of the authors' half-acre suburban yard! The most commonly seen jumping spider in Tennessee is the daring Phidippus audax, often found in our yards and gardens. This spider has iridescent scales on its fangs and a white-to-orange spot on top of its abdomen. Jumping spiders, like all spiders, are predators with venom in a pair of fangs, or chelicerae, at the front of their bodies. They have the greatest visual acuity of all spiders. Salticids hunt their insects and other prey by stalking. This is followed by a sudden jump to accurately land on their victims and inject venom. Their behavior is quite reminiscent of cats, but rather than play with their prey, all spiders inject enzymes and then suck out a "prey milkshake." A male Phidippus whitmani, a mimic of velvet ants. These spiders hunt during daylight hours. They can be recognized by their distinctive arrangement of eyes. Like most spiders, they possess eight eyes but the two middle eyes in the front row are huge and cartoonish. These two eyes function like miniature telephoto lenses. One author of this article, in an attempt to reduce his college students' fear of spiders, proclaims that salticids are "as cute as teddy bears" due to the disarming appearance of their eyes, as well as their compact shape. Arachnologists now think that the eight simple eyes of salticids are superior to the two compound eyes of insects. Because salticids hunt during the day, they also possess color vision, which is important in their courtship displays. Though all spiders produce and use silk, salticids do not construct webs but do construct small, silken retreats, sometimes referred to as "pup tents" of their silk. Jumping spiders like to build their homes under bark, between stones, or in any small area of the right size so they can rest during the night, hibernate, and shed their exoskeletons. It is possible that you have discovered a jumping spider when its retreat was mistaken for an egg sac. Salticids are most active on sunny days, when their color vision works best, choosing to remain in their retreats during cloudy or rainy days. The second important use for their silk is to make draglines. Draglines are the most important tool of jumping spiders. When you see a jumping spider you are also likely to see a silk line running from its spinnerets and attached to a substrate. Draglines assist in hunting, escaping, and other types of locomotion. One of the most prominent functions of a dragline is to act as an anchor in case a spider needs to jump away from danger; in this case the dragline keeps the spider from descending too far or into further danger. A female emerald jumping spider, Paraphidippus aurantis, on an author's hand. Draglines also help spiders as they jump towards prey, acting as a stabilizer for the spider as it flies through the air. Additionally, the dragline allows the spider to slow itself down in midair so it does not miss its target. Perhaps most relatable for those of us who are clumsy, the dragline allows a spider that misses its landing a way to climb back to its starting position. This ability to tether itself to its starting location is also important when a spider senses that it has "made a mistake" in its choice of a landing area. Finally, salticids can also use their silk to travel distances further than they can jump. To achieve this, a jumping spider will climb to a high point, stick its spinnerets into the wind and allow its silk to be carried by the wind until the free end lands on a distant object; at this point the spider crawls across the silk line to its new destination. This is similar to the ballooning "flight" behavior that spiderlings use to disperse after leaving their mother's egg sac. Though surprisingly little is known about the effects of the venoms of common spider species, it is known that the venom of a few salticid species contains cytotoxins which can cause necrotic lesions that are slow to heal. The venom of a bright red species, Phidippus johnsoni, can cause a dull throbbing pain that can persist for a few hours, and the bite site can remain swollen and tender for up to four days. A closeup view of Phidippus clarus. Mimicry and crypsis/camouflage are both common among the species found in North America. During a Tennessee Naturalist Program class at Cedars of Lebanon State Park in 2019, one author of this article showed a jumping spider to his students. It was such a good mimic of carpenter ants that he first thought he had collected an ant on his beat sheet! These salticids have thin legs and a constricted waist, just like an ant. Even their behavior supports this deception since these spiders run in a jerky fashion and wave their first pair of legs like ant antennae. Why look and act like an ant? This affords protection from birds and other predators. Other species blend in to tree bark, or resemble leaf litter so well that they are difficult to discover until they move. Some jumping spiders resemble velvet ants, with contrasting colors signifying warning. Other species' gaudy colors get both our attention as well as that of potential mates. Salticid courtship behaviors can be quite complex, with males, the primary actors, giving the appearance of a flagman at the airport as they wave their second pair of appendages, the pedipalps, in a ritualized fashion. Some species such as the emerald jumper, Paraphidippus aurantius, take bright colors to the next level by flashing iridescent hairs that change color depending on how they reflect light. You may want to place a mirror a few inches in front of a male jumping spider and observe its behavior. (Interestingly, one fruit fly species, the snowberry fly, is protected from predation by salticids because it has a striped wing pattern resembling the legs of jumping spiders.) Note the iridescent scales on the fangs of this female daring jumping spider, Phidippus audax. Perhaps the gaudiest of all salticid displays is that of the Australian peacock spider, whose Internet videos are interesting. Of course, if males do not "get it right" they end up getting pounced upon and eaten by females. If jumping spiders could have nightmares, they would dream about the spider wasp, Agenioideus cinctellus, a salticid hunter which, like other spider wasp species, paralyzes it prey and buries it alive in a burrow where its larvae later feast upon the still-alive victim. How do you determine if a spider is male or female? For some species such as the emerald jumper, it can be easy because the species is sexually dimorphic, meaning that males and females have different characteristics, to the point that the casual observer might think they are two different species. A species in the genus Platycryptus, seen on the chain link of a fence included for scale. Females have large abdomens and are colored shades of brown with bright green iridescence. Males have very slim abdomens, are black with two white stripes running down their body and have only a few iridescent green setae. Most other jumping spider species native to Tennessee, such as the bold jumper, have no major differences, except that the pedipalps of mature males appear swollen and are used in courtship and mating. Also, females are commonly larger than their male counterparts, especially while pregnant, with their larger, rounder abdomens. Phidippus putnami has the best of both worlds. Males and females of this species look identical until the male molts its final exoskeleton. After molting, the male's normal camouflage pattern of browns and tans changes to a vibrant blue head with orange under its eyes and tan patterns running down its legs and over its fangs, making it resemble a human skeleton. A species in the genus Platycryptus is perched on a grape shown for scale. Though small in size, jumping spiders are among the most charismatic of the arthropods. They play an important role in the natural world. Like so many arthropod groups, the more one learns about them, the more fascinating and less intimidating they become. Most importantly, their abundance and variety makes jumping spiders an ideal aspect of nature to keep an eye out for, whether during a hike or just taking a walk around the yard. To see images of North American salticids, visit bugguide.net/node/ view/1962. A video of a male bold jumper can be found at youtube.com/ watch?v=1560DOYU_AY. --------------------------------------------------------------------- (Jackson Gibson works for Tennessee State Parks as a member of the parks education team. He has been a seasonal interpreter for Old Stone Fort State Park and for Cedars of Lebanon State Park. Steve Murphree is an entomologist and professor of biology at Belmont University. He has authored or co-authored several articles about Tennessee's arthropods, particularly those of public health importance.) (c)The Tennessee Conservationist. View All Articles. 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