Jumping spiders are mighty predators of small insects and invertebrates. However, they are tiny animals, even in comparison to other spiders; the largest species commonly found in the United States, Phidippus regius (regal jumper) is only about the size of a quarter. Most creatures in the natural world – even the most powerful predators – serve as prey for something else and jumping spiders are no exception.
This post is the last in a series about jumping spiders and focuses on the second of the two roles jumping spiders play in their niche; that of prey.
Also known as “salticid spiders” or “salticids”, jumping spiders use their excellent vision and jumping ability to spot, stalk, and attack their insect prey. But sometimes, even a jumping spider’s impressive abilities aren’t enough to save it from becoming something’s next meal.
Jumping spiders are hunted by birds, wasps, reptiles and other spiders, including individuals of the same species, and are vulnerable at every age.
Jumping spiders leverage two main, advanced skills in their day to day lives; incredible vision and the ability to jump great distances relative to their size. Both of these skills are discussed in detail in previous posts in this series (check them out here “Jumping Spiders #2 – A look at their incredible vision” and “Jumping Spiders #3 – A detailed look at a special skill: Jumping“) and represent their major defenses against predation.
Predation requires close contact between the predator and its prey; no predator on earth can simply will its prey to keel over and die from a distance. A predator must physically connect with its victim in order to bite, strangle, poison, drown, or otherwise kill it.
Thanks to the unique arrangement and function of their eight eyes, salticid spiders are hyper-alert to movement in their environment and visually assess anything that catches their attention. If all goes well, they spot predators approaching and either run for cover or leap out of range before the predators can physically close on them.
With these special skills, how do predators ever succeed in catching jumping spiders? The answer lies in the fact that every strategic advantage can become a disadvantage in certain circumstances.
First, jumping spiders are diurnal animals; they are active during the day and hide under loose bark, under leaves, and sometimes in special silken shelters at night. This lifestyle makes them visible to any other creature that hunts by day; without cover of darkness, salticids are easily spotted and tracked, despite being moving targets.
Second, jumping spiders’ vision is adapted for the bright light of day, when there is high contrast between light, shadow, and colors. They see less well at night when colors are washed out, contrast is reduced, and there is minimal light. Nocturnal predators who either see well in low light or use other senses to locate prey can sneak up on them.
Third, hunkering in constrained areas at night limits the spiders’ escape routes; they have less space in which to jump away to safety so become stationary targets and easily trapped.
Fourth, jumping spiders are arthropods and sensitive to environmental temperatures. This is another reason they are well adapted to a day-based lifestyle; day time temperatures are warmer so the spiders can move faster. Cool temperatures slow them down; they can’t react as quickly, run as fast, or jump as far when they are too cold and predators hunting at night can capitalize on this.
Jumping spiders have exceptional peripheral and central vision thanks to the unique arrangement of their eyes, which are spread out around their cephalothoraxes. But the secondary eyes that see to the sides and behind the spider sense movement only and the primary eyes that see colors, details, and judge distances are restricted to a small field of view directly in front to the spiders.
Since jumping spiders rely on movement to warn of approaching predators behind or to the side of themselves, they risk overlooking a looming predator if it stays still. Some predators remain motionless until prey wanders within striking range. A jumping spider may back too close to a lurking predator they don’t even notice until it is too late.
In addition to avoiding attack by spotting danger and fleeing, jumping spiders can defend themselves by biting an attacker with their fangs and injecting venom. This can be a successful strategy because their venom is powerful enough that jumping spiders can routinely kill prey larger than themselves. But a spider’s fangs are on the front of its cephalothorax; any attacker positioned towards the rear or attacking from above would be out of reach.
Some salticids have evolved another defensive strategy as well – hiding in plain sight by mimicking dangerous animals such as ants. Many predators avoid attacking ants, either because of instinct or experience; these jumping spiders gain protection by pretending to be more dangerous than they are.
Species in the Sarinda, Syngales, and Peckhamia genuses are especially good ant impersonators. They hold their front legs over their heads to mimic antennae, they move in fits and starts like ants, and some of them even look like they have three body segments instead of just two (Bradley 2012).
However, this strategy can backfire since ants and some wasps are social creatures which evolved the means to identify intruders and are themselves powerful predators. Salticids who pose as these animals risk being attacked by the very creatures they are mimicking.
Jumping spiders are also at risk of being attacked by members of their own species.
Spiders are voracious predators and are not above attacking their fellow arachnids. Some jumping spider species prefer hunting other spiders; others attack any likely creature they find.
Regardless of how it happens, jumping spiders are always at risk of being preyed upon by their fellow arachnids, including fellow jumping spiders.
Size plays an important role in spider-against-spider predation. Jumping spiders are powerful for their size and consider anything smaller than themselves as potential prey; this includes other spiders. Jumping spiders within the same species vary in size for two reasons; age and sex. Younger spiders are smaller than more mature ones and males are smaller than females.
When salticids of the same sex meet, they visually size each other up. If one is significantly larger than the other, the smaller spider may flee. But competition for dominance is fierce in the natural world, even at the small scale of jumping spiders, so actual fights happen. When they do, the losing spider must escape quickly or risk becoming a meal for the winner.
The same risk applies when it comes time to mate. Females have the immediate advantage over males because they are larger and thus more dangerous; a female may just as easily view an approaching male as a delicious meal as a sexual partner. But females need males to breed and perpetuate the species. So a female jumping spider can be persuaded to mate – if she decides the approaching male is worthy.
Male jumping spiders search for females with whom to mate; females wait for males to present themselves. Once a male finds a female, he must convince her that he is physically fit and reproductively viable.
Spiders use many strategies to accomplish this; depending on the species, these may include sending chemical, vibrational, and visual signals. Because jumping spiders have such good vision, their techniques rely heavily on visual communication.
To learn how a less visually advanced spider species handles the tricky aspects of mating with a predatory member of the opposite sex, check out the post “What are wolf spiders?“.
Female jumping spiders are drab and inconspicuous while male jumping spiders are boldly colored and highly visible.
For example, Phidippus clarus is a species of jumping spider found in habitats with lots of low vegetation, like old fields and thickets. The females can be nearly double the size of the males, at approximately 8–10 mm (0.3–0.4 in) to the males’ 5-7 mm (0.2-0.3 in) and are tan or rusty red with iridescent green chelicerae (the thick appendages on the front of the spiders’ cephalothoraxes that end in their fangs).
Males also have iridescent green chelicerae but are jet black. Their abdomens are striped in bright red and ringed in white and their legs are fringed with fine black and white hairs.
Color pigments are contained in the thin, outer layer of a spider’s body called the cuticle (Taylor 2011). The cuticle can be scuffed or damaged as the spider ages, dulling the colors. Females are easily able to distinguish bright versus dull colors from a distance and brightly colored males are more attractive.
Male jumping spiders twitch their abdomens, wave their legs in the air, and bounce their bodies up and down to entice the females to mate with them. Females favor males who put on the most vigorous and sustained shows.
As the interaction continues, the male salticid gradually moves closer and if all goes well, the two mate. But he must be on guard for signs that the female disapproves of his courtship. If he sees one, he must retreat quickly or risk being leaped upon and killed.
Once mating occurs, the female lays her eggs in a silk cocoon which she guards until the spiderlings hatch. But her defense is not impenetrable. She can die before the eggs hatch, predators like ants can overrun the nest and carry the eggs off and parasites like mites can sneak into the cocoon and wreak destruction. Some jumping spider species lay their eggs in existing nests. The interloper eggs hatch first and the spiderlings attack the host female’s babies as they emerge.
Jumping spiders face many threats in their day to day lives. They evolved fabulous abilities over millions of years that help them survive but they can be tricked, surprised, or trapped. And sometimes the greatest danger they face comes from their fellow spiders.
Classification of jumping spiders
Related Now I Wonder Posts
For more information about spiders, check out these other Now I Wonder posts:
- What are wolf spiders?
- Jumping Spiders #1 – An Introduction
- Jumping Spiders #2 – A look at their incredible vision
- Jumping Spiders #3 – A detailed look at a special skill: Jumping
- Jumping Spiders #4 – As Predators
- Are spiders bugs?
- Do spiders have teeth?
- Do spiders have blood?
For more information about spider relatives in class Arachnida, check out these other Now I Wonder posts:
Bradley, Richard A. 2012. Common Spiders of North America. Berkeley: University of California Press.
Taylor LA, Clark DL, Mcgraw KJ. 2011. Condition dependence of male display coloration in a jumping spider (habronattus pyrrithrix). Behav Ecol Sociobiol. 65(5):1133-46. Available at: https://doi.org/10.1007/s00265-010-1127-5