Jumping spiders (family Salticidae) are renowned for their acute vision and agile hunting techniques, relying on stealth and powerful leaps to capture prey. Their diets are diverse. While most spiders actively avoid aggressive and well-defended ants, some specialized jumping spiders target them as a consistent food source.
The Direct Answer: Ant Consumption in Salticidae
Ants are an abundant, protein-rich resource, but they pose a considerable risk to most arthropod predators. Most jumping spiders are generalist hunters. However, many species in the Salticidae family are known to be myrmecophagic, meaning they actively incorporate ants into their diet. This predation is not universal, as many common jumping spiders avoid ants entirely.
Specialized ant-eating species are motivated by the high nutritional value and low competition for this prey item. Ants possess formidable defenses, including powerful mandibles, stings, and chemical sprays, making them difficult targets. Despite these risks, certain genera have adapted their behavior and anatomy to capitalize on the sheer number of ants available.
The twin-flagged jumping spider, Anasaitis canosa, demonstrates a strong preference for ants when given a choice. These spiders have developed distinct hunting routines that differ completely from how they approach less hazardous prey. This specialization requires unique tactical measures to secure the meal, though ants are not their exclusive food source.
Specialized Predators: Ant-Mimicking Spiders
A different group of jumping spiders has evolved to resemble ants for defensive reasons, a phenomenon known as myrmecomorphy, or ant-mimicry. This adaptation is a form of Batesian mimicry, where a harmless species imitates a dangerous one to deter shared predators. Visual predators, such as birds and wasps, avoid ants due to their aggressive defense mechanisms. By looking like an ant, the spider gains protection.
Ant-mimicking spiders, such as those in the genus Myrmarachne, display remarkable physical and behavioral changes for this deception. Physically, their bodies are elongated and constricted to create the illusion of the ant’s three distinct body segments. They also possess specific colorations and patterns that closely match the particular ant species they live alongside.
Behavioral mimicry is essential since spiders normally walk on eight legs. These mimics hold their first pair of legs aloft and wave them to simulate ant antennae. Studies show they walk using all eight legs but incorporate rapid pauses to lift the forelegs, maintaining the illusion of six walking legs and two antennae. Their walking paths are often winding and erratic, resembling an ant following a chemical pheromone trail.
Overcoming Ant Defenses
For the specialized ant-eating spiders, the mechanics of a successful, fast attack are paramount. They must overcome the ant’s defenses before the prey can bite, sting, or release alarm pheromones that would summon dozens of nestmates. The challenge involves neutralizing the ant swiftly and avoiding its immediate chemical or physical counterattack.
The species Anasaitis canosa utilizes a highly specific and effective ambush tactic. The spider carefully maneuvers to the front of the ant before leaping directly onto the victim’s head or the dorsal side of its alitrunk. This attack angle prevents the ant from effectively using its mandibles or sting against the spider’s body.
Upon securing this vulnerable spot, the spider delivers a quick, paralyzing venom injection. The speed and potency of the venom are paramount to success, allowing the predator to subdue the ant almost instantly. This rapid immobilization ensures the ant cannot release chemical signals that would trigger a swarm response. Ant-eating species show a significantly higher survival rate in encounters with ants, confirming the effectiveness of their refined hunting strategies.