Yes, spiders eat ants, but most species avoid them. Out of more than 40,000 known spider species, roughly 0.3 percent regularly feed on ants. The rest treat ants as more trouble than they’re worth, and for good reason: ants bite back, spray formic acid, and can summon reinforcements. Still, a small but fascinating group of spiders has evolved specifically to hunt ants, and even some common household spiders will grab a stray ant that wanders into their web.
Why Most Spiders Avoid Ants
Ants are one of the most abundant food sources on the planet, yet the vast majority of spiders ignore them. The reason comes down to risk versus reward. Ants have strong mandibles, chemical defenses like formic acid, and the ability to act collectively. A single ant can release alarm pheromones that recruit dozens of nestmates to attack a predator. For a spider trying to catch a quiet meal, that’s a dangerous gamble.
There’s also the nutritional problem. Ants are tiny, and much of their body is hard exoskeleton with relatively little soft tissue inside. A spider has to eat a lot of ants to get the same caloric payoff as one plump fly or caterpillar. So most spiders simply choose easier, better-defended prey. The small number of species that do specialize in ants have developed remarkable strategies to deal with these challenges.
Spiders That Specialize in Eating Ants
More than 20 species of jumping spiders (family Salticidae) show a strong, experimentally confirmed preference for ants as prey. These include species in the genera Zenodorus, Aelurillus, and Habrocestum. When given a choice between ants and other insects of similar size, these spiders consistently go for the ants.
The zodariid spiders are another major group of ant specialists. The genus Zodarion, found across Europe and Asia, feeds almost exclusively on ants. These spiders hunt on the ground near ant trails, using quick strikes and potent venom tailored to subdue their prey. The entire family Zodariidae, which includes genera like Mallinus, is closely associated with ant predation.
Other spider families with known ant-eating species include cobweb spiders (Theridiidae), crab spiders (Thomisidae), ground spiders (Gnaphosidae), and lynx spiders (Oxyopidae). Some cobweb spiders in the genus Euryopis have a particularly clever method: they throw sticky silk onto ants passing below their web, then hoist the immobilized ant up like a package on a rope.
How Ant-Eating Spiders Hunt
Catching an ant without getting bitten, stung, or sprayed with acid requires specialized tactics. Researchers at the University of Hamburg documented one species that uses an acrobatic two-phase attack. First, the spider attaches a silk line to a tree trunk, then launches itself over the ant’s body, landing on the other side. During that leap, it pulls silk from its spinnerets with its hind legs, attaching the strand to the ant mid-jump. In the second phase, the spider circles the ant, wrapping it further in sticky silk before delivering a venomous bite. The whole sequence is so fast that every successful silk attachment led to a capture. Failures only happened when the ant fell off the tree before the silk made contact.
Other spiders use different approaches. Some zodariid species employ a “stab and release” strategy: they dart in, deliver a quick venomous bite, then retreat and wait for the venom to take effect before the ant can mount a defense. A few species even carry dead ants around. The chemical compounds on the dead ant’s exoskeleton act as a disguise, masking the spider’s own scent so it can approach ant trails without being detected.
Common House Spiders and Ants
You don’t need a specialized ant hunter to see spiders eating ants in your home. Cellar spiders, those leggy, delicate spiders that hang upside down in corners and basements, regularly eat ants along with flies, mosquitoes, and moths. Their messy, irregular webs are surprisingly effective at snagging ants that wander along walls or ceilings. Cobweb spiders commonly found indoors, like species of Steatoda, also catch ants in their webs.
That said, a few house spiders won’t put a dent in an ant colony. Ants reproduce in enormous numbers, and a spider picking off the occasional forager is more of a minor hazard than a population control measure. If you’re seeing lots of ants indoors, the spiders in your corners aren’t going to solve the problem.
Spiders That Pretend to Be Ants
Some spiders have taken the relationship with ants in a completely different direction: instead of eating them, they disguise themselves as ants. The jumping spider genus Myrmarachne includes hundreds of species that look and move like ants. This mimicry isn’t for hunting. It’s for survival. Because most predators avoid ants (they taste bad and fight back), looking like an ant gives these spiders protection.
Harvard researchers used high-speed cameras to study how Myrmarachne formicaria pulls off the disguise. The spiders don’t actually walk on six legs, as scientists had long assumed. They walk on all eight but take tiny pauses, about 100 milliseconds long, to lift their front pair of legs so they resemble antennae. They also weave back and forth as they walk, mimicking the path an ant takes when following a pheromone trail. The visual resemblance isn’t perfect up close, but the movement is convincing enough to fool predators scanning for an easy meal. As one researcher put it, the mimicry doesn’t need to be a perfect reproduction. It just needs to “sow the seeds of doubt.”
This is a useful reminder of how dangerous ants are as prey. The fact that hundreds of spider species have evolved to look like ants, specifically to avoid being eaten by other predators, tells you something about how universally ants are avoided. The small group of spiders that actually hunts them has had to evolve highly specialized tools and behaviors to do it safely.