Jumping spiders can and sometimes will eat dead insects, but they strongly prefer live prey. In the wild, most jumping spiders hunt actively and rely on visual cues to identify something as food. A motionless insect isn’t automatically ignored, but it’s far less likely to trigger the full hunting sequence that leads to a strike.
How Jumping Spiders Find Prey
Jumping spiders have one of the most sophisticated visual systems of any arthropod. Their two large front-facing “principal” eyes handle fine detail and object recognition, while six smaller secondary eyes detect movement across a wide field of vision. When something moves in the periphery, the spider turns to face it, bringing the principal eyes into play to figure out what it’s looking at: prey, a potential mate, or a rival.
Movement is a powerful trigger for this process, but research from the British Arachnological Society found it isn’t strictly necessary. When tested with completely motionless lures shaped like prey, every species in the study occasionally stalked and attacked them. The spiders even showed their normal prey preferences and used prey-specific hunting techniques on the still targets, meaning they can identify what type of prey they’re looking at without any motion at all.
That said, “sometimes” is the key word. A moving insect gets noticed faster, triggers the hunting response more reliably, and is far more likely to be eaten. A dead insect sitting in a corner may go unnoticed for hours or be investigated and then ignored.
Why Live Prey Works Better
Beyond the visual trigger, live prey matters for nutrition and hydration. Jumping spiders are arboreal hunters that get a significant portion of their water from the body fluids of the insects they eat. A freshly caught live insect is full of fluid. A dead insect, especially one that’s been sitting out, dries quickly. The exoskeleton may look intact, but the internal moisture that a spider depends on can be largely gone within hours.
In captivity, even live feeder insects are often dehydrated from poor care, which means they pass along less moisture than a wild-caught meal would. A dead insect that’s been sitting in a dish is significantly worse on this front. If a jumping spider does eat a dried-out dead insect, it’s getting calories but very little water, which can become a problem over time.
Feeding Dead Insects in Captivity
If you keep a jumping spider as a pet, you may wonder whether you can skip live feeders and offer pre-killed or frozen insects instead. Some keepers have had success with this, particularly by using freshly killed insects or placing a dead insect on the tip of a toothpick or tweezers and gently wiggling it. That simulated movement can be enough to catch the spider’s attention and provoke a strike. Once the spider grabs on and bites, it will typically feed normally.
This approach works better with some individual spiders than others. Younger spiders and hungrier spiders tend to be less picky. Some individuals will readily grab a pre-killed fly from tongs, while others will ignore it entirely. If your spider isn’t interested, leaving a freshly killed insect near where it rests can sometimes work, since the research on motionless lures shows they do recognize still prey. But don’t count on it as a reliable feeding method.
A few practical considerations if you go this route:
- Freshness matters. A fly that died minutes ago still has most of its internal fluids. One that’s been dead for a day is significantly less nutritious and less hydrating.
- Simulate movement when possible. Holding a dead insect with soft-tipped tweezers and moving it gently near the spider dramatically increases the chance of a feeding response.
- Provide water separately. Since dead insects are poor sources of hydration, make sure your spider always has access to water. A light misting on the enclosure walls or a small water droplet on a leaf gives them a chance to drink directly.
- Remove uneaten prey. Dead insects left in an enclosure can mold quickly. If your spider doesn’t eat it within a few hours, take it out.
Scavenging in the Wild
Jumping spiders are not natural scavengers. Their entire body plan is built for active hunting: exceptional vision, powerful legs for leaping, and fast-acting venom for subduing live prey. In the wild, they would rarely encounter a conveniently placed dead insect in a context where they’d choose to eat it over hunting something fresh. That said, spiders are opportunistic. A hungry jumping spider that stumbles across a recently dead insect may feed on it, particularly if it still has moisture and hasn’t begun to decompose.
The bottom line is that jumping spiders are capable of recognizing and eating dead insects, but their biology is tuned for live hunting. Dead prey is a fallback, not a preference. If you’re keeping one as a pet, live feeders will always be the most reliable and nutritious option, with freshly killed insects offered via tongs as a workable backup.