Most adult jumping spiders do well eating about twice a week, or roughly every three to four days. Spiderlings need food much more often, sometimes daily. But the single best indicator of when to feed isn’t a calendar. It’s your spider’s abdomen.
Feeding by Life Stage
Baby jumping spiders (slings) have fast metabolisms and small energy reserves. Offer them two to three small fruit flies per day. At this stage, fruit flies from a culture pot are the right size and the easiest prey to source. As the spiderling grows and its abdomen reaches the size of a curly wing fly or green bottle fly, you can graduate to larger prey and start spacing meals further apart.
Subadults, roughly the teenage stage, typically eat about once a week. Adults can go even longer between meals. Most keepers offer food every three to four days, which works out to about twice a week. Some adult spiders will refuse food for a week or more, especially females sitting on an egg sac. This is normal and not a reason to worry.
Use the Abdomen as Your Guide
Rather than sticking rigidly to a schedule, watch the size and shape of your spider’s abdomen (the rounded back section of its body). A healthy, well-fed jumping spider has a plump but not overly tight abdomen. If it looks shrunken or noticeably smaller than the front half of the body, your spider is hungry. If the skin looks stretched tight, like a balloon about to pop, skip a meal or two.
This visual check matters more than any fixed number of days because individual spiders vary. A smaller species burns through a meal faster than a large regal jumping spider. A spider kept in a warmer room metabolizes food more quickly than one in a cooler space. Research on spider metabolism confirms that metabolic rate rises with temperature in the 10 to 30°C range, so a spider in a warm room will genuinely need food sooner.
What Happens if You Overfeed
Overfeeding is a real risk, not just a cosmetic one. A spider carrying too much weight in its abdomen can experience abdominal separation, where the plates of the exoskeleton pull apart. The extra bulk also makes falls more dangerous (jumping spiders climb a lot, and falls happen) and can make it harder for the spider to grip the walls of its enclosure. Over time, consistently overfeeding shortens a spider’s lifespan.
If your spider’s abdomen ever looks uncomfortably round after a meal, simply wait longer before offering the next one. They are naturally adapted to inconsistent food supplies. Going a few extra days without eating is far safer than eating too much.
What to Feed
Variety keeps your spider healthy. Good staple prey includes fruit flies (for slings and small juveniles), curly wing flies, house flies, green bottles, and blue bottles (for subadults and adults). Small crickets and locusts also work well. Prey should be roughly 50 to 80 percent of your spider’s body length. Anything much larger than the spider itself will usually be ignored, and prey that’s too big can injure a small spider.
Mealworms and waxworms are high in fat and should be occasional treats, not staples. Waxworms are especially useful right after a molt, when a spider needs to replenish energy quickly. Avoid leaving crickets or mealworms loose in the enclosure for long periods. Both are omnivorous and can bite or harass a resting spider, especially one that’s about to molt.
Feeding Around Molts
Jumping spiders stop eating before a molt. You’ll notice your spider retreating into a web hammock and refusing food. This is your cue to stop offering prey and, critically, to remove any live insects from the enclosure. A molting spider is soft and defenseless, and a cricket left inside can seriously injure or kill it.
After the molt, your spider needs time for its new exoskeleton to harden. This takes anywhere from a few days to over a week. During this period, the spider’s mouthparts are too soft to eat. Wait until it leaves its web hammock on its own before offering food. If your spider molted outside of a hammock (which sometimes happens), try offering a small fly about 24 hours after the molt. If the spider avoids it, wait another 24 hours and try again.
Water Matters More Than Food
Jumping spiders can go a week or more without food, but they need fresh water every single day. Mist the enclosure lightly once or twice daily with a fine spray bottle. The spider will drink droplets off the walls and web, and the misting also raises humidity, which is important for healthy molts. If you’re going out of town, skipping a few feedings is fine, but arrange for someone to mist the enclosure daily while you’re away.
Quick Reference by Age
- Slings: 2 to 3 small fruit flies per day
- Juveniles (growing but not yet subadult): A fly or small insect every 2 to 3 days
- Subadults: One appropriately sized prey item every 5 to 7 days
- Adults: One prey item every 3 to 4 days, or twice a week
These are starting points. Always adjust based on your spider’s abdomen size, activity level, and whether it’s approaching a molt. A spider that refuses food is almost always telling you something useful: it’s full, it’s about to molt, or it’s not interested in that particular prey item. Try a different feeder insect before assuming something is wrong.