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The wrong feeder at the wrong size does not just go uneaten. A large cricket left overnight with a molting spider is not a feeding strategy: it is a hazard. A waxworm fed daily to a juvenile becomes an addiction that makes the spider refuse everything nutritious. This guide covers every feeder worth knowing, ranked by life stage, with sizing rules and gut-loading specifics so you never have to guess.
Key Takeaways
- The universal sizing rule: prey body length should be no longer than the spider’s abdomen width. Not body length, not leg span: abdomen width.
- Fruit flies (D. melanogaster for slings, D. hydei for juveniles) are the backbone of the early diet
- Bottle flies are the best adult staple: high protein, low fat, and their movement triggers hunt drive immediately
- Dubia roach nymphs are the most nutritionally complete feeder for adults willing to take them
- Crickets are manageable when small but require supervision at every feeding; never leave them overnight
- Waxworms are junk food: useful once post-molt, not as a staple at any stage
- Never feed wild-caught insects: pesticide and parasite risk is real, not theoretical
- Gut-load for 24 hours minimum before any feeding; dubia roaches need 3 full days
What Can You Feed a Jumping Spider?
Jumping spiders eat live invertebrates. The best feeder insects for pet jumping spiders are flightless fruit flies, bottle flies, house flies, small dubia roach nymphs, small crickets, bean beetles, mealworms, and waxworms. Match prey size to the spider’s abdomen width and rotate feeders across a few types for balanced nutrition.
The one exception to “live only”: mealworms should have their heads pinched before offering, because the mandibles can injure a spider that does not dispatch prey cleanly.
Feeder Comparison Table
| Feeder | Size | Protein | Fat | Availability | Gut-load | Best life stage | Notes |
|---|---|---|---|---|---|---|---|
| D. melanogaster | 2-3 mm | Medium | Low | Easy | 24 hr | Spiderlings | Slow-moving; safest sling feeder |
| D. hydei | 3-4 mm | Medium | Low | Easy | 24 hr | Juveniles | Bridges slings to bottle flies |
| Bean beetle | 3-4 mm | Medium | Medium | Moderate | Minimal | Spiderlings, juveniles | Walks, does not fly |
| House fly | 6-7 mm | High | Low | Easy | 24 hr | Juveniles (larger), adults | Active; good mid-size transition |
| Bottle fly pupae | 8-12 mm | High | Low | Easy (online) | 24 hr | Adults | Best adult staple; erratic movement |
| Pinhead cricket | 2-4 mm | High | Low | Easy | 24-48 hr | Juveniles | Supervise every feeding |
| Dubia roach nymphs | 6-25 mm | Very high | Low | Easy (online) | 3 days | Adults, large juveniles | Best nutrition; size by instar |
| Mealworms (small) | 10-20 mm | Medium | High | Easy | 24 hr | Adults (occasional) | Pinch head before offering |
| Waxworm | 15-20 mm | Low | Very high | Easy | None | Any (treat only) | Nutritionally poor; highly addictive |
The Prey-to-Spider Size Rule
This is the most important concept in feeder selection, and the one most often ignored.
Prey body length should be no longer than the spider’s abdomen width.
The abdomen is the rounded posterior section of the spider, not the legs, not the cephalothorax. For a spiderling with a 2 mm abdomen, that means fruit flies only. For an adult Phidippus regius female with an 8-10 mm abdomen, that opens up bottle flies, house flies, and small dubia nymphs.
Why the abdomen specifically? Jumping spiders strike at prey’s center mass. Prey that is longer than the abdomen width can reorient after the strike and bite back. A cricket with working mandibles that contacts a spider during a vulnerable moment, especially near a molt, causes real injury. Some sources say “no larger than 1.5x body length.” We think that is too generous. The abdomen-width rule is more conservative and more practical.
For feeding schedules paired with enclosure sizing, see the jumping spider care guide.
Best Feeders by Life Stage
Spiderlings (Under 1 cm body length)
Primary: Drosophila melanogaster (flightless fruit fly)
D. melanogaster at 2-3 mm is the right size for almost every spiderling from first instar onward. They move slowly enough that a young spider can track and reliably strike. A fresh culture gives you hundreds of feeders over 4-6 weeks for a low cost. Keep two cultures running in rotation so you always have one at peak production when the other starts declining.
Secondary: Bean beetles
Bean beetles (Callosobruchus maculatus) are 3-4 mm and crawl rather than fly, which keeps them visible and trackable in the enclosure. When your D. melanogaster culture crashes or between restocks, bean beetles fill the gap. They are at the upper size limit for the smallest slings, so check the abdomen-width rule before using them with very young spiders.
Avoid at this stage: Anything over 4 mm. Even small house flies can be too large for the smallest slings.
Frequency: once per day, 2-3 prey items. Remove uneaten prey after 24 hours.
For sling-specific care including enclosure size and misting at this stage, see the feeding jumping spider slings guide.
Juveniles (1-2 cm body length)
Primary: Drosophila hydei (flightless fruit fly)
D. hydei runs 3-4 mm, about 50% larger than melanogaster. Move to hydei as soon as the spider is reliably taking food and has passed the 1 cm mark. A single culture bridges most of the juvenile stage. At the larger end of this stage (1.5-2 cm), hydei starts to look small; begin rotating in house flies.
Secondary: House flies, bean beetles, pinhead crickets
House flies at 6-7 mm become viable as the spider approaches 1.5-2 cm body length. Pinhead crickets (newly hatched, under 4 mm) are safe and nutritious but require close supervision during every feeding. Do not offer crickets and walk away.
Frequency: every 2-3 days, 2-4 prey items per feeding.
Adults (Over 2 cm body length)
Primary: Bottle flies (Calliphora / blue bottle / green bottle)
Bottle flies are the best all-around adult feeder. They run 8-12 mm of body length, which is correct for most adult Phidippus species. They are high in protein, low in fat, and their erratic buzzing movement triggers a jumping spider’s hunt response immediately. Adult P. regius females chase bottle flies with obvious engagement. The flies cannot harm the spider even if the strike misses.
Order as pupae online. A batch of pupae emerges over 7-14 days at room temperature, giving you a staggered supply rather than a hundred flies at once. Refrigerating the pupae slows emergence further, letting you manage the supply.
Secondary: Dubia roach nymphs
Small dubia nymphs are the most nutritionally complete feeder on this list. Match instar size to the abdomen-width rule: a 2nd or 3rd instar nymph at 6-8 mm works for a mid-size adult. They are active, easy to keep, and cannot bite the spider. Gut-load dubia for 3 full days before offering: their digestive tract is long and a single overnight gut-load does not adequately change their nutritional content.
If your spider will take roaches, rotate them in every few feedings alongside bottle flies.
Treats: Waxworms, head-pinched mealworms
Waxworms once a week at most, and only after a recent molt when the spider needs easy calories. Mealworms with pinched heads can be offered occasionally for variety but are high in fat and nutritionally thin as a rotation staple.
Frequency: every 3-5 days, 1-2 appropriately sized prey items per feeding.
Gut-Loading: Why It Matters and How to Do It
A feeder insect kept on sawdust or plain cornmeal has almost nothing to offer nutritionally. Gut-loading means feeding your feeders something nutritious 24-72 hours before offering them. When the spider eats the feeder, it gets whatever the feeder ate. The difference in nutritional value between a gut-loaded and non-gut-loaded feeder is significant, particularly for calcium and micronutrient content.
What to gut-load with
Fruit flies and house flies: Mashed ripe fruit (banana, mango, or apple), commercial fly media, or bee pollen mixed into a small amount of sugar water. Feed for at least 24 hours before use.
Dubia roaches: Dark leafy greens (collard greens, dandelion greens, kale), carrot, sweet potato, apple slices. Gut-load for 3 full days. Dubia have long digestive tracts and a single overnight load is not sufficient.
Crickets: Dark greens, carrot, squash, commercial cricket food. 24-48 hours is adequate.
Mealworms: Oats plus carrot for moisture. 24 hours minimum.
Avoid: Citrus, onion, avocado, and heavily processed foods. These can harm the feeders themselves. Fireflies and any bioluminescent species are toxic to most invertebrates; do not use them.
Live, Pre-Killed, or Frozen-Thawed?
Live is correct for almost every feeding. Jumping spiders respond to movement. A motionless mealworm on the substrate gets ignored. The hunt sequence (stalk, pause, strike, wrap) is also part of the spider’s behavioral health: not just nutrition, but engagement.
Pre-killed is necessary for mealworms specifically. Pinch the head with tweezers before offering. The body twitches enough to trigger a strike while the bite risk is eliminated. Apply the same approach to any cricket you cannot supervise.
Frozen-thawed does not work for most jumping spiders. Still prey is ignored almost universally. Do not use it as a primary method.
The cricket problem: Crickets left overnight are the leading cause of spider injuries in home collections. Crickets chew when hungry. One that cannot find other food will investigate the spider. During a molt, the spider cannot defend itself. Offer crickets individually, watch the feeding, and remove anything uneaten within 30 minutes.
Feeders to Avoid
Wild-caught insects
This seems logical to beginners: go outside, catch a fly, feed it. Do not do this. Wild insects may carry pesticides from lawns and agricultural areas that are lethal at very small concentrations, parasites including mites and parasitoid wasps, and pathogens that captive-bred feeders are not exposed to. Keepers who feed wild-caught insects regularly report higher mortality rates than those using cultured feeders. The cost difference between a fruit fly culture and a dead spider is not a close comparison.
Fireflies and bioluminescent species
Firefly bioluminescence comes from lucibufagins, compounds that are cardiotoxic to many animals including arachnids. A single firefly can kill a spider. Do not use them under any circumstances.
Ants
Wild ants bite, sting, and carry formic acid. Some species are genuinely aggressive. Do not offer ants.
Large crickets for small spiders
A 1 cm cricket offered to a 1 cm juvenile is roughly the same mass as the spider. Even if the spider strikes successfully, the cricket can reorient and cause a serious bite. Always apply the abdomen-width rule.
Mealworms as a staple
Mealworms are high in fat and low in key micronutrients. Spiders fed mealworms as a primary feeder often develop fatty deposits and can become “addicted,” refusing other feeders. Occasional rotation item only, never a daily staple.
For enclosure and humidity context that affects feeding behavior, see the jumping spider enclosure setup guide.
Where to Buy Feeder Insects
Fruit fly cultures (D. melanogaster and D. hydei): Search Amazon for fruit fly cultures, Josh’s Frogs, and Etsy specialty sellers. Buy fresh and check the culture date; old cultures are already declining. See the fruit fly culture setup guide for raising your own.
Bottle flies and house flies: Blue bottle fly pupae on Amazon. Pupae emerge over 1-2 weeks for a staggered supply.
Dubia roaches: Dubia nymphs on Amazon or Dubia.com and Dubiaroaches.com. Buy mixed-instar nymphs and sort by size at home.
Bean beetles: Bean beetle cultures on Amazon. A useful backup culture to keep alongside fruit flies; bean beetles are easy to maintain.
Crickets: Crickets on Amazon or available at most pet stores. Gut-load for 48 hours before use; store crickets are kept on minimal nutrition.
Waxworms: Waxworms on Amazon. Refrigerate to slow metabolism. Treat only.
Springtails (cleanup crew): Springtails are not a feeder for adult spiders but are useful in bioactive enclosures as a cleanup crew and supplemental prey for very small slings. See the springtail culture guide.
FAQ: Feeder Insects for Jumping Spiders
What is the best feeder insect for jumping spiders?
For most keepers: Drosophila melanogaster for spiderlings and D. hydei for juveniles, transitioning to bottle flies as the adult staple. Bottle flies are the best single feeder for adult jumping spiders: high protein, low fat, and their movement immediately triggers hunting behavior. Dubia roach nymphs are the most nutritionally complete but not all spiders will take them.
Can jumping spiders eat crickets?
Yes, with supervision. Pinhead crickets (newly hatched, under 4 mm) are appropriate for juveniles. Crickets for adults should be sized to the abdomen-width rule and offered one at a time. Never leave a cricket unsupervised with a spider, especially near a molt. Cricket mandibles cause genuine injuries.
How often should I feed my jumping spider?
Spiderlings: once per day, 2-3 prey items. Juveniles: every 2-3 days, 2-4 items. Adults: every 3-5 days, 1-2 appropriately sized items. Females that are gravid or recently molted may eat more frequently. A spider that refuses 3 consecutive feedings is likely pre-molt: check for dull coloration, a sealed retreat, and reduced activity. See the jumping spider dehydration guide if you suspect environmental factors rather than pre-molt behavior.
Can jumping spiders eat mealworms?
Yes, occasionally. Always pinch the head first to eliminate the bite risk. Mealworms are high in fat, so use them as a rotation item at most, not as a staple. Spiders that eat mealworms frequently can develop fatty deposits and may start refusing other feeders.
What feeders are safe for a molting jumping spider?
None. Remove all live prey from the enclosure as soon as you notice pre-molt signs: sealed retreat, dull coloration, loss of appetite. A spider that is actively molting is completely vulnerable. Even a small fruit fly can bother a molting spider. Keep the enclosure clear and do not disturb the retreat. For the full molting process, see the jumping spider molting guide.
How do I keep feeder insects alive longer?
Fruit fly cultures: store at room temperature (72-78F), away from direct light. Do not refrigerate cultures. Bottle fly pupae: refrigerate to slow emergence. Remove only what you need for the next 2-3 days at a time. Dubia roaches: keep at 80-90F with high protein food and a dark hide. Crickets: room temperature with ventilation, access to water crystals, and food. Crickets kept in poor conditions cannibalize each other rapidly.