Slings are where most first-time jumping spider breeders lose animals. Not because sling care is mysterious, but because the requirements at L1 through L3 are different enough from adult care that adult-keeper instincts actively mislead you. The enclosures feel too small. The prey feels absurdly tiny. The urge to add a water bowl is strong. Most of those instincts are wrong for early slings.
This guide is for anyone who has just hatched a clutch or received slings and needs a reliable system for keeping them alive through to juvenile stage.
Key Takeaways
- House each sling individually in the smallest appropriate enclosure from the moment it disperses
- Feed Drosophila melanogaster fruit flies to L1 through L3 slings every 2 to 3 days
- Switch to D. hydei at L4 to L5; small crickets or dubias at L6 onward
- Mist one inner wall lightly every other day; never use water dishes for early slings
- Remove all prey before molting begins; a single cricket can kill a molting sling
- L4 is the key survival milestone: slings that reach it in good health have excellent odds
What Is a Jumping Spider Sling?
A sling, short for spiderling, refers to a juvenile jumping spider from first instar (L1) through approximately the fifth or sixth instar (L5 to L6), when the spider begins to resemble a miniature adult. The term is used throughout the invertebrate hobby to describe any spider that has hatched but not yet reached subadult stage.
Instar is the term for each growth stage between molts. L1 is the first instar after hatching; each molt advances the spider one number. Most jumping spiders reach adulthood after 7 to 10 instars depending on species and sex.
Early instars (L1 through L3) are the highest-risk stage. The spiders are small enough that humidity errors and prey size mistakes are immediately lethal. The good news: slings that reach L4 are meaningfully more robust, and by L6 they behave essentially like small adults.
Jumping Spider Sling Care: The Short Answer
House each sling individually in the smallest appropriate container (4 oz deli cup for L1 to L2, scaling up with each molt). Feed Drosophila melanogaster every 2 to 3 days at L1 through L3, switching to D. hydei at L4 to L5. Mist one inner wall lightly every other day to maintain humidity. Never use water dishes for early slings. Check for pre-molt signs before each feeding and skip feeding if the sling has sealed its hammock. Upgrade enclosure size at each instar stage.
Enclosure Setup by Instar
Smaller is better for early slings. This sounds counterintuitive, but in a large enclosure a tiny sling struggles to locate prey, struggles to find the right humidity gradient, and often fails to build a proper hammock. A sling that cannot hunt reliably will starve.
| Instar | Sling Size | Recommended Enclosure | Volume |
|---|---|---|---|
| L1 to L2 | 1 to 3 mm | 4 oz deli cup or 2 oz vial | 120 to 240 ml |
| L3 to L4 | 3 to 6 mm | 8 oz deli cup | 240 ml |
| L5 to L6 | 6 to 12 mm | 16 oz deli cup or small arboreal enclosure | 480 ml |
| L7 and up (juvenile) | 12 to 18 mm | Small adult-sized arboreal enclosure | 500 to 1000 ml |
Ventilation: Cross-ventilation (holes on the side and top, or opposite sides) keeps air moving without drying the enclosure too fast. A single top-only ventilation panel loses humidity too quickly for early slings. Start with fewer holes than you think you need and add more only if you see persistent condensation.
Orientation: Many keepers use deli cups upside down (with the lid as the floor) because jumping spiders naturally build hammocks at the top of their space. Upside-down cups let you open the bottom without disturbing the hammock anchored at the original lid level.
Substrate: A thin layer of coconut fiber or a damp paper towel on the floor is enough. At L1 through L3 you do not need deep substrate. Keep it simple; the easier it is to find a sling during maintenance, the better.
Hammock anchor points: Add a small piece of cork bark, a plastic plant, or a bent strip of paper towel so the sling has something to anchor its hammock to. Slings build hammocks from L1 onward and will be stressed without an anchoring surface.
Feeding Jumping Spider Slings by Instar
Prey must be no longer than the spider’s abdomen. A prey item that is too large will stress or injure a small sling. When in doubt, go smaller.
| Instar | Recommended Prey | Prey Size | Feeding Frequency |
|---|---|---|---|
| L1 to L3 | Drosophila melanogaster (flightless fruit flies) | 1.5 to 2 mm | Every 2 to 3 days, 2 to 3 flies per feeding |
| L4 to L5 | D. melanogaster or D. hydei | 2 to 3 mm | Every 2 to 3 days, 3 to 5 flies per feeding |
| L6 to L7 | D. hydei or small crickets (1/8 inch) | 3 to 4 mm | Every 3 days, 1 to 2 prey items |
| L7 and up (juvenile) | Small crickets, small dubias, D. hydei | Up to 1x abdomen length | Every 3 to 4 days |
Why D. melanogaster for early slings: Melanogaster are smaller than hydei, slower-moving, and easier for a tiny sling to track and catch. Do not offer hydei at L1 to L2; they are often too large and too fast for young slings to reliably catch.
Culturing your own: A D. melanogaster culture and a D. hydei culture are both essential if you are raising a full clutch. Store-bought feeder flies are expensive at scale and unreliable in timing. See fruit fly culture setup for how to establish and maintain cultures.
Prey removal: Remove any live flies or crickets that are not eaten within 24 hours. This is especially important around molting. A single cricket left in the enclosure when a sling molts can kill it. Check for pre-molt signs before every feeding and skip the feeding if you see them.
Humidity: The Most Critical Variable
Humidity management is more critical for slings than for any other life stage. A sling has a much higher surface-area-to-volume ratio than an adult, which means it loses moisture faster relative to body size. Dehydration is rapid and typically fatal before you notice visible signs.
At the same time, excess moisture causes mold, which is lethal in a small enclosed container.
The correct approach:
- Mist one inner wall of the enclosure lightly every other day at L1 through L3
- The misted wall should be damp but not dripping
- Allow the opposite side to dry out between mistings, creating a moisture gradient
- The sling will position itself in the humidity zone it prefers
Do not use water bowls or water gel crystals with early slings. An L1 or L2 sling that walks into a water droplet can drown. The misted wall approach provides adequate hydration through contact and ambient humidity.
From L5 onward, slings approach adult robustness in humidity tolerance. You can reduce misting frequency slightly, and the spider will increasingly seek water on the enclosure walls as adults do.
Molting in Slings
Slings molt frequently: L1 through L4 may molt every 2 to 4 weeks under good conditions. The molting process and signs are the same as in adults, just faster. See jumping spider molting for a full reference.
Key differences at sling stage:
- Pre-molt signs can be subtle; the sling may simply seal itself in a tiny hammock and disappear from view
- The active molt (ecdysis) takes 15 to 30 minutes at early instars, much faster than in adults
- Do not feed for 3 to 5 days post-molt (vs. the 5 to 7 days for adults)
- Check the enclosure before every feeding for a sealed hammock; if sealed, skip the feeding entirely
Post-molt slings look transparent and pale. This is normal. Within 24 to 48 hours color returns and the sling will be hunting again.
Cannibalism and Why Individual Housing Matters
Every sling must be housed individually. Even siblings from the same clutch will cannibalize each other, especially when one molts while the other is active and hungry. This is not aggression in a behavioral sense; it is simply how predatory instinct works. Movement triggers a strike response.
If you are separating slings from a communal container after hatching, work methodically:
- Use a soft, clean paintbrush to move slings one at a time
- Work from the outside of the cluster inward (edge slings are already dispersing)
- Have individual containers prepared in advance with substrate and an anchor point
- Label every container with the hatch date and instar number
The brief communal clustering phase immediately after hatching (typically the first 3 to 7 days) is normal and does not require intervention. Once slings begin moving independently around the enclosure, separation becomes urgent.
Troubleshooting Early Sling Losses
Some sling loss in early instars is expected, particularly at L1 and L2. A realistic first-clutch outcome is 60 to 80% survival to L3 with attentive care. Here are the most common causes of early death:
| Problem | Most Likely Cause | Adjustment |
|---|---|---|
| Sling found dead, no visible injury | Dehydration | Increase misting frequency; check ventilation is not too aggressive |
| Sling found dead with prey nearby | Killed by prey during molt | Remove prey before any pre-molt signs appear |
| Sling not visible for days, then dead | Failed molt (dysecdysis) | Maintain humidity consistently; reduce over-ventilation |
| Sling refusing prey for 5 or more days | Pre-molt, or enclosure too cold | Check temperature; look for sealed hammock |
| Mold visible in enclosure | Too wet with insufficient air movement | Reduce misting; improve ventilation; replace substrate |
The single most common preventable cause of early sling death is insufficient humidity combined with too much ventilation. New keepers often punch too many holes in deli cups. Start conservative and adjust from there.
Instar-by-Instar Milestones
L1 to L2: The sling is nearly transparent. It builds a tiny hammock within 24 to 48 hours of individual housing. Begin offering D. melanogaster on the second day. Mortality risk is highest here.
L3: First recognizable jumping spider markings appear. The sling hunts more actively and prey consumption increases. Surviving to L3 is a good sign.
L4: A meaningful checkpoint. A sling that reaches L4 in good health has an excellent chance of reaching adulthood. You can begin transitioning to D. hydei if the sling is large enough to catch them reliably.
L5 to L6: The spider begins to look like a miniature adult. Females can be tentatively sexed using the epigyne method at this stage (see jumping spider male or female). Enclosure upgrades become important as the spider grows more active.
L7 and beyond (juvenile stage): Behavior closely matches an adult. The spider builds a proper maintained hammock, hunts confidently, and begins showing individual personality. From here, standard adult care applies. See the jumping spider care guide for the full adult routine.
When to Transition to Adult Care
The transition from sling-specific care to adult care is gradual rather than a single moment. By L6 to L7, your spider:
- Can eat small crickets and other appropriately sized prey
- Can tolerate a very shallow water dish (no deeper than 2 to 3 mm, with pebbles or cotton to prevent drowning)
- Needs a larger enclosure with full arboreal features
- Can be handled briefly and gently
The full adult care routine, including feeding schedule, enclosure cleaning, and handling guidelines, is in the jumping spider care guide. For Phidippus regius specifically, the Phidippus regius care guide covers adult requirements in depth.
Sling care has a steep learning curve for about the first two weeks, and then it clicks. Once you have a working misting schedule, a reliable feeder fly culture, and a labeled rack of deli cups, the whole system becomes surprisingly manageable. The first sling you raise to juvenile stage makes the whole clutch worth it.