Jumping Spider Spiderling Care: Raising Babies from Egg Sac

Raising jumping spider spiderlings from an egg sac is one of the most rewarding projects in the hobby and one of the most logistically demanding. A single Phidippus regius egg sac can release 50 to 200 spiderlings (source: Animal Diversity Web), each requiring its own enclosure within weeks of emergence, daily feeders, careful hydration, and roughly one to three hours of one-by-one separation work when the time comes. This guide covers the full timeline from egg sac to rehoming: incubation, the first-instar cluster phase that confuses many new breeders, when sibling cannibalism actually starts, how to prepare individual sling enclosures, an instar-by-instar feeding schedule, realistic mortality expectations, and how to find responsible homes for the survivors. If you have not yet seen a successful pairing in your collection, our jumping spider breeding guide covers everything that happens before the egg sac appears.

What Happens Inside the Egg Sac

A fertilized jumping spider egg sac takes two to four weeks to mature at typical room temperature, with pacing tied to ambient warmth and humidity. Eggs develop into pre-larval embryos, then into eggs-with-legs (EWLs) living on yolk, and finally molt into first-instar spiderlings ready to emerge. The mother guards the sac throughout.

For Phidippus regius, the most commonly bred species in the hobby, eggs hatch in about two to three weeks at 75 to 80 degrees Fahrenheit (24 to 27 degrees Celsius). Cooler ambient temperature stretches the incubation period; sustained temperatures below 68 degrees Fahrenheit slow embryo development and can compromise viability. Warmer temperatures speed development but increase the risk of dehydrated sacs if humidity drops below 50 percent. Some breeders pull the sac for artificial incubation around week two to three (source: The Tarantula Collective), but this is not necessary in most cases and adds risk of mishandling.

What you can observe through the sac:

• Week 1: The sac appears solid and uniform. No movement visible. Eggs are still in the embryo stage.
• Week 2: Tiny dark dots become visible through translucent areas of the silk. These are developing eyespots.
• Week 3: Subtle movement may be detectable. Some breeders report a faint “rolling” appearance through the silk.
• Week 3 to 4: First spiderlings break through the silk and cluster on or near the sac.

If the sac changes color significantly (browning, blackening, or developing visible mold patches), the eggs may not be viable. A non-viable sac usually means the female was too young, unmated, or stressed during construction. Female jumping spiders can produce infertile sacs from stored sperm or from unsuccessful matings, and not every egg sac will hatch. For broader context on the female’s reproductive biology and the events leading up to the sac, see our Phidippus regius care guide.

Do not disturb the sac during incubation. Do not open the enclosure to inspect it, do not move the enclosure to a new location, and do not handle the female. Stressed mothers occasionally eat their own egg sacs. Mist one corner of the enclosure lightly every two to three days to maintain ambient humidity near 60 percent without wetting the sac directly. Keep the enclosure in a stable temperature zone away from drafts, heat vents, and direct sunlight.

Hatching and the First-Instar Cluster Phase

Newly emerged spiderlings cluster on or near the silk sac for several days, surviving entirely on yolk reserves carried in their tiny abdomens. They are 1 to 2 mm long, translucent, and do not eat prey or need misting yet. Do not feed them and do not attempt to separate them during this first-instar cluster phase.

The cluster phase typically lasts three to seven days for Phidippus regius. During this window, the maternal nest is in full effect: the female guards the cluster and will not eat her own offspring. Comparative arachnology research on related species like Phidippus apacheanus documents spiderlings remaining in the nest for up to 21 days after hatching, staying through their first molt under maternal protection (source: Animal Diversity Web). For Phidippus regius in captivity, the cluster usually disperses faster because the enclosure is smaller and the spiderlings exhaust their yolk reserves sooner at typical room temperature.

An important taxonomic note many new keepers miss: what hatches from the sac is technically a post-embryo, sometimes called an EWL (eggs with legs). These are not true first-instar spiderlings yet. They molt once inside or just outside the sac to become first-instar spiderlings capable of hunting. Some breeders define instar numbering differently (some count the EWL stage as i1, others count the first hunting stage as i1), so when a care sheet or seller references “second instar,” confirm whether they mean the second hunting stage or the second post-hatching stage. In this guide, we use the hunting-stage convention: first instar = first stage that actively hunts.

Signs the cluster is dispersing:

• Spiderlings begin walking away from the sac in different directions.
• Abdomens look less plump as yolk reserves deplete.
• Webbing appears across the enclosure from individual draglines.
• Some spiderlings may begin testing prey items if any are present (do not introduce prey yet).

Once two or three spiderlings are wandering independently, the dispersal phase has begun and you have roughly 5 to 14 days before serious sibling predation risk emerges, depending on temperature and how quickly the slings deplete their yolk.

When to Actually Separate Spiderlings

Separate spiderlings once they begin actively hunting and showing predatory interest in siblings, which is typically late first to early third instar (10 days to 3 weeks after dispersal in Phidippus regius). Sibling cannibalism in jumping spiders is not driven by hunger alone; it is predatory behavior that intensifies as the slings’ hunting drive develops. Watch the cluster, not the calendar.

This is one of the most commonly misunderstood pieces of sling rearing. Many older care guides recommend separation “within hours” of mobility, which is more conservative than the welfare biology of the species supports. Comparative research on Salticidae brood care, including the well-known maternal care work on Toxeus magnus (source: Zoological Research, 2019), shows that jumping spider mothers and sibling groups commonly remain together through the first one to several molts without significant cannibalism, because the spiderlings are still living off yolk and have not yet developed the prey-recognition drive that triggers attacks. In captivity, experienced keepers commonly hold Phidippus regius clutches together until the third or fourth instar, when slings reach roughly the size of a house fly, before separating (source: Por Amor Art).

Reliable separation triggers:

• Active hunting of introduced prey. If a spiderling stalks and eats a springtail or fruit fly, it has the hunting drive that can target siblings.
• Visible size disparity in the clutch. A few siblings noticeably larger than the rest signals that some have been eating sooner (or eating each other).
• Direct predation observed. A spiderling actively pursuing another sibling means separation is overdue. Begin immediately.
• Late second to early third instar reached. By this stage, all surviving slings have prey-recognition behavior and the risk curve climbs sharply.

How to separate spiderlings safely. Separation is the single most labor-intensive day of sling rearing. For a clutch of 100, plan one to three hours and work in batches:

1. Prepare all individual enclosures first. Lids labeled, ventilation holes punched, substrate placed, climbing structure inside. Have them lined up in a tray before you open the parent enclosure.
2. Use a soft size 0 or 00 watercolor brush. Gently nudge a single sling onto the brush tip. Their light weight lets them ride the bristles without injury.
3. Work over a large light-colored tray or inside a bathtub. Escaped 2 mm slings are nearly invisible on most surfaces. Containment prevents losing them.
4. One sling per transfer. Never herd a group. The risk of crushing or losing slings rises sharply if you try to move more than one at a time.
5. Count as you go. A rough count gives you mortality and feeding-success data later.
6. Take breaks every 20 to 30 slings. Fatigue causes accidents. Crushed slings are a routine separation-day loss.

Leave the mother with the partial cluster while you work. She does not attack her own spiderlings, and her presence keeps the unseparated slings calm. Once you have separated as many slings as you can comfortably house, return the female to her own enclosure and either accept that the remaining slings will sort out cannibalism naturally or continue separating over the next day or two.

Preparing Sling Enclosures Before the Hatch

Sling enclosures must be tiny, well-ventilated, escape-proof, and prepared in bulk weeks before the egg sac is due. Each spiderling needs its own container by the time it reaches active hunting. For a clutch of 100 to 200 slings, plan on 100 to 150 individual enclosures, accounting for mortality and rehoming during separation.

Enclosure Specifications

The standard early-instar enclosure is a small clear deli cup or condiment cup. Specifications:

• Size: 2 to 4 oz condiment cups for first to third instar. Larger (16 to 32 oz) is wasteful and makes prey-tracking harder for tiny slings.
• Material: Clear plastic with a snap-on or screw-on lid. You need to be able to see the spider for daily checks.
• Ventilation holes: Use a heated pin, fine needle, or push pin to make small holes on two opposite sides for cross-ventilation. Holes must be small enough that a 2 mm sling cannot squeeze through, which is smaller than most people initially assume.
• Substrate: A thin layer of dry paper towel, a small square of dry sphagnum moss, or 1 to 2 mm of slightly damp coconut fiber. Avoid loose substrates at this stage because tiny slings can become trapped in the spaces.
• Climbing structure: A short piece of artificial vine, a sliver of cork bark, or a tightly coiled pipe cleaner. Slings are arboreal and need a vertical surface to anchor their first retreat web.

Test ventilation with a fruit fly first. Place a flightless fruit fly in a prepared enclosure for a few minutes. If the fly escapes through any hole, the hole is too large for the slings. Punch new, smaller holes and re-test. This 5-minute investment before separation day prevents the worst-case scenario of escaped slings spread across your home.

Feeder Culture Setup

Feeders must be ready to use the day spiderlings become active, not started the day they hatch. Both standard feeders need a head start of one to two weeks:

• Springtails (Collembola): Best first food for the smallest first and second instars. Soft-bodied, slow-moving, and appropriately tiny. Start a culture in a small container with damp coco coir and rice or yeast about two weeks before separation day. A productive springtail culture sustains feedings for months and integrates with bioactive setups later.
• Flightless fruit flies (Drosophila melanogaster): The standard sling food from late first instar onward. D. melanogaster are smaller than D. hydei and appropriate for young slings. Start your fruit fly culture at least two weeks before the expected hatch date, ideally three to four weeks before, so you have a producing colony with several stages in rotation.

For complete culture setup, sourcing, and feeder rotation logistics across the spider’s full life cycle, see our jumping spider feeder insects guide. Having two cultures of each feeder type running in parallel is good insurance because cultures occasionally crash with no warning.

Feeding Spiderlings by Instar Stage

Spiderling feeding follows a clear instar progression: springtails for first and second instar, melanogaster fruit flies from second onward, hydei flies and pinhead crickets from late third, and standard adult feeders by the fifth. Prey should be smaller than the spiderling’s abdomen, offered every one to three days depending on size, and consumed within 24 hours or removed.

First and Second Instar (1 to 2 Weeks Post-Dispersal)

Start offering springtails or freshly emerged D. melanogaster fruit flies every one to two days once spiderlings have left the cluster and begun moving independently. Place two or three prey items in each enclosure and check 24 hours later. Remove uneaten prey, especially fruit flies that have died, because they decompose quickly in a humid sling cup and seed bacterial and fungal problems.

For slings that seem timid or too small to chase live prey, offer a lightly crushed (immobilized, not pulverized) fruit fly. Many first-instar slings accept pre-killed prey readily once they detect the chemical cues, even before they have the confidence to hunt. Crushing is also useful for any sling that has gone several days without eating and seems to be losing condition.

Third Instar (2 to 4 Weeks)

Continue with D. melanogaster. Slings at this stage are confident hunters: they will stalk prey from across the enclosure, attach a dragline before pouncing, and immobilize and consume flies efficiently. Feed every two days. Toward late third instar, you can begin introducing the larger D. hydei fruit flies, especially for larger species like Phidippus regius whose third instar already approaches small fly size. Hydei flies are more nutritious per item, so feeding frequency can stretch slightly.

Fourth Instar and Beyond (1 to 2 Months)

Transition to D. hydei and pinhead crickets (1/8 inch or smaller). Feed every two to three days. At this stage, spiderlings are robust enough to handle slightly larger prey, the risk of accidental death from handling or enclosure issues drops significantly, and growth visibly accelerates between molts. By the fifth instar, most slings can eat the same prey as sub-adults of their species, though the size rule (no prey larger than the abdomen) still applies.

The jumping spider feeding schedule guide covers prey sizing, gut-loading, and frequency through all life stages including adulthood, so you do not need to relearn each transition when your slings outgrow this article.

Hydration Without Drowning Risk

Mist one side of each individual enclosure lightly every one to two days. Use a fine mist bottle on the lightest spray setting; heavier droplets can drown a 2 mm sling on contact or collapse the silk retreat. Droplets that form on the side wall or climbing structure are what the spider drinks from. If droplets are forming pools on the substrate, you are misting too heavily. Reduce to a single light pass per enclosure and let the previous misting evaporate before the next.

Do not place an open water dish in a sling enclosure under any circumstance. Even a millimeter of standing water is a drowning hazard for first and second instars. From late third instar onward, a small bottle cap with a wet sponge piece is acceptable for keepers who want a dedicated water source, but droplet misting remains the safer default. For more on droplet drinking behavior, signs of dehydration, and how it differs across life stages, see our jumping spider hydration guide.

Growth, Molting, and Enclosure Upgrades

Spiderlings grow exclusively by molting, shedding the old exoskeleton inside a sealed silk hammock every two to four weeks in early life and slowing to every four to eight weeks at mid-juvenile stage. Each molt needs adequate humidity, an undisturbed retreat, and no live prey in the cup. Enclosure size scales with the spider, with upgrades at roughly each second molt.

Upgrade by size, not by date. A well-fed Phidippus regius can move through the early instars in three to four weeks at room temperature, while an underfed or cooler-kept clutch can take twice that long. Going by visible body length and how much space the sling uses in its current cup is more reliable than counting weeks since hatch. Our dedicated jumping spider enclosure size guide covers the size-based decision rules in more detail.

Molting in slings: Slings seal themselves in a silk pocket near the top or side of the enclosure, often pulling debris around the entrance. They hang upside down inside the pocket and shed the old exoskeleton over several hours. Do not disturb the retreat, do not open the enclosure for misting (skip the misting cycle if the sling is mid-molt), and do not introduce prey. Live feeders can bite a vulnerable molting sling and kill it. The jumping spider molting guide covers stuck molts (dysecdysis), post-molt timing, and emergency response in detail.

Post-molt, the sling waits 24 to 72 hours for the new exoskeleton to harden before resuming feeding. Colors are often more vivid immediately after a molt. The first feeding after a molt is typically smaller and faster than usual because the sling is rebuilding fuel reserves.

Realistic Mortality and Common Sling Problems

Expect to lose a meaningful percentage of any clutch regardless of preparation. Hobby breeders commonly report 25 to 95 percent total mortality across rearing depending on species, husbandry, and luck (source: My Pet Jumping Spider), with attentive captive runs typically losing 30 to 50 percent. Some loss is biological and some is husbandry-driven; going in with realistic expectations prevents demoralization.

Mortality timeline patterns:

• Egg sac (pre-emergence): 5 to 30 percent of eggs may be non-viable, especially in first-time mothers or younger females.
• First instar molt (cluster phase): 10 to 20 percent typical mortality, mostly from failed first molts.
• Dispersal and separation: 5 to 15 percent additional loss from accidental crushing during separation, escaped slings, or unseparated cannibalism.
• Early juvenile (instars 3-5): 5 to 20 percent from feeding failures, dehydration, and stuck molts.
• Late juvenile to sub-adult: Mortality drops sharply. Surviving slings at this stage are usually robust.

Spiderlings Not Eating

A sling that refuses food for more than three to five days after reaching second instar may be:

• Too cold. Ensure ambient temperature is 75 to 80 degrees Fahrenheit (24 to 27 degrees Celsius). Below 70 degrees Fahrenheit, metabolism slows and prey interest drops sharply.
• Offered prey that is too large. Switch to springtails or pre-killed (lightly crushed) fruit flies.
• In pre-molt. Even young slings fast for several days before molting. If the sling appears slightly darker, sluggish, or has anchored itself in a silk pocket, leave it alone and check again in three to five days.
• Dehydrated. A shrunken, wrinkled abdomen indicates dehydration. Mist the enclosure lightly and observe whether the sling drinks from droplets within 24 hours.

Our broader troubleshooting walkthrough at when your jumping spider won’t eat covers additional causes that apply to juveniles and adults.

Dehydration

Dehydrated slings have a visibly shrunken abdomen and move sluggishly. Increase misting frequency to once per day, place a tiny piece of damp sphagnum moss in the enclosure as a humidity reservoir, and observe whether the sling rehydrates within 24 to 48 hours. Severely dehydrated slings sometimes do not recover even with intervention. Prevention through consistent misting is more reliable than rescue.

Molting Failures (Dysecdysis)

Stuck molts are the leading cause of death in juvenile jumping spiders after the initial cluster-phase mortality window. Low humidity during pre-molt is the primary cause. Maintain ambient humidity in the upper end of the species’ range (60 to 70 percent for P. regius) once the sling enters pre-molt, and never introduce live prey while the sling is sealed in its molt retreat. If a molt fails partially, you can sometimes assist by raising humidity sharply and giving the sling 12 to 24 hours, but most stuck molts in slings are fatal regardless of intervention.

Mold and Mites

Sling cups develop mold problems if uneaten prey is left behind, if substrate is consistently over-misted, or if ventilation is inadequate. A single moldy fruit fly carcass can seed an entire cup. Remove uneaten prey within 24 hours, mist lightly, and rotate slings into fresh cups every two to three weeks during the early instars. Grain mites can ride into sling cups on contaminated feeder cultures and reproduce rapidly in the humid environment. If you see small pale dots moving on the cup walls or around prey remains, transfer the spider to a clean cup with paper towel substrate and discard the old container.

Rehoming a Clutch Responsibly

Unless you are running a deliberate breeding operation with established buyers, plan to rehome 70 to 90 percent of any clutch. A successful sac releasing 100 surviving juveniles is more spiders than any single keeper can house and feed to welfare standards. Start identifying rehoming channels before the eggs hatch, not after.

Rehoming timing. Most breeders sell or place spiderlings at third to fourth instar, when they are robust enough to survive shipping and transition to a new keeper’s care. For Phidippus regius, this is typically three to six weeks after dispersal. Slings rehomed earlier (first or second instar) have lower survival in transit. Slings held longer (fifth instar or later) command higher prices but require significantly more feeders and individual enclosure space during the holding period.

Rehoming channels:

• MorphMarket (morphmarket.com) is the largest online marketplace for captive-bred invertebrates and reptiles. Listings are searchable by species and morph, and the platform handles buyer reputation tracking.
• Species-specific Facebook groups and Discord communities for jumping spider keepers, which often function as both peer support and informal marketplaces.
• Local reptile and invertebrate expos, where you can sell slings in person and meet buyers face-to-face. Expo sales avoid shipping risk entirely.
• Arachnoboards (arachnoboards.com) classified listings, which are an older but still active hobbyist marketplace.

Shipping considerations. Spiderlings can be shipped via USPS Priority Mail in small, ventilated containers with a damp paper towel for humidity, padded inside an insulated box. Ship early in the week (Monday or Tuesday) so the package does not sit in a warehouse over the weekend. Include a heat pack in cold weather (below 60 degrees Fahrenheit at origin or destination) and a cold pack in hot weather (above 85 degrees Fahrenheit). Always check the buyer’s local weather forecast for delivery day before shipping. Most breeders include a basic care instruction card with each sling and offer a live-arrival guarantee that covers replacement or refund if the spider does not survive transit.

Pricing context. Standard wild-type Phidippus regius slings typically sell for $15 to $30 USD each at third instar, with premium morphs (Bahama, Soroa, apricot) commanding $40 to $200+. Pricing varies by species, instar age, lineage, and current market demand. For broader market context across the hobby, see our jumping spider cost guide and the buyer-side perspective at our where to buy a jumping spider guide.

Responsible-breeder ethics. Producing 100 slings only to euthanize the unsold ones is the dark side of casual hobby breeding. Three things separate responsible from irresponsible: confirming buyer interest before letting the pairing go forward, holding slings only as long as you can guarantee their welfare, and being honest with buyers about the species’ real lifespan and husbandry needs rather than oversimplifying. In our keeper community, the most experienced breeders we work with often plan clutches around an existing buyer list and decline to pair if the rehoming network is uncertain.

Frequently Asked Questions

How long does it take for jumping spider eggs to hatch?

Jumping spider eggs typically hatch in two to four weeks at room temperature (75 to 80 degrees Fahrenheit), with Phidippus regius averaging two to three weeks. Cooler temperatures stretch incubation, sometimes to five weeks below 70 degrees Fahrenheit, while warmer temperatures speed development at the cost of increased dehydration risk. The first visible sign of imminent hatching is usually tiny dark dots (developing eyespots) becoming visible through translucent areas of the silk sac around week two. Do not open or disturb the sac to check progress; let the female manage it.

How many spiderlings survive from a typical clutch?

Survival from emergence to sellable third-instar age varies widely with husbandry quality. Hobby breeders commonly report total clutch mortality between 25 and 95 percent, with attentive captive runs typically losing 30 to 50 percent of the original hatched count. The biggest losses occur in the first-instar molt (failed transitions from EWL to hunting instar) and during the separation window if cannibalism is not managed. A clutch of 150 emergents can realistically yield 75 to 100 juveniles ready for rehoming.

Can I keep spiderlings together if I feed them enough?

No, not past the early juvenile stage. Sibling cannibalism in jumping spiders is not driven by hunger alone; it is predatory and territorial behavior that activates as the slings’ prey-recognition develops. Even well-fed slings will eventually kill and eat siblings once housed past the third or fourth instar, because at that point they recognize moving spiders the same way they recognize moving prey. The honest rule is: keep them together while they cluster, watch for active hunting behavior, and separate as soon as you see size disparity or direct predation.

What temperature is best for raising spiderlings?

Maintain 75 to 80 degrees Fahrenheit (24 to 27 degrees Celsius) for optimal development speed and survival in Phidippus regius and most commonly kept species. Temperatures below 70 degrees Fahrenheit significantly slow growth and increase early mortality. Temperatures above 85 degrees Fahrenheit cause dehydration and heat stress in tiny slings that cannot regulate water loss. A small heat mat on one side of a sling rack with a thermostat is the most reliable winter setup. See the jumping spider temperature and humidity guide for the full thermal physiology.

How long until spiderlings are big enough to sell?

Most breeders sell Phidippus regius slings at third to fourth instar, approximately three to six weeks after dispersal from the egg sac at normal room temperature. Buyers who prefer older juveniles (fifth instar or later) wait another two to four weeks. Slings sold earlier than third instar carry higher transit mortality risk; slings held longer require significantly more feeder culture output and individual cups during the holding period.

Do I need to remove the mother from the egg sac enclosure?

No, not during incubation or the early cluster phase. The female typically guards the sac and does not harm her own spiderlings. Leave her in place until the spiderlings have dispersed across the enclosure and you are ready to separate the clutch. At that point, return her to her own enclosure so you can work the slings out one by one without her in the way. She may produce another sac within several weeks if she is well-fed and was successfully mated with stored sperm reserves. Our breeding guide covers the full mating-to-egg-sac sequence in detail.

What do I do if spiderlings hatch while I am away?

If you return to find mobile spiderlings already dispersing across the enclosure, prepare to separate them within the next 24 to 72 hours. Some cannibalism will likely have occurred, but most clutches still yield enough survivors to be worth working. Set up individual enclosures, gather a paintbrush and a containment tray, and work through the slings systematically as you would on planned separation day. Plan ahead next time: most breeders check egg sacs daily as the expected hatch window approaches so they can be home for the dispersal phase.

Are jumping spider mothers protective of their spiderlings?

Yes. Female Phidippus species build a thicker silk retreat around the egg sac and remain with it through incubation, often refusing food for part of this period. After hatching, the mother typically tolerates the cluster for several days to weeks without attacking her own offspring. Comparative arachnology has documented extreme maternal care in some Salticidae, including the well-known case of Toxeus magnus, an ant-mimicking jumping spider that produces a nutritious milk-like secretion that her spiderlings feed on for the first three to five weeks of life (source: Science). Phidippus does not produce milk, but the broader pattern of maternal protection during the cluster phase is consistent across the family.

Related guides

• jumping spider breeding guide

This article was researched and written by the ExoPetGuides editorial team with AI-assisted drafting. All husbandry parameters, life-cycle stages, and species references were independently verified against peer-reviewed arachnology literature, recognized husbandry authorities, and experienced keeper community sources. ExoPetGuides does not sell spider supplies and has no affiliate relationship with any breeder, platform, or supplier named in this guide.

This guide provides general husbandry information for breeders raising jumping spider clutches. It is not a substitute for professional veterinary advice. If a spiderling or adult in your collection shows persistent illness signs that do not resolve with parameter correction, consult a qualified exotic-animal veterinarian experienced with invertebrates.