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Jumping Spider Breeding, Sexing, Eggs & Spiderling CAre.

Determining the sex of your jumping spider.

Determining the sex of your jumping spider.

Determining the sex or gender of a jumping spider, also known as spider sexing, can be challenging, but some physical characteristics can help. One way to tell the difference between males and females is by looking at the pedipalps, the appendages near the spider's mouth. In females, the pedipalps are thin and straight, while in males, they are bulbous and resemble boxing gloves. Additionally, females have plump abdomens, while males have smaller, narrower abdomens.

Another way to tell the difference is by looking at the epigynum, a small structure on the underside of the female spider's abdomen. It looks like a discrete belly button and appears near maturity. If it looks well-defined and shiny, you have a mature spider. However, it's important to note that some species may have different colorations or sizes for males and females.

Epigynum on the underside of the female spider.
Male pedipalps are bulbous like boxing gloves.

Males are generally smaller than females, but it's not a reliable way to tell the sex of a spider, as size can vary. Males may also be more active and explore their enclosures often, as adults looking for mating opportunities, while females may spend more time near or in their hammocks. Females also generally feed more and longer in preparation for the resources needed to lay eggs.

How to breed jumping spiders?

How to breed jumping spiders?

Breeding can only happen once the female and male have reached adulthood. Both spiders should be of the same species, as cross-breeding is often genetically impossible and not advised. 

To determine if your jumping spiders are ready to mate, it is essential to check if they are adults, meaning they have completed their last molt and have fully developed sexual characteristics. For males, check if the bulbs at the tip of the pedipalps are clear and comma-shaped. For females, check if the epigyne, the sexual opening between the booklungs on the abdomen, is clearly defined as a black, shiny spot. The number of molts until sexual maturity can vary depending on external factors such as heat and can even differ for individual spiders.

Female and male jumping spiders mating

When pairing male and female spiders, do so 1 to 2 weeks after the female's final molt to ensure the best chance of fertilization; otherwise, she may already be getting ready to lay infertile eggs that won't get fertilized even if mated. Waiting a tiny bit after the molt also ensures their exoskeleton has fully hardened. It's also vital to ensure they are well-fed and have extra food available; a hungry female is more likely to attempt to eat a male. Finally, although mating usually goes smoothly, it's still possible for the female to attack and kill the male. To prevent this, keeping them together for a short period in a neutral enclosure for mating purposes is best. Be prepared to intervene with a paintbrush if needed. Some breeders prefer to keep the female in her enclosure and have the male enter the space; this means the male will detect the female pheromones faster and find the female. Mating can take from 5 minutes up to an hour or longer. Once the male is done, you should remove him and place him back in his enclosure. 

When the male sees the female, he will dance by tapping, moving and waving his front legs at her. If she consents, he will climb onto her back, facing in the opposite direction. He will then tap or massage her and turn her abdomen over to the side to access her epigynum to deposit sperm with the bulbs, which she will store for the rest of her life and lay eggs whenever she's ready. The process may take as little as two or five or more weeks and is known as "sperm induction" or "sperm transfer."

If you captured your female spider from the wild as a mature specimen, there's a possibility she may already be fertile. In their natural habitat, it's common for mature males to linger near the molt sac (or hammock) of a sub-adult female, waiting to mate with her as soon as she molts. Consequently, if you try to pair her with a male for mating, there's a risk she might attack him, given her potentially already fertile state.

Caring for egg sacs.

Caring for egg sacs.

Once mated, female jumping spiders spin a silk egg sac to protect and nourish their eggs. They may lay multiple sacs or more eggs after the previous batch hatches. This is because they can store sperm for fertilizing eggs, and mating with one male may be enough. However, if a female is kept without a male and never mates, she may lay unfertilized eggs which will dry up or be consumed. It is common for females to lay eggs one to two weeks after mating. Once a female spider is fertile, it is best to house her in an enclosure secure enough to prevent the tiny little spiderlings from escaping. 

Make sure the sac's outer part does not dry out. Mist it once a week with a spray bottle, but avoid spraying in the direction of the entrance to the sac or ensure the air inside the enclosure has a high humidity content at all times. Check that the babies have not started emerging, as misting the sac during this period could drown them. The enclosure should have small ventilation holes or lines to prevent the tiny slings from escaping. If there is a risk of the slings escaping, you can cover the enclosure with pantyhose. It usually takes 2-4 weeks for the babies to become visible in the sac, where they will shed their skin once before they start exploring. After that, allow the spiders to emerge independently, which may take up to one month.

Separate the spiderlings when they show signs of treating each other as prey, usually around 4th-Instar (i4). The spiderlings can stay with their mother, but she may eat them at any stage of their development. To remove the mother, wait for her to come out of the sac after laying eggs and move her to a separate enclosure; while you wait for her to come out, provide her with food even if she doesn't come out to eat.

There is a debate regarding whether a mother should be separated right after laying the egg sac or once the spiderlings have left the sac. However, most experts agree that leaving the egg sac with the mother spider throughout the entire process results in healthier spiderlings. This is because the mother knows precisely what to do, and often the resources from the non-viable eggs, or weaker slings, make the survivors stronger. Remember, there is a risk of the mother spider eating some or all eggs due to stress, lack of resources, unviable eggs or even random factors. 


To avoid such risk and as a safer alternative, some breeders remove the mother spider from the enclosure as soon as possible. Other, only after she decides to leave the sac and comes out of her hammock. Others do so after four weeks of being laid (allowing her to provide care for at least some time). Finally, some breeders (only after the mother has left the sac and separated) open the egg sac and monitor it closely to separate the slings from the unviable (bad) eggs. The reason is that leaving them unattended may lead to leaking fluid or popping of the bad eggs, which can stick to and suffocate the newborn spiders. 


It is important to note that monitoring the egg sac in this way is a delicate process that experienced individuals should only attempt. This can be time-consuming and requires precision. We are not deciding for you what is best as this depends on your experience and skills.

Caring for spiderlings (slings).

Caring for spiderlings (slings).

If you've unexpectedly been gifted a batch of baby spiders from your adopted female jumping spider, connect with others seeking pets (reach out to us as we can help you find them), or release them into the wild during mild weather (for local species). Adult jumping spiders enjoy sun exposure, but young spiders are susceptible to drying out quickly. Therefore, releasing them in a protected location that offers shelter options from both sun and rain is crucial.

spiderlings - tiny baby jumping spider

Once the baby spiders leave the sac, you can start separating them. Still, as mentioned before, they can be kept together until they reach the 3rd or 4th instar, when they look roughly the size of a house fly, or if you notice any aggressive behaviour. As the spiders grow larger, they should be placed into individual enclosures. It is also possible to introduce larger insects as food, but it is important to avoid ants as they are not a suitable food source and can also spray formic acid when threatened, which is toxic to spiders. Additionally, it is essential to provide water to the spiders; our feeding bottles with a cotton plug are a great option to ensure the tiny spiders do not drown.

Housing for spiderlings.

Housing for spiderlings.

When they hatch, the baby spiders are known as 1st instar (i1). As soon as they leave the sac as 2nd instar (i2), they will be hungry. Young spiders are tiny and will require small prey, such as springtails or fruit flies. You can purchase fruit flies at local pet stores or save money by keeping your own fruit fly cultures using our fruit fly culture kit. Starting a new culture every week or two will ensure a steady supply of live flies for your baby spiders.

Since spiders lay many eggs at once, purchasing expensive enclosures to separate them all may be overwhelming. Instead, 4 oz deli cups with lids or any small clear plastic container can be used as an alternative. For ventilation, you can poke holes in the lid and walls. If the holes are too big, you can glue small pieces of mesh pantyhose over them to prevent escapees. We suggest using a tiny needle for this purpose. To provide climbing surfaces, add a small piece of coiled pipe cleaner or small fake plastic plants; for a hide, glue a small piece of hollow tubing inside the cup (straw).

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