How To Breed & Raise Black Widows

Preparation & Pairing

Black widows are solitary, defensive spiders with potent venom. Breeding them is not difficult, but safety and containment must be your top priorities. A single egg sac can produce 100–400 spiderlings, so plan ahead.

Before Pairing, Make Sure You Have:

  • A mature male and female
  • Escape‑proof enclosures
  • Feeder insect cultures (melanogaster, hydei, pinhead crickets)
  • Nymph containers — deli cups, vials, or tubs
  • Long tweezers, catch cups, and gloves

Determining Sexual Maturity

  • Females: Large, glossy black, with the classic red hourglass. Mature females have a full, rounded abdomen and fully developed coloration.
  • Males: Much smaller, long‑legged, brownish, with reduced venom and distinct pedipalps used for mating.

Conditioning Before Pairing

Widow females commonly cannibalize males, especially if hungry.

To reduce risk:

  • Feed the female heavily for several days before pairing.
  • Offer a large roach or cricket immediately before introducing the male.
  • Ensure the male is well-fed and active.

Place their enclosures near each other for 24–48 hours so the male can detect the female’s pheromones.

Setting Up the Pairing

A 32oz deli cup, or the females main enclosure works well. The male needs room to approach safely.

Pairing Steps

  1. The female should have a proper web.
  2. Introduce the male on the opposite side of the enclosure.
  3. Keep a catch cup ready in case the male panics or the female becomes aggressive.

Courtship Behavior

Males typically:

  • Tap and pluck the female’s web
  • Vibrate their abdomen
  • Approach slowly and cautiously

If the female is receptive, she will:

  • Remain still
  • Allow the male to climb onto her abdomen
  • Permit copulation, which may last several minutes to over an hour

Important Notes

  • Cannibalism is common even after successful mating.
  • Remove the male as soon as he dismounts if you want to preserve him.
  • Some females may mate multiple times in one session.

Egg Sacs & Spiderlings

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After mating, a female may produce 5+ egg sacs, each containing 100–400 eggs.

Egg Sac Production

The female will:

  • Build a dense, messy web
  • Create a round, papery egg sac
  • Guard it aggressively

Egg sacs hatch in 20–30 days depending on temperature.

Monitoring the Female

Females usually continue eating while guarding sacs, but if she becomes thin:

  • Gently coax her away with a soft brush
  • Offer a feeder
  • Return her once she has eaten

Removing the Egg Sac

You may:

  • Leave it with the female
  • Remove it for controlled hatching

If removing:

  • Use long tweezers
  • Place the sac in a ventilated 32oz deli cup with mesh‑covered holes
  • Add a small piece of excelsior for emerging spiderlings

Widow slings are extremely small and can escape through tiny ventilation holes. Use fine mesh or micropore tape to secure openings.

Caring For Slings

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Supplies Needed

  • 32oz deli cups
  • 5.5oz deli cups or spiderling tubes
  • Fine mesh or micropore tape
  • Excelsior or fake plants
  • Fruit fly cultures (melanogaster & hydei)
  • Mister bottle

Start multiple feeder cultures before hatching.

Communal Housing

Black widow slings can be kept communally for a short time:

  • L1–L2 can remain together in a 32oz deli cup
  • Provide dense climbing material
  • Feed heavily to reduce cannibalism

Separating Slings

Widow slings should be separated once they reach i2–i3.

Recommended progression:

  • i1–i2: Communal
  • i2–i3: Begin separating
  • i3–i5: 5.5oz deli cups
  • i5–Adult: 16–32oz enclosures

Widows grow slowly compared to jumping spiders.

Feeding

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Feeding Schedule

  • i1–i2: Melanogaster fruit flies daily
  • i2–i3: Hydei fruit flies every 1–2 days
  • i3–i4: Pinhead crickets or small roaches every 2–3 days
  • i5–Adult: Appropriately sized prey every 4–6 days

Important Feeding Notes

  • Remove uneaten prey
  • Widow slings dehydrate easily — mist lightly every 2–3 days
  • Adults require less frequent feeding than juveniles

Safety Notes (Critical)

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  • Black widows are medically significant.
  • Never handle them directly.
  • Always use long tweezers and secure lids.
  • Keep enclosures double‑contained (inside a larger bin or rack).
  • Label all containers clearly.
  • Never allow slings to roam freely — they disperse rapidly.
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