🕷️ Spiders

Black widow

Latrodectus mactans

Glossy black, red hourglass underneath, and almost always outdoors.

Size
Female body about half an inch; males are much smaller and not a concern
Colour
Glossy jet black
Risk
Medically significant
When
Most active and most often encountered in warm months

How to identify it

Work down these in order — the first one is usually enough on its own.

  • A red hourglass on the underside of the abdomen — you have to look from below
  • Very glossy, rounded abdomen
  • Irregular, strong, messy web rather than a neat orb
  • Often hangs upside down in the web

What it gets mistaken for

Most people arrive at a pest name by ruling things out. These are the ones that genuinely look similar, and the detail that separates them.

Where you will find it

  • Under eaves, in garage corners and sheds
  • Woodpiles, stacked bricks and stone
  • Inside water meter boxes and utility covers
  • Under outdoor furniture and children's play equipment

Signs it is already there

You will nearly always see the evidence before you see the pest itself.

  • Strong, irregular webbing in sheltered outdoor corners
  • Round tan egg sacs about half an inch across in the web
  • Consistent sightings in the same low sheltered spot

Medically significant. Can cause injury. Seek medical attention if you are bitten or stung.

Why it is harder to deal with than it looks

They favour exactly the places people reach into without looking — meter boxes, under furniture, inside stored items. That, rather than aggression, is how most bites happen.

What actually works

Wear gloves when moving stored outdoor items, woodpiles or furniture. Check before reaching into meter boxes or under seating. Remove webs regularly from eaves and corners, keep woodpiles away from the house and off the ground, and clear clutter from the garage perimeter.

Common questions

How do I tell a black widow from a cellar spider?

Cellar spiders are pale with very long thin legs and no red marking.

How do I tell a black widow from a brown recluse?

Recluses are brown, not black, and have no red marking at all.

Where are black widow usually found in a home?s

Under eaves, in garage corners and sheds Woodpiles, stacked bricks and stone Inside water meter boxes and utility covers.

Is a black widow dangerous?

Medically significant. They are not aggressive and bite defensively, usually when pressed against skin. If bitten, seek medical attention promptly.

Identification guidance only. Under Texas law, applying pest control treatments for hire requires a licence from the Texas Department of Agriculture. This page describes what a pest looks like — it is not a diagnosis of your property or a treatment recommendation for it.