Pest Library
Southern Black Widow
The southern black widow is a glossy black spider with a red hourglass marking on the underside of the abdomen. It builds a tangled, irregular web in dark, undisturbed low places — garages, meter boxes, crawl spaces, under patio furniture and inside stored items.
Profile
- Scientific name
- Latrodectus mactans
- Identification
- Mature females are shiny black with a red hourglass beneath the abdomen. Egg sacs are smooth, round and grayish-white.
- Typical size
- Female body about 1/2 inch, with a leg span up to 1.5 inches.
- Behavior
- Shy and reluctant to leave the web. Bites usually occur when someone reaches into a hidden space or puts on stored gloves or shoes.
- Habitat
- Meter and irrigation boxes, garage corners, crawl spaces, woodpiles, stored boxes and outdoor furniture.
- Diet
- Insects captured in the web.
- Lifecycle
- Females guard multiple egg sacs; activity peaks through the warm season.
- Why it matters
- Black widow venom is medically significant. If you believe you have been bitten, seek medical care promptly — do not wait to see how it develops. Wear gloves when moving stored items where widows may be hiding.
- DIY considerations
- Web removal and decluttering are effective and safe; reaching blindly into stored items is the main risk to avoid.
- Professional considerations
- Service includes web removal, targeted treatment of harborage areas and recommendations for reducing clutter and insect prey.
Signs of activity
- Irregular tangled webs in low, sheltered corners
- Smooth round egg sacs in the web
- Shed skins and insect remains in web debris
- Spiders in stored boxes, gloves or seldom-used equipment
Prevention
- Wear gloves when handling stored boxes, firewood and outdoor equipment
- Reduce clutter in garages, sheds and crawl spaces
- Knock down webs regularly around meter boxes, eaves and furniture
- Reduce exterior insect attraction from lighting
- Seal gaps into garages and crawl spaces
Sources
Related information
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