Black widow spiders: common, shy and best left to us.

Identifying black widows

Latrodectus hesperus

Adult female western black widows are glossy black with a round abdomen and a red hourglass on the underside. Their bodies are roughly half an inch long, with long legs. Males are smaller and brownish, and young spiders are often tan or gray with orange and white markings, so not every widow looks like the classic picture.

Black widows build messy, irregular webs with very strong silk, usually low to the ground in dark, protected places. The female hangs upside down in the web at night and retreats into a crevice during the day. Their round, papery egg sacs are tan and hold many spiderlings.

West Valley homes have plenty of spots they like: weep holes and gaps in block walls, meter and irrigation boxes, pool equipment, patio furniture, BBQ grills, stacked pots and cluttered garage shelves. Crickets and other insects drawn to porch lights give them a steady food supply.

Why they matter

Black widows are shy and bite mainly when pressed against skin, like when you reach into a glove, shoe or meter box. Children and older adults are especially at risk. Bites can be medically significant: call Poison Control at 1-800-222-1222, or 911 for a severe reaction.

Signs of activity

• Tangled, sticky webs low in garage corners, under furniture or along block walls
• Round, tan, papery egg sacs hanging in webs
• Shiny black spiders hanging upside down in webs after dark
• Webs inside meter boxes, irrigation boxes or around pool equipment
• Lots of crickets and other insects around exterior lights

Prevention tips for Arizona homes

• Wear gloves when gardening, moving stacked pots or opening meter and irrigation boxes
• Clear clutter on garage shelves and floors, and store items in sealed plastic bins
• Shake out shoes, gloves and clothes left in the garage or patio before using them
• Knock down webs and egg sacs regularly around patio furniture and grills
• Switch porch lights to yellow bulbs to draw fewer insects to the house
• Seal gaps in block walls and around garage doors where spiders shelter

When to call a pro

If you keep finding widows in the garage or around the house, there is an established population and likely a lot of insects feeding them. Bryce treats harborage areas, clears webs and egg sacs, and cuts down their food source. Monthly plans include free re-service between visits.