Brown Widow

latrodectus geometricus

The brown widow spider (Latrodectus geometricus) is a highly adaptable, cosmopolitan arachnid closely related to the famous black widow. Originally believed to be native to Africa or South America, this resilient species has successfully established itself in urban and suburban environments throughout tropical and subtropical regions worldwide. While they possess potent neurotoxic venom, brown widows are generally shy and non-aggressive, preferring to retreat into their messy, tangled webs when disturbed rather than confront a threat. What truly sets the brown widow apart is its incredible reproductive rate and unique, spiky egg sacs, which look like tiny, pale yellow landmines. They play a significant role in local ecosystems by consuming a wide variety of pest insects, though they also pose ecological challenges in areas where they displace native spider species, including their native black widow cousins.

Habitat: Typically found in dark, dry, sheltered environments, often preferring artificial structures such as under outdoor patio furniture, inside recessed fence panels, and within garages or sheds.

Appearance

Brown widows are medium-sized spiders featuring a mottled mix of tan, grey, and dark brown on their bulbous abdomens, accented by geometric patterns and white stripes. On their underside, they display a signature hourglass-shaped marking that is a bright orange or yellow color, rather than the crimson red of a black widow. Their long, slender legs are distinctly banded with dark brown and light tan stripes. Females measure up to sixteen millimeters in body length, while the tiny, inconspicuous males are barely half that size.

KingdomAnimaliaPhylumArthropodaClassArachnidaOrderAraneaeFamilyTheridiidaeGenusLatrodectus

Brown Widow

Interesting facts

Although their venom is actually more toxic drop-for-drop than that of a black widow, brown widows are far less dangerous because they inject significantly less venom and are very hesitant to bite.

Brown widows often perform 'death feigning' or thanatosis when threatened, curling their legs tightly into a ball to appear dead and escape predator attention.

Unlike the smooth, round egg sacs of black widows, the brown widow constructs highly distinctive silk sacs covered in tiny, spiky silk projections, resembling tiny landmines.

Special abilities

Constructs highly distinctive silk egg sacs covered in tiny, spiky projections that serve as a physical deterrent against predators and parasitic wasps.

Weaves exceptionally strong, highly irregular tangled webs with sticky drop lines that easily snag heavy, crawling insects.

Exhibits thanatosis by curling up its legs and dropping to the ground to blend in with debris when a large threat is detected.

Measurements & details

Length: 1-2 cm
Weight: 0.0001-0.0005 kg
Lifespan: 1-2 years
Clutch Size: 50-150
Incubation: 14-30 days

Diet & Feeding

Feeds primarily on flying and crawling insects caught in its tangled webs, including ants, beetles, and crickets.

Age differences: Spiderlings feed on tiny invertebrates like fruit flies, while mature adults tackle larger prey like beetles.

Primary Foods

Ants
Beetles
Flies
Crickets
Other spiders

Foraging Method

Ambush

Ecological connections

eaten by

Blue Mud Dauber

Chalybion californicum

The blue mud dauber wasp paralyzes brown widow spiders to stock its nests for its developing larvae.

competitor

Argentine Ant

Linepithema humile

Argentine ants frequently compete for territory and can swarm and prey upon brown widow spiders, especially spiderlings and egg sacs.

competitor

Southern Black Widow

Latrodectus mactans

The brown widow often displaces the native southern black widow in urban habitats through competitive exclusion.

Traits

No trait badges are assigned for this object yet.

Also known as

No aliases listed yet.

Collections

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Safety

Danger

1/5 · Very low

No special safety notes yet.

Frequently Asked Questions

How to identify Brown Widow?

The easiest way to identify Brown Widow is to use the Snappit nature identifier app.

How long is Brown Widow?

1-2 cm

How much does Brown Widow weigh?

0.0001-0.0005 kg

How long does Brown Widow live?

1-2 years

What does Brown Widow eat?

Feeds primarily on flying and crawling insects caught in its tangled webs, including ants, beetles, and crickets.

Where is Brown Widow usually found?

Typically found in dark, dry, sheltered environments, often preferring artificial structures such as under outdoor patio furniture, inside recessed fence panels, and within garages or sheds.

How does Brown Widow hunt?

Ambush

How many eggs does Brown Widow lay?

50-150