Brown Widow

Latrodectus geometricus

The brown widow (Latrodectus geometricus) is a widow spider in the comb-footed family Theridiidae. Probably African in origin, it has travelled with people to warm regions around the world, where it builds tangle webs on fences, outdoor furniture and play equipment. Females have an orange-yellow hourglass under the abdomen and make spiky egg sacs that are easy to recognise. Bites are uncommon and usually milder than a black widow’s.

Also known as brown button spider, house button spider, geometric button spider

Brown widow abilities

Orange hourglass, not red
Flip a female over and you’ll usually see an orange or yellowish hourglass under the abdomen. It is a clue, but not the whole answer.
- The brown widow’s hourglass usually has a bigger bottom half with rough edges. A young black widow’s has a bigger top half with crisp, straight edges.
- Young black widows also have pale hourglass marks that turn orange-red as they grow, so the two are easy to mix up.
- Experts also look at the abdomen: brown widows have large, squarish black spots on the side stripes.
Sources [1, 2]
≈130 eggs per sac
A female wraps about 130 eggs in a round silk sac covered in spikes. She can make 20 or more of them in her life.
- The spiky sac looks like a giant pollen grain and is the surest way to tell a brown widow from a young black widow.
- A female can have several egg sacs developing at the same time.
- The eggs themselves are covered in tiny spheres that fight bacteria.
- The silk keeps out most water-based bug sprays, so spraying egg sacs rarely works.
Sources [2, 11, 12]
0–5% egg sacs parasitised in dense colonies
Tiny wasps try to lay their eggs inside widow egg sacs. The brown widow’s silk spikes, and a watchful mother, help keep them out.
- When scientists removed the spikes from half of an egg sac, wasps laid more eggs on the bare side.
- Females that had met a wasp made later egg sacs with even more spikes.
- Mothers guard their sacs, and in tests they dodged and killed the wasps.
- In Israel, very dense brown widow colonies had only 0–5% of egg sacs parasitised, while the native white widow had up to 55%.
Egg sacs parasitised by wasps
Brown widow (dense colonies)0–5%
White widow (native to Israel)up to 55%
Field surveys in Israel.
Sources [13, 14]
3D tangle of silk
Instead of a neat wheel, the brown widow strings an untidy 3D tangle of silk out from a hiding hole.
- Comb-footed spiders often build these tangle webs, which is why the family is also called cobweb or tangle-web spiders.
- Some lines run down to the ground and carry sticky silk, which catches prey walking past.
- The spider waits in its retreat at the edge of the web.
Sources [2, 9]
Drop then play dead
Disturb a brown widow and it usually doesn’t bite. It pulls its legs in, drops out of the web and plays dead.
- Scientists call playing dead thanatosis.
- This habit is one reason bites are unlikely.
- A curled-up widow can look like a bit of debris, so never pick one up.
Sources [2]
Lips & handles favourite hiding spots
Brown widows tuck themselves into sheltered gaps outdoors, often exactly where people put their fingers.
- In southern California they hid under the curled lips of plant pots and in the recessed handles of plastic bins.
- Picnic tables, lawn chairs, play equipment and fences are favourite spots too.
- In Malaysia, two men were bitten on the ear by brown widows that had settled inside their motorcycle helmets.
Sources [2, 4, 5]
15 of 45 widow bites in one study, all mild
Like all widows, the brown widow has a nerve-acting venom. In people, its bites are usually mild and stay near the bite.
- The main toxin, α-latrotoxin, is similar to the black widow’s. Other toxins target insects.
- In a South African series of 45 widow bites, the 15 brown widow bites were mild, while black widow bites were more severe.
- A few bites have been more serious, and doctors have treated them successfully with widow antivenom.
- California researchers found brown widow bites less toxic than western black widow bites.
Widow bites in a South African study (1987–1992)
Brown widow15 (mild)
Black widow30 (more severe)
Brown widow symptoms mostly stayed near the bite.
Sources [3, 5, 6, 10, 15, 16]
1 scorpion recorded meal in Brazil
Walking prey can get stuck on the sticky lines of the web. The brown widow’s venom includes toxins made for insects.
- These insect toxins, the latroinsectotoxins, are separate from the toxin that affects people.
- In Brazil, a brown widow was recorded eating a scorpion.
- The sticky ground lines of comb-footed spiders are good at catching walking prey.
Sources [9, 10, 17]

Tap a pin on the model or a part below.

Orange hourglass under the belly
- Under the round abdomen sits an hourglass mark. In the brown widow it is usually orange or yellowish, not the red of a black widow.
- Compared with a young black widow, the brown widow’s hourglass has a bigger bottom half and rougher edges.
- The hourglass alone is not a safe ID: young black widows also have pale, orange-ish marks, so experts check the egg sacs too.
Sources [1, 2]
≈10 mm adult female body
- The usual colour is a mottled mix of tan, brown and grey, but brown widows vary a lot. Very dark ones look flat black rather than shiny black.
- Along the sides of the abdomen run stripes with large, squarish black spots.
- Adult females are about 10 mm long, smaller than an adult western black widow (about 13 mm).
Sources [2]
α-latrotoxin main venom protein
- The fangs (chelicerae) inject venom that is similar to a black widow’s. Its main ingredient is a nerve toxin called α-latrotoxin.
- Brown widows don’t hunt people. Bites happen when a spider is pressed against skin, for example inside a motorcycle helmet or under the lip of a plant pot.
- Documented bites are rare, and most are mild.
Sources [3, 4, 5, 6]
4–5 mm adult male body
- Palps are the small leg-like feelers beside the fangs. In adult males they are swollen at the tips and are used for mating.
- Males are tiny, only 4–5 mm long, so they are easy to overlook.
- A male finds a female by her scent, carried in the air and on her silk, then courts her with vibrations on the web.
Sources [2, 7, 8]
Leg 4 has a bristle comb
- Widows belong to the comb-footed spiders. Each back leg has a comb of toothed bristles on its foot.
- The family, Theridiidae, has about 3,000 species and is the most common group of arthropods found in houses worldwide.
- When disturbed, a brown widow pulls its legs in tight, drops from the web and keeps still.
Sources [2, 9]
- Silk comes out of the spinnerets at the tip of the abdomen.
- Brown widows spin untidy tangle webs that spread out from a hiding hole.
- In comb-footed spiders, some lines run down to the ground and carry sticky silk that traps walking prey.
Sources [2, 9]
- The venom holds α-latrotoxin, which acts on vertebrates, plus latroinsectotoxins that target insects.
- Scientists found α-latrotoxin being made in every life stage they tested, from spiderlings to adults.
- No latroinsectotoxins were found in the eggs.
Sources [3, 10]
≈130 eggs per sac
- The egg sac is covered in little silk spikes, like a very large pollen grain. It is the surest sign of a brown widow.
- A female lays about 130 eggs per sac and can make 20 or more sacs in her life, sometimes several at once.
- The eggs inside are coated with tiny spheres that help keep bacteria out.
Sources [2, 11]
Playgrounds a favourite spot in California
- In Los Angeles, scientists found brown widows all around homes, in parks, in plant nurseries and especially under playground equipment.
- They were very rare in garages, crop fields and natural areas, and none were found in the living spaces of homes.
- They also sit in more open places, such as chain-link fences, where black widows are rarely found.
Sources [2, 5]

Real brown widows

Photos from Wikimedia Commons. Some of them can repaint the 3D model.

Adult femaleAbout 10 mm long with a round abdomen, mottled tan, brown and grey, and an orange hourglass underneath.Builds the tangle web and guards the egg sacsThe orange hourglass, Los Angeles, California. Photo: Mfield (Matthew Field), GFDL 1.2
Female with egg sacsA female beside her pale, spiky egg sacs. She can have several at once.Guards the sacs from egg-laying waspsA female with three spiky egg sacs. Photo: SidShakal, CC BY-SA 3.0
Adult maleOnly 4–5 mm long, with swollen palp tips. Much smaller than other widow spiders, so easy to miss.Finds females by scent and courts them with web vibrationsMale and female together, Fullerton, California. Photo: Davefoc, CC BY-SA 4.0
Playing dead after dropping from the webPhoto: JonRichfield, CC BY-SA 3.0
Adult femaleAbout 10 mm long with a round abdomen, mottled tan, brown and grey, and an orange hourglass underneath.Builds the tangle web and guards the egg sacsKgalagadi Transfrontier Park, South Africa. Photo: Bernard DUPONT, CC BY-SA 2.0
Female with egg sacsA female beside her pale, spiky egg sacs. She can have several at once.Guards the sacs from egg-laying waspsEgg sacs in Vietnam. Photo: Sundance Kid VN, CC BY-SA 4.0
Adult maleOnly 4–5 mm long, with swollen palp tips. Much smaller than other widow spiders, so easy to miss.Finds females by scent and courts them with web vibrationsA male in San Diego, California. Photo: LFrImagery, CC BY-SA 3.0
Adult femaleAbout 10 mm long with a round abdomen, mottled tan, brown and grey, and an orange hourglass underneath.Builds the tangle web and guards the egg sacsLow view with the hourglass showing, Los Angeles. Photo: Mfield (Matthew Field), GFDL 1.2
Adult femaleAbout 10 mm long with a round abdomen, mottled tan, brown and grey, and an orange hourglass underneath.Builds the tangle web and guards the egg sacsA house button spider in Pretoria, South Africa. Photo: JMK, CC BY-SA 4.0
Adult femaleAbout 10 mm long with a round abdomen, mottled tan, brown and grey, and an orange hourglass underneath.Builds the tangle web and guards the egg sacsOn a grass leaf in São Carlos, Brazil. Photo: Leoadec, CC BY-SA 3.0

Brown widow by the numbers

Measured by scientists, with comparisons you can picture.

Female body: ≈10 mm; adult female, legs not included⁠[2]; Female10 mmMale4.5 mm
Male body: 4–5 mm; smaller than other widow spiders⁠[2]
Eggs per sac: ≈130; in one spiky silk sac⁠[2]
Egg sacs: 20+; in one female’s life; 20 sacs × 130 eggs ≈ 2,600 eggs⁠[2]
Wasp-hit sacs: 0–5%; in very dense colonies in Israel⁠[14]; Brown widow5 %White widow55 %
Tahiti egg sacs: 31%; held a parasitoid wasp⁠[19]
Egg sac heat limit: 55 °C; for 10 minutes stopped all hatching⁠[20]
Brown widow bites: 15 of 45; widow bites in a South African study, all mild⁠[6]
US widow species: 5; the brown widow is one of them⁠[15]
Widow species: ≈30; in the genus Latrodectus (2004 count)⁠[21]

Brown widow myths and facts

Brown widows are often in the news. Here is what the evidence says.

0 of 8 answered

“Brown widows are more dangerous than black widows because their venom is stronger.”
“An orange hourglass is all you need to identify a brown widow.”
“The spikes on brown widow egg sacs are just for show.”
“Brown widows chase people to bite them.”
“Brown widows mostly live inside people’s houses.”
“Spraying an egg sac with bug spray kills the eggs.”
“Female widows always eat their mates.”
“Brown widows are spreading around the world.”

Brown widow records

Superlatives and big numbers, each checked against its source.

The globetrotter widow
Nearly worldwide
Brown widow
has spread around the world more successfully than its famous cousins, the black widow and the redback⁠[25, 23]
Hard to parasitise
0–5%
Brown widow colonies in Israel
of egg sacs parasitised, even in very dense colonies; a native widow had up to 55%⁠[14]
Egg-sac machine
20+ sacs
Female brown widow
in one life, about 130 eggs each⁠[2]
First scorpion on the menu
1st
A brown widow in Brazil
the first recorded case of a brown widow eating a scorpion⁠[17]
Heat-proof up to a point
52.8 °C
Brown widow egg sacs in Japan
the heat that stopped 90% of eggs hatching after 10 minutes; at 55 °C none hatched⁠[20]

A brown widow’s life

From spiky egg sac to tangle web.

Egg sac
About 130 eggs
A female wraps about 130 eggs in a spiky silk sac. The eggs are coated with tiny spheres that fight bacteria.⁠[2, 11]
In the sac
A guarded nursery
The mother stays close and fights off egg-laying wasps. The spikes help too.⁠[13]
Hatching
Spiderlings with venom
Tiny spiderlings crawl out. They already make α-latrotoxin, the main venom toxin.⁠[10]
Up to 40 days
Sharing the web
Females tolerate young spiderlings on their web, even other females’ young.⁠[18]
About 80 days
No longer welcome
By about 80 days after hatching, young spiders on a female’s web get attacked rather than tolerated.⁠[18]
Adult male
The search
The tiny male follows a female’s scent and courts her with vibrations on her web.⁠[8]
Adult female
A web of her own
She builds a tangle web in a sheltered spot and can make 20 or more egg sacs, sometimes several at once.⁠[2]

How the brown widow spread around the world

Brown widows hitchhike with people. Genetics shows that spiders from different continents are very closely related, a sign of recent travel.

Africa?
likely home
Its closest relative is an African widow, and scientists treat South Africa as part of its native range. Some still think it could have started in South America.⁠[21, 26, 1]
By 1841
South America
Brown widows were living in South America by at least 1841.⁠[25]
Decades
Florida only
For many decades, the only North American brown widows were in Florida. Surveys in 2006–2008 found them in Georgia, Texas, Louisiana and Mississippi too.⁠[2, 23]
2000s
southern California
They became established in southern California in the 2000s and now greatly outnumber western black widows around homes.⁠[5]
2006
French Polynesia
First recorded on Moorea, they then spread to Tahiti and the Cook Islands.⁠[19]
2 lineages
Japan
Brown widows near Tokyo belong to two genetic groups, a sign they arrived more than once.⁠[24]

Are brown widows pushing black widows out? They outnumber western black widows in urban California, but scientists have not proven they are replacing them. If they are, bites may actually become milder overall.

Staying safe around brown widows

Brown widows don’t hunt people, and most bites are mild. A few simple habits prevent almost all bites.

Shake
shoes, gloves and clothes
Shake out shoes, gloves, towels and clothes that have been left outside or in a shed before you use them.⁠[27]
Look
before you grab
Don’t put your fingers where you can’t see, like under pot rims, bin handles, chair seats and play equipment.⁠[5, 2]
Gloves
for clearing up
Wear gloves when moving clutter, wood or garden things, and store gardening gloves in a sealed bag.⁠[2, 27]
Check
helmets and boots
Look inside helmets and boots that have been stored for a while.⁠[4, 27]
Wash
if bitten
Tell an adult. Wash the bite with soap and water, hold a cold, damp cloth on it and raise the bitten arm or leg if you can.⁠[27]
Doctor
get it checked
Get medical advice, and take a photo of the spider if that is safe. Widow antivenom exists and has been used for brown widow bites.⁠[27, 2, 3]

Never pick up a widow spider. To remove one from indoors, an adult can trap it under a jar, slide paper underneath and take it outside.

Brown widow vs black widow vs false widow

Two true widows and the look-alikes most often mistaken for them. All three are comb-footed spiders.

Brown widow spider vs western black widow vs false widow spiders
	Brown widow	Western black widow	False widows
Scientific name⁠[2]	Latrodectus geometricus	Latrodectus hesperus	Steatoda grossa, Steatoda nobilis and others
Family⁠[2]	Theridiidae	Theridiidae	Theridiidae
Adult female body⁠[2]	≈10 mm	≈13 mm	≈10 mm (false black widow)
Colour⁠[2]	Mottled tan, brown and grey	Shiny jet black	Chocolate brown, or tan with a pale pattern
Belly mark⁠[1, 2]	Orange or yellowish hourglass	Red hourglass	Never a red mark
Egg sac⁠[2]	Round, covered in silk spikes	Smooth, yellowish teardrop	—
Bites⁠[6, 2, 28, 29]	Usually mild, near the bite	Can be more severe; antivenom exists	Noble false widow: mostly mild to moderate
In southern California⁠[5, 2]	Common around homes, parks and playgrounds	Mostly in dry habitats, less around homes	False black widow: very common in Pacific Coast homes

Not sure? Don’t touch it. Look for the egg sac: the spiky brown widow sac is the easiest clue.

Is the brown widow endangered?

No. It has never been assessed for the IUCN Red List, and its range is still growing.

IUCN Red List

Not Evaluated (NE)

Population increasing

It is common around people in many warm countries. It is reportedly listed as Least Concern in South Africa’s national assessment.⁠[30, 31, 1]

Not evaluated by the IUCN (checked October 2026)

Threats

No known major threats
It thrives in towns and gardens and keeps reaching new places.⁠[22, 25, 24]
Egg-sac wasps31%
A tiny wasp, Philolema latrodecti, was found in 31% of brown widow egg sacs on Tahiti.⁠[19]
Pest control
People remove widows with vacuums and sprays, but insecticides don’t give long-term control.⁠[2]

What’s helping

Correct ID
Checking the egg sac helps people tell brown widows from black widows and harmless look-alikes.⁠[2]
Tracking the spread
Genetic studies show where new brown widows came from and how often they arrive.⁠[24, 21]
Tidy, not toxic
Clearing clutter and sweeping webs works better than spraying, and spares other wildlife.⁠[2, 12]

Brown widow quiz

12 questions. Every answer is somewhere on this page.

Question 1 of 12Score 0

What colour is the hourglass under a brown widow’s belly?

Brown Widow field notes

Diet, food web, safety and badges from the Snappit field guide.

Diet & Feeding

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

Primary Foods

Ants
Beetles
Flies
Crickets
Other spiders
Foraging Method: Ambush

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

Ecological connections

Blue Mud DauberEaten by
The blue mud dauber wasp paralyzes brown widow spiders to stock its nests for its developing larvae.
Argentine AntCompetitor
Argentine ants frequently compete for territory and can swarm and prey upon brown widow spiders, especially spiderlings and egg sacs.
Southern Black WidowPossible competitor
Brown widows now greatly outnumber black widows around homes in parts of southern California, but it has not been proven that they push black widows out.

Safety

Danger 3/5 · Moderate

Never touch or pick up a widow spider, even one that looks dead or curled up. Don't put your fingers where you can't see, such as under pot rims or bin handles. If you see one, tell an adult. If you are bitten, tell an adult right away, wash the bite with soap and water and get medical advice.

Classification

Kingdom: Animalia
Phylum: Arthropoda
Class: Arachnida
Order: Araneae
Family: Theridiidae
Genus: Latrodectus

Also known as

brown button spider · house button spider · geometric button spider · grey widow

Sources for these brown widow facts

31 studies and references · checked Oct 16, 2026

Frequently Asked Questions

How to identify Brown Widow?

Compare body proportions, leg shape, abdomen markings and the web, if there is one. Eye arrangement can be decisive but rarely shows up in a casual phone photo. A web is a supporting clue, not proof of who built it. Spider Identifier: upload a photo and compare the visible details.

How long is Brown Widow?

0.4-1 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 sheltered gaps outdoors, such as under plant-pot rims, chair seats and play equipment, in bin handles and on fences. In one Los Angeles survey they were very rare in garages and none were found in the living spaces of homes.

How does Brown Widow hunt?

Ambush

How many eggs does Brown Widow lay?

50-150

Is the brown widow spider dangerous?

It is venomous, but bites are uncommon and usually mild. In one South African study, all 15 brown widow bites were mild and stayed near the bite. A few bites have been more serious, so anyone bitten should get medical advice.

How can you tell a brown widow from a black widow?

Adult brown widows are mottled tan, brown and grey with an orange or yellowish hourglass. Black widows are shiny black with a red hourglass. Young black widows can look similar, so the spiky brown widow egg sac is the best clue.

What do brown widow egg sacs look like?

They are round, pale and covered in little silk spikes, a bit like a giant pollen grain. Black widow egg sacs are smooth and teardrop-shaped.

What should I do if a brown widow bites me?

Tell an adult. Wash the bite with soap and water, put a cold, damp cloth on it, raise the bitten arm or leg and get medical advice. Widow antivenom exists for serious cases.

Where do brown widows hide?

In sheltered gaps outdoors: under plant-pot rims and chair seats, in bin handles, on fences and under play equipment. In one Los Angeles survey, none were found in the living spaces of homes.

Where did the brown widow come from?

Probably Africa. Its closest relative is African, and spiders from different continents are almost identical genetically, which shows that people have carried them around the world fairly recently.

Are brown widows replacing black widows?

In urban southern California, brown widows now greatly outnumber western black widows around homes. Scientists haven’t proven they are pushing black widows out, but if they are, bites may become milder overall.

How many eggs does a brown widow lay?

About 130 eggs per egg sac, and a female can make 20 or more sacs in her life. That is roughly 2,600 eggs if she makes 20 sacs.