# Brown Widow (*Latrodectus geometricus*)

The brown widow spider (Latrodectus geometricus) is a comb-footed spider and a relative of the black widow. It probably came from Africa, but people carried it to warm places all over the world, where it builds untidy tangle webs on fences, outdoor furniture and play equipment. It is venomous, but it is shy: it usually drops from its web and plays dead instead of biting, and bites are uncommon and usually mild. Its round egg sacs, covered in tiny silk spikes, are the surest sign of a brown widow. Never touch one.

- **Category:** [Invertebrate](https://www.snappit.app/explore/categories/invertebrate)
- **Rarity:** Common
- **Danger:** 3/5 · Moderate
- **Snaps:** 5
- **Habitat:** 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.

![Brown Widow](https://inaturalist-open-data.s3.amazonaws.com/photos/2558788/medium.JPG)

Photo: Jesse Rorabaugh, CC BY 4.0 · [iNaturalist](https://www.inaturalist.org/photos/2558788)

## 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. Adult females are about ten millimeters long, while the tiny, inconspicuous males are only four to five millimeters.

## Taxonomy

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

## Brown widow, up close

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 called: brown button spider, house button spider, geometric button spider, grey widow.

A comb-footed spider with an orange hourglass and spiky egg sacs, now found in warm places all over the world. Find the hourglass, check the egg sacs, then test yourself.

### Special abilities

- **Hourglass Check** (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. [1][2]
  - 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.
- **Spiky Egg Sacs** (≈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. [2][11][12]
  - 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.
- **Spike Shield** (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. [13][14]
  - 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%
- **Tangle Trap** (3D tangle of silk): Instead of a neat wheel, the brown widow strings an untidy 3D tangle of silk out from a hiding hole. [2][9]
  - 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.
- **Drop and Freeze** (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. [2]
  - 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.
- **Shadow Lodger** (Lips & handles favourite hiding spots): Brown widows tuck themselves into sheltered gaps outdoors, often exactly where people put their fingers. [5][2][4]
  - 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.
- **Venom Kit** (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. [3][10][6][15][16][5]
  - 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 widow 15 (mild); Black widow 30 (more severe)
- **Wrap and Eat** (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. [10][17][9]
  - 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.

### Body parts

- **Hourglass** (Orange hourglass under the belly) [1][2]
  - 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.
- **Abdomen pattern** (≈10 mm adult female body) [2]
  - 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).
- **Fangs** (α-latrotoxin main venom protein) [3][4][5][6]
  - 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.
- **Palps** (4–5 mm adult male body) [7][2][8]
  - 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.
- **Legs** (Leg 4 has a bristle comb) [9][2]
  - 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.
- **Spinnerets** [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.
- **Venom glands** [10][3]
  - 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.
- **Egg sacs** (≈130 eggs per sac) [2][11]
  - 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.
- **Web corner** (Playgrounds a favourite spot in California) [5][2]
  - 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.

### Stats

| Stat | Value | Notes |
|---|---|---|
| Female body | ≈10 mm | adult female, legs not included [2] |
| 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] |
| 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] |

### Photos

- [The orange hourglass, Los Angeles, California](https://commons.wikimedia.org/wiki/File:Brown_widow_spider_Latrodectus_geometricus_underside.jpg) (photo: Mfield (Matthew Field), GFDL 1.2)
- [A female with three spiky egg sacs](https://commons.wikimedia.org/wiki/File:Eggsacs_of_Latrodectus_geometricus_in_Captivity.jpg) (photo: SidShakal, CC BY-SA 3.0)
- [Male and female together, Fullerton, California](https://commons.wikimedia.org/wiki/File:LatrodectusGeometricus_8576FS.jpg) (photo: Davefoc, CC BY-SA 4.0)
- [Playing dead after dropping from the web](https://commons.wikimedia.org/wiki/File:Latrodectus_geometricus_female_in_thanatosis_IMG_2765s.JPG) (photo: JonRichfield, CC BY-SA 3.0)
- [Kgalagadi Transfrontier Park, South Africa](https://commons.wikimedia.org/wiki/File:Geometric_Button_Spider_(Latrodectus_geometricus)_(6857121274).jpg) (photo: Bernard DUPONT, CC BY-SA 2.0)
- [Egg sacs in Vietnam](https://commons.wikimedia.org/wiki/File:Nh%E1%BB%87n_g%C3%B3a_ph%E1%BB%A5_n%C3%A2u_Latrodectus_geometricus_(tr%E1%BB%A9ng).jpg) (photo: Sundance Kid VN, CC BY-SA 4.0)
- [A male in San Diego, California](https://commons.wikimedia.org/wiki/File:Latrodectus_geometricus.jpg) (photo: LFrImagery, CC BY-SA 3.0)
- [Low view with the hourglass showing, Los Angeles](https://commons.wikimedia.org/wiki/File:Brown_widow_spider_Latrodectus_geometricus_low_oblique_view.jpg) (photo: Mfield (Matthew Field), GFDL 1.2)
- [A house button spider in Pretoria, South Africa](https://commons.wikimedia.org/wiki/File:Latrodectus_geometricus%2C_wyfie%2C_Pretoria%2C_a.jpg) (photo: JMK, CC BY-SA 4.0)
- [On a grass leaf in São Carlos, Brazil](https://commons.wikimedia.org/wiki/File:Widow_spider_1.jpeg) (photo: Leoadec, CC BY-SA 3.0)

### Questions

- **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. [6][3][15][16]
- **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. [2][1]
- **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. [2]
- **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. [27][2][3]
- **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. [5][2]
- **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. [21][25][26]
- **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. [5]
- **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. [2]

### Brown widow myths and facts

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

- "Brown widows are more dangerous than black widows because their venom is stronger." **Myth!** In a South African study, brown widow bites were mild and stayed near the bite, while black widow bites were more severe. California researchers also found brown widow bites less toxic. You may read that its venom is stronger “drop for drop”, but we couldn’t find a study we could check. [6][5][2]
- "An orange hourglass is all you need to identify a brown widow." **Myth!** Young black widows also have pale or orange-ish marks, and an adult female brown widow looks a lot like a young western black widow. The spiky egg sac is a much surer clue. [2]
- "The spikes on brown widow egg sacs are just for show." **Myth!** When scientists removed spikes from half a sac, egg-laying wasps chose the bare side. Females that met wasps made spikier sacs afterwards. [13]
- "Brown widows chase people to bite them." **Myth!** When disturbed they pull in their legs, drop and play dead. Bites happen when a spider is trapped against skin, such as inside a helmet. [2][4]
- "Brown widows mostly live inside people’s houses." **Myth!** In a Los Angeles survey they were common outside homes, in parks and under play equipment, but none were found in the living spaces of homes. [5]
- "Spraying an egg sac with bug spray kills the eggs." **Myth!** In tests, almost all water-based sprays failed, because the silk keeps them out. Spiderlings hatched as if the sac hadn’t been sprayed. [12]
- "Female widows always eat their mates." **Myth!** Brown widow males that mate with adult females usually end up eaten. But males also mate with females that are one moult from adult, and those males are not eaten. [7][8]
- "Brown widows are spreading around the world." **Fact!** Carried by people, they now live in almost every country of the Americas and in parts of Asia, Australia and the Pacific. New populations keep turning up, for example in Japan. [22][23][24]

### Brown widow records

Superlatives and big numbers, each checked against its source.

- The globetrotter widow: Brown widow, Nearly worldwide (has spread around the world more successfully than its famous cousins, the black widow and the redback) [25][23]
- Hard to parasitise: Brown widow colonies in Israel, 0–5% (of egg sacs parasitised, even in very dense colonies; a native widow had up to 55%) [14]
- Egg-sac machine: Female brown widow, 20+ sacs (in one life, about 130 eggs each) [2]
- First scorpion on the menu: A brown widow in Brazil, 1st (the first recorded case of a brown widow eating a scorpion) [17]
- Heat-proof up to a point: Brown widow egg sacs in Japan, 52.8 °C (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 | 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)
- **Threat: No known major threats**: It thrives in towns and gardens and keeps reaching new places. [22][25][24]
- **Threat: Egg-sac wasps** (31%): A tiny wasp, Philolema latrodecti, was found in 31% of brown widow egg sacs on Tahiti. [19]
- **Threat: Pest control**: People remove widows with vacuums and sprays, but insecticides don’t give long-term control. [2]
- **Helping: Correct ID**: Checking the egg sac helps people tell brown widows from black widows and harmless look-alikes. [2]
- **Helping: Tracking the spread**: Genetic studies show where new brown widows came from and how often they arrive. [24][21]
- **Helping: Tidy, not toxic**: Clearing clutter and sweeping webs works better than spraying, and spares other wildlife. [2][12]

### Brown widow signals

- Sitting in the hole at the edge of its web: Resting in its retreat and waiting for prey. [2]
- Legs pulled in, dropped from the web, not moving: Disturbed and playing dead. [2]
- Standing over an egg sac, lunging at a wasp: Guarding her eggs. [13]
- A small male vibrating a female’s web: Courting. [8]

### Life stages

- **Adult female**: About 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 sacs) [2][1][13]
- **Adult male**: Only 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 vibrations) [2][7][8]
- **Spiderling**: Tiny young spiders fresh out of the spiky sac. Their venom toxin is already being made. (Females let young spiderlings share the web for up to about 40 days) [10][18]
- **Female with egg sacs**: A female beside her pale, spiky egg sacs. She can have several at once. (Guards the sacs from egg-laying wasps) [2][13]

### Brown widow quiz

1. What colour is the hourglass under a brown widow’s belly? **Orange or yellowish.** The brown widow’s hourglass is usually orange or yellowish, not red. [1]
2. What does a brown widow egg sac look like? **A ball covered in silk spikes.** It is covered in silk spikes, like a very large pollen grain. [2]
3. About how many eggs are in one brown widow egg sac? **About 130.** About 130 eggs per sac. [2]
4. How many egg sacs can a female make in her life? **20 or more.** She can make 20 or more, sometimes several at once. [2]
5. What does a disturbed brown widow usually do? **Drops and plays dead.** It pulls in its legs, drops from the web and plays dead. [2]
6. What do the spikes on the egg sac help keep out? **Egg-laying wasps.** Wasps laid more eggs on the side where spikes had been removed. [13]
7. Which spider family does the brown widow belong to? **Comb-footed spiders.** Widows are comb-footed spiders (Theridiidae), with a bristle comb on each back leg. [9]
8. Where did scientists find lots of brown widows in Los Angeles? **Under playground equipment.** They were common around homes and in parks, especially under playground equipment. [5]
9. What should you do with gloves and shoes left outside before you use them? **Shake them out.** Shake out shoes, gloves and clothes that have been left outside or in a shed. [27]
10. Where do scientists think the brown widow most likely first lived? **Africa.** Its closest relative is African, and South Africa is treated as part of its native range. [21][26]
11. How long is an adult male brown widow’s body? **4–5 mm.** Males are only 4–5 mm long, much smaller than females. [2]
12. In a South African study, what were brown widow bites usually like? **Mild, staying near the bite.** The 15 brown widow bites were mild, while black widow bites were more severe. [6]

### Sources (checked 2026-10-16)

1. [Wikipedia. Latrodectus geometricus.](https://en.wikipedia.org/wiki/Latrodectus_geometricus)
2. [UC Statewide IPM Program. Pest Notes: Widow Spiders and Their Relatives (Publication 74149). University of California.](https://ipm.ucanr.edu/PMG/PESTNOTES/pn74149.html)
3. [Keyler DE, et al. (2020). Latrodectus geometricus (Aranea: Theridiidae) envenoming: rapid resolution of symptoms following F(ab')2 antivenom therapy. Toxicon 188:31–33.](https://doi.org/10.1016/j.toxicon.2020.10.009)
4. [Mokhtar AS, et al. (2021). Bite envenomation by Latrodectus geometricus (Araneae: Theridiidae) spiders in Malaysia. Tropical Biomedicine 38:567–570.](https://doi.org/10.47665/tb.38.4.100)
5. [Vetter RS, et al. (2012). The prevalence of brown widow and black widow spiders (Araneae: Theridiidae) in urban southern California. Journal of Medical Entomology 49:947–951.](https://doi.org/10.1603/me11285)
6. [Müller GJ (1993). Black and brown widow spider bites in South Africa: a series of 45 cases. South African Medical Journal 83:399–405.](https://pubmed.ncbi.nlm.nih.gov/8211456/)
7. [Sentenská L, et al. (2025). Alternative mating tactics in brown widow spiders: mating with or without male self-sacrifice does not affect the copulatory mechanism. Frontiers in Zoology 22.](https://doi.org/10.1186/s12983-025-00560-8)
8. [Sentenská L, et al. (2022). Risky business: males choose more receptive adults over safer subadults in a cannibalistic spider. Behavioral Ecology 33.](https://doi.org/10.1093/beheco/arac023)
9. [Wikipedia. Theridiidae.](https://en.wikipedia.org/wiki/Theridiidae)
10. [Torres SL, et al. (2022). Expression of brown and southern black widow spider (Araneae: Theridiidae) latrotoxins is tissue- and life stage-specific. Journal of Medical Entomology 59.](https://doi.org/10.1093/jme/tjab168)
11. [Makover V, et al. (2019). Eggshell spheres protect brown widow spider (Latrodectus geometricus) eggs from bacterial infection. Journal of the Royal Society Interface 16:20180581.](https://doi.org/10.1098/rsif.2018.0581)
12. [Vetter RS, et al. (2016). Efficacy of several pesticide products on brown widow spider (Araneae: Theridiidae) egg sacs and their penetration through the egg sac silk. Journal of Economic Entomology 109:267–272.](https://doi.org/10.1093/jee/tov288)
13. [Arabesky V, et al. (2025). Maternal care thwarts parasitoids in the invasive brown widow spider (Latrodectus geometricus). Proceedings of the Royal Society B 292:20242735.](https://doi.org/10.1098/rspb.2024.2735)
14. [Mowery MA, et al. (2023). Invasive brown widow spiders avoid parasitism despite high densities. Oecologia 202.](https://doi.org/10.1007/s00442-023-05378-x)
15. [Goddard J, et al. (2008). Severe reaction from envenomation by the brown widow spider, Latrodectus geometricus (Araneae: Theridiidae). Southern Medical Journal 101:1269–1270.](https://doi.org/10.1097/SMJ.0b013e31817f4d89)
16. [Earwood RC, et al. (2020). A case of brown widow envenomation in central Florida. Cureus 12:e9165.](https://doi.org/10.7759/cureus.9165)
17. [Lira AFA, et al. (2014). First record of a brown widow spider Latrodectus geometricus Koch, 1841 (Araneae, Theridiidae) feeding on a scorpion (Scorpiones, Bothriuridae) in Brazil. Brazilian Journal of Biology 74.](https://doi.org/10.1590/1519-6984.18013)
18. [Guimarães IC, et al. (2016). Chemical signals might mediate interactions between females and juveniles of Latrodectus geometricus (Araneae: Theridiidae). Behavioural Processes 126.](https://doi.org/10.1016/j.beproc.2016.03.001)
19. [Marie J, Vetter RS (2015). Establishment of the brown widow spider (Araneae: Theridiidae) and infestation of its egg sacs by a parasitoid, Philolema latrodecti, in French Polynesia and the Cook Islands. Journal of Medical Entomology 52:1291–1298.](https://doi.org/10.1093/jme/tjv127)
20. [Hayasaka D, et al. (2021). Dry-heat tolerance of egg sacs of invasive Latrodectus spiders (Araneae: Theridiidae) in Japan. Journal of Economic Entomology 114.](https://doi.org/10.1093/jee/toab189)
21. [Garb JE, González A, Gillespie RG (2004). The black widow spider genus Latrodectus (Araneae: Theridiidae): phylogeny, biogeography, and invasion history. Molecular Phylogenetics and Evolution 31:1127–1142.](https://doi.org/10.1016/j.ympev.2003.10.012)
22. [Taucare-Ríos A, et al. (2016). Using global and regional species distribution models (SDM) to infer the invasive stage of Latrodectus geometricus (Araneae: Theridiidae) in the Americas. Environmental Entomology 45:1379–1385.](https://doi.org/10.1093/ee/nvw118)
23. [Brown KS, Necaise JS, Goddard J (2008). Additions to the known U.S. distribution of Latrodectus geometricus (Araneae: Theridiidae). Journal of Medical Entomology 45:959–962.](https://doi.org/10.1603/0022-2585(2008)45[959:ATTKUD]2.0.CO;2)
24. [Katahira H, et al. (2026). Multiple genetic lineages of the invasive brown widow spider (Araneae: Theridiidae) from inland areas in the Kanto region, Japan. Journal of Medical Entomology.](https://doi.org/10.1093/jme/tjag077)
25. [Muslimin M, et al. (2015). First report of brown widow spider sightings in Peninsular Malaysia and notes on its global distribution. Journal of Venomous Animals and Toxins including Tropical Diseases 21:11.](https://doi.org/10.1186/s40409-015-0010-2)
26. [Mowery MA, et al. (2024). Endosymbiont diversity across native and invasive brown widow spider populations. Scientific Reports 14.](https://doi.org/10.1038/s41598-024-58723-2)
27. [CDC / NIOSH. Venomous Spiders at Work.](https://www.cdc.gov/niosh/outdoor-workers/about/venomous-spiders.html)
28. [Dunbar JP, et al. (2022). Bites by the noble false widow spider Steatoda nobilis can induce Latrodectus-like symptoms and vector-borne bacterial infections. Clinical Toxicology 60:59–70.](https://doi.org/10.1080/15563650.2021.1928165)
29. [Johnson AG, et al. (2023). What's eating you? Noble false widow spider (Steatoda nobilis). Cutis 112.](https://doi.org/10.12788/cutis.0872)
30. [GBIF. Latrodectus geometricus C.L.Koch, 1841 (Theridiidae), species 2157944.](https://www.gbif.org/species/2157944)
31. [Wikidata. Latrodectus geometricus (Q82243).](https://www.wikidata.org/wiki/Q82243)

## Measurements & details

- **Length:** 0.4-1 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](https://www.snappit.app/explore/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*) — 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.

## 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

## Where to spot

- [Bainbridge Commercial Historic District](https://www.snappit.app/guides/places/bainbridge-commercial-historic-district) — Georgia, US · Historic District
- [Desert Garden Conservatory](https://www.snappit.app/guides/places/desert-garden-conservatory) — California, US · Botanical Garden
- [Hakone Gardens](https://www.snappit.app/guides/places/hakone-gardens) — California, US · Botanical Garden
- [Harry P. Leu Gardens](https://www.snappit.app/guides/places/harry-p-leu-gardens) — Florida, US · Botanical Garden
- [Ortega](https://www.snappit.app/guides/places/ortega) — Florida, US · Neighborhood

[View all places to see Brown Widow](https://www.snappit.app/guides/where-to-see/brown-widow)

## More Invertebrate

- [Coral](https://www.snappit.app/explore/coral)
- [Crab Spider](https://www.snappit.app/explore/crab-spider) (*Mecaphesa asperata*)
- [Garden Spider](https://www.snappit.app/explore/garden-spider) (*Araneus diadematus*)
- [Brown Recluse Spider](https://www.snappit.app/explore/brown-recluse-spider) (*Loxosceles reclusa*)

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Source: [Brown Widow: Facts & Places to See — Snappit](https://www.snappit.app/explore/brown-widow)