---
title: "What the sources say about the Southern Black Widow | AnimalTracks.wiki"
description: "40 claims from the Southern Black Widow profile, each beside the words of the source that backs it."
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---

# What the sources say about the Southern Black Widow (*Latrodectus mactans*)

> 40 claims from the Southern Black Widow profile, each beside the words of the source that backs it. A "..." marks a cut in a quote and [brackets] an insertion.

Profile: [Southern Black Widow](https://animaltracks.wiki/animals/southern-black-widow/)

## Eiden & Kaufman (2013). Southern black widow Latrodectus mactans (Fabricius) (Arachnida: Araneae: Theridiidae). EDIS.

https://doi.org/10.32473/edis-in1000-2013

| The page says | The source says |
| :--- | :--- |
| Shiny black spider | is a shiny black spider |
| Not Evaluated | The Southern black widow spider, Latrodectus mactans (Fabricius), is a venomous spider found throughout the southeastern United States. (note: GBIF's copy of the Red List returns NOT_EVALUATED for Latrodectus mactans (Fabricius, 1775), usage key 2157949, checked 2026-09-27 (api.gbif.org/v1/species/2157949/iucnRedListCategory). Crossref has no Red List assessment DOI for this name either.) |
| Often in wood and rock piles, rodent burrows, and hollow stumps outdoors, or sheds, garages, basements, and outhouses indoors | Typical outdoor habitats in which spiders are often found include wood and rock piles, rodent burrows, and hollow tree stumps. Indoor habitats include outhouses, garages, sheds, and basements (note: stats.habitat; the range half of this field (north to Ohio, west to Texas) is the same-source claim below) |
| north to Ohio and west to Texas | the Southern black widow is found in the southeastern region and has been found as far north as Ohio and as far west as Texas (note: stats.habitat, range clause) |
| Flies, crickets, grasshoppers, moths, beetles, and other arthropods trapped in its web | Widow spider diet includes a wide range of insects such as flies, crickets, grasshoppers, moths, beetles, and various other arthropods that become trapped in the web (note: stats.diet; dropped ADW's old chilopods/scorpions since EDIS (current) lists centipedes and scorpions as known predators of the species, not prey) |
| is a shiny black spider | is a shiny black spider with a distinctive red hourglass on the abdomen |
| found across the southeastern United States, its range reaching as far north as Ohio and as far west as Texas | the Southern black widow is found in the southeastern region and has been found as far north as Ohio and as far west as Texas |
| a body about 1.25 cm (0.5 in) long, typically 3.75 to 5 cm (1.5 to 2 in) including the legs | Females are typically 3.75 to 5 cm long including the leg span, while their bodies are 1.25 cm long. (note: imperial conversions are the page's own (1.25 cm = 0.5 in; 3.75-5 cm = 1.5-2 in); reviewer changed 'a leg span of' to 'including the legs', since the source's 3.75-5 cm is total length with legs, not a leg span) |
| Males are smaller, typically with a body just 0.6 cm long, and lack the female's hourglass | Male Southern black widows are smaller, typically with a 0.6 cm long body (Mote and Gray 1935). Male Southern black widows lack the characteristic hourglass of the female |
| Females typically live around 1.5 years; males survive just two to five months | The female Southern black widow typically lives an average of 1.5 years while the male survives between two to five months. |
| Both primarily inhabit low-lying areas, and are often found in wood and rock piles, rodent burrows, and hollow stumps outdoors, or in sheds, garages, basements, and outhouses indoors | Typical outdoor habitats in which spiders are often found include wood and rock piles, rodent burrows, and hollow tree stumps. Indoor habitats include outhouses, garages, sheds, and basements (D’Amour et al. 1936). Although they primarily inhabit low-lying areas |
| The venom contains the neurotoxin alpha-latrotoxin. | Widows have potent venom, which contains the neurotoxin alpha-latrotoxin (note: EDIS species account; its sentence is about 'widows') |
| The web is built in an erratic manner with no distinguishable pattern | Black widow webs are constructed in an erratic manner without a distinguishable pattern (Mote and Gray 1935). |
| Flies, crickets, grasshoppers, moths, beetles, and other arthropods become trapped in it. | Widow spider diet includes a wide range of insects such as flies, crickets, grasshoppers, moths, beetles, and various other arthropods that become trapped in the web |
| Widow spiders got their name from the belief that females kill and eat their mates after mating, but that was mainly observed in crowded laboratory conditions. | Widow spiders received their name from the belief that they would kill and consume their mate following copulation. However, the practice was mainly observed in laboratory settings under crowded conditions. |
| In natural settings, it is believed to have more to do with the male's physical inability to escape than with the female's interest in eating him. | It is believed that sexual cannibalism within the widow species in natural settings is more associated with the male’s physical inability to escape rather than the female’s interest in consuming him |
| In 2010, people in the United States self-reported 2,168 black widow bites, and 892 of those cases were treated in health care facilities. That year's survey recorded no deaths, and death from a black widow bite is rarely reported. Patients usually recover within 24 hours after treatment, or in 3 to 5 days without supportive care. | In 2010, there were 2,168 self-reported black widow bites reported in the United States, with 892 cases treated in health care facilities (Bronstein et al. 2011). Death due to a black widow bite is rarely reported (Timms and Gibbons 1986). In the 2010 survey, over 50% of reported cases occurred in patients over 20 years of age with no deaths (Bronstein et al. 2011). Patients usually recover within 24 hours following treatment or 3 to 5 days without supportive care (note: faq 1; US black widow bites of any species, so the question now asks about black widows generally) |
| The behavior was mainly seen in widows kept crowded together in the lab. | the practice was mainly observed in laboratory settings under crowded conditions (note: faq 2) |
| In the wild, the thinking is that it is linked more to a male being physically unable to get away than to any real interest on the female's part in eating him. | It is believed that sexual cannibalism within the widow species in natural settings is more associated with the male’s physical inability to escape rather than the female’s interest in consuming him (note: faq 2; 'the leading idea' carries the source's 'It is believed') |
| Typically around 220, in a beige egg sac about 1 to 1.25 cm across. | The female produces a beige-colored egg sac that is approximately 1.0-1.25 cm in diameter and typically contains around 220 eggs (note: faq 4) |
| After an incubation of one month the spiderlings emerge | after an incubation period of one month the spiderlings emerge from the egg sac (note: faq 4) |
| white and without the hourglass or spots, and look more like adults with each molt. | Spiderlings are initially white and lack the hour-glass or spot patterns, but gain coloration and patterns more resembling adults with progressive molts (note: faq 4) |
| for a spider whose cobweb is built in an erratic manner with no distinguishable pattern | Black widow webs are constructed in an erratic manner without a distinguishable pattern (note: vibe.reason mechanism, re-paired in wave 112 (screenshot test).) |

## Latrodectus mactans. Animal Diversity Web, University of Michigan.

https://animaldiversity.org/accounts/Latrodectus_mactans/

| The page says | The source says |
| :--- | :--- |
| usually a red hourglass mark on the underside of the abdomen | Usually on the underside of the female's abdomen (venter) is a red hourglass mark |
| The species averages about 1 gram. | Average mass 1 g (note: ADW gives the mass unsexed, so the sentence is species scope rather than the female list it used to sit in) |
| a mature male abandons his home and spends considerable effort finding a female | A mature male spins a small “sperm web” and deposits a small quantity of semen on it. He then charges his palps with the sperm, abandons his habitat, and spends considerable effort to locate a female of his species |
| The spider has a row of strong, curved bristles on its hind legs, forming a comb, which it uses to fling silk over its prey. | The spider has a row of strong, curved bristles on the hind pair of legs, which form a distinct comb. The comb is used for flinging silk over its prey. |
| It then bites the prey and later drags it to its hub, or retreat, to be eaten. | the black widow spider enswathes prey caught in its snare, bites it, and later drags it to its hub, or retreat, to be eaten |
| The female hangs upside down in her web so that her red hourglass serves as a warning signal to predators. | the female spider hangs upside down in her web so that her red hourglass mark serves as a warning signal to a predator |

## Binder (1989). Acute Arthropod Envenomation: Incidence, Clinical Features and Management. Medical Toxicology and Adverse Drug Experience.

https://doi.org/10.1007/bf03259994

| The page says | The source says |
| :--- | :--- |
| venom floods the nerve-muscle junction with acetylcholine and noradrenaline | affecting the presynaptic motor endplate to allow massive noradrenaline (norepinephrine) and acetylcholine release into synapses (note: tagline; reviewer dropped 'alpha-latrotoxin': Binder attributes the effect to 'the venom', not to a named toxin) |
| Venom that acts on the motor endplate to allow a massive release of noradrenaline and acetylcholine, causing excessive stimulation and fatigue of the muscle. | affecting the presynaptic motor endplate to allow massive noradrenaline (norepinephrine) and acetylcholine release into synapses causing excessive stimulation and fatigue of the motor end plate and muscle (note: stats.superpower) |
| Black widow venom acts on the presynaptic motor endplate, where nerve meets muscle, releasing massive amounts of noradrenaline and acetylcholine into the synapses. | Black widow spider (Latrodectus mactans) envenomation is found throughout both the temperate and tropical latitudes, and is one of the leading causes of death from arthropod envenomations worldwide. The venom is highly neurotoxic, affecting the presynaptic motor endplate to allow massive noradrenaline (norepinephrine) and acetylcholine release into synapses (note: blockquote; Binder names Latrodectus mactans; 'where nerve meets muscle' glosses 'motor endplate') |
| The result is excessive stimulation and fatigue of the motor end plate and muscle. | release into synapses causing excessive stimulation and fatigue of the motor end plate and muscle (note: blockquote) |

## Grishin (1998). Black widow spider toxins: the present and the future. Toxicon.

https://doi.org/10.1016/s0041-0101(98)00162-7

| The page says | The source says |
| :--- | :--- |
| In the venom of a close relative, *Latrodectus tredecimguttatus*, researchers isolated alpha-latrotoxin, which provokes a massive transmitter release from vertebrate nerve endings, alongside five latroinsectotoxins that act on insects and one latrocrustatoxin active only on crustaceans | The venom of the black widow spider Latrodectus mactans tredisimguttatus was found to contain a family of high molecular weight toxic proteins ... Along with the known alpha-latrotoxin, five latroinsectotoxins affecting the neurotransmitter release from presynaptic endings of insects and one latrocrustatoxin active only for crustaceans were isolated and studied in detail. Alpha-latrotoxin provokes a massive transmitter release from different nerve endings of vertebrates (note: other species: Grishin's spider is L. mactans tredecimguttatus (the source misspells it 'tredisimguttatus'), treated as its own species, L. tredecimguttatus, by Oldrati 2017 in this pack; the sentence names it and does not attribute the toxin set to L. mactans) |

## Oldrati et al. (2017). Peptidomic and transcriptomic profiling of four distinct spider venoms. PLOS ONE.

https://doi.org/10.1371/journal.pone.0172966

| The page says | The source says |
| :--- | :--- |
| By 2017 only 19 toxins had been identified from widow spider venom, and 10 of them are latrotoxins, large proteins more than 1,000 amino acids long that make up the major fraction of venom in this spider family | Despite its medical importance for humans, only 19 toxins from the Latrodectus venom have been identified and investigated thus far. Of these, 10 are large proteins (latrotoxins, length > 1000 amino acids), representing the major fraction of Theridiidae venom. (note: genus scope (Latrodectus) and family scope (Theridiidae), labelled as such; 'By 2017' dates the source's 'thus far') |
| Its heavy hitters are the latrotoxins, large proteins made of more than 1,000 amino acids. They are extremely neurotoxic to both insects and mammals through their activity at the presynaptic level, the sending end of a nerve connection, which leads to a massive release of neurotransmitter. | Of these, 10 are large proteins (latrotoxins, length > 1000 amino acids), representing the major fraction of Theridiidae venom. These toxins are extremely neurotoxic to insects and mammals due to their activity at the presynaptic level, which leads to massive neurotransmitter release. (note: faq 3; 'the sending end of a nerve connection' glosses 'presynaptic') |

## Blackledge, Summers & Hayashi (2005). Gumfooted lines in black widow cobwebs and the mechanical properties of spider capture silk. Zoology.

https://doi.org/10.1016/j.zool.2004.11.001

| The page says | The source says |
| :--- | :--- |
| widow cobwebs carry sticky "gumfooted" lines | we use the sticky gumfooted lines of black widow cobwebs (note: the abstract names no species, so the sentence says 'widow cobwebs') |

## Cabrera-Espinosa & Valdez-Mondragón (2021). Distribución y modelaje de nicho ecológico, comentarios biogeográficos y taxonómicos del género de arañas Latrodectus (Araneae: Theridiidae) de México. Revista Mexicana de Biodiversidad.

https://doi.org/10.22201/ib.20078706e.2021.92.3665

| The page says | The source says |
| :--- | :--- |
| a study of females in Mexico recorded 40 distinct hourglass patterns, and the authors suggest Mexico may hold more widow species than are currently recognized | la descripción de la variación geográfica de los patrones de coloración dorsales y ventrales del opistosoma en hembras de L. mactans ... L. mactans presentó la mayor variación, registrando 40 patrones distintos. Dada la amplia variación morfológica y de patrones de coloración, la diversidad de especies en México podría estar subestimada (note: Spanish: 'geographic variation of the dorsal and ventral colour patterns of the opisthosoma in L. mactans females ... L. mactans showed the greatest variation, recording 40 distinct patterns. Given the wide variation ... species diversity in Mexico could be underestimated'. The ventral pattern was described for L. mactans only, so the old 'most variable of the species compared' was cut) |

## Coticchio, Vetter & Cassill (2023). Predation by the Introduced Brown Widow Spider (Araneae: Theridiidae) May Explain Local Extinctions of Native Black Widows in Urban Habitats. Annals of the Entomological Society of America.

https://doi.org/10.1093/aesa/saad003

| The page says | The source says |
| :--- | :--- |
| In Florida, where the native spider has been rapidly disappearing, cohabitation experiments found introduced brown widows were six times more likely to kill and eat southern black widows than to kill bold cobweb spiders. | we report possible causes for the rapid disappearance of Florida’s Southern Black Widows ... In our experiments on cohabitation with neighbors, bold Brown Widows were six times more likely to kill and consume shy Southern Black Widows than bold cobweb spiders (note: experiments, not field observation: the old 'documented hunting in parts of Florida' is fixed) |
| The researchers suggest this predation is a significant factor in its local extinction from urban structures. | this study is the first to suggest that aggressive predation by Brown Widows is a significant factor contributing to the local extinction of the shy Southern Black Widow in urban structures |