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Southern Black Widow
Latrodectus mactans
The Latrodectus mactans, the very famous 'Southern Black Widow'. It is probably the most famous and feared venomous spider in the world. Very similar to its congener L. hesperus, the adult female is a spider of modest size but of extraordinary lethal beauty: completely hairless, spherical body of a deep shiny Raven Black. On the ventral abdomen it shows off the perfect and bright 'red hourglass' (aposematism), sometimes accompanied by red spots on the back as well. It is a weaver of irregular webs (cobwebs) in which it lives upside down. Timid and shy, it bites only if pressed, but its neurotoxic venom (Latrodectism) is an absolute clinical emergency. Only for responsible and super expert keepers.
- Taxonomy
- Class:ArachnidaOrder:AraneaeFamily:TheridiidaeGenus:LatrodectusSpecies:Latrodectus mactans
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Environment
Terrestrial
Humidity
50 - 60 %
Day temperature
24 - 30 °C
Night temperature
20 - 23 °C
UVB
None
Species description
Taxonomy and distribution: University of Florida IFAS Extension identifies Latrodectus mactans as the southern black widow. In the United States it documents the species in the southeastern region, as far north as Ohio and as far west as Texas.
Documented appearance: UF/IFAS describes the adult female as shiny black with a distinctive red hourglass; the body is about 1.25 cm long. Males are smaller and lack the female’s characteristic hourglass, though they can show red spotting.
Habitat context: The source records wood and rock piles, rodent burrows and hollow tree stumps outdoors, with garages, sheds and basements among indoor sites. Those occurrence records are not captive-environment settings.
Documented ecology: UF/IFAS describes irregular webs used to trap a wide range of insects and other arthropods. It also records that wasps, scorpions and centipedes may prey on southern black widows.
Care, breeding and tankmates
Safety boundary: University of Florida IFAS Extension reports potent widow-spider venom containing alpha-latrotoxin and adverse reactions in victims. This is a factual safety warning, not a handling, treatment or captive-care protocol.
Documented life history: UF/IFAS reports spring and summer mating, egg sacs retained in the web and spiderlings emerging after about one month. It also notes that reported sexual cannibalism was mainly observed under crowded laboratory conditions; this does not establish a general compatibility rule.
Evidence limit: The cited source does not establish a safe captive setup, environmental setpoint, feeding schedule or medical protocol; none is inferred here.
Geographic Origin and Distribution
This species originates from: Nord America (Boschi, fienili e zone urbane degli Stati Uniti sud-orientali).
Origin
Extra-Amazon South AmericaNorth America
Terrestrial invertebrate profile
- Diet
- Carnivore
- Latrodectus mactans requires a diet rich in live invertebrate prey, relying on its keen senses and agility to hunt. Common feeder choices include small crickets, fruit flies for spiderlings, and appropriately sized roaches. Their fast metabolism sometimes necessitates more frequent feeding schedules depending on their specific size and age. Hydration is also crucial, often obtained from the moisture in their prey or a fine mist. Uneaten prey should be promptly removed to prevent enclosure contamination.
- Adult size
- 1.25 cm
- The catalog's scalar value is 1.25 cm. The University of Florida IFAS — Southern Black Widow source reports a maximum adult measurement of 1.25 cm for this species, recorded as body length. The taxonomic record consulted is Latrodectus mactans. These figures are not interchangeable: the first is the profile's editorial reference, whereas the second is a published maximum under a specific measurement convention; differences among sources can reflect sex, population, life stage and measuring method.
- Lifestyle/Microhabitat
- Terrestrial
- The lifestyle of Latrodectus mactans demands a carefully structured environment that caters to its specific terrestrial or arboreal nature. Owners must ensure a proper temperature gradient, allowing the animal to thermoregulate as needed. Their enclosures should offer multiple hides and climbing opportunities if appropriate for the species. Solitary housing is absolutely necessary to prevent territorial disputes and injury. Maintaining high standards of hygiene is critical for their long-term health.
- Activity cycle
- Nocturnal
- The activity pattern of Latrodectus mactans typically aligns with crepuscular or nocturnal cycles. During the day, they remain securely tucked away in their hides to avoid desiccation and predators. As light levels drop, they emerge to actively forage, hunt, or explore their immediate surroundings. Artificial lighting in their enclosure should mimic natural day-night cycles without being overly intense. Disruptions to this cycle can cause feeding strikes or lethargy over time.
- Sociality
- Solitary
- They are strictly solitary and highly cannibalistic. They must always be housed individually in separate enclosures, as cohabitation will inevitably lead to predation, regardless of the size of the enclosure.
- Reproduction
- Oviparous
- Reproduction in Latrodectus mactans requires careful conditioning and precise environmental parameters to ensure success. The male must be properly introduced to the female's enclosure to avoid immediate predation or aggressive behaviors. Following successful mating, the female will typically begin to construct an egg sac after a gestation period that varies by species. It is crucial to monitor the temperature and humidity to ensure the viability of the eggs. Once the young emerge, they should be separated promptly to prevent cannibalism.
- Venom level
- Highly venomous
- This spider possesses a highly medically significant neurotoxic venom, primarily containing alpha-latrotoxin. Bites can cause severe muscle pain, intense abdominal cramps, diaphoresis, and other severe systemic symptoms requiring medical attention.
- Handling tolerance
- Display only
- Handling Latrodectus mactans is generally strongly discouraged due to the risk of stress to the animal and potential injury. A fall from even a short height can result in a fatal abdominal rupture or severe trauma. If moving the specimen is absolutely necessary, use a soft catch cup or a sterile brush to gently guide them. Owners should respect the creature's need for personal space and observe them strictly as display animals. Avoiding direct handling minimizes the chance of unpredictable defensive bites or stings.
- Brumation
- Not required
- In its natural habitat, Latrodectus mactans may experience seasonal cooling that slows down its metabolic rate. In captivity, true brumation is rarely required unless breeding is explicitly planned. If temperatures naturally drop during winter, feeding frequency should be adjusted accordingly to match their reduced metabolism. It is important never to let the enclosure become freezing or excessively damp during these cooler periods. Careful monitoring ensures the specimen remains healthy until warmer conditions resume.
- Molting
- Regular
- Molting is a critical and highly sensitive phase in the life cycle of Latrodectus mactans. Leading up to a molt, they will often refuse food, become sluggish, and sometimes seal themselves entirely inside their hide. It is absolutely crucial to maintain proper humidity and never disturb the animal while it is molting. After shedding its exoskeleton, the animal will be extremely soft and vulnerable for several days. Feeding must be strictly withheld until the fangs or pincers have fully hardened to prevent fatal injuries.
Image gallery
Licensed images linked to the species or, when marked, to the closest representative taxon.
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