Western black widow (Latrodectus hesperus)

Short answers

Western black widow: How big does the enclosure need to be?

20×20×25 cm (tall).

Western black widow: What temperature does it need?

Daytime 24–30 °C, at night 18–22 °C.

Western black widow: Does it need UVB lighting?

UVB: No UVB needed (nocturnal).

Western black widow: How long do they live?

Life expectancy: females ~1–3 years (up to 4 in captivity), males considerably shorter.

Western black widow: Is it suitable for beginners?

No – better suited to experienced keepers (difficulty: Expert).

Climate

Daytime temperature

24–30 °C

Night temperature

18–22 °C

Basking spot

—

Humidity

40–60 %, rather dry, well ventilated

UVB

No UVB needed (nocturnal)

Enclosure

Minimum size

20×20×25 cm (tall)

Substrate

Mostly dry (a thin layer of coco or sand), one corner slightly damp; twigs and cork as anchors for the web

Feeding

Food

Beetles, roaches, flies, crickets

Feeding interval

adults ~1×/week, juveniles 2×/week

Key facts

Adult size

females ~8–16 mm body (leg span up to ~5 cm), males about half that size

Life expectancy

females ~1–3 years (up to 4 in captivity), males considerably shorter

Origin

Western North America (the deserts and western USA, south-western Canada, northern Mexico)

Protection status

Not native, no CITES. A medically significant venomous spider (latrodectism) → observe the German states' dangerous-animal law (a ban with grandfathering in North Rhine-Westphalia, a permit requirement in Bavaria).

Brumation

Not essential; in cold regions they become inactive in winter

Cohabitation

Keep them singly. Widows are solitary, opportunistic cannibals: a conspecific is eaten when food is scarce, and spiderlings eat their siblings soon after hatching. That the female eats the male after mating happens less often than once assumed. For breeding, put the male in only briefly and under observation and separate them again afterwards.

Notes

The commonest widow in the western USA, in dry, warm desert habitats. A red hourglass. A safety-catch container is essential. A common mistake is keeping it too damp.

Do you keep this species?

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Related species

• Brown widow (Latrodectus geometricus) – Expert
• Mediterranean black widow (Latrodectus tredecimguttatus) – Expert
• Northern black widow (Latrodectus variolus) – Expert
• Red widow (Latrodectus bishopi) – Expert
• Redback spider (Latrodectus hasselti) – Expert
• Southern black widow (Latrodectus mactans) – Expert
• Pale widow (Latrodectus pallidus) – Expert
• Noble false widow (Steatoda nobilis) – Intermediate

All species in the care wiki →

What you need to start

To keep Western black widow (Latrodectus hesperus) you typically need: a suitable enclosure (20×20×25 cm (tall)), substrate (Mostly dry (a thin layer of coco or sand), one corner slightly damp; twigs and cork as anchors for the web), a heat source with a thermostat, UVB lighting, thermometer and hygrometer, a water dish and hides. You will find equipment in the Reptoria marketplace.