Peruvian Black & White Dwarf Tarantula

Cyriocosmus ritae Care Guide

The Peruvian Black & White Dwarf Tarantula

Revision Date: March 2025

Introduction

Cyriocosmus ritae, commonly known as Rita’s Dwarf Tarantula, is a stunning New World dwarf tarantula endemic to the forests of Peru and Brazil. As part of the Cyriocosmus genus, it shares the characteristic small size, rapid growth rate, and striking patterns with its close relatives. This species is particularly known for its vibrant contrast of black, white, and golden markings, along with its unique abdominal pattern. Despite its tiny stature, C. ritae is an active and hardy species that makes for a fascinating display tarantula.

While generally reclusive as a spiderling, adults often exhibit semi-arboreal tendencies, frequently moving between burrowing and climbing behaviors. Due to its ease of care and gentle disposition, C. ritae is an excellent choice for keepers looking to explore dwarf tarantulas without the challenges associated with more defensive species.

Quick Species Snapshot

• Scientific Name: Cyriocosmus ritae

• Common Name: Rita’s Dwarf Tarantula

• Type: Terrestrial (with semi-arboreal tendencies)

• Category: New World

• Native Range: Peru and Brazil

• Body Length: Approximately 1" (2.5 cm)

• Diagonal Leg Span (DLS): Up to 2.5" (6.5 cm)

• Urticating Hairs: Yes

• Growth Rate: Fast

• Life Expectancy:

  • Females: Up to 7 years

  • Males: Approximately 2 years

• Recommended Experience Level: Beginner

Taxonomy, Etymology & Natural Environment

Cyriocosmus ritae, commonly known as the Peruvian Black and White Dwarf Tarantula, is a captivating species within the Theraphosinae subfamily. Described by Pérez-Miles in 1998, this species stands out due to its diminutive size, bold black-and-white coloration, and metallic carapace. Like other members of the Cyriocosmus genus, it features a distinctive abdominal pattern, making it an eye-catching yet elusive species.

The genus name Cyriocosmus is derived from the Greek words "kyrios", meaning "lord" or "master," and "kosmos", meaning "ornament" or "decoration," referring to the intricate markings characteristic of species in this genus. The species name ritae honors an individual named Rita, likely in recognition of her contributions or significance in the species’ discovery.

Natural Range & Habitat

Native to Peru, C. ritae inhabits tropical rainforests, where it thrives in warm, humid environments with dense vegetation. As a fossorial species, it constructs burrows in the moist forest floor, using them for shelter and ambushing prey. It is an opportunistic burrower, meaning it will utilize pre-existing hideouts such as leaf litter, fallen logs, or crevices if suitable conditions are present.

Given its native climate, C. ritae requires moderate to high humidity levels, though good ventilation is still necessary to prevent excessive moisture buildup. Providing a deep, soft substrate that retains humidity while allowing burrowing is essential for replicating its natural environment in captivity.

Behavior & Temperament

Like most Cyriocosmus species, C. ritae is shy and reclusive, preferring to remain in its burrow rather than actively exploring the enclosure. It is not a defensive species but will retreat at high speeds when disturbed rather than standing its ground. Due to its small size and fragile build, handling is highly discouraged, as even a minor fall can be fatal.

Despite its reclusive nature, C. ritae has a strong feeding response, eagerly ambushing prey near the entrance of its burrow. While it possesses urticating hairs, it rarely uses them, relying instead on its speed and burrowing behavior for defense.

Housing & Substrate – Semi-Arboreal Setup

Spiderlings

• Enclosure Size: Use a small acrylic enclosure (e.g., Sling Crib, 3" Tarantula Cube, Small Slider Crib, Small Cuboid, Terrestrial Sling Crib, Slider Crib Mini, or Cuboid Mini) that is no smaller than three times the tarantula’s leg span.

• Substrate: Fill at least 2/3rds of the enclosure with Terra Aranea by The Bio Dude.

• Humidity: Maintain a slightly damp substrate (but not swampy) by offering a small water dish or gently dripping water on one corner about once a week.

Juveniles

• Enclosure Size: Use a medium enclosure (e.g., Medium Slider Crib, 6" Tarantula Cube, 8" Tarantula Cube, or Medium Cuboid) that is at least 3–4× the tarantula’s leg span.

• Substrate: Fill the enclosure 1/3 to 1/2 full with Terra Aranea by The Bio Dude. This depth allows for effective burrowing and minimizes the risk of injury from falls.

• Humidity: Keep the substrate mostly dry with a full water dish; occasionally overflow one corner to create a slightly damp area.

• Additional Features: Provide a half cork bark round for a secure hide and include vertical branches, cork bark pieces, or small fake plants as web anchors to facilitate natural web tunnel construction.

Adults

• Enclosure Size: Use a large enclosure (e.g., Large Slider Crib, 12" Cube Switch, 12" Cube, 18" Cube, or Terrestrial XL) that is at least 3× the tarantula’s leg span (ideally 4–5× for enhanced natural behavior, while still considering escape risks).

• Substrate: Fill the enclosure 1/3 to 1/2 full with Terra Aranea by The Bio Dude to provide ample depth for burrowing while reducing fall distance.

• Additional Features: Include a secure hide (preferably a half cork bark round), a shallow water dish, and tasteful decorations such as vertical branches or cork bark pieces leaned diagonally. Ensure the enclosure is a horizontal rectangle (wider than it is deep) with secure ventilation and a tight, secure lid to prevent escapes.

Note: "Semi‑arboreal" is not an official behavioral classification but rather a descriptive term used in the hobby to design enclosures that allow a tarantula to display some climbing and web anchoring behavior without exposing it to dangerous falls. For semi‑arboreal species, the enclosure is typically a square or horizontal rectangle rather than a tall arboreal setup. This design minimizes fall distance and risk of injury. Never use an arboreal enclosure for a species that is not truly arboreal.

Affiliate: Please use Tarantula Cribs (affiliate code TTC10) and Terra Aranea by The Bio Dude for substrate.

Temperature & Humidity

• Temperature: Maintain ambient temperatures between 68°F and 76°F (20°C to 24°C).

• Humidity: Aim for moderate humidity. Ensure that the substrate remains moist in the lower layers to support effective burrowing while allowing the top layers to dry between waterings.

• Water Dish: Always provide a shallow water dish, even for juveniles.

Feeding Schedule

Spiderlings

• Frequency:
  Feed twice a week.

• Prey:
  Offer small prey such as flightless fruit flies, confused flour beetles, or pre-killed tiny crickets/roach nymphs. Remove any uneaten prey after 24 hours. increase the size of the prey as the spider grows. Prekill any prey that is over 2/3 the size of the sling. For more detailed information on feeding spiderlings, watch this video: How To Feed Spiderlings & Scorplings (Baby Tarantulas & Scorpions)

• Post-Molt:
  Wait 24–48 hours after a molt before feeding. Ensure that the tarantula’s fangs are solid black and its exoskeleton is not soft or shiny.

Juveniles

• Frequency:
  Feed every 7–10 days.

• Prey:
  Provide 2–3 small to medium crickets or a medium Dubia roach.

• Feeding Guidelines:

  • If the abdomen is thinner than the widest part of the carapace, feed more prey more often.

  • If the abdomen is wider than the carapace, feed less prey, less often.
    This strategy helps prevent obesity, which can lead to molting complications or increase the risk of an abdomen rupture from even a small fall.

• Post-Molt:
  Wait 3–7 days after a molt before feeding, ensuring that the tarantula’s fangs are solid black and its exoskeleton is fully hardened.

Adults

• Frequency:
  Feed every 2–3 weeks (or as needed).

• Prey:
  Offer 4–5 large crickets or one large Dubia roach.

• Feeding Guidelines:

  • If the abdomen is thinner than the carapace’s widest part, increase feeding frequency.

  • If the abdomen is wider than the carapace, reduce feeding frequency.
    This is crucial to avoid obesity, which can interfere with proper molting or cause dangerous issues such as an abdomen rupture.

• Post-Molt:
  Wait 5–10 days after a molt before feeding, ensuring that the tarantula’s fangs are solid black and its exoskeleton is fully hardened.

Behavior & Temperament

Cyriocosmus ritae is a docile and fast-moving species that exhibits a balance of burrowing and climbing behavior. Unlike some terrestrial species, C. ritae often utilizes vertical spaces when given cork bark or other climbing structures. While it prefers to burrow as a spiderling, juveniles and adults may create intricate webbing around hides and bark.

This species has a mild temperament and rarely shows defensive behavior. If startled, it is more likely to retreat to its burrow than throw a threat posture. Handling is not recommended, both due to its fragility and potential for sudden bursts of speed.

Breeding Cyriocosmus ritae in Captivity

Breeding Cyriocosmus ritae (Rita’s Dwarf Tarantula) is a rewarding challenge due to their tiny size, fast movements, and delicate spiderlings. Since this species is not commonly bred in captivity, successful pairings help establish healthy captive populations while ensuring that wild specimens remain protected.

Sexual Maturity & Pairing

• Male Maturity: Males mature quickly, usually within 1–2 years, developing enlarged pedipalps for sperm transfer.

• Female Maturity: Females take 2–3 years to reach reproductive maturity.

• Pre-Pairing Preparation: We should ensure the female is well-fed before introducing the male to reduce defensive reactions. Some breeders find that slightly increasing humidity before pairing improves receptivity.

Mating Process

• Introduce the male at night, as they are more active in dim lighting.

• The male will drum on the substrate or webbing to signal his presence.

• If receptive, the female may drum back or remain still, allowing the male to approach and insert his emboli.

• Once mating is complete, the male should be removed immediately, as females may become defensive post-mating.

Egg Sac Production

• If fertilized, the female will produce an egg sac 4–8 weeks after mating.

• Maintain temperatures around 75–80°F (24–27°C) with humidity levels of 65–75 percent, ensuring good airflow to prevent mold.

• The egg sac typically contains 50–150 eggs, a relatively high number for a dwarf species.

Egg Sac Handling (Optional)

• Some breeders choose to pull the egg sac after 30–40 days for artificial incubation.

• If left with the mother, first instar spiderlings will emerge in 6–8 weeks and molt into second instar within 3–4 weeks.

Raising Spiderlings

• C. ritae spiderlings are extremely small and fast, requiring micro enclosures with stable humidity.

• Provide ventilated enclosures with a shallow layer of moist substrate to prevent desiccation.

• Feed them pre-killed pinhead crickets, flightless fruit flies, or small roaches every 2–3 days due to their rapid metabolism.

Challenges & Considerations

• Tiny and fragile spiderlings require precise humidity and feeding schedules to prevent desiccation.

• Fast and skittish adults make pairing and handling more difficult than with larger species.

• Short male lifespan, usually 6–12 months after maturity, means breeding should be attempted as soon as possible.

Cyriocosmus ritae is rarely seen in the hobby, making every successful breeding project an important step toward maintaining a stable, self-sustaining population. By focusing on captive breeding efforts, we help ensure that this fascinating species remains available without impacting wild populations. Every successful pairing strengthens the future of C. ritae in the hobby and contributes to ethical tarantula keeping.

Final Thoughts

Cyriocosmus ritae is a stunning and rewarding dwarf tarantula that is ideal for keepers of all experience levels. Its beautiful coloration, rapid growth, and active yet mild temperament make it a fascinating species to observe. Whether it’s burrowing deep into the substrate or exploring its enclosure, C. ritae is sure to be a standout in any collection.

For those interested in keeping dwarf tarantulas, this species offers the best of both worlds, hardy, easy to care for, and visually striking. If you’re looking to expand your collection with a low-maintenance, high-reward species, Cyriocosmus ritae is an excellent choice.

Additional Recommendations

For enclosures, consider Tarantula Cribs (affiliate code TTC10 for 10% off), and use Terra Aranea by The Bio Dude for substrate. For tarantulas, check out Spider Shoppe (use code TTC10 for 10% off), and visit the Dealer & Discounts section on my website for a curated list of recommended dealers and discount codes.