Borean Neon-Blue Leg Tarantula

Birupes simoroxigorum Care Guide

Borean Neon-Blue Leg Tarantula

Malaysian Blue Tarantula

Revision Date: March 2025

Introduction

Birupes simoroxigorum, commonly known as the Borean Neon-Blue Leg Tarantula or Malaysian Blue Tarantula, is a stunning fossorial species endemic to the rainforests of Sarawak, Malaysia. This relatively new species quickly gained popularity due to its striking metallic blue coloration, which is rarely seen in fossorial tarantulas.

Unlike many other fossorial species, B. simoroxigorum exhibits burrowing and arboreal tendencies as well as sometimes almost seeing terrestrial, often utilizing vertical retreats in rotting wood or loose substrate and sometimes they will spend days hanging out on the surface out in the open. This species is known for its skittish and defensive temperament, making it better suited for experienced keepers who are comfortable working with fast Old World species. With its fast growth rate, beautiful coloration, and fascinating behaviors, B. simoroxigorum is an exciting species to observe in captivity.

Quick Species Snapshot

• Scientific Name: Birupes simoroxigorum

• Common Names: Borean Neon-Blue Leg Tarantula

• Type: Fossorial (with some semi-arboreal tendencies)

• Category: Old World

• Native Range: Sarawak, Malaysia

• Size: Up to 5” (13 cm) DLS

• Growth Rate: Fast

• Life Expectancy: Females ~12–15 years; Males ~3–4 years

• Recommended Experience Level: Advanced

• Urticating Hairs: No

• Venom Potency: Strong (potentially medically significant)

Taxonomy, Etymology & Natural Environment

Birupes simoroxigorum was first described in 2019 and is part of the Birupes genus, a group of tarantulas found exclusively in Malaysia. The genus name "Birupes" derives from the Malay word “biru,” meaning "blue," referencing the species’ vibrant coloration. The species name “simoroxigorum” is a combination of the names of the children of the researchers who first described the species.

This species inhabits the tropical rainforests of Sarawak, where it constructs deep burrows in loose, sandy soil or uses natural cavities in decaying trees. Unlike many other fossorial tarantulas, B. simoroxigorum has been observed taking advantage of both subterranean and arboreal hides, suggesting a degree of adaptability in its habitat preferences.

Due to its limited distribution and the ongoing deforestation of Malaysian rainforests, B. simoroxigorum is considered a rare species, and its collection from the wild is highly discouraged.

Behavior & Temperament

B. simoroxigorum is a fast and defensive species, often retreating into its burrow at the slightest disturbance. While not overtly aggressive, it will not hesitate to stand its ground if provoked. Like many Old World species, this tarantula lacks urticating hairs and instead relies on its speed, potent venom, and defensive posturing as primary means of deterrence.

This species is best suited for observation rather than interaction, as its speed and unpredictable movements make rehousing or maintenance a challenge. It is not recommended for beginners due to its defensive temperament and venom potency. This is NOT a tarantula to get in the hopes of handling them.

Housing & Substrate – Fossorial Setup

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Spiderlings

• Enclosure Size: OG Sling Crib, 3” Tarantula Cube, 4” Tarantula Cube

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

• Humidity: Keep the substrate slightly damp, but not swampy. Provide a tiny water dish if space allows or drip water onto webbing weekly.

Juveniles

• Enclosure Size: Crib 360-4” Fossorial, 5” Hex Crib, 6” Tarantula Cube, 8” Cube

• Substrate: Fill ½ to ¾ of the enclosure with Terra Aranea by The Bio Dude to support deep burrowing.

• Humidity: Let part of the substrate dry out while keeping one corner slightly damp by overflowing the water dish occasionally.

• Additional Features: Cork bark or dried leaves as web anchors.

Adults

• Enclosure Size: 8” Hex Crib, Crib 360-8” Fossorial, 12” Tarantula Cube, 18” Tarantula Cube

• Substrate: Fill at least ½–¾ of the enclosure with Terra Aranea by The Bio Dude.

• Additional Features: A deep burrow setup is essential. I like to add some branches or plants so they can web up around their burrow entrance as well.

Tarantula Cribs offers the best enclosures—use code TTC10 for 10% off.

Temperature & Humidity

• Temperature: 70–78°F (21–26°C)

• Humidity: 50–60%

• Ventilation: Ensure good airflow to prevent stale conditions.

• Water Dish: Keep one filled and overflow occasionally to maintain a moisture gradient.

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.

Breeding Birupes simoroxigorum in Captivity

Sexual Maturity & Pairing

• Males: Reach maturity in 2–3 years.

• Females: Reach reproductive maturity in 4–5 years.

• Pairing: Introduce the male into the female’s enclosure at night, ensuring multiple escape routes for him.

Mating Process

• Males initiate courtship with palp drumming and leg tapping.

• If receptive, the female will allow insertion before retreating.

• Males should be removed immediately after mating to prevent potential predation.

Egg Sac Production

• Females produce an egg sac 4–6 months post-mating.

• Egg sacs contain 80–150 eggs.

• Maintain 75-80°F (24-27°C) with high humidity (75-80%).

Raising Spiderlings

• First instar spiderlings emerge 6-8 weeks post-sac.

• Feed pinhead crickets or fruit flies every 3-4 days.

• Provide high humidity with proper airflow.

Challenges & Considerations

• B. simoroxigorum’s speed and defensiveness make pairing tricky.

• High humidity balance is critical to avoid dehydration or mold growth.

• Ethical breeding is crucial to reducing wild collection and sustaining this species in the hobby.

Final Thoughts

Birupes simoroxigorum is a breathtaking tarantula with its vivid metallic blue coloration and fascinating burrowing behaviors. While its care requirements are manageable for experienced keepers, its defensive temperament and fast movements make it unsuitable for beginners. Observing this species create intricate burrows and webbed retreats is a truly rewarding experience, but patience and respect for its speed and sensitivity are necessary.

Due to its limited distribution and conservation concerns, supporting captive breeding efforts is crucial to ensure the continued availability of this species in the hobby while minimizing the impact on wild populations. If you’re looking for a rare and visually striking fossorial tarantula, B. simoroxigorum is an excellent addition to a well-maintained collection.

Additional Recommendations

For enclosures, consider Tarantula Cribs (TTC10 for 10% off), and use Terra Aranea by The Bio Dude for substrate. For legal captive-bred tarantulas, check out Spider Shoppe (TTC10 for 10% off).