Bothriomyrmex costae

Bothriomyrmex costae

Bothriomyrmex costae is a small ant species native to Italy, belonging to the Dolichoderinae subfamily. Workers are tiny, typically measuring 2-4mm, with the characteristic tapered abdomen shape that gives the genus its name. The species was described by Emery in 1869 and was later recognized as a valid species after being previously considered a synonym of Bothriomyrmex meridionalis ^[1].

This species is part of a genus known for interesting social biology, Bothriomyrmex ants are temporary social parasites that invade colonies of other ant species, particularly related Dolichoderinae like Tapinoma. The queen infiltrates a host colony, kills or replaces the host queen, and uses the host workers to raise her first brood before the colony becomes established ^[1].

Quick Summary

• Difficulty: Expert
• Origin & Habitat: Italy (mainland), found in the Palaearctic region ^[2][1]
• Colony Type: Temporary social parasite, colony structure unconfirmed for this specific species
  • Colony: Monogyne
  • Queen: Socially parasitic, Temporary parasitic
• Size & Growth:
  • Queen: Estimated 4-5mm based on genus patterns
  • Worker: 2-4mm ^[1]
  • Colony: Unknown for this species, genus colonies typically reach several hundred workers
  • Growth: Unknown
  • Development: Unknown, estimated 6-8 weeks based on related Dolichoderinae (Development timeline unconfirmed for this species. Related Dolichoderinae species typically develop in 6-8 weeks at warm temperatures.)
• Antkeeping:
  • Temperature: Keep at 22-26°C based on typical Mediterranean ant requirements, no specific data for this species
  • Humidity: Moderate humidity, typical for Mediterranean species, aim for 50-60% with some dry areas
  • Diapause: Likely requires a mild winter rest period (diapause) given Italian distribution, reduce temperature to 10-15°C for 2-3 months
  • Nesting: In nature, they likely nest in soil or under stones. In captivity, a test tube setup works for founding, then a small formicarium with soil substrate. Avoid overly wet conditions.
• Behavior: This species is not well-studied in captivity. As a temporary social parasite, the founding queen would normally invade a host colony (likely Tapinoma species). Workers are small and may be able to escape through small gaps, use fine mesh barriers. Temperament is likely docile like most Dolichoderinae, but the parasitic nature makes them challenging to establish ^[1].
• Common Issues: temporary social parasitism makes them extremely difficult to establish, finding compatible host colony is challenging, very limited distribution data means exact care requirements are uncertain, small size creates escape risk, fine mesh barriers essential, colony may fail if host colony is rejected or incompatible, limited availability in antkeeping trade makes this an expert-only species

Understanding Bothriomyrmex Biology

Bothriomyrmex costae belongs to a genus of ants with fascinating and unusual biology. Unlike most ant species where a queen founds a colony alone (claustral founding), Bothriomyrmex queens are temporary social parasites. This means the founding queen must invade an established colony of another ant species, typically related Dolichoderinae like Tapinoma, to establish her colony ^[1].

The parasitic process works like this: the queen enters a host colony, kills or replaces the host queen, and uses the host workers to raise her first brood. Once her own workers emerge, they gradually replace the host workers until the colony becomes purely B. costae. This makes them exceptionally difficult to keep in captivity since you essentially need to establish them with a compatible host colony ^[1].

The genus Bothriomyrmex is distributed primarily around the Mediterranean and into Asia, with B. costae being one of the Italian endemics. They are not aggressive ants and lack a functional stinger, making them harmless to humans.

Housing and Nest Setup

Keeping Bothriomyrmex costae presents unique challenges due to their parasitic lifestyle. For a newly acquired colony, you cannot simply set up a test tube like most ants. Instead, you would need to introduce them to a compatible host colony, typically Tapinoma species which are commonly available and often considered pests ^[1].

If you manage to establish the colony successfully, use a small formicarium with a soil-based substrate. Keep the nest relatively dry, these are Mediterranean ants that prefer conditions closer to dry than damp. A small water tube for humidity is sufficient. The chambers should be appropriately sized for their tiny workers, with narrow passages that help them feel secure.

Escape prevention is critical due to their very small size. Use fine mesh (at least 0.5mm) on all openings and consider applying fluon to the rim of the outworld. These ants can squeeze through remarkably small gaps.

Temperature and Seasonal Care

As an Italian species, Bothriomyrmex costae likely experiences seasonal temperature variations in the wild. Keep the colony at 22-26°C during the active season, this is warm but not extreme, matching Mediterranean summer conditions. A small heating cable on one side of the nest can create a gentle gradient if your room temperature runs cooler.

During winter, reduce temperatures to around 10-15°C for 2-3 months to simulate their natural dormancy period. This diapause is important for colony health and likely triggers reproductive behavior. Do not feed during the hibernation period and keep moisture minimal to prevent mold issues.

Avoid temperature extremes, do not exceed 30°C or drop below 5°C. Stable, moderate temperatures are better than dramatic fluctuations.

Feeding and Nutrition

In the wild, Bothriomyrmex workers likely forage for honeydew and small insects, similar to other Dolichoderinae. In captivity, offer a varied diet: sugar water or honey diluted 1:4 with water should be available constantly. For protein, offer small insects like fruit flies, pinhead crickets, or small mealworm pieces ^[1].

However, remember that established colonies will have workers from the host species initially. The host workers will need their normal diet, which is essentially the same as Bothriomyrmex, sweet liquids and small prey. As your B. costae workers replace the host workers, continue offering the same diet.

Feed small amounts 2-3 times per week, removing any uneaten prey within 24 hours to prevent mold. Sugar water can be provided in a cotton-filled test tube or small feeder.

Establishing a Parasitic Colony

The biggest challenge with Bothriomyrmex costae is actually establishing a colony. Unlike most ants you can buy as a founding queen, these require a host colony to survive. This makes them one of the most difficult species to keep and is really only suitable for experienced antkeepers with specific knowledge of parasitic ant establishment ^[1].

The process typically involves introducing a newly mated B. costae queen to a mature Tapinoma colony. The introduction must be done carefully, the host colony may attack the intruder queen. Some keepers have had success by introducing the queen when the host colony is queenless or by using a large host colony that cannot focus all its defenses on the intruder.

If successful, the queen will kill the host queen and begin laying eggs. The host workers will care for her brood as if it were their own. Over time, B. costae workers will emerge and gradually replace the host colony. This process can take many months and requires patience and experience.

References