Tetramorium bicarinatum

Tetramorium bicarinatum - "Guinea Ant"

Tetramorium bicarinatum is a small, robust ant measuring 3.4-4.5mm with a distinctive bicolored appearance, the head, mesosoma, and waist range from yellow to orange-brown while the gaster is always much darker, appearing dark brown to nearly black ^[1]. The species gets its scientific name from the two prominent ridges (carinae) running parallel on the face from the antenna bases to the back of the head ^[1]. This ant is one of the world's most successful tramp species, originally native to Southeast Asia but now found throughout tropical and subtropical regions globally, spread primarily through human commerce ^[1][2]. In temperate areas, colonies survive in greenhouses, zoos, and heated buildings ^[2].

What makes T. bicarinatum particularly interesting is its social structure, it's polygynous, meaning colonies can have multiple queens, and it reproduces through budding (where a queen leaves with workers to start a new nest) as well as semi-claustral founding ^[2][3]. This flexibility helps explain its success as an invasive species. The species is also known for its potent venom containing antimicrobial peptides called bicarinalins, which have been studied for their antibacterial properties ^[4][5].

Quick Summary

• Difficulty: Easy
• Origin & Habitat: Native to Southeast Asia (Indo-Pacific region), now found worldwide in tropical and subtropical areas. In temperate regions, lives in greenhouses and heated buildings ^[1][2].
• Colony Type: Polygynous (multiple queens per colony). Colonies can be unicolonial in introduced ranges with no inter-colony aggression. Reproduces by budding and semi-claustral founding ^[2][3][6].
  • Colony: Optionally polygyne, Supercolonial
  • Founding: Semi-claustral
• Size & Growth:
  • Queen: 4.4 mm average (3.9-4.9 mm) ^[7]
  • Worker: 3.0 mm average (2.5-3.3 mm) ^[7]
  • Colony: Up to several hundred workers in established colonies, can form large dispersed colonies ^[8]
  • Growth: Moderate
  • Development: 6-8 weeks (estimated based on related Tetramorium species) (Development time inferred from genus-level data, specific timing for this species not directly studied)
• Antkeeping:
  • Temperature: Keep at 24-28°C. This species has a maximal activity temperature around 32°C and can tolerate up to 30-50°C ^[9][10]. Avoid temperatures below 20°C for extended periods.
  • Humidity: Moderate humidity (50-70%). Native to tropical regions but adaptable. Provide a water tube and allow the nest area to dry slightly between rehydration.
  • Diapause: No true diapause. In temperate climates, reduce feeding and keep slightly cooler (18-20°C) during winter months when activity naturally decreases.
  • Nesting: Will readily accept most nest types, test tubes, Y-tong (AAC), plaster, or acrylic nests. In the wild, they nest under rocks, in rotting wood, and in soil ^[11]. Provide moderate humidity in the nest chamber.
• Behavior: Generally non-aggressive and not considered a serious stinging pest, though they can sting if handled ^[2]. Workers are active foragers both on the ground and in vegetation, and they recruit nestmates to food sources using pheromone trails ^[12]. They tend aphids and scale insects for honeydew and will readily accept protein foods and sugars. Medium escape risk, standard barriers are sufficient.
• Common Issues: colonies may decline if kept too cool, maintain warm temperatures year-round, queen loss can be tolerated due to polygynous structure, but multiple queens should be maintained if possible, can be outcompeted by more aggressive ant species in multi-species setups, escape prevention needed but not critical, they are not strong climbers

Housing and Nest Setup

Tetramorium bicarinatum adapts well to various captive setups. Test tubes work perfectly for founding colonies, simply fill a tube one-third with water, plug with cotton, and place the queen inside. For established colonies, Y-tong (AAC) nests, plaster nests, or acrylic formicaria all work well. The key is maintaining moderate humidity in the nest chamber while allowing some drying between waterings. In the wild, these ants nest under stones, in rotting logs, and in soil, so they appreciate a nest that mimics these conditions ^[11]. An outworld for foraging is essential, they readily accept protein foods and sugar sources there. Standard escape prevention (Fluon on container edges) is sufficient since they are moderate climbers.

Feeding and Diet

These ants are omnivorous and opportunistic feeders. In captivity, they readily accept: protein sources like small crickets, mealworms, fruit flies, and other small insects, sugar sources including honey, sugar water, and ripe fruit, and they'll even scavenge on small amounts of grease or meat. A balanced approach works best, provide protein 2-3 times per week and keep a constant sugar source available. In the wild, they heavily exploit honeydew from aphids and scale insects, sometimes protecting these hemipterans from predators ^[13][14]. This trophobiotic relationship is so strong that in some regions they're considered agricultural pests due to their tending of sap-feeding insects ^[1]. For your colony, occasional offering of sweet foods like honey water will satisfy this preference.

Temperature and Seasonal Care

As a tropical species, T. bicarinatum prefers warm conditions. Keep the nest area at 24-28°C for optimal colony development and brood growth. They can tolerate temperatures from around 20°C up to 30-50°C, with maximal activity occurring around 32°C ^[9][10]. In temperate climates, this species does best in heated setups, room temperature alone may be too cool. During winter in unheated rooms, you may notice reduced activity, which is normal. Unlike temperate species, they do not require true hibernation. Simply maintain their normal care routine with perhaps slightly less feeding during the cooler months if activity decreases. Avoid sudden temperature swings and keep them away from air conditioning vents.

Colony Structure and Behavior

One of the most interesting aspects of T. bicarinatum is its flexible social structure. Colonies are typically polygynous, meaning they contain multiple reproductive queens ^[2]. This allows the colony to survive even if one queen dies, and enables reproduction through budding, where a queen leaves with a group of workers to establish a new nest nearby. In their introduced range, colonies often become unicolonial, showing no aggression between colonies from different origins ^[6]. This is likely because they share similar chemical signatures (cuticular hydrocarbons). Workers are medium-sized (3-4.5mm), copper-brown with a dark gaster, and they forage both on the ground and in vegetation. They use mass recruitment, when a worker finds a good food source, it lays a pheromone trail to recruit nestmates ^[12]. This makes them efficient foragers and explains their success in urban environments.

Defense and Venom

While not considered aggressive, T. bicarinatum can deliver a sting when threatened. Their venom is actually quite remarkable from a scientific perspective, it contains potent antimicrobial peptides called bicarinalins that have been studied for their antibacterial properties ^[4]. Research has shown bicarinalin is effective against various bacteria including Staphylococcus aureus and even Helicobacter pylori ^[4]. The venom also contains other bioactive peptides. For antkeepers, this means while they're generally docile, you should handle them gently and avoid provoking them. The sting is not considered dangerous to healthy humans, but may cause mild irritation.

Frequently Asked Questions

References