Cladomyrma sirindhornae

Quick Summary

• Difficulty: Hard
• Origin & Habitat: Eastern Thailand (Chachoengsao, Rayong, and Chanthaburi Provinces). Found in plantations and secondary forests, living inside branches of the climbing plant Sphenodesme involucrata ^[1][2].
• Colony Type: Monogyne (single queen colonies). Queens are highly physogastric (abdomen swollen with eggs) and found with a single dealate queen per colony. Queenless colonies also occur in the wild ^[2].
• Size & Growth:
  • Queen: size data unavailable, no total body length measurements exist for this species ^[1]
  • Worker: size data unavailable, only head measurements are available for this species ^[1]
  • Colony: Up to 7,160 workers in queenright colonies, queenless colonies average around 3,600 workers ^[2]
  • Growth: Moderate, based on colony size data and seasonal reproduction patterns ^[2]
  • Development: Unknown, no specific development data exists for this species (Sexual production increases significantly during wet season, but worker pupae production slightly decreases. This suggests seasonal breeding cycles typical of tropical ants.)
• Antkeeping:
  • Temperature: Keep at 24-28°C. This species comes from tropical Thailand where temperatures are consistently warm year-round. A gentle heat gradient allows ants to regulate their own temperature ^[2].
  • Humidity: High humidity is essential. These ants live inside plant stems where humidity stays consistently high. Keep the nest substrate moist but not waterlogged, and provide a water tube for drinking water ^[2].
  • Diapause: No, this is a tropical species from Thailand where temperatures remain warm year-round. They do not require hibernation ^[2].
  • Nesting: This species requires specialized housing. They are obligate plant-dwellers that need to live inside cavities. A naturalistic setup with hollow plant stems or bamboo sections works best. The nest must have multiple small entrance holes that major workers can block with their heads. Y-tong nests may work but these ants prefer plant-like structures ^[2].
• Behavior: These ants are relatively docile and not aggressive. Major workers serve as living doorways, blocking nest entrances with their heads when the colony is undisturbed. They are not known to sting and pose no danger to keepers. Minor workers are very small so escape prevention is critical, use fine mesh barriers. They are slow-moving and spend most of their time inside their nest chambers ^[2].
• Common Issues: tiny minor workers escape easily, fine mesh is essential for housing, requires high humidity, dry conditions will kill the colony quickly, specialized diet, they primarily eat plant food bodies and scale insect honeydew, not standard ant foods, colonies may not accept artificial nests, they prefer living plant material or stem-like structures, queenless colonies can form, if the queen dies, the colony may persist but will eventually die out without a replacement

Housing and Nest Setup

Cladomyrma sirindhornae requires specialized housing that mimics its natural plant-dwelling lifestyle. In the wild, these ants live inside the hollow stems of Sphenodesme plants, where they have around 97 small entrance holes along the vine. Entrance diameter averages 0.72 cm. For captivity, the best option is a naturalistic setup with hollow bamboo sections or artificial plant stems. The stems should have multiple small entrance holes that major workers can block with their heads. If using an artificial nest like a Y-tong, ensure chambers are appropriately sized and provide a water tube for humidity. Minor workers can squeeze through small gaps, so ensure all connections are sealed with cotton or fine mesh ^[2].

Feeding and Diet

This species has a highly specialized diet that differs from typical ants. In the wild, C. sirindhornae feeds primarily on food bodies produced by their host plant, soft, light orange, gel-like masses that workers actively transport throughout the nest. They also farm scale insects (Pseudococcidae) that live in the domatia with them, feeding on the honeydew these scale insects produce. In captivity, you should attempt to replicate this diet. Offer small amounts of honey water or sugar water as a substitute for honeydew. Live scale insects would be ideal but are difficult to obtain. You might experiment with small amounts of fruit, but acceptance is uncertain. Protein should be offered rarely and in very small amounts, these ants are not primarily predatory. The key insight is that they are plant-dependent specialists, not generalist foragers ^[2].

Temperature and Humidity

As a tropical species from eastern Thailand, C. sirindhornae requires warm, humid conditions year-round. Keep the nest at 24-28°C with a gentle gradient so workers can regulate their own temperature. Room temperature in most homes may be slightly cool, consider using a heating cable on one side of the nest. Humidity is critical: these ants live inside plant stems where conditions are consistently moist. Keep the nest substrate damp but not waterlogged, and always provide a water tube. Mist the outworld occasionally but avoid creating standing water. Never let the nest dry out, this will kill the colony quickly. Since they do not hibernate, maintain these conditions year-round ^[2].

Colony Structure and Behavior

C. sirindhornae colonies are monogyne, meaning they have a single queen. The queen is highly physogastric, her abdomen becomes dramatically swollen with eggs. She has 27-37 ovarioles and a large, ellipsoidal spermatheca. Colonies can also become queenless in the wild (7 out of 20 colonies in one study had no queen), which suggests workers may not be able to replace her. The colony is dimorphic: major workers (about 30% of the workforce) have large heads they use to block nest entrances, while minor workers are more numerous and handle most foraging and brood care. This head-plugging behavior (phragmosis) is one of the most interesting aspects of their behavior, major workers essentially become living doors. Alate queens and males are produced seasonally, with significantly more sexuals appearing during the wet season ^[2].

Obtaining and Establishing a Colony

This species is not commonly available in the antkeeping hobby, and wild colonies are protected in Thailand. If obtained, establishing a colony requires patience. Queens found colonies by chewing through young plant stems below a node, creating a primary entrance that they block with their head. In captivity, provide a suitable plant stem or hollow bamboo section. The queen will need to lay eggs and raise the first workers (nanitics) alone. Initial colonies with a founding queen, brood, and nanitic workers are found more often in the wet season in the wild. Feed the founding colony very sparingly, they may not accept food during the claustral phase. Once workers emerge, offer tiny amounts of sugar water and observe acceptance before offering other foods ^[2].

Frequently Asked Questions

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References