Polyrhachis dives (Asian Spiny Weaver Ant)
Introduction
Polyrhachis dives, commonly known as the Asian Spiny Weaver Ant, is one of the most distinctive and biologically fascinating species in the ant world. Found across Southeast Asia, from India and Thailand to the Philippines and Australia, this species is famous for two things: the formidable, needle-like spines on their thoraxes and their incredible ability to "weave" silk nests. Unlike the Oecophylla weaver ants that live in high canopies, Polyrhachis dives often builds its silk-and-debris nests closer to the ground, in low vegetation, or even under rocks. For the ant keeper, Polyrhachis dives offers a unique opportunity to witness "social weaving" in a species that is robust, active, and visually spectacular.
Watching a Polyrhachis dives colony is a dynamic experience. They are highly active, fast-moving, and display a level of coordination that is truly impressive. Their "spiny" appearance gives them a prehistoric, armored look, while their silk-weaving behavior provides a constant source of architectural fascination. They are a "high-performance" ant—growing quickly, foraging aggressively, and reacting with incredible speed to their environment. For those looking for an exotic species that is both visually unique and behaviorally complex, Polyrhachis dives is a premier choice.
Taxonomy and Distribution
Polyrhachis dives belongs to the subfamily Formicinae and the genus Polyrhachis, which contains over 600 species characterized by their impressive thoracic and petiolar spines. P. dives is one of the most widespread and successful species within the genus, ranging across the Indo-Australian region. They are highly adaptable and can be found in a variety of habitats, including tropical rainforests, mangroves, coastal scrublands, and even urban gardens.
Taxonomically, they are identified by the specific arrangement of their spines and the presence of fine, silvery hairs (pubescence) on their bodies, which gives them a slightly metallic or velvety appearance. Their success across such a vast geographical range is a testament to their resilience and their ability to utilize silk as a versatile building material in almost any environment.
Physical Characteristics
Polyrhachis dives is a monomorphic species, meaning the workers are all roughly the same size, typically measuring between 6mm and 8mm in length. Their most striking feature is their "armor." They possess long, sharp spines on their pronotum (thorax) and on their petiole (the node between the thorax and gaster). These spines serve as a potent defense against predators, making the ants difficult to swallow or crush.
Their bodies are a deep black, but they are covered in a dense layer of fine, silvery-gold hairs that give them a distinct metallic sheen under bright light. Their legs are long and built for speed and climbing, which they do with incredible agility. The queen is slightly larger, around 10-12mm, and while she also possesses spines, they are usually shorter and more robust than those of the workers. She is a highly productive layer and often the heart of a large, multi-queen colony.
Colony Behavior and Social Structure
One of the keys to the rapid growth and success of Polyrhachis dives is its polygynous (multi-queen) social structure. A single colony can contain dozens of queens, which allows for explosive population growth and the ability to quickly expand into new territories. They are also known for forming "super-colonies" or polydomous nests, where multiple silk-woven structures are connected by busy foraging trails.
The "weaving" behavior is their most famous trait. To build their nests, the workers carry their own larvae between their mandibles. The larvae produce silk, which the workers use like a "glue gun" to bind together leaves, soil, bark, and other debris. This allows them to create secure, weather-resistant homes in almost any location. Socially, they are very coordinated; when a new nest site is found or a repair is needed, hundreds of workers will work together, moving larvae back and forth to weave the structure into place.
Diet and Foraging
Polyrhachis dives is a generalist omnivore with a strong preference for liquid carbohydrates. In nature, they are frequent visitors to extrafloral nectaries and are known for tending honeydew-producing insects like aphids and mealybugs. In captivity, they should be provided with a constant and generous supply of sugar water, honey water, or specialized ant nectars. They have a high metabolism and are always on the move, requiring plenty of energy.
Protein is equally critical, especially for the larvae that must produce the silk for the nest. They are opportunistic hunters and scavengers, readily accepting a variety of feeder insects like fruit flies, crickets, and roaches. Because they are fast and aggressive, they can quickly overwhelm small prey. Providing a varied diet is essential to ensure the colony remains healthy and that the larvae are well-fed and capable of producing high-quality silk.
Life Cycle and Reproduction
The development time for Polyrhachis dives is relatively fast, typically taking 6 to 8 weeks from egg to adult worker at temperatures of 26-28°C. Like other Formicinae, they pupate in silk cocoons. However, unlike most other ants, their larvae are not just a "life stage" but also a "tool" used for nest construction. The workers are very careful with the larvae, often moving them to the most secure parts of the silk nest.
Nuptial flights occur during the warm, humid months in their native range, often after heavy rains. However, because they are polygynous, new queens frequently return to their home colony or start a new nest nearby with a group of workers (a process called "budding"). This makes it relatively easy for established colonies to expand and thrive without the high risks associated with independent colony founding.
Environmental Requirements
As a tropical and subtropical species, Polyrhachis dives requires warm and humid conditions. The nest temperature should be kept between 25°C and 30°C (77-86°F). Humidity should be relatively high, ideally between 60% and 80%, to ensure the health of the brood and the flexibility of the silk nests. They are somewhat more tolerant of fluctuations than some other tropical species, but consistency is key for rapid growth.
They are excellent climbers and require a vertical environment to thrive. In the outworld, providing branches, cork bark, and artificial plants will allow them to display their natural foraging and climbing behaviors. Because they are active and inquisitive, they require a secure, escape-proof habitat with a fluon (PTFE) barrier. They are sensitive to vibrations but are generally less bothered by light once the colony is established.
Keeping Polyrhachis dives as Pets
Keeping Polyrhachis dives is a high-energy and visually spectacular experience. They are rarely still, and the "weaving" behavior provides a constant source of fascination. They are a great choice for keepers who want a species that grows quickly and reacts strongly to feeding. Their unique "spiny" look and metallic sheen make them a beautiful display ant. While they require attention to humidity and frequent feeding, they are a robust and rewarding species that offers a unique glimpse into one of the ant world's most specialized building behaviors.
Recommended Habitats
To best accommodate the climbing and weaving nature of Polyrhachis dives, we recommend the following ANT SHACK products:
- All-in-One Desktop Ant Habitat - The vertical space and secure design of this habitat make it perfect for the arboreal-leaning Polyrhachis dives. It provides a compact yet stimulating environment for a growing colony to weave their first silk structures.
- Ant Habitat “Paris“ - For a larger colony, the "Paris" habitat offers plenty of room for their extensive foraging trails and multiple silk nest sites. The clear acrylic allows for great observation of the weaving process.
- Natural Ant Habitat Kit - Large - This kit allows you to create a naturalistic tropical environment with branches and bark, giving the ants the building materials and space they need to display their full range of natural behaviors.