Polyrhachis dives

Polyrhachis dives - "Rich Spiny Sugar ant"

Polyrhachis dives is a medium-sized weaver ant known for its distinctive black body covered in golden-yellow pubescence and sharp spines protruding from the thorax and petiole. Workers measure 5-7.7mm with a robust, heavily-sculptured body ^[1]. This species builds remarkable silk-woven nests by stitching together leaves and twigs using larval silk, similar to the better-known Oecophylla weaver ants ^[2]. Colonies are polygynous with around 50 queens and can contain 1500-2500 workers ^[3]. P. dives has an extremely wide distribution spanning from China and Japan through Southeast Asia to northern Australia and New Guinea ^[1]. They are well-known for their painful bite and aggressive defense of their territory ^[4].

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Found across Asia and Australia, from China, Japan, Philippines, Southeast Asia to northern Australia and New Guinea. In Australia, they inhabit open savannah woodlands and swampy coastal plains. In Japan (Okinawa), common in rural and agricultural areas ^[4]. Prefers open habitats with shrubs and small trees where it builds nests.
• Colony Type: Polygynous (multi-queen) colonies with approximately 50 queens per colony ^[4]. Polydomous, builds multiple connected nests across branches. Single and multiple queen colonies both documented ^[1].
  • Colony: Polygyne
  • Founding: Claustral
• Size & Growth:
  • Queen: 8.72-9.32mm ^[1]
  • Worker: 5.39-7.71mm ^[1]
  • Colony: 1500-2500 workers in established colonies ^[3]
  • Growth: Moderate
  • Development: Estimated 6-8 weeks based on typical Formicinae development at warm temperatures (Development time inferred from related Formicinae species, specific data for P. dives unavailable)
• Antkeeping:
  • Temperature: Keep at 24-28°C. They tolerate temperatures up to 39°C but show stress behaviors above 32.75°C ^[3]. Provide a temperature gradient allowing workers to self-regulate.
  • Humidity: Moderate humidity (50-70%). As an arboreal species, they prefer somewhat humid conditions but the nest structure helps regulate moisture. Mist occasionally but ensure ventilation to prevent mold.
  • Diapause: Not required. This is a tropical/subtropical species that does not hibernate. Keep at stable warm temperatures year-round ^[5].
  • Nesting: Arboreal weaver, requires vertical space for nest-building. Provide live plants, branches, or artificial structures they can weave. A naturalistic setup with living foliage works best. They will stitch together leaves/twigs with silk ^[6].
• Behavior: Active and aggressive foragers with strong territorial behavior. They patrol extensively around nest periphery and will aggressively defend against intruders including fire ants ^[7]. Known for their painful bite. Workers forage on trees, soil, and leaves, often tending aphids for honeydew ^[8]. Polydomous colonies maintain multiple nest sites connected by trails. Escape prevention is moderate, medium-sized ants but good climbers, use barrier gel or fluon on edges.
• Common Issues: queen loss during founding, polygynous colonies may have tensions between queens, nest collapse, silk weaves can deteriorate if humidity fluctuates too much, escape through small gaps, good climbers despite medium size, competition with other ants, aggressive but may lose to fire ants without support, fungal growth in nest, requires good ventilation despite humidity needs

Housing and Nest Setup

Polyrhachis dives is an arboreal weaver ant that requires vertical space to build its characteristic silk-woven nests. Unlike ground-nesting ants, they need access to foliage, branches, or artificial structures they can stitch together. The best housing option is a naturalistic setup with live plants or a formicarium with branches/mesh panels where they can construct their nest. Provide small twigs, leaves, or synthetic mesh that workers can weave with silk. Test tubes alone are not suitable for this species, they need space to create their woven nest structure. A hybrid setup works well: a formicarium connected to an outworld with live plants or branches. Ensure the setup allows for multiple nest sites since colonies are polydomous. Humidity should be moderate (50-70%) with good ventilation to prevent mold in the silk nest material. ^[1][6][2]

Feeding and Diet

P. dives is omnivorous with a strong preference for protein and honeydew. In captivity, feed them a varied diet including: protein sources like mealworms, small crickets, and other small insects offered 2-3 times weekly, sugar sources including honey water, sugar water, or ripe fruit provided continuously, and they will readily accept honeydew if available (aphids on plants in the setup). Workers forage actively and will patrol to find food, demonstrating strong recruitment behavior ^[8]. In China, they are known to prey on pine caterpillars and other forest pests ^[9]. Provide a shallow water source. Unlike some ants, they do not store food in the nest, remove uneaten prey after 24 hours to prevent mold.

Temperature and Heating

Keep colonies at 24-28°C for optimal activity and brood development. This species is thermolerant up to about 39°C but shows signs of stress above 32.75°C ^[3]. At higher temperatures, workers show increased grouping behavior and escape urgency. Provide a temperature gradient so workers can self-regulate, a heating cable on one side of the nest area creates this gradient. Room temperature (22-26°C) is generally acceptable in most homes. Avoid temperatures below 20°C as this species is adapted to tropical/subtropical conditions. No hibernation or winter rest is required, maintain warm temperatures year-round.

Colony Structure and Queen Care

P. dives is polygynous with colonies typically containing around 50 queens ^[4]. This is unusual among ants and affects how you should house them. Multiple queens can coexist in the same nest, which makes colony establishment easier, you can introduce multiple founding queens together. However, established colonies may still show queen aggression during certain periods. Queens measure 8.72-9.32mm and are significantly larger than workers ^[1]. The colony grows quickly once workers emerge, and you should expect the first workers (nanitics) within 6-8 weeks under warm conditions. Colonies can reach 1500-2500 workers in a couple of years ^[3]. As the colony grows, they will expand to multiple nest sites, this polydomous behavior is natural.

Behavior and Defense

This species is known for its aggressive defense and powerful bite. Workers will actively patrol the nest perimeter and attack any perceived threats ^[7]. When encountering fire ants (Solenopsis invicta), P. dives shows significantly higher aggressive behavior than defensive responses, with aggressive behaviors 2-15 times more frequent ^[7]. They demonstrate experience-dependent behavioral modification, when repeatedly encountering major fire ants, their aggressive behavior gradually decreases but remains dominant. Their painful bite comes from potent venom that also has antimicrobial properties, which may compensate for the absence of a metapleural gland in this genus ^[10]. Workers are active foragers that will search for food both on the ground and in vegetation.

Weaver Nest Building

P. dives is a weaver ant that uses larval silk to stitch together leaves and twigs, creating secure nest structures ^[6]. The larvae have specialized spinneret glands that workers use like shuttles to produce silk ^[2]. In captivity, provide materials they can work with: small live plants, twigs, or synthetic mesh panels work well. The nest construction is an active process, workers coordinate to hold leaves together while others apply silk. This behavior is fascinating to observe and is one of the main reasons keepers enjoy this species. The nests can become quite large in established colonies, often spanning multiple branches or sections of the enclosure.

Frequently Asked Questions

References