Strumigenys benten

Strumigenys benten

Strumigenys benten is a tiny predatory ant measuring just 2.1-2.6mm in total length. Workers have the characteristic short mandibles typical of the Strumigenys genus, with distinctive hair patterns on their head and body that help separate them from similar species like S. alecto ^[1]. The head in profile shows short erect hairs only behind the highest point of the vertex, with no more than 8-10 visible from occipital view. The dorsal surfaces of middle and hind tibiae have only appressed hairs, and the pronotal dorsum lacks erect hairs except at the humeri. This species belongs to the Strumigenys leptothrix group and is found across Japan (southern Honshu to Kyushu, Okinawa, Ryukyu Islands) and Taiwan ^[2].

Quick Summary

• Difficulty: Hard
• Origin & Habitat: Japan and Taiwan. This species nests at the margins of broadleaf forests and adjacent open land, typically in soil or under stones ^[2]. One colony was collected under a concrete stone among thinly spaced trees on temple precincts in Osaka Prefecture, Japan. Most commonly found in the southern part of Honshu south to Kyushu ^[2].
• Colony Type: Single-queen colonies (monogyne). One documented colony collection contained more than 150 workers.
  • Colony: Monogyne
  • Founding: Claustral
• Size & Growth:
  • Queen: Described in original 1996 description but measurements not fully detailed in available sources
  • Worker: 2.1-2.6mm total length, HL 0.60-0.65mm, HW 0.44-0.50mm
  • Colony: At least 150+ workers documented in wild colonies
  • Growth: Unknown, no specific development data available for this species
  • Development: Unknown, no direct development studies available. Based on related Strumigenys species, expect 6-10 weeks at optimal temperature (Development timeline unconfirmed for this specific species)
• Antkeeping:
  • Temperature: Keep at room temperature around 20-24°C. This species is found in temperate Japan and Taiwan, suggesting they prefer moderate temperatures without extreme heat ^[2]
  • Humidity: High humidity required, they inhabit forest floor litter in damp environments. Keep nest substrate consistently moist but not waterlogged ^[3]
  • Diapause: Likely requires winter diapause given temperate distribution. Reduce temperature to around 10-15°C for 2-3 months during winter months
  • Nesting: Natural nesting in soil or under stones at forest margins. In captivity, a naturalistic setup with moist substrate (like a mix of soil and sand) or a plaster/acrylic nest with small chambers works well. Keep nesting area dark and undisturbed ^[2]
• Behavior: These are specialized predators that hunt springtails (Collembola) using their trap-jaw mandibles. They are shy and not aggressive toward keepers. Workers are tiny (under 3mm) and can escape through very small gaps, excellent escape prevention is essential. They are slow-moving compared to many ants and spend considerable time hunting through leaf litter. Colonies are small and sensitive to disturbance
• Common Issues: escape prevention is critical, tiny workers can squeeze through standard test tube cotton and small gaps, specialized diet makes them difficult to feed, they require live springtails or other micro-arthropods, colonies are small and slow-growing, requiring patience, wild-caught colonies may decline in captivity if not provided appropriate prey, sensitive to substrate dryness, desiccation kills colonies quickly

Housing and Nest Setup

Strumigenys benten are tiny ants that require carefully designed housing. A naturalistic setup with a shallow container filled with moist forest floor substrate (a mix of soil, sand, and leaf litter) works best, as it mimics their natural environment. Alternatively, a small acrylic or plaster nest with tight chambers and a water reservoir can work, but ensure the chambers are appropriately sized for their tiny workers. The key is maintaining high humidity while preventing flooding. Use a small test tube setup for founding colonies, but ensure the cotton is tightly packed to prevent escapes, these ants are incredibly small. Cover the nest to create dark, humid conditions that simulate the forest floor environment they naturally inhabit ^[2][3].

Feeding and Diet

This is the most challenging aspect of keeping Strumigenys benten. They are specialized predators that primarily hunt springtails (Collembola) in the wild. In captivity, you must provide live springtails as their main food source, this is non-negotiable for their survival. Springtails can be cultured separately on moist charcoal or soil and added to the colony enclosure. Some keepers report success with other tiny arthropods like booklice (Psocoptera), but these should be considered supplementary at best. Sugar sources are generally not accepted, these are obligate predators. Do not attempt to feed them standard ant foods like mealworms or honey water, they will not survive on such diets. The hunting behavior is fascinating to watch as they use their trap-jaw mandibles to capture prey

Temperature and Seasonal Care

Keep Strumigenys benten at moderate room temperatures, ideally around 20-24°C. They originate from temperate Japan and Taiwan, so they do not require extreme warmth. During summer months, room temperature is typically suitable. In winter, they likely require a diapause period, reduce temperatures to approximately 10-15°C for 2-3 months to simulate winter conditions. This period of cooler temperatures is important for colony health and may trigger reproductive behavior in spring. Avoid placing the nest near heating elements or in direct sunlight, as overheating can quickly kill colonies. Stable, moderate temperatures are preferred over fluctuating conditions

Behavior and Colony Dynamics

Strumigenys benten colonies are relatively small, with documented wild colonies reaching at least 150 workers. They are shy, non-aggressive ants that prefer to avoid confrontation. Workers hunt individually through leaf litter, using their specialized mandibles to capture tiny prey. The colony will likely show increased activity at dusk and during night hours, reflecting their natural forest floor activity patterns. These ants are not defensive and do not pose any threat to keepers. However, their small size means they are easily lost or crushed during colony maintenance. Handle any nest disturbances with extreme care. Colonies may be slow to establish and reluctant to expand their nest chambers initially, this is normal behavior for this genus

Finding and Acquiring Colonies

In the wild, Strumigenys benten is considered relatively uncommon. They are found almost exclusively in forests, particularly at forest margins and in leaf litter samples. In Japan, they have been collected from locations in southern Honshu through Kyushu and the Ryukyu Islands. The most reliable method to obtain colonies is through careful field collection, searching under stones in forested areas, particularly at forest edges. Berlese funnel extraction from forest litter is also effective for collecting workers. If purchasing from a supplier, ensure they specialize in exotic or difficult species, as these are not commonly available in the antkeeping hobby. Wild-caught colonies may experience significant stress during collection and transport, so quarantine and careful observation is essential in the first weeks ^[4][2]

Frequently Asked Questions

References