Vollenhovia emeryi

Vollenhovia emeryi - "Ant"

Vollenhovia emeryi is a small myrmicine ant native to East Asia, with workers measuring 2.5mm in length ^[1]. Their body is reddish brown to dark brown, with a darker gaster featuring a blackish spot on the forehead, and yellowish legs ^[1][2]. This species is famous for having one of the most unusual reproductive systems in the ant world, queens reproduce asexually through parthenogenesis, while males are clones of their fathers, and only workers are produced sexually ^[3][4]. The species also shows queen polymorphism with two morphs: long-winged queens that can disperse and short-winged queens that cannot fly ^[5]. Colonies nest in decaying wood in forests, and the species has become invasive in parts of the United States, likely introduced with Japanese cherry trees in the early 1900s ^[6].

Quick Summary

• Difficulty: Medium
• Origin & Habitat: Native to Japan, Korea, China, Taiwan, and Southeast Asia. Found in secondary forests, nesting in decaying wood and under bark of fallen trees ^[7]. In the United States, established in Washington D.C., Maryland, Virginia, and Pennsylvania in riparian and floodplain forests ^[6].
• Colony Type: Two colony types exist: Type 1 colonies are usually monogynous (single queen) with long-winged alate females, found mainly in mountain forests, Type 2 colonies are usually polygynous (multiple queens) with short-winged females, found in or near riverside forests ^[1]. Both types can coexist in the same area.
  • Colony: Optionally polygyne
  • Founding: Semi-claustral
• Size & Growth:
  • Queen: Long-winged (L) queens: head width 0.56mm, Short-winged (S) queens: head width 0.54mm ^[5]
  • Worker: 2.5mm ^[1]
  • Colony: Small colonies, workers number in the dozens to low hundreds. One US colony had only 28 workers ^[6].
  • Growth: Moderate
  • Development: Unknown for this species. Based on typical Myrmicinae development, estimated 6-10 weeks at optimal temperature. (Development timeline not directly studied. Related Myrmicinae species suggest several months from egg to adult worker.)
• Antkeeping:
  • Temperature: Keep at room temperature, roughly 20-25°C. This species tolerates a range but prefers moderate warmth.
  • Humidity: Requires high humidity. In captivity, colonies show strong preference for extremely moist nest locations and will move into gaps near water sources ^[6]. Keep nest substrate consistently damp but not waterlogged.
  • Diapause: Yes. Alate females and males hibernate within the nests ^[1]. Provide a winter rest period of 2-3 months at 10-15°C.
  • Nesting: Provide decaying wood or a moist nest setup. Test tubes with water reservoirs work well, but ensure the cotton remains damp. They prefer tight, humid chambers and will abandon dry areas.
• Behavior: Workers are slow-moving and non-aggressive ^[6]. They do not have a painful sting ^[6]. When disturbed, workers quickly move eggs and larvae to protected locations ^[6]. Foragers frequently come and go while queens remain inside the nest chamber. They are not escape artists despite their small size, but standard escape prevention still recommended.
• Common Issues: high humidity is critical, colonies will abandon dry nests and may fail if substrate dries out, queen reproduction system is complex, short-winged queens mate inside the nest before hibernation, small colony sizes mean slower population growth than many common ants, parasitic ant Vollenhovia nipponica may be present in wild colonies, watch for smaller companion ants, invasive in the USA, do not release outside their native range

Understanding the Unique Reproductive System

Vollenhovia emeryi has one of the most unusual reproductive systems known in ants. Queens produce new queens through parthenogenesis (asexual reproduction), the daughters are genetically identical clones of their mother ^[8]. Males are produced through androgenesis, they are clones of their fathers, containing only the father's genetic material with the mother's genome eliminated ^[4]. Workers, however, are produced through normal sexual reproduction ^[3]. This creates two completely separate genetic lineages: the queen lineage (clonal) and the male lineage (also clonal), with no gene flow between them ^[9]. This system is called AQS + MC (Asexual Queen Succession + Male Cloning) ^[10]. The practical implication for keepers is that your colony's queen will produce more queens like herself, while workers come from sexually produced eggs.

Queen Morphs and Colony Types

This species has two distinct queen morphs that determine colony structure. Long-winged (L) queens have fully developed wings averaging 3.0mm in length and can fly to disperse and found new colonies ^[5]. Short-winged (S) queens have reduced wings averaging only 2.0mm and cannot fly, they mate inside their natal nest before hibernation ^[8]. L-queen colonies tend to be monogynous (single queen) and are found mainly in mountainous forests. S-queen colonies tend to be polygynous (multiple queens) and are found in lowland riverside forests ^[1]. The short-winged morph is evolutionarily derived from the long-winged morph ^[11]. In the laboratory, colonies fed more food produce both queen types, while poorly-fed colonies produce only short-winged queens ^[8]. This means nutrition strongly influences which type of queen develops.

Housing and Nest Setup

Vollenhovia emeryi requires moist, humid conditions. In the wild, they nest in decaying wood and fallen branches in forests ^[7]. In captivity, they show a strong preference for extremely wet nesting sites, one study observed colonies moving into the gap between a water hose and plastic container wall ^[6]. Use test tubes with water reservoirs or acrylic nests with moisture chambers. The nest material should remain damp but not flooded. They do well in naturalistic setups with rotting wood pieces. Keep the outworld moderately humid as well. These ants are not aggressive and handle disturbance by moving brood to safer locations rather than fleeing ^[6]. Use standard escape prevention, while not particularly good climbers, their small size means they can slip through small gaps.

Feeding and Diet

Like most Myrmicinae ants, Vollenhovia emeryi is likely omnivorous, feeding on small insects, honeydew, and nectar. Their small worker size (2.5mm) means prey items should be appropriately sized. Offer small insects like fruit flies, pinhead crickets, or other tiny arthropods. Sugar sources like honey water or sugar water are typically accepted. Feed small amounts regularly and remove uneaten food to prevent mold. Colonies in the study were fed standard ant diets in laboratory settings ^[12]. The complex reproductive system means well-nourished colonies produce more reproductive individuals (both queen types), while poorly-fed colonies produce fewer ^[8].

Seasonal Care and Hibernation

In their native range, alate reproductive females and males hibernate within the nests ^[1]. New reproductives emerge from late summer to autumn ^[12]. Provide a winter dormancy period of 2-3 months at temperatures around 10-15°C. During this time, reduce feeding and keep the colony slightly cooler. In spring after hibernation, colonies that produced short-winged queens will split through budding, the queens and some workers establish new nest locations nearby ^[8]. This is an important part of their natural cycle and should be replicated in captivity for colony health.

Invasive Status and Legal Considerations

Vollenhovia emeryi is invasive in the eastern United States, established in Washington D.C., Maryland, Virginia, and Pennsylvania ^[6][13]. The first US population was discovered in 1986 in Rock Creek Park, Washington D.C. ^[7]. It is believed to have been introduced with Japanese cherry trees gifted to the US in 1910-1912 ^[6]. If you live in these areas and collect wild colonies, do not release them outside their native range. Conversely, if you are outside the invasive range and obtain this species, it should be kept in secure enclosures to prevent accidental establishment. Always check local regulations before keeping ant species.

Frequently Asked Questions

References