Myrmecina cooperi

Myrmecina cooperi

Myrmecina cooperi is an exceptionally tiny ant species, with workers measuring under 2mm in length ^[1]. They are dark reddish brown in color with yellow mandibles and appendages, and can be identified by their short triangular propodeal spines and a distinctive forward-pointing ventral protrusion on the postpetiole ^[1]. This species was only described in 2015 and is known from a very restricted range in the Florida Panhandle and adjacent Alabama ^[1][2].

What makes M. cooperi particularly interesting is how rarely it is encountered despite targeted collecting efforts. Specimens have been found in various habitats including steephead edges, mesic forests, ravines, and even dwarf forest on beach dunes ^[1]. The species appears to be a southeastern endemic with an extremely limited geographic range, making it one of North America's most obscure ant species ^[1].

Quick Summary

• Difficulty: Expert
• Origin & Habitat: Florida Panhandle and adjacent Alabama, USA, found in hardwood forests, steephead edges, mesic forests, ravine habitats, and dwarf forest on beach dunes ^[1][2]
• Colony Type: Unknown, only worker caste has been described, queen and male are unknown ^[1]. Colony structure has not been documented.
• Size & Growth:
  • Queen: Unknown, queen has not been described ^[1]
  • Worker: 1.9mm total length (under 2mm) ^[1]
  • Colony: Unknown, no colony size data available
  • Growth: Unknown, no development data available
  • Development: Unknown, no direct measurements available. Based on typical Myrmecina genus patterns and their tiny size, development likely takes 6-10 weeks at optimal temperature, but this is an estimate. (No species-specific development data exists. Related Myrmecina species are known to develop relatively slowly due to their small size and specialized diet.)
• Antkeeping:
  • Temperature: Keep at room temperature (20-24°C). No specific thermal studies exist for this species, but related litter-dwelling ants in the southeastern US typically thrive in moderate temperatures ^[3].
  • Humidity: High humidity is essential. In nature, they inhabit mesic forests and are collected from leaf litter in damp environments ^[1]. Keep the nest substrate consistently moist but not waterlogged, with some drier areas available.
  • Diapause: Unknown, no specific studies on overwintering requirements. The Florida Panhandle experiences mild winters, so they likely have a reduced diapause period compared to northern species. Consider providing a cool period (15-18°C) during winter months.
  • Nesting: Natural nesting occurs in leaf litter and soil. In captivity, use a small test tube setup or a miniature formicarium with tight chambers scaled to their tiny size. A thin layer of moist soil or plaster works well. Because of their minute size, escape prevention must be excellent, they can squeeze through incredibly small gaps.
• Behavior: Myrmecina cooperi is a cryptic, litter-dwelling species that is rarely seen on the surface. They are likely predatory or omnivorous, with probable diet including oribatid mites based on mandible morphology similar to Japanese Myrmecina species ^[1]. Workers are tiny and slow-moving. Aggression levels are unknown but likely low, these are not defensive ants. Escape risk is extremely high due to their minute size, even standard test tube setups require careful examination for gaps. They are not known to sting and pose no danger to keepers.
• Common Issues: escape prevention is critical, they are tiny enough to squeeze through standard mesh and gaps in equipment, no queen or colony structure data exists, finding a mated queen would be extremely difficult, diet is uncertain, they likely need tiny live prey like oribatid mites or springtails, not standard ant foods, very rare in the hobby and potentially protected in its limited range, slow growth and small colony sizes mean colonies are fragile and slow to establish

Discovery and Identification

Myrmecina cooperi was only described in 2015 by Mark Deyrup, making it one of the most recently described North American ant species ^[1]. The species was named in honor of the Robert J. Cooper family of Palm Beach, Florida, in recognition of their support for the biodiversity program at Archbold Biological Station ^[1].

Identification is challenging due to their tiny size, workers are under 2mm, making them one of the smallest ants in North America ^[1]. Key diagnostic features include the short triangular propodeal spines, a strong forward-pointing ventral protrusion on the postpetiole, and parallel carinae on the head and mesosoma ^[1]. The gastral tergites are shagreened (roughened texture) rather than glossy, which helps distinguish them from the similar Myrmecina americana ^[1]. Specimens have been collected from Walton County, Liberty County, and Okaloosa County in Florida, as well as Houston and Baldwin Counties in Alabama ^[1][2].

Natural History and Habitat

This species inhabits the unique hardwood forests of the Florida Panhandle, which represent one of the six most significant centers of biodiversity in the United States ^[1]. These southern habitats contain relict distributions of Appalachian flora that survived Pleistocene climate changes in riverine forests and steepheads ^[1].

Specimens have been collected from multiple habitat types: edges of steepheads, mesic (moist) forests, dwarf forest on beach dunes, and ravine habitats ^[1]. All specimens were extracted from leaf litter using Berlese funnels, confirming they are strictly litter-dwelling ants that rarely if ever venture above the forest floor ^[1]. The Florida Panhandle's sandy uplands continue to release water even during dry periods, providing consistently moist conditions that this species appears to require ^[1].

Feeding and Diet

The probable diet of Myrmecina cooperi includes oribatid mites, based on mandible morphology similar to Japanese Myrmecina species ^[1]. This suggests they are specialized micro-predators rather than generalist omnivores. In captivity, you would need to culture or obtain tiny live prey such as springtails, oribatid mites, or other micro-arthropods.

Standard ant foods like mealworms and fruit flies are likely too large for these tiny ants. Sugar sources may be accepted but should not be relied upon as a primary food. The best approach is to establish a culture of springtails or other tiny arthropods to provide a consistent food source. Feeding should be done sparingly, offer small amounts of prey every few days and remove any uneaten prey to prevent mold.

Housing and Escape Prevention

Housing Myrmecina cooperi presents significant challenges due to their minute size. Standard ant-keeping equipment is not designed for ants this small, and escape prevention requires extra attention. Examine all test tube setups, connections, and enclosure edges for gaps, these ants can squeeze through openings that would hold back larger species.

A small test tube setup with a cotton plug works for founding colonies, but you must ensure the cotton is packed tightly and consider using additional barriers. For established colonies, a small formicarium with very tight chambers and passages is needed. The nesting area should be kept moist but not wet, as these forest-floor ants require high humidity without saturation. A thin layer of substrate (soil or plaster) that can hold moisture without flooding is ideal. ^[1][3]

Conservation Status and Collection

Myrmecina cooperi has an extremely restricted geographic range and is considered a southeastern endemic ^[1]. It has only been found in a handful of locations across the Florida Panhandle and adjacent Alabama. The species appears to be genuinely rare rather than simply overlooked, despite extensive collecting efforts and examination of hundreds of Myrmecina americana specimens, only a small number of M. cooperi individuals have been found ^[1].

This rarity has implications for antkeepers: wild collection should be avoided or done very cautiously, and established colonies in captivity are extremely valuable for conservation purposes. If you obtain a colony, it should be treated as a precious specimen that may be the only captive population of this species. Never release any ant colonies in North America, but this is especially important for species with restricted ranges like M. cooperi.

Frequently Asked Questions

References