Temnothorax longispinosus

Temnothorax longispinosus - "Long-spined Acorn Ant"

Temnothorax longispinosus is a small, dark ant native to eastern North America. Workers measure 2.25-2.5mm and are nearly black with long, distinctive propodeal spines that are nearly twice as long as the distance between their bases ^[1]. The head is mostly smooth and glossy with fine striolae, and the 11-segmented antenna has a 3-jointed club ^[1]. This species gets its name from these remarkably long spines, which easily separate it from most other Temnothorax species ^[1]. Queens are larger at 3.5-4mm, and males measure 2-2.5mm ^[2].

What makes T. longispinosus particularly interesting is its complex social structure. Colonies are facultatively polygynous, meaning they can have one queen or multiple queens working together ^[3]. They are also polydomous, during summer months, colonies spread across multiple nest sites (often in acorns, twigs, or hollow plant stems), then coalesce into a single nest for winter ^[3][4]. This species is also a common host for three species of slave-making ants: Protomognathus americanus, Temnothorax duloticus, and Temnothorax pilagens ^[1][5].

Quick Summary

• Difficulty: Easy
• Origin & Habitat: Eastern North America, found from Quebec and Ontario south to Georgia and Alabama, west to Michigan, Iowa, and Missouri ^[1]. Inhabits deciduous and mixed forests with dense tree shade, often in moist woods of oak and hickory mixed with red maple or black cherry, on slopes of hollows or near swamps ^[6]. Also found in open woods and forest edges with good drainage ^[1].
• Colony Type: Facultatively polygynous, colonies can have single or multiple queens. Polydomous in summer, with colonies spread across multiple nest sites, then coalescing for winter. Worker reproduction occurs in queenright colonies ^[3][7].
  • Colony: Optionally polygyne
  • Founding: Claustral, Pleometrosis
• Size & Growth:
  • Queen: 3.5-4mm ^[2]
  • Worker: 2.25-2.5mm ^[2]
  • Colony: Typically under 100 workers, average around 45-50 workers per colony. Maximum recorded around 140-150 workers in a single nest ^[1][8].
  • Growth: Moderate
  • Development: 6-8 weeks (estimated based on related species) (Egg laying begins mid-May and continues through September. Overwintered larvae pupate in early June, with pupae present through September. Peak worker emergence is late summer ^[8].)
• Antkeeping:
  • Temperature: Keep at room temperature, around 20-24°C. Upper thermal tolerance is 42-46°C, and they benefit from a temperature gradient ^[9]. They are a forest species that does well at cooler temperatures than many ants.
  • Humidity: Moderate to high. These are forest floor ants that prefer moist conditions. Keep the nest substrate damp but not waterlogged. They do well in naturalistic setups that mimic the leaf litter environment.
  • Diapause: Yes, requires a winter dormancy period. In the wild, colonies coalesce in winter and nest mortality can reach 30-50% ^[4]. Keep at 5-10°C for 2-3 months during winter, mimicking natural seasonal cycle.
  • Nesting: Prefers small cavities, acorns, hickory nuts, hollow twigs, or preformed cavities in rotting wood. A Y-tong (AAC) nest or plaster nest with small chambers works well. They will readily occupy artificial nests that mimic these tight spaces ^[1].
• Behavior: Generally peaceful and non-aggressive, but can be territorial. Workers forage on low vegetation, tree trunks, and the ground in shaded forest areas ^[1]. They are skilled at recognizing and defending against slave-making ants, increasing aggression when exposed to parasites ^[10]. They have a well-developed circadian rhythm, with peak foraging activity during midday ^[11]. Escape prevention is important due to their small size, use fine mesh barriers.
• Common Issues: slave-maker invasion, this species is a common host for three species of slave-making ants, monitor colonies closely and remove any invading parasites ^[1][5], nest site limitation, scarcity of suitable nest sites influences colony structure, provide plenty of small cavity options like acorns or twigs ^[3], winter mortality, 30-50% of nests may not survive winter, ensure proper hibernation conditions and avoid disturbing colonies during dormancy ^[4], small colony size, colonies typically stay under 100 workers, this is normal, not a sign of problems ^[1], polydomous stress, colonies may attempt to spread to multiple nests, ensure adequate space and multiple chambers to prevent stress from crowding

Housing and Nest Setup

Temnothorax longispinosus is a cavity-nesting species that naturally lives in preformed holes in the leaf litter, think acorns, hickory nuts, hollow twigs, and crevices under bark or stones ^[1]. For captive care, a Y-tong (AAC) nest or plaster nest with small, tight chambers works best. The chambers should be appropriately scaled to their tiny size, these are not large ants, and they feel secure in snug spaces.

You can also create a naturalistic setup with actual acorns or small twigs as nest sites, placed in a container with leaf litter and forest soil. This mimics their natural environment and can be quite rewarding to watch. Whatever nest type you choose, ensure excellent escape prevention, these small ants can squeeze through surprisingly tiny gaps. Use fine mesh on any ventilation and apply fluon or another barrier to tube connections.

Because they are polydomous in summer, providing multiple small nest sites can help reduce stress. Some keepers offer 2-3 potential nest areas connected by tubing, allowing the colony to choose their preferred setup.

Feeding and Diet

In the wild, T. longispinosus workers forage for honeydew on leaf surfaces and attend extrafloral nectaries of trees like bigtooth aspen ^[1]. They are generalist feeders that also scavenge small insects and other protein sources.

For captive colonies, offer a mix of sugar sources (honey water, sugar water, or a small drop of honey) and protein (small crickets, fruit flies, mealworms, or other tiny insects). They are small ants with modest appetites, a small drop of honey and a few tiny prey items twice weekly is usually sufficient. Remove any uneaten prey after 24-48 hours to prevent mold.

Their small size means you should cut prey into appropriately small pieces or offer already small insects. They are not aggressive foragers and prefer to collect easily accessible liquid foods and small, manageable prey.

Temperature and Seasonal Care

Keep T. longispinosus at room temperature, ideally around 20-24°C. They are a forest species with good cold tolerance, upper thermal limits are 42-46°C, but they do best in cooler conditions than many ant species ^[9]. A temperature gradient is beneficial, allowing workers to choose their preferred spot.

Winter care is essential. This species requires a diapause (winter rest) period of 2-3 months at cool temperatures (5-10°C). In the wild, colonies coalesce into single nests for winter, often in acorns or twigs buried in leaf litter ^[4]. During this time, metabolic activity slows dramatically, and you should not disturb the colony or offer food.

Come spring, colonies become active again. Egg-laying begins around mid-May in the wild, and you should resume normal feeding and temperatures as the colony breaks dormancy ^[8]. Expect increased activity and brood production as the seasons warm.

Colony Structure and Behavior

One of the most fascinating aspects of T. longispinosus is their flexible colony structure. They are facultatively polygynous, colonies can have one queen or multiple queens working together ^[3]. Research shows that about 37% of wild nests are queenless,48% have one queen, and 14% have multiple queens ^[3].

Equcially interesting is their polydomous nature. In productive summer months, colonies spread across multiple nest sites, with each site potentially having its own queen(s). This fragmentation appears to be a response to nest site limitation and resource availability ^[3]. During winter, these nests coalesce back into a single structure.

Workers themselves can reproduce in queenright colonies, a rare trait among ants ^[7]. This adds another layer of complexity to their social organization. When a colony loses its queen, workers may lay male-producing eggs, providing a backup reproductive strategy.

Their behavior is generally peaceful, but they are known to increase aggression when exposed to slave-making ants, particularly Protomognathus americanus ^[10]. They can recognize this parasite as an enemy and mount collective defenses.

Dealing with Social Parasites

Temnothorax longispinosus is unfortunately a popular host for three species of slave-making ants: Protomognathus americanus, Temnothorax duloticus, and Temnothorax pilagens ^[1][5]. These parasites raid host colonies, stealing brood to raise as slaves that work for the parasite colony.

If you keep this species, be vigilant for signs of parasitic invasion. Slave-maker scouts may enter your colony setup, and if established, you may see mixed workers (the slaves) that look different from your host workers. The slaves will be Temnothorax species, typically darker or differently shaped.

The good news is that T. longispinosus has evolved defenses. Colonies that have been exposed to slave-makers increase their aggression and are better at defending against raids ^[10]. Some enslaved workers even engage in 'slave rebellion, ' killing parasite brood to increase their indirect fitness ^[12]. If you detect a slave-maker invasion early, you can remove the parasite queen and her workers, allowing the host workers to potentially take over.

Growth and Development Timeline

Understanding the seasonal cycle helps with colony management. In the wild, egg-laying begins around mid-May and continues through September ^[8]. Overwintered larvae (only larvae overwinter, not eggs or pupae) begin pupating in early June. Pupae are present through September, with the peak of pupation in August.

Worker populations hit their lowest point in June before the year's new workers emerge. Numbers build through summer and peak in September ^[8]. This means your colony will look smallest in early summer and largest in late summer/early fall.

Winged reproductives (alates) appear in summer. Males and winged females are found in nests starting in July, with mating flights occurring from mid-July through early September ^[1]. If you want to try colony founding, this is when you would collect newly mated queens.

For estimating development time: from egg to worker takes approximately 6-8 weeks at warm room temperature. The first workers (nanitics) will be smaller than mature workers and may take several months to reach full size as the colony grows.

Frequently Asked Questions

References