Temnothorax curvispinosus (The Acorn Ant)

Temnothorax curvispinosus, affectionately known as the Acorn Ant, is a charming and peaceful species that inhabits the deciduous forests of North America. As its name suggests, this ant is a specialist of "micro-habitats," frequently nesting inside abandoned acorns, hickory nuts, or small hollow twigs on the forest floor. For the ant keeper, Temnothorax curvispinosus is a true delight: they are tiny, meticulously clean, and exhibit complex social behaviors within a very small space. They are the perfect species for those who appreciate the "bonsai" of the ant world—a complete and thriving society that can fit inside the palm of your hand.

Natural History and Identification

Temnothorax curvispinosus is a very small ant, with workers typically measuring between 2.0mm and 3.0mm in length. Their coloration is a beautiful, warm yellowish-tan to a light amber, often with a slightly darker, brownish-black band across the middle of the gaster. One of the most identifying features of the species is the pair of long, curved spines (the "curvispinosus" of their name) that extend backward from the thorax. They have a sleek, slender build and a deliberate, methodical way of moving that is very different from the frantic pace of larger field ants.

The queens are only slightly larger than the workers, typically ranging from 3.5mm to 4.5mm. They share the same golden-amber coloration and are often seen moving gracefully among their workers and brood. One of the most interesting aspects of Temnothorax is that the queens are very long-lived and the colonies remain small, making them an excellent long-term pet. Unlike many other ants, Temnothorax curvispinosus is monomorphic, meaning all workers are of a similar size and shape, though there is a clear division of labor based on age.

Distribution and Native Habitat

This species is native to North America and is widely distributed across the eastern and central United States, from southern Canada down to the Gulf States. They are strictly forest dwellers, preferring deciduous woodlands with a rich layer of leaf litter and a consistent supply of fallen nuts and twigs. They are particularly common in oak-hickory and beech-maple forests.

Their nesting habits are one of their most fascinating traits. Temnothorax curvispinosus is an "obligate" cavity nester. Their primary choice of home is a hollow acorn or hickory nut that has been vacated by a weevil or other insect. A single acorn can house an entire colony, including the queen, dozens of workers, and all of their brood. They are also known to nest in small hollow twigs, galls, or even in the crevices of bark on standing trees. This preference for small, pre-made cavities makes them very easy to observe in captivity.

Diet and Foraging Behavior

Temnothorax curvispinosus is a generalist scavenger with a very peaceful foraging style. They are rarely seen in long trails; instead, they forage as individuals or in very small groups, searching the leaf litter for small dead insects, organic debris, and floral nectar. They are also known to collect "extrafloral" nectar from certain forest plants. Because they are so small and non-aggressive, they often forage in the same areas as much larger and more aggressive ant species, using their small size and "slow" movement to avoid detection.

In captivity, they are a joy to feed. Because their colonies are small, they require very little food—a single fruit fly or a small drop of honey-water can sustain a colony for several days. They are meticulously clean and will often create a small "refuse pile" far away from their nest entrance. They are not picky eaters and will accept a variety of proteins and sugars. Watching them "scaffold" their food items and communicate through subtle chemical signals is a highlight of keeping this species.

Colony Lifecycle and Social Structure

The lifecycle of Temnothorax curvispinosus begins with the nuptial flights, which typically take place in mid-summer (July and August) on warm, humid afternoons. The queens are fully claustral founders and will seek out a small wooden cavity or an empty nut to begin their first brood. One of the most interesting aspects of Temnothorax is that they are often "polydomous"—a single colony may be spread across several different acorns within a few feet of each other, with workers moving brood and food between the different "apartments."

Their social structure is generally monogynous (having one queen), but some populations may exhibit occasional polygyny. A mature colony rarely exceeds 100 to 200 workers. One of their most famous behaviors is "tandem running," where one worker leads another to a new food source or a better nesting site. The two ants move in a coordinated line, with the follower keeping its antennae in constant contact with the leader's gaster. This is one of the most sophisticated forms of individual recruitment in the ant world.

Ant Keeping: Care and Housing

Temnothorax curvispinosus is widely considered the "ultimate" beginner species for ant keepers. They are exceptionally hardy, take up very little space, and are completely non-aggressive. They prefer temperatures between 20°C and 24°C during their active season. While they are more tolerant of lower humidity than subterranean species, they still require a consistent water source and a localized area of higher humidity within the nest for the health of the brood.

Hibernation is a requirement for this temperate species, with a 3-4 month period at temperatures between 5°C and 10°C. One of the best things about keeping Acorn Ants is that you can provide them with "natural" nesting sites like cleaned-out acorns or small hollow twigs, which they will quickly move into and defend. They are also highly resistant to stress and are not easily disturbed by light or vibrations, making them perfect for close observation.

Recommended Setup

Because they are tiny and live in small cavities, the All-in-One setup is a fantastic choice for both founding and established colonies. It provides a compact and secure environment that is perfectly scaled to their needs. For those who want a more permanent and aesthetically pleasing home, the Paris formicarium is highly recommended. The Paris nest's material is excellent for maintaining the humidity levels these ants need, and its structured chambers provide the perfect "cavity-like" feel that Acorn Ants love. The excellent visibility of the Paris nest ensures you can see every detail of their tandem running and social interactions. Even a mature colony of Temnothorax curvispinosus will thrive in the Paris nest for many years.

Fun Facts and Advanced Observations

• The "Tandem Run": If you move a colony to a new nest, you can watch the fascinating process of tandem running, where the ants "teach" each other the path to their new home.
• Acorn Architects: While they don't chew the wood, they will use small pieces of debris to "wall off" the entrance of their acorn to a size that allows only one ant to pass at a time, making it much easier to defend.
• Long-Lived Queens: A Temnothorax queen can live for over 10 years, which is an incredible lifespan for such a small insect.
• Peaceful Neighbors: In the forest, you can sometimes find multiple colonies of different Temnothorax species living in acorns just inches apart, with no signs of conflict between them.