Scientific illustration of Temnothorax curvispinosus (Bent-spined Acorn Ant) - showing key identification features including head, thorax, and gaster.

Bent-spined Acorn Ant

Temnothorax curvispinosus

Monogynous Polygynous species.list.oligogynous species.list.optionally polygynous Non-Parasitic Queen No Gamergate
Sci. Name
Temnothorax curvispinosus
Tribe
Crematogastrini
Subfamily
Myrmicinae
Author
Mayr, 1866
Common Name
Bent-spined Acorn Ant
Distribution
Found in 1 countries
Nuptial Flight
From June to July
Peak flight Time
23:00
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Introduction

Temnothorax curvispinosus is a small yellow ant native to eastern North America, easily recognized by its very long, inwardly curved propodeal spines that sit close together at the base . Workers measure about 2.4 mm in length, while queens are larger at 3-3.3 mm . These ants are cavity‑nesting specialists that live inside fallen acorns, hickory nuts, hollow twigs, and other small plant cavities on the forest floor . They are one of the most thoroughly studied ant species in the eastern United States, making them excellent candidates for antkeepers who want to observe complex social behaviors . This species is facultatively polygynous, meaning colonies can have either a single queen or multiple queens working together, and they are polydomous, meaning a single colony may occupy multiple nest sites .

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Status by country, from Kass et al. 2022 & Wong et al. 2023

Native Invasive Introduced (indoor) Intercepted Unknown
2000 - 2026

Quick Summary

  • Difficulty: Easy
  • Origin & Habitat: Eastern United States, from Maine south to Florida and west to Texas, living in deciduous forest habitats [7]. They nest in preformed plant cavities like acorns, hickory nuts, hollow twigs, and dead branches in leaf litter [8].
  • Colony Type: Facultatively polygynous, colonies can have one queen (monogyne) or multiple queens (polygynous). Queenless colonies are common, and workers can lay eggs to produce males. Colonies are also polydomous, meaning they spread across multiple nest sites in summer but coalesce into a single cavity for winter [5][9].
  • Size & Growth:
    • Queen: 3-3.3 mm [2]
    • Worker: 2.4 mm [2]
    • Colony: Typically 80-100 workers, occasionally up to 369 workers in larger colonies [7][10]
    • Growth: Moderate
    • Development: Exact time not specified in research. Eggs laid from mid‑April, larvae overwinter, then pupate in early June [10]. (Overwintering larvae develop into workers the following spring.)
  • Antkeeping:
    • Temperature: Keep at room temperature, around 20-24°C. They can tolerate 11.6°C to 34.1°C for colony growth, with optimal growth at 2-4°C above ambient [11]. Avoid sustained temperatures above 34°C, limited activity below 20°C [12].
    • Humidity: Keep nest substrate slightly moist but not waterlogged. In the wild, colonies move within their acorn to avoid overly damp or moldy areas [13]. They prefer stable conditions rather than extreme moisture.
    • Diapause: Yes, colonies are less active in winter and may cluster in a single cavity. Foraging stops during winter [14]. Keep at cool room temperature (10-15°C) for 2-3 months.
    • Nesting: Provide small cavities like test tubes, Y‑tong nests, or 3D‑printed nests with narrow chambers. They prefer compact, high‑ceilinged cavities over thin, flat spaces [15]. A test tube setup works well for founding colonies.
  • Behavior: Workers are diurnal and forage actively during daylight hours, primarily in spring and early summer [14]. They use tandem running to recruit nestmates to food sources [16]. These ants are relatively non‑aggressive and are poor competitors at food baits [17]. They feed on honeydew, plant nectar, seeds, and small insects. Escape prevention is critical due to their tiny size, use fine mesh barriers. Colonies relocate when disturbed or conditions become unfavorable [14].
  • Common Issues: tiny size means escapes are likely without fine mesh barriers, colonies often fail during hibernation if kept too wet, queenless colonies are common in the wild, may affect colony stability, slow growth can frustrate beginners who overfeed or overhandle the colony, wild‑caught colonies may have parasites that kill them in captivity [22][6]
Nuptial Flight Activity Analysis 218 observations
Jan
Feb
Mar
Apr
May
120
Jun
74
Jul
Aug
Sep
Oct
Nov
Dec

Temnothorax curvispinosus exhibits a clear seasonal flight window. Peak flight activity is concentrated in June, with the overall period spanning June to July. The concentrated timeframe makes peak months critical for sightings.

Flight Activity by Hour 218 observations
24
00:00
13
01:00
02:00
03:00
04:00
05:00
06:00
07:00
08:00
09:00
8
10:00
11:00
12:00
13:00
14:00
15:00
7
16:00
17:00
18:00
19:00
8
20:00
42
21:00
35
22:00
43
23:00

Temnothorax curvispinosus nuptial flight activity peaks around 23:00 during the night. Activity is spread across a 24-hour window (00:00–23:00). A secondary activity peak occurs around 21:00. Times may be influenced by human observation patterns.

Housing and Nest Setup

Temnothorax curvispinosus is a cavity‑nesting ant that thrives in small, enclosed spaces. In the wild, they live inside fallen acorns, hickory nuts, hollow twigs, and other natural cavities on the forest floor [3]. For captivity, a simple test tube setup works perfectly for founding colonies. As the colony grows, you can upgrade to a Y‑tong (AAC) nest or a 3D‑printed nest with narrow chambers. Laboratory studies show they prefer larger cavities with compact, high‑ceilinged spaces over thin, flat crevices, even when the total volume is the same [15]. This means providing chambers that are proportionally deep rather than wide. A small entrance hole leading to a chamber of about 1-2 cm works well. Keep the nest area dark or covered, as these ants prefer dim conditions. Escape prevention is critical, use fluon on the edges of any open setups and ensure lid seals are tight, as these tiny ants can squeeze through remarkably small gaps.

Feeding and Diet

In the wild, Temnothorax curvispinosus workers forage for honeydew droplets on leaf surfaces, feed at extrafloral nectaries of plants like bracken fern and bigtooth aspen, collect seeds, and scavenge dead insects [7]. They do not tend aphids but will readily attend extrafloral nectaries. For captive colonies, offer a constant source of sugar water or honey, and provide small protein sources like fruit flies, pinhead crickets, or other tiny insects. They are not aggressive foragers and are considered poor discoverers of food resources compared to other ant species [17], so place food near their nest entrance. Feed protein 2-3 times per week and keep sugar water available at all times. Remove any uneaten prey after 24 hours to prevent mold.

Temperature and Seasonal Care

Keep your colony at room temperature, ideally around 20-24°C. Research shows colony growth optimizes at intermediate temperatures, with the highest growth occurring in warming chambers 2-4°C above ambient [11]. The minimum temperature for colony growth is around 11.6°C, while the maximum is about 34.1°C, above this, colonies stop growing [11]. Their critical thermal maximum (CTmax) is around 43.4°C, but sustained temperatures above 34°C will stress the colony [11]. During winter, reduce temperatures to simulate dormancy. Keep them at cool room temperature (10-15°C) for 2-3 months. In the wild, foraging activity is highest in spring and early summer, drops in fall, and stops entirely during winter [14]. Do not feed during the winter dormancy period.

Colony Structure and Social Organization

One of the most fascinating aspects of Temnothorax curvispinosus is their flexible social structure. Colonies can be either monogyne (single queen) or polygynous (multiple queens), and this can change seasonally [5]. Studies show about 36-37% of wild colonies are queenless at any given time, and workers can reproduce in queenright colonies, laying eggs that develop into males [9][18]. New colonies are likely founded through pleometrosis, where multiple queens start a nest together, and new queens can be adopted into existing nests [5]. This flexibility makes them robust but also means colony dynamics can be complex. In summer, colonies become polydomous, spreading across multiple nest sites with varying queen numbers, but in winter they coalesce into a single cavity [14]. Understanding this can help you interpret behaviors like variable brood production or occasional queenless periods.

Behavior and Observation

Temnothorax curvispinosus is an excellent species for observing complex ant behaviors. They use tandem running to recruit nestmates to food sources or new nest sites, one worker leads another to the target while maintaining physical contact [16]. They are also known for their sophisticated house‑hunting behavior when colonies need to relocate, using quorum sensing to make collective decisions [19]. These ants are diurnal and most active during daylight hours, with foraging peaking in spring and early summer [14]. They are relatively non‑aggressive and are poor competitors at food baits, often losing to more dominant species [17]. Their small size and preference for cavity nesting make them easy to observe in captive setups. Watch for their characteristic long, curved propodeal spines, this is the feature that gives them their scientific name 'curvispinosus' meaning 'curved spine'.

Winter Care and Hibernation

Temnothorax curvispinosus requires a winter rest period to maintain healthy colony cycles. In the wild, colonies become less active in fall and stop foraging entirely during winter [14]. They overwinter within their nest cavity, typically in a single acorn or nut embedded in leaf litter. About one‑third to one‑half of all wild nests do not survive the winter, either from colony death or migration to new sites during warm winter days [14]. Queens have about a 50% chance of surviving winter, while workers have roughly 50-67% survival rates [14]. For captive colonies, reduce temperatures to around 10-15°C for 2-3 months during winter. Do not feed during this period. Keep the nest slightly moist but not wet, excessive moisture combined with cool temperatures can be fatal. In spring, gradually warm the colony and resume normal feeding.

Host Species and Parasites

Temnothorax curvispinosus is an important host species for several social parasites, which is worth knowing about if you collect colonies from the wild. It is the preferred host of the slave‑making ant Temnothorax duloticus, which raids their colonies to steal brood [20][21]. It is also host to Temnothorax americanus and the inquiline parasite Temnothorax minutissimus [22][6][23]. If you collect a wild colony and notice unusual ants or behaviors, the colony may be parasitized. Signs include the presence of different‑looking ants, suppressed queen reproduction, or workers showing aggression toward what appear to be nestmates. Healthy colonies can sometimes coexist with parasites for some time, but parasitized colonies often decline over time. Purchasing from reputable sellers who verify colony health is recommended if you want to avoid this issue.

Frequently Asked Questions

Can I keep Temnothorax curvispinosus in a test tube?

Yes, test tubes work perfectly for these tiny ants. They are cavity‑nesting ants that naturally live in small spaces like acorns and hollow twigs. A standard test tube with a cotton water reservoir provides ideal conditions. Make sure the tube is dark or covered, as they prefer dim conditions. Upgrade to a larger setup like a Y‑tong nest when the colony reaches 50+ workers.

How long does it take for Temnothorax curvispinosus to produce first workers?

The exact egg‑to‑worker time is not documented in research. Eggs are laid from mid‑April, larvae overwinter, and pupate in early June [10]. In captivity at room temperature the process can be faster, but a precise timeline is unknown. Queens are claustral, they seal themselves in and raise the first brood alone without foraging.

Do Temnothorax curvispinosus ants sting?

They do not have a functional stinger in the typical sense. As members of tribe Crematogastrini (subfamily Myrmicinae), they have a modified spatulate stinger used to smear venom onto enemies rather than piercing flesh. This is not painful to humans, their main defense is escape.

Are Temnothorax curvispinosus good for beginners?

Yes, they are excellent for beginners. They are small, docile, and have straightforward care requirements. They don't need additional heating in most home environments, and their cavity‑nesting behavior makes them easy to house in simple setups. The main challenges are escape prevention due to their tiny size and providing appropriate protein foods. Their fascinating social behaviors make them rewarding to watch.

Can I keep multiple queens together in one colony?

Yes, Temnothorax curvispinosus is facultatively polygynous, meaning colonies can have either one queen or multiple queens. In the wild, about 17% of nests have multiple queens, and queenless colonies are common [5]. Multiple foundress queens can start a colony together (pleometrosis), though some may eventually be rejected. It's generally safer to start with a single queen to ensure stability.

How big do Temnothorax curvispinosus colonies get?

Colonies typically reach 80-100 workers, though larger colonies can grow to around 200-370 workers [7][10]. The average colony size in studies was about 82 workers per colony. They are not large colony formers, their small size and cavity‑nesting lifestyle keep populations moderate.

Do Temnothorax curvispinosus need hibernation?

Yes, they benefit from a winter rest period. In the wild, foraging stops during winter and colonies become dormant [14]. Keep them at cool temperatures (10-15°C) for 2-3 months during winter. Reduce feeding to nothing during this period and keep the nest slightly moist. This rest period helps maintain natural colony cycles and supports healthy reproduction in spring.

What do Temnothorax curvispinosus eat?

They are omnivores with a preference for sugary foods. In the wild, they feed on honeydew from leaves, plant nectar from extrafloral nectaries, seeds, and dead insects [7]. In captivity, offer sugar water or honey constantly, and provide small protein sources like fruit flies, pinhead crickets, or other tiny insects 2-3 times per week. They are poor foragers, so place food near their nest entrance [17].

Why are my Temnothorax curvispinosus dying?

Common causes include: temperatures above 34°C (which stops colony growth), excessive moisture causing mold, escape due to inadequate barriers, stress from overhandling, or parasites from wild‑caught colonies [11][22]. Check that your setup is at room temperature (20-24°C), not too wet, and has secure escape prevention. If the colony was wild‑caught, parasites may be the issue. Ensure you're not overfeeding, as uneaten food causes mold.

When should I move Temnothorax curvispinosus to a formicarium?

You can keep them in a test tube setup indefinitely for most colony sizes. Consider upgrading to a Y‑tong or 3D‑printed nest when the colony reaches 50+ workers and the test tube feels crowded. These ants prefer small, compact cavities, so don't give them excessive space. A gradual transition works best, connect the new nest to the test tube and let them relocate on their own.

When is the nuptial flight of Temnothorax curvispinosus?

The nuptial flight of Temnothorax curvispinosus typically occurs From June to July.

What time of day does Temnothorax curvispinosus fly?

The nuptial flight of Temnothorax curvispinosus peaks around 23:00 during the night, with most activity between 00:00 and 23:00. Times may be influenced by human observation patterns.

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References

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