Pseudomyrmex concolor

Pseudomyrmex concolor

Pseudomyrmex concolor is a small, vibrant myrmecophytic ant native to the Amazon basin of South America. Workers measure 0.86-1.11mm in head width and have a uniformly light yellow-brown to orange-brown body color, making them quite distinctive among arboreal ants ^[1]. These ants are obligate plant symbionts, they exclusively inhabit the hollow domatia (specialized structures) of Tachigali trees, particularly Tachigali myrmecophila, T. paniculata, and T. poeppigiana ^[1]. Unlike most ants you might keep, these are arboreal ants that live inside living plants rather than in soil or wooden nests.

What makes P. concolor particularly fascinating is their mutualistic relationship with their host plants. The ants aggressively defend Tachigali trees from herbivores and competing plants, while the trees provide shelter in their hollow leaf rachis and petioles. Colonies tend mealybugs (Cataenococcus) inside the domatia for honeydew, which makes up a significant portion of their diet ^[1]. These ants are highly territorial and will bite and sting intruders, including other ant colonies, to protect their host plant.

Quick Summary

• Difficulty: Expert
• Origin & Habitat: Amazonian rainforest of Brazil, French Guiana, Guyana, Suriname, and Colombia. They live exclusively inside Tachigali trees (Fabaceae) in the hollow domatia of young to mature trees ^[1][2].
• Colony Type: Polygynous colonies with 1-8 dealate (wingless) queens, ranging from 22 to over 1100 workers ^[1]. Colony size is strongly limited by the amount of nesting space available in the host plant domatia.
  • Colony: Polygyne
• Size & Growth:
  • Queen: Unconfirmed, no specific measurements found in available literature
  • Worker: 0.86-1.11mm head width,0.97-1.24mm head length ^[1]
  • Colony: 22 to 1104 workers in wild colonies ^[1]
  • Growth: Moderate, growth is constrained by domatia space
  • Development: Unknown, not directly studied (Development likely follows typical Pseudomyrmecinae patterns but specific timeline unconfirmed)
• Antkeeping:
  • Temperature: Tropical species, keep at 24-28°C. Research shows patrolling activity increases with humidity and decreases with high temperature in rainy season (r=-0.75 to r=-0.82) ^[2].
  • Humidity: High humidity required, these are rainforest ants. Keep at 70-85% humidity. They respond strongly to humidity changes, with significantly more patrolling activity during rainy seasons ^[2].
  • Diapause: No, these are tropical ants without a true diapause. However, activity may reduce during dry seasons ^[2].
  • Nesting: This is the critical challenge, P. concolor is an obligate plant-dweller. In captivity, they need domatia-like structures (hollow stems, bamboo sections) or a naturalistic setup with live Tachigali plants. Standard test tubes and formicaria are NOT suitable. They require plant-based nesting sites with internal chambers.
• Behavior: Highly aggressive and territorial. Workers actively patrol three main plant regions: stems, domatia entrances, and leaves ^[2]. They defend their host plant fiercely against herbivores, other ants, and competing queens. They use olfactory cues for nestmate recognition, workers will attack and reject non-nestmates even if they're from the same species. Escape risk is moderate since they're arboreal and quite active, but they're not particularly small.
• Common Issues: Finding suitable housing is extremely difficult, they need plant-based domatia structures which are hard to replicate, Colony growth is limited by nesting space, making captive expansion challenging, They require live host plants or at least plant material to thrive, standard formicaria will not work, Wild-caught colonies may have parasites or be stressed from removal from host plant, They are aggressive defenders and will bite/sting readily when threatened

Housing and Nest Setup

This is the most critical and challenging aspect of keeping P. concolor. These are obligate plant-ants that require domatia (hollow plant structures) to thrive. Standard ant-keeping setups like test tubes, acrylic nests, and Y-tong nests are NOT suitable. You will need to create a naturalistic setup with either live Tachigali plants or artificial domatia structures. Hollow bamboo sections, cut stems with pith, or custom-built wooden chambers can work as alternatives. The key is providing enclosed spaces similar to the hollow leaf rachis and petioles they naturally inhabit. The nesting structure should have multiple chambers connected by narrow passages, mimicking the natural domatia architecture. Because they patrol the plant surface extensively, the setup should allow them access to a 'plant' area where they can forage and patrol ^[2].

Feeding and Diet

In the wild, P. concolor derives most of its nutrition from tending mealybugs (Cataenococcus) inside the host plant domatia ^[1]. The ants protect the mealybugs and consume their honeydew secretions, this makes up the majority of their diet. They also supplement with protein from small insects and arthropods they catch while patrolling the plant surface. In captivity, you should provide a constant sugar source (honey water or sugar water) and regular protein offerings like small crickets, fruit flies, or other tiny insects. Live prey is preferred since these are active hunters. The honeydew relationship is essential, so if you can establish a small mealybug culture (related to Cataenococcus) on a plant fragment in the setup, that would be ideal. Without a honeydew source, you'll need to provide more frequent sugar water to compensate.

Temperature and Humidity

As Amazonian rainforest ants, P. concolor requires warm and humid conditions. Keep temperatures in the range of 24-28°C. Research shows that during rainy seasons, worker patrolling activity actually increases, but high temperatures negatively correlate with activity (r=-0.75 to r=-0.82) ^[2]. This suggests they prefer warm but not hot conditions, and humidity is crucial. Maintain humidity at 70-85%, this can be achieved by keeping the setup in a humid room, using a moist substrate, or misting regularly. The setup should allow for some moisture gradient so ants can self-regulate. Avoid temperature spikes above 30°C and ensure good ventilation to prevent mold while maintaining humidity.

Behavior and Colony Dynamics

P. concolor colonies are polygynous, meaning they have multiple queens (1-8) living together in the same nest ^[1]. This is unusual among many ant species and affects how you might set up a colony. Workers are highly active patrollers, covering three main zones: stems, domatia entrances, and leaves ^[2]. They show distinct day vs night activity patterns that vary by season, significant differences between day and night occur in both dry and rainy seasons for different plant regions ^[2]. The most remarkable behavior is their aggressive defense of the host plant. They will readily bite and sting intruders, including competing ant colonies and herbivores. They also have sophisticated nestmate recognition using olfactory cues, workers can distinguish colony members from non-members and will attack even closely related ants from different colonies. When introducing workers to a new colony, be aware they may initially be aggressive toward individuals from different colonies.

Seasonal Activity and Cycles

Unlike temperate ants, P. concolor does not undergo true hibernation or diapause. However, they do show seasonal variation in activity. Research documented significantly more patrolling activity during rainy seasons compared to dry seasons (Season df=3,F=16.40,P ^[2]

Colony Size Constraints

A unique aspect of P. concolor biology is that colony size is strongly limited by nesting space. Research found significant correlations between domatia internal space and colonial components: eggs (Spearman P=0.001), larvae (P=0.003), pupae (P=0.008), and workers (P=0.003) ^[2]. Queen height also correlates with domatia size (r=0.522,P=0.008), and worker number correlates with domatia internal space (r=0.576,P=0.011) ^[2]. This means in captivity, your colony will not grow beyond the capacity of your nesting structure. If you want a larger colony, you must provide more domatia space. This is fundamentally different from most ant species where colony growth is limited by food or queen egg-laying rate. Plan accordingly, if you want 500+ workers, you'll need substantial plant-based nesting volume.

Frequently Asked Questions

References