Acromyrmex laticeps

Acromyrmex laticeps

Acromyrmex laticeps is a medium-sized leafcutter ant native to the Neotropical region, found from Argentina and Uruguay north through Brazil to Bolivia and Paraguay ^[1]. Workers measure approximately 8.5 mm with notably widened heads above the eyes and dark brownish to blackened bodies ^[2]. Like all Attini, they are true fungus-farmers, cutting fresh plant material to cultivate gardens of Leucoagaricus gongylophorus rather than eating the leaves directly ^[3][4].

What makes this species unusual is their remarkably peaceful nature between colonies. Workers show no aggression toward non-nestmates and cannot distinguish between their own brood and foreign brood, accepting both equally ^[5][6]. They are primarily nocturnal foragers, becoming active when temperatures drop and humidity rises ^[7].

Quick Summary

• Difficulty: Expert
• Origin & Habitat: Neotropical region including Argentina, Bolivia, Brazil, Paraguay, and Uruguay ^[1][8]. Found in secondary forests, Eucalyptus plantations, native pastures, and palm tree microhabitats ^{[9][10][11][12]}.
• Colony Type: Monogyne (single-queen) colonies documented, though polygyny is characteristic of the genus ^[6].
  • Colony: Monogyne
• Size & Growth:
  • Queen: Unknown, based on Acromyrmex patterns, likely 10-14 mm.
  • Worker: 8.5 mm ^[2].
  • Colony: Field nests reach approximately 12,000 workers ^[13], laboratory colonies typically contain 3,000-4,000 individuals ^[5].
  • Growth: Moderate
  • Development: Unknown, estimated 8-12 weeks based on related Acromyrmex species. (Timeline inferred from genus patterns, maintain at 25-27°C for best results ^[6].)
• Antkeeping:
  • Temperature: 25-27°C for laboratory maintenance ^[6].
  • Humidity: 75% relative humidity required ^[6].
  • Diapause: Unknown, likely not required given tropical distribution.
  • Nesting: Underground fungus gardens required, natural nests range from shallow (11 cm) to deep (100-150 cm) with one to three chambers ^[13][8].
• Behavior: Nocturnal foragers that prefer cool, humid conditions ^[7]. Show remarkably low aggression between colonies and do not discriminate against foreign brood ^[5][6].
• Common Issues: Fungus garden collapse from Escovopsis parasitic infection ^[16][14]., Maintaining constant supply of fresh dicotyledonous leaves acceptable to the colony., High humidity requirements can lead to mold if ventilation is poor., Nocturnal activity means foraging happens primarily at night.

Nest Preferences

75%) and allow the ants to process leaf material into the fungus comb. Ventilation must be adequate to prevent mold while keeping humidity high. ^{[13][8][11][2][6]}

Feeding and Diet

As leafcutter ants, they do not eat the leaves they cut. Instead, they chew the plant material into a pulp to cultivate their symbiotic fungus Leucoagaricus gongylophorus, which produces nutritious structures called gongylidia that the ants eat ^[3][4]. They prefer dicotyledonous plants ^[11][14], and in Eucalyptus plantations, they favor E. urophylla and E. camaldulensis while avoiding E. cloeziana, which causes adverse effects on the colony ^[15][7].

You must provide fresh leaves constantly, they cannot survive on sugars or proteins alone. Acceptable leaves include rose, bramble, oak, or the preferred Eucalyptus species. Remove old or moldy leaves promptly to prevent contamination of the fungus garden.

Temperature and Care

Laboratory colonies thrive at 25-27°C with relative humidity above 75% ^[6]. They show predominantly nocturnal activity, foraging more when temperatures drop and humidity rises ^[7]. Activity correlates negatively with air temperature and positively with relative humidity in natural settings ^[7].

Given their tropical to subtropical distribution across South America, they likely do not require a winter diapause. However, you may simulate natural seasonal changes by slightly cooling the nest to 20-22°C during winter months while maintaining the fungus garden.

Behavior and Temperament

These ants show remarkably peaceful behavior between colonies. Workers do not discriminate between nestmate and non-nestmate brood, accepting both at similar rates of 55-62% ^[5][6]. Adult workers show no aggression toward non-nestmates, only making antennal contact ^[5]. The aggression index between non-nestmates is as low as between nestmates (zero) ^[5].

They are strictly nocturnal foragers, so expect most activity at night ^[7]. During the day, they remain in the nest tending the fungus garden.

Fungus Garden Management

The symbiotic fungus grows best at pH 4.0-5.0 ^[4]. The garden is vulnerable to the parasitic fungus Escovopsis, which was found in 20% of field nests ^[16]. Maintain strict hygiene, remove moldy leaves immediately, ensure good air circulation to prevent stagnant moisture, and avoid disturbing the fungus comb. The fungus produces enzymes to break down plant polymers including pectin, xylan, amylase, and cellulase ^[17], so providing diverse leaf types helps garden health.

Colony Founding

Founding behavior has not been directly documented for this species. Based on patterns seen throughout the Attini tribe, queens likely seal themselves in (claustral founding) and raise the first workers using stored body fat while tending an initial fungus garden started from mycelium carried from the parent nest. However, this remains unconfirmed for Acromyrmex laticeps specifically.

Frequently Asked Questions

References