Pseudoatta (Pseudoatta argentina)

GenusPseudoatta (1)

This species is classified as Vulnerable (VU) on the IUCN Red List (1).

Very little is known about Pseudoatta argentina. A social parasite, Pseudoatta argentina is an ant that parasitises the colony of its host species, the fungus-growing leafcutter ant, Acromyrmex lundi (2).

Unlike other ants with a similar lifestyle, Pseudoatta argentina does not closely resemble its host species. Pseudoatta argentina is light brown and nearly hairless, with a remarkably smooth and glossy cuticle. The antennae of the male are reduced, having only eleven segments instead of the thirteen usual for fungus-growing leafcutter ants (2).

This species is endemic to Argentina, South America, and lives within the same range as its host species, Acromyrmex lundi (1).

This specialised ant is a type of ‘inquiline parasite’, which means that it lives in the nest of another species. The preferred host of Pseudoatta argentina is Acromyrmex lundi, a species of leafcutter ant that is found in the rainforests of South America. Acromyrmex lundi build very large and complex nests with many chambers, in which Pseudoatta argentina also live (3).

Pseudoatta argentina is a social parasite, meaning that it parasitises the nest of its host species, Acromyrmex lundi, rather than the host itself. Acromyrmex lundi lives in extremely large and complex colonies, permitting the parasitic ant, Pseudoatta argentina to go unnoticed.

Leafcutter ants such as Acromyrmex lundi gather leaves on which to cultivate ‘fungus gardens’ within the nest, which they then eat (4). Though there has been little research into the diet of Pseudoatta argentina, it is likely that it primarily consumes the fungus cultivated by its host, though it may also eat the brood or eggs of the host leafcutter ant (3).

Pseudoatta ants produce only fertile male and female offspring. As a parasite, it has no need for the infertile female “worker” caste which is found in most social ants (3). The male Pseudoatta argentina cannot fly, therefore it mates with related females near the entrance of the nest instead of conducting mating flights (2).

As an obligate parasite, Pseudoatta argentina suffers from the same threats as its host species. Deforestation in South America is a serious threat to this species (5).

Leafcutter ants are also considered a crop pest and populations are often destroyed by farmers, further reducing their numbers. As a consequence, numbers of Pseudoatta argentina are also reduced (6).

There are no specific conservation measures for Pseudoatta argentina, but the conservation of its rainforest habitat will help to ensure its numbers are secured.

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  1. IUCN Red List (September, 2011)
  2. Schultz, T.R., Bekkevold, D. and Boomsma, J.J. (1998) Acromyrmex insinuator new species: an incipient parasite of fungus-growing ants. Insectes Sociaux, 45: 457-471.
  3. De Souza, D.J., Soares, I.M.F. and Della Lucia, T.M.C. (2007) Acromyrmex ameliae sp. n. (Hymenoptera: Formicidae): A new social parasite of leaf-cutting ants in Brazil. Insect Science, 14: 251-257.
  4. Holldobler, B. and Wilson, E.O. (1990) The Ants. Harvard University Press, Cambridge, Massachusetts.
  5. Rainforest Alliance - Leafcutter Ant (September, 2011)
  6. Fowler, H.G., Pagani, M.I., Da Silva, O.A., Forti, L.C., Da Silva, V.P. and De Vasconcelos, H.L. (1989) A pest is a pest is a pest? The dilemma of neotropical leaf-cutting ants: Keystone taxa of natural ecosystems. Environmental Management, 13: 671-675.