Acromyrmex hispidus
Encyclopedia
Acromyrmex hispidus is a species
of leaf-cutter ant, a New World ant of the subfamily Myrmicinae
of the genus
Acromyrmex. This species is from one of the two genera of advanced attines
(fungus-growing ants) within the tribe Attini. It is found in the wild naturally in southern Brazil
and Bolivia
.
within the tribe Attini.
Acromyrmex can be identified from the closely related Atta genus
of leafcutter ants since they have 4 pairs of spines and a rough exoskeleton on the upper surface of the thorax
.
A mature Acromyrmex hispidus colony contains mostly sterile female workers. They are divided into castes
, based mostly on size, that perform different functions. Acromyrmex exhibit a high degree of biological polymorphism
, four castes being present in established colonies - minims (or "garden ants"), minors, mediae and majors. Majors are also known as soldiers or dinergates. Each caste has a specific function within the colony. Acromyrmex ants are less polymorphic than the other genera of leafcutter ants Atta, meaning that there is comparatively less differential in size from the smallest to largest types of Acromymex. The high degree of polymorphism in this genus is also suggestive of its high degree of advancement.
Like Atta, Acromyrmex subsists mostly on a particular species of fungus (genus Leucocoprinus
) which it cultivates on a medium of masticated leaf tissue. This is the sole food of the queen
and other colony members that remain in the nest. The media workers also gain subsistence from plant sap they ingest whilst physically cutting out sections of leaf from a variety of plants.
Before leaving their parent colonies, winged females take a small section of fungus into their bucchal pouches
and it is with this that the subsequently wingless queens 'seed' the fungus gardens of incipient colonies, cutting and collecting the first few sections of leaf themselves.
Acromyrmex has evolved to change foodplant constantly, preventing a colony from completely stripping off leaves and thereby killing trees, thus avoiding negative biological feedback on account of their sheer numbers. However, this does not diminish the huge quantities of foliage they harvest.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of leaf-cutter ant, a New World ant of the subfamily Myrmicinae
Myrmicinae
Myrmicinae is a subfamily of ants. There are about 140 genera within the group, with the family being cosmopolitan. The pupae lack cocoons. Some species retain a functional sting. The petioles of Myrmicinae consist of two nodes...
of the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Acromyrmex. This species is from one of the two genera of advanced attines
Fungus-growing ants
The fungus-growing ants comprises all the known fungus-growing ant species in the world participating in ant-fungus mutualism. Leafcutter ants, including Atta and Acromyrmex, make up 2 of the genera.-See also:...
(fungus-growing ants) within the tribe Attini. It is found in the wild naturally in southern Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
and Bolivia
Bolivia
Bolivia officially known as Plurinational State of Bolivia , is a landlocked country in central South America. It is the poorest country in South America...
.
Overview
Commonly known as "leaf-cutter ants" they are a species of ant from one of the two genera of advanced attinesFungus-growing ants
The fungus-growing ants comprises all the known fungus-growing ant species in the world participating in ant-fungus mutualism. Leafcutter ants, including Atta and Acromyrmex, make up 2 of the genera.-See also:...
within the tribe Attini.
Acromyrmex can be identified from the closely related Atta genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of leafcutter ants since they have 4 pairs of spines and a rough exoskeleton on the upper surface of the thorax
Thorax (insect anatomy)
The thorax is the mid section of the insect body. It holds the head, legs, wings and abdomen. It is also called mesosoma in other arthropods....
.
A mature Acromyrmex hispidus colony contains mostly sterile female workers. They are divided into castes
Eusociality
Eusociality is a term used for the highest level of social organization in a hierarchical classification....
, based mostly on size, that perform different functions. Acromyrmex exhibit a high degree of biological polymorphism
Polymorphism (biology)
Polymorphism in biology occurs when two or more clearly different phenotypes exist in the same population of a species — in other words, the occurrence of more than one form or morph...
, four castes being present in established colonies - minims (or "garden ants"), minors, mediae and majors. Majors are also known as soldiers or dinergates. Each caste has a specific function within the colony. Acromyrmex ants are less polymorphic than the other genera of leafcutter ants Atta, meaning that there is comparatively less differential in size from the smallest to largest types of Acromymex. The high degree of polymorphism in this genus is also suggestive of its high degree of advancement.
Like Atta, Acromyrmex subsists mostly on a particular species of fungus (genus Leucocoprinus
Leucocoprinus
Leucocoprinus is a genus of fungi in the family Agaricaceae. Its best known member is the yellow pot-plant mushroom , found worldwide. The type species is Leucocoprinus cepistipes...
) which it cultivates on a medium of masticated leaf tissue. This is the sole food of the queen
Eusociality
Eusociality is a term used for the highest level of social organization in a hierarchical classification....
and other colony members that remain in the nest. The media workers also gain subsistence from plant sap they ingest whilst physically cutting out sections of leaf from a variety of plants.
Before leaving their parent colonies, winged females take a small section of fungus into their bucchal pouches
Cheek
Cheeks constitute the area of the face below the eyes and between the nose and the left or right ear. They may also be referred to as jowls. "Buccal" means relating to the cheek. In humans, the region is innervated by the buccal nerve...
and it is with this that the subsequently wingless queens 'seed' the fungus gardens of incipient colonies, cutting and collecting the first few sections of leaf themselves.
Acromyrmex has evolved to change foodplant constantly, preventing a colony from completely stripping off leaves and thereby killing trees, thus avoiding negative biological feedback on account of their sheer numbers. However, this does not diminish the huge quantities of foliage they harvest.
Subspecies
- Acromyrmex hispidus fallax SantschiFelix SantschiFelix Santschi was a Swiss entomologist.Santschi is known for his pioneering work on the navigational abilities of ants. In one experiment, he investigated the way harvester ants used the sky to navigate. He found that as long as even a small patch of sky was visible, the ants could return...
, 1925 - Acromyrmex hispidus formosus SantschiFelix SantschiFelix Santschi was a Swiss entomologist.Santschi is known for his pioneering work on the navigational abilities of ants. In one experiment, he investigated the way harvester ants used the sky to navigate. He found that as long as even a small patch of sky was visible, the ants could return...
, 1925 - Acromyrmex hispidus hispidus SantschiFelix SantschiFelix Santschi was a Swiss entomologist.Santschi is known for his pioneering work on the navigational abilities of ants. In one experiment, he investigated the way harvester ants used the sky to navigate. He found that as long as even a small patch of sky was visible, the ants could return...
, 1925