Acromyrmex heyeri
Encyclopedia
Acromyrmex heyeri 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.
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 heyeri 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.
Acromyrmex heyeri workers construct the colonies nest by thatching
together cut grass. At temperatures ranging from 20–30°C, workers created more openings in the nest thatch as the internal nest temperature goes up as a method of temperature regulation for the colony. The workers will close openings in the nest thatch as the air humidity
surrounding the nest decreases to reduce water loss for the colony.
Studies using isoenzyme systems MDH
, a-GPDH, and AMY
show the occurrence of monogyny
and polygyny
associated or not with polyandry
, which indicates that the social organization is colony-specific. The polygyny and polyandry observed are likely to be responsible for the great genotypic diversity of the species colonies. The average inbreeding coefficient per colony is higher in Acromyrmex striatus
than in Acromyrmex heyeri, which may reflect the different patterns of production of sexual individuals and nuptial flight
of those two species.
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.
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 heyeri 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 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.
Acromyrmex heyeri workers construct the colonies nest by thatching
Thatching
Thatching is the craft of building a roof with dry vegetation such as straw, water reed, sedge , rushes, or heather, layering the vegetation so as to shed water away from the inner roof. It is a very old roofing method and has been used in both tropical and temperate climates...
together cut grass. At temperatures ranging from 20–30°C, workers created more openings in the nest thatch as the internal nest temperature goes up as a method of temperature regulation for the colony. The workers will close openings in the nest thatch as the air humidity
Humidity
Humidity is a term for the amount of water vapor in the air, and can refer to any one of several measurements of humidity. Formally, humid air is not "moist air" but a mixture of water vapor and other constituents of air, and humidity is defined in terms of the water content of this mixture,...
surrounding the nest decreases to reduce water loss for the colony.
Studies using isoenzyme systems MDH
Malate dehydrogenase
Malate dehydrogenase is an enzyme in the citric acid cycle that catalyzes the conversion of malate into oxaloacetate and vice versa...
, a-GPDH, and AMY
Amylase
Amylase is an enzyme that catalyses the breakdown of starch into sugars. Amylase is present in human saliva, where it begins the chemical process of digestion. Food that contains much starch but little sugar, such as rice and potato, taste slightly sweet as they are chewed because amylase turns...
show the occurrence of monogyny
Monogyny
- Definition and Distinction :Monogyny is one of several mating systems observed in nature, and it is usually referred to as a male’s tendency to mate with only a single female; the female, however, mates with multiple males. It is important to emphasize the distinctions between monogyny and...
and polygyny
Polygyny
Polygyny is a form of marriage in which a man has two or more wives at the same time. In countries where the practice is illegal, the man is referred to as a bigamist or a polygamist...
associated or not with polyandry
Polyandry
Polyandry refers to a form of marriage in which a woman has two or more husbands at the same time. The form of polyandry in which a woman is married to two or more brothers is known as "fraternal polyandry", and it is believed by many anthropologists to be the most frequently encountered...
, which indicates that the social organization is colony-specific. The polygyny and polyandry observed are likely to be responsible for the great genotypic diversity of the species colonies. The average inbreeding coefficient per colony is higher in Acromyrmex striatus
Acromyrmex striatus
Acromyrmex striatus 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 within the tribe Attini....
than in Acromyrmex heyeri, which may reflect the different patterns of production of sexual individuals and nuptial flight
Nuptial flight
Nuptial flight is an important phase in the reproduction of most ant, termite and some bee species. During the flight, virgin queens mate with males and then land to start a new colony, or, in the case of honey bees, continue the planned succession of an existing hived colony.- Before the flight :A...
of those two species.
Synonyms
- Acromyrmex gaudens FowlerFowlerFowler can refer to:* A hunter of wildfowl* Fowler's solution* A Fowler flap* Fowler's Modern English Usage, an English language style guide originally by Henry Watson Fowler* John Fowler & Co...
, 1988 - Acromyrmex lillensis FowlerFowlerFowler can refer to:* A hunter of wildfowl* Fowler's solution* A Fowler flap* Fowler's Modern English Usage, an English language style guide originally by Henry Watson Fowler* John Fowler & Co...
, 1988 - Moellerius heyeri Forel, 1899
External links
- Genetics and Molecular Biology, 25, 2, 173-178 (2002), Isoenzyme variation in the leaf-cutting ants Acromyrmex heyeri and Acromyrmex striatus Hymenoptera, formicidae)", Brazilian Society of Genetics
- GENETIC VARIABILITY AND SOCIAL STRUCTURE OF COLONIES IN Acromyrmex heyeri AND A. striatus (HYMENOPTERA: FORMICIDAE)