Atta mexicana characteristics, nutrition, biological and chemical control

2573
Egbert Haynes

Mexican Atta o Chicatanas is a kind of drover ant or leaf cutter of the Attini tribe that is characterized by presenting a great polymorphism; On the one hand there are the fertile and winged forms and on the other the infertile and devoid of wings, which in turn can be classified into minimal, minor, medium and soldier.

The reproduction of the colony is in charge of the queen and the drones. After the nuptial flight (of fertilization), the queen will not mate again and will produce several generations of offspring with that single copulation. In turn, the drones die after the nuptial flight. Infertile individuals carry out leaf hauling, cleaning and protection of the colony, among other activities.

Queen and workers of Atta mexicana. Taken and edited from: Acrocynus [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)].

Members of the colonies of arrieras ants, as well as those of other species of Atta, They have a very high potential as defoliators (they can leave a whole tree completely devoid of leaves in one night), which is why they are classified among the main agricultural pests in Latin America.

In some localities, mainly in Mexico and Colombia, this species is used for food purposes and its nutritional value is high, with a high protein content..

Article index

  • 1 General characteristics
  • 2 Taxonomy
  • 3 Life cycle
  • 4 Nutrition
  • 5 Biological and chemical control
    • 5.1 Chemical control
    • 5.2 Biological control
  • 6 Food use of Atta mexicana
  • 7 References

General characteristics

In general, they are large ants, with a dark-colored body, which is divided into the head, the mesosome, the waist, and the gaster. The head has a pair of antennae, a pair of compound eyes, and a pair of highly developed jaws that open laterally..

The mesosome is dorsally armed with spines and consists of three segments of the thorax as well as the first segment of the abdomen. The three pairs of legs of the ants articulate with this part of the body. The waist is made up of the second and third abdominal segments..

Its nest is large, close to 80 square meters and is built at a depth that sometimes exceeds 5 meters. It is one of the ant species that reaches not only the largest individual sizes, but also the largest population size. In the following video you can see this species:

Taxonomy

Archer ants are taxonomically located in the order Hymenoptera, family Formicidae, subfamily Myrmicinae, tribe Attini and in the genus Atta. This genus was erected by Fabricius in 1805 and the type species selected for it was Atta cephalotes, a species described by Linnaeus in 1758.

The ants of this genus are exclusive to the American continent, where they are distributed in tropical and subtropical regions, from the south of the United States to the north of Argentina, at a maximum height of 2000 meters above sea level..

The genus has 17 registered species, among which is Mexican Atta, which was first described by F. Smith in 1858.

Lifecycle

The reproductive process of the ants begins with the nuptial flight, in which the winged females and males participate and occurs at the beginning of the rainy season in the early morning hours, just before dawn.

Fertilized females will become queens and bury themselves to start a new colony, while males will die after mating. Each queen can deposit more than a million eggs throughout her life, which are selectively fertilized with the sperm stored in the spermatheca..

If the larva is born from a fertilized egg it will be female, otherwise it will be male. This means that males have a single chromosome load (haploid) while females are diploid..

The larvae undergo several molts before moving to a pupal stage, from which an adult will emerge. The larva is practically immobile and must be cared for and fed by the workers. The pupa has appendages not fused to the body.

The first females to be born will be workers and smaller and weaker than those of the following generations, but they will quickly begin the work of caring for the queen and other larvae, as well as collecting leaves and building galleries..

Diploid larvae will develop in any of the four worker castes or in winged females depending on genetic factors and the diet they receive..

Annually fertile individuals will leave the colony for the nuptial flight and to start a new colony, while the queen remains in the colony. In some ant species researchers have found that, in the absence of the queen, a few workers can become reproductive, although this has not been seen in A. mexicana.

Nutrition

Although the arriera ant spends much of its life carrying pieces of leaves and other plant parts to the colony, it does not really feed on them. The elements brought to the colony are used to cultivate fungi that are actually the food source of these ants..

Mexican Atta. Defoliating workers. Taken and edited from: Acrocynus [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)].

An anthill of Mexican Atta It can consume between 50 and 150 kilos of leaves daily to maintain the cultivation of the fungus that will serve as food, in an obligatory mutualistic relationship between both organisms that began more than 50 million years ago..

This fungus belongs to the Agaricaceae family and to the species Leucocoprinus gonglylophorus. Its appearance is that of a sponge, with a mycelium that forms a structure called gongilidium that contains food reserves that the ants take advantage of..

The ant, in addition to providing the leaf fungus for food, cleans it of any foreign material and deposits on it (and on the substrate in which it develops) fecal material and saliva that researchers believe contain antibiotic substances responsible for inhibiting development. from other contaminating fungi or bacteria.

The ants feed on the fungus through a mechanism called trophalaxis, which consists in that some workers predigest the fungus in the colony and then share it as liquid food with the larvae or with other adults in the colony..

Biological and chemical control

Ants of the genus Atta They are considered among the main crop pests in Latin America. The losses caused by these ants could exceed one billion dollars annually, due to this, enormous efforts are made in order to try to eradicate them from the crops..

Chemical control

The earliest methods of chemical control of the arriera ant included powder and liquid formulations. These products are very ineffective in controlling the pest. Chemical insecticides, in addition to being not very useful, have low specificity and high toxicity with consequent adverse effects on the environment..

In 1958, a new chemical control mechanism for mule ants began in the United States, which consisted of the use of baits treated with chemical agents, such as chlorinated compounds or such as fipronil, an insecticide of the phenylpyrazole chemical family..

The adverse effects of chemical pesticides on the environment, and the possibility of development of resistance to these pesticides by the organisms to be eradicated, have led to the search for biological mechanisms to control these pests..

Biologic control

Biological control programs are based on the search for organisms or microorganisms capable of negatively affecting the survival of another species..

The first attempt to control ants with biological agents was made in the United States. They employed Pseudacteon spp., a genus of flies in the family Phoridae (Diptera), to attack populations of invasive ants of the genus Solenopsis, getting encouraging results.

Microbiological control, for its part, has been based on the search for pathogens capable of infecting and causing the death of insects in a short time. Currently, researchers have tried to develop mechanisms to indirectly attack ants, by affecting the fungus on which they feed..

In this order of ideas, Metarhizium anisopliae, is a pathogenic fungus of insects that affects a wide diversity of species, which colonizes through the formation of appressoria and the production of proteolytic and chitinolytic enzymes.

On the other hand, fungi of the genus Trichoderma they have antagonistic activity with other fungi. This activity has been associated with the production of lytic enzymes and antibiotics from the trichorzianine group. Because of this, they have been considered potentially useful in controlling the ant symbiote fungus..

The use of these two microorganisms as insecticides has been shown to be effective in controlling populations of Atta cephalotes, for which it is probably also used for the control of Mexican Atta.

This biological control mechanism has yielded mortalities above 80%, compared to mortalities of 60% obtained with insecticides. Additionally, survivors of biocontroller treatment decrease or completely cease foraging activity..

Food use of Mexican Atta

Mexican Atta It is a common ingredient in some traditional dishes in Latin America, mainly in Mexico and Colombia, where they are highly appreciated. In Mexico, for example, they use them as ingredients in tacos and other traditional dishes. They can be eaten roasted, fried, spicy, etc..

Side view of a Mexican Atta ant. Taken and edited from: April Nobile / © AntWeb.org.

In Colombia they usually consume them toasted after submerging them in salty water, placed directly on the grill or in spicy dressings.

These ants have a protein and lipid content of more than 30%, in addition to 6.13% fiber and 7.58% minerals.

It is considered that the proportion of essential proteins in this species is high and beneficial for the human body, in addition to being a booster of the immune system. In turn, the fiber it contains helps digestion and the maintenance of the gastrointestinal microbiota..

References

  1. Mexican Atta. On Wikipedia. Recovered from: en.ikipedia.org.
  2. Atta (genus). On Wikipedia. Recovered from: en.ikipedia.org.
  3. V. Melo-Ruiz, A. Vilchis-Pérez & K. Sánchez-Herrera (2018). Macronutrient composition of the Chicatana ant (Mexican Atta), edible insect during the rainy season in Mexico. Journaal of Nutrition, Health and Food Engineering.
  4. Mexican Atta. In AntWiki. Recovered from: antwiki.org.
  5. E. López & S. Orduz (2002). Metarhizium anisopliae Y Trichoderma viride control colonies of Atta cephalotes in the field better than a chemical insecticide. Colombian Journal of Biotechnology.
  6. A. Mintzer (1995). Diet of the leafcutting ant, Atta mexicana (Hymenoptera: Formicidae), in a Sonoran desert habitat. Journal of the Arizona-Nevada Academy of Science.

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