Natural Selection in Action

Ritika Elenkovan 2A

The Natural Selection of Warrior Ants

Species Names (Common and Scientific)

Scientific Name: Eciton burchelliiCommon Name: Army Ants aka Warrior Ants

The army ant travels in very large numbers. Many colonies of these ants have around 1,000,000 in the colony. It is not uncommon for an attack of army ants to use over 200,000 in the attack. Small animals do not have a chance. The perimeter of the army attack contains the specialists: the larger soldiers that have pinchers and will protect the flanks of the advancing army. Birds will actually follow behind the army and pick off insects as they attempt to get out the way. This army will kill small lizards, snakes, and frogs if they fail to move out of the way. Small ponds and streams are not a problem: the army will morph into a large ball and cross the water.

Background Info.

- Army ants are normally found in hot and humid lowland tropical rain forests. Their nests are typically found at the base of tree trunks.- They are found in the southern United States but are more common in Central America, South America, Africa, and parts of Asia. - Deserts are the more predominant location to find them in.

Habitat and Geographical Location

According to Sean O’Donnell, a professor of psychology at the University of Washington and the paper’s primary author, army ants occupy an important ecological niche in the montane forests of Costa Rica, and that migrating birds rely on these ants to flush out a portion of their food supply.

Niche

Warrior Ants & The Theory of Natural Selection

The theory of natural selection gives organisms the survival and reproduction stages that are needed in life. Natural Selection does not lead to the development of new organisms, the majority of the time, but gives organisms the adaptations they need to survive and reproduce, such as great eyesight or thicker fur. In this scenario, The Warrior Ants have the ability to imitate another Ant's colony signal, so they will go undetected and become part of the colony, unnoticed. The Warriors put to use this method of natural selection to prevent their ant families from being separated.

Nomadic Living:

Killing Adaptations/Working in Groups:

What adaptation(s) do the Warrior Ants population present?

Because army ants live in such large numbers, they are adapted for nomadic living. Instead of living in one overstuffed nest, they travel throughout the habitat and swarm on whatever prey they come across. When they need to temporarily settle down, they form short-term nests in hollow logs and trees, where they hook their bodies together to form a living shield around the queen and her eggs.

Army ants are well-equipped for killing prey. As they swarm in large numbers, this accounts for their ability to devour creatures much larger than themselves. They have distinctly large mandibles and stingers, which they use to overwhelm their prey when they swarm.

The idea of natural selection is that traits that can be passed down allow organisms to adapt to the environment better than other organisms of the same species. Relating back to this, the adaptations of quick killing movements and working in groups as well as learning to adapt to live nomadically, all increase the fitness of the Warrior Ant population as this enables better survival and reproduction compared with other members of the species, leading to evolution.

How did this trait promote fitness?

There were no environmental factors caused by selective pressures. However, Warrior Ants have a chemical signal that tells other Ant's in the family not to attack. Some have adapted and learned to imitate the chemical signal from other colonies so they can invade and take over and their colony and the workers will never know. They emit a chemical signal that lets the other's know to not attack. Ultimately, this allows the Warrior ants to live longer through natural selection, making it possible for the ants to reproduce and expand their colonies.

Enviornmental Factors & Pressures

Curley, Karen. “How Do Spiders Reproduce: by Live Birth or by Eggs?” Pets on Mom.com, 19 Nov. 2020, animals.mom.com/spiders-reproduce-live-birth-eggs-7404.html.

R., Angie. “Army Ants Facts & Information.” Blades of Green, 2 July 2020, www.bladesofgreen.com/blog/army-ants.

“Why Traveling Birds Need Army Ants.” Futurity, 24 Sept. 2010, www.futurity.org/why-traveling-birds-need-army-ants/#:~:text=Sean%20O'Donnell%2C%20professor%20of,portion%20of%20their%20food%20supply.

“Army Ant Species Eciton Burchellii. Facts, Identification.” Antark, 4 Apr. 2019, antark.net/ant-species/army-ant-eciton-burchellii/.

Works Cited: