Last week I came across hundreds (if not thousands) of tiny worker ants (Hymenoptera: Formicidae) foraging for food. They were particularly dense in an area of about four square feet, although they trailed off in lesser numbers in several directions. In the first segment of this video you can see many of them crawling around on a dead insect, chewing off bits to bring back to their colony. All of these workers are sterile females. The only fertile female is the queen, and the winged males only live long enough to engage in mating flights with her.
Ants have elaborate social behavior and large numbers of workers that effectively exploit resources, making them arguably the most successful of all insect groups (Triplehorn and Johnson 2005). They could even be considered the most successful of all macroscopic terrestrial animals (Schultz 2000). In addition to effectively foraging all available food in an area, they collectively participate in symbioses with over 465 plant species, thousands of arthropod species, and and unknown number of fungi and microorganisms (Schultz 2000). Some ants collect plant matter to farm fungi for food, and some herd aphids to feed on their honeydew excretions. They interact with their environments in many diverse and fascinating ways.
Ants make up 15 to 25% of all terrestrial animal biomass depending on location (Schultz 2000). In terms of total mass, all of the ants on earth outweigh all of the humans. The complexity of activity in this short video is in many ways no less impressive than the complexity of human activity in a given city.
Schultz, T.R. 2000. In search of ant ancestors. Proceedings of the National Academy of Sciences of the United States of America.
Triplehorn, C.A. and N.F. Johnson. 2005. Borror and DeLong’s Introduction to the Study of Insects. Seventh Edition. Thomson Brooks/Cole, Belmont, CA.