Evolution: how country ants urbanize (Introduction)

by David Turell , Sunday, October 02, 2022, 18:31 (784 days ago) @ David Turell

In common country ants:

https://www.sciencedaily.com/releases/2022/09/220930133700.htm

"Research by Texas A&M AgriLife Research scientists in the Texas A&M Department of Entomology showed a common ant species undergoes physiological and behavioral changes in unnatural settings.

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"The study focused on Tapinoma sessile, a relatively small ant species commonly known as the house ant or sugar ant. It is the most common house-invading ant across the U.S.

"In its native environment, the house ant creates small, single-queen colonies typically found under leaf litter, rocks and logs, Vargo said. But in suburban/urban settings, these house ants build ever-expanding multi-queen colonies around human-made structures such as sidewalks, plant containers and landscape mulching.

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"Odorous house ants were observed and analyzed in natural and disturbed locations around the country including Indiana, Arkansas, Colorado and California.

"The team analyzed the ant's chemistry, such as hydrocarbons, genetic makeups of colonies and behaviors, such as aggression toward familial and outsider ants, and found stark differences based on the environment, Vargo said.

"The study found that house ants in urban and natural areas showed adaptations that resulted in genetic concentration. Vargo said house ant queens in their natural habitat typically leave the colony they were born in, fly to another suitable location and attempt to establish a new colony. Queens in urban colonies stay in the nest and expand the colony rather than leave.

"As a result, urban queens were closely related and less aggressive toward ants with genetic relation. Behavioral analyses showed ants in super-colonies were aggressive toward ants with outside genetics.

"Additionally, polydomous colonies, which are ant colonies that are spatially separate but socially connected, were only present in urban habitats, Vargo said. This suggests house ants only create super-colonies in developed areas. Ants from different urban areas shared some genetic similarities, suggesting they are adapting to features that are common in the urban environment.

"As a next step, researchers plan to compare stable isotopes in the ants to look at dietary changes and how they might relate to natural vs. urban environments and possible contributing factors like temperature and the urban heat island effect."

Comment: so far it is a descriptive study showing how ants adapt easily to city life.