Ant’s Body Temperature Depends on the Environment But Behaviors Not Affected in Warm Ecosystem

A recent study by North Carolina State University scientists discovered that ants do not change their actions when faced with rising temperatures and continue to reside in less-than-ideal environments even when better ones are available. This suggests ants cannot adapt their behavior to changing temperatures in their ecosystem.

The study found that ants, as ectotherms, have a body temperature determined by their environment. They prefer habitats that are cooler than their optimal temperature, where they can perform all their life functions at their best. If they are exposed to temperatures higher than their optimal temperature range, they risk reaching a temperature that would be lethal for them. In simpler terms, if it gets too hot for them, they will not survive.

Surviving the Heat

It is not well understood how or if insects and ectotherms like ants will change their behavior to avoid warmer but not lethal temperatures, which are becoming more common due to climate change. These warmer temperatures may not be optimal for the ants' physiology, but it still allows them to survive, as stated by the university press.

To understand the potential response of insect species to the sublethal temperatures caused by global warming, researchers at North Carolina State University examined five common species of ants found in the state. They counted and collected ants in different forest ecosystems and recorded the temperature at the collection sites to determine the distribution of microhabitats. They used a specially developed thermometer to measure the temperature of the ants. Additionally, they placed some ants in a controlled chamber with a temperature gradient to determine the preferred temperature of each species.

The study found that the ants in the lab had distinct thermal preferences, but when observed in their natural habitats, they were active in their preferred temperatures only slightly more often than would be expected by chance. This suggests that most species were found in warmer environments than they preferred, indicating that they may not be aware of or are limited in their ability to adapt to rising temperatures, as Phys added.

Ant Study Continues

Sara Prado, an adjunct professor and co-author of the study, is interested that the worker ants the team observed were willing to put themselves in uncomfortable situations while foraging. Prado wondered if the food was 'profitable' enough for the ants to stretch their comfort levels or if they were willing to sacrifice their well-being for the sake of the colony.

Elsa Youngsteadt, a professor of applied ecology at NC State and co-author of the study, said that humid times and places make warmer ants, and they're not adjusting their activity to match their preferred conditions. From the research sand, this may be a tradeoff that functions out fine for them. But if people think of the huge biomass of ants underfoot, their metabolic rates are all creeping upward as the climate changes. Even if it doesn't kill them outright, what does that amped-up metabolism mean for their life cycle and even the whole forest ecosystem, she noted?

Youngsteadt plans to continue this research by studying urban ants already living in the warmer climates of cities, which represent future climate change. The research paper, "Can behavior and physiology mitigate effects of warming on ectotherms? A test in urban ants," will be published on January 16th in the Journal of Animal Ecology.

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