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Climate conundrum: Study shows ants don’t change behavior as temperatures rise

news7g01/17/2023

4 3 minutes read

A peer-reviewed publication

NORTH CAROLINA STATE UNIVERSITY

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In a recent study, researchers at North Carolina State University found that ants do not adjust their behavior in response to warming temperatures and persist in microhabitats. suboptimal even in the presence of optimal habitats. This finding suggests that ants may not be able to adapt their behavior in response to ecosystem warming.

Ants are ectothermic – animals whose body temperature depends on the environment. Although these animals experience a wide range of temperatures in everyday life, most endothermic animals prefer habitats that are slightly cooler than the so-called optimal operating temperature at which they live. Thermoplastics can best perform all the functions of life. If it encounters an environment warmer than the optimal point, an exothermic runs the risk of approaching the lethal end of its physiological spectrum. In other words, if it gets too hot, the ectothermic species will die.

However, little is known about how – or if – extrathermic insects will adapt their behavior to avoid the warmer but sublethal temperature range where the activity is physiologically possible. but not optimal – increasingly likely due to global climate change.

To learn more about how the insects might respond to those warmer, below-lethal temperatures, researchers at NC State studied five common ant species in North Carolina. The researchers counted and collected ants in forest ecosystems and measured air temperatures at collection sites to determine the distribution of available microhabitats. The researchers also used a unique ant thermometer to measure the temperature of the ants themselves (which varies with the color and body size of the ants). Finally, to determine each species’ preferred temperature, the researchers collected several ants for the lab and placed them in a rectangular chamber with a controlled temperature gradient.

The researchers found that laboratory ants do indeed have distinct temperature preferences, but field ants are only active in their preferred climates slightly more often than in their preferred climates. expected by chance. Instead, most species were collected in warmer-than-preferred locations, suggesting a lack of awareness or some limitation in their growing ability to regulate temperature.

“It’s interesting that the worker ants we observed willingly put themselves in uncomfortable situations while feeding,” said Sara Prado, an adjunct professor and co-author of the study. “I wonder if the food is ‘beneficial’ enough to make the ants more comfortable or if they are simply willing to sacrifice their health for the good of the colony.”

“Warmer times and places make ants warmer, and they don’t adjust their activities to their preferred conditions,” says Elsa Youngsteadta professor of applied ecology at NC State and co-author of the study. “For now, this could be a trade-off in their favor. But if you think about the biomass of giant ants at their feet, their metabolic rates all increase as the climate changes. Even if it doesn’t kill them outright, what does that enhanced metabolism mean for their life cycle and even the entire forest ecosystem?”

Youngsteadt plans to further investigate this question with urban ants effectively living the future of climate change in relatively warm cities.

Article, “Can behavior and physiology mitigate the effects of warming on endothermic organisms? An Experiment With Urban Ants,” to be published January 16 in the journal Journal of Animal Ecology. The article is co-authored by Michelle Kirchner from NC State University and Kirsten Keleher from Cornell University. The work was supported by USDA National Institute of Food and Agriculture, Bloom Project #1018689 for Youngsteadt, and North Carolina State University.