Urban Ants Handle Heat Better The heat of cities is transforming
how urban ants respond to extreme temperatures, providing
glimpses of the impacts that changes in global climate might
trigger, an international team of scientists now reports. Cities
can be 10 to 15 degrees Fahrenheit hotter than surrounding rural
zones, with their asphalt roads and other features absorbing and
holding more of the sun's energy than natural landscapes.
Researchers call this the urban "heat island" effect. The
researchers investigated colonies of leaf-cutter ants (Atta
sexdens rubropilosa) inside and outside of São Paulo,Brazil,
South America's largest city with a population of more than 11
million people. They focused on how well urban and rural ants
tolerated extremes of heat and cold in experimental chambers. At
107.6 degrees Fahrenheit, the scientists found urban ants lasted
20 percent longer than ants from outside the city before the
extreme heat knocked them out. Surprisingly, although the
researchers expected that extreme