Study: Nature, nurture control ant caste

CHAMPAIGN, Ill., Aug. 25 (UPI) -- U.S. scientists say they've found a complex interplay of genetic and environmental factors determines whether some ants grow to become queens or workers.

Researchers from the University of Illinois, the University of Arizona, Arizona State University and Linfield College in Oregon studied the Florida harvester ant that lives in the southeastern United States. They chose that ant species to study because its social structure comprises three castes or classes: queens, major workers and minor workers.

Major workers weigh nearly four times that of minors, but the minors outnumber the majors by 20 to 1. Queens grow to eight times the weight of minor workers.

To explore the role of the environment in development, the researchers used an isotope analysis to determine how much nitrogen or carbon the ants consumed..

The scientists said differences in the nutrition that an individual assimilated during larval growth are strong predictors of caste.

"Our study shows there is a large genetic component to caste determination, but that there is also a very strong environmental component," said Christopher Smith, one of the study's authors.

The research, led by University of Illinois Professor Andrew Suarez, appears in the journal American Naturalist.