for National Geographic News
The complex group behavior of social insects such as ants and bees has long intrigued scientists and other observers. This activity is thought to be shaped by a combination of factors, including genetics, learning, and the environment. But a new study shows that when it comes to fire ants, a single gene plays a major role.
The finding may offer important insight to researchers who are working to determine what genes influence social behavior in people.
Tracing the roots of human behavior is difficult because a complicated web of neural processes governs how people behave and interact, and these workings in the brain are controlled by a broad and diverse range of genes.
The new research, said Gene Robinson, a professor of entomology and neuroscience at the University of Illinois at UrbanaChampaign, raises the possibility that "it will be possible to trace the effects of genes through the long and winding roads that lead through effects on brain function, to elucidate effects on behavior."
The study focused on the social organization of South American fire ants, an aggressive species that invaded the United States in the 1920s.
The ants form two kinds of colonies. Some of the ants live in robust, sprawling compounds of interconnected nests that are inhabited by many queens. Others form tight settlements and are fiercely loyal to a single fat queen.
The research results showed that whether a colony has one queen or many is a matter of what variant of a particular gene the ants possess.
The gene, named Gp-9, is one of about 15,000 genes in the genome of fire ants. The gene encodes a protein involved in the perception of an odorant that appears to be crucial in determining how ants perceive the world.
Entomologists Michael Krieger and Kenneth Ross of the University of Georgia in Athens conducted the study, which was published last November in the journal Science.
Explaining the significance of the results, Krieger said the finding "demonstrates that single genes of major effect can underlie the expression of complex behaviors important in social evolution."
"However," he added, "it is possible that variation in particular genes can cause striking variation in social behavior."
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