Ant genome reveals the hardy pest’s survival secrets

The ants also appear to have adapted to the variety of poisons they may encounter in their diet by developing "a large number of cytochrome P450 genes, which are important in detoxifying harmful substances," the study said. – Photo © Alex Wild / Eureka Alert WASHINGTON: The kitchen-invading Argentine ant has acute senses of smell and taste and possesses a built-in genetic shield against harmful substances, researchers who sequenced its genome said Monday. Knowing more about how the brown pests operate may help eradicate the larger threats they pose to crops and native species, said the study in the journal Proceedings of the National Academy of Sciences. "The Argentine ant is a species of special concern because of its enormous ecological impact," said Neil Tsutsui, associate professor at UC Berkeley's Department of Environmental Science. "When the Argentine ants invade, they devastate the native insect communities while promoting the population growth of agricultural pests," said Tsutsui, corresponding author on the Argentine ant paper and co-author of two other papers on the genomes of the red harvester and leaf-cutter ants. "This genome map will provide a huge resource for people interested in finding effective, targeted ways of controlling the Argentine ant."The genome project showed that Argentine ants have a whopping 367 sensory receptors for odor and 116 for taste, more than double the honeybee's capacity for smell and almost well above the mosquito's 76 taste sensors. "Ants are ground-dwellers, walking along trails, and for many, living most of their lives in the dark, so it makes sense that they would have developed keen senses of smell and taste," said Tsutsui. The ants also appear to have adapted to the variety of poisons they may encounter in their diet by developing "a large number of cytochrome P450 genes, which are important in detoxifying harmful substances," the study said. "Argentine ants have 111 such genes, while European honeybees, in comparison, have 46."While the Argentine ants may excel beyond the honeybee in some aspects, in social ways the two are rather similar, each with a dominant queen who is responsible for reproduction in the colony and workers who hunt for food. "We now know that ants have the genes and genome signature of DNA methylation — the same molecular mechanism that published honeybee studies have shown is responsible for switching whether the genome is read to be a worker or queen," said Christopher Smith, assistant professor of biology at San Francisco State University, an author on three of the four genome studies. Further study of the ant's genes, particularly those that detoxify it, could help determine whether the ants are resistant to pesticides, and possibly move researchers toward a new way to kill them. But such developments can take a long time, and are trickier than they may appear. "In biology, the idea is that once we know the genome of a pest species, we can come up with a magic bullet or smarter bullet to defeat it," said Smith. "In reality, the genome is really just information; we now have to put that into action, and in order to do that, we must genetically manipulate ants to confirm if a target gene does what we think it does," he said. "Having a genome is like being handed a big book with a bunch of words we don't understand. Now we have to figure out the grammar and syntax."