Graduate student Christian Rabeling excavates fungus-farming ant colonies in Brazil as part of his doctoral research on the evolution and ecology of the fascinating creatures.
Over two meters deep in this hole in Brasília, Brazil, graduate student Christian Rabeling is carefully and delicately dissecting the underground nests of a fungus-gardening ant called Mycocepurus obsoletus.
These agriculturalists evolved agriculture millions of years before humans, and the fungus crops they grow in chambers beneath the soil are their sole source of food.
To get to the nest chambers without destroying them, Rabeling first dug a deep hole to the side of an area full of nest entrances. He then lowered himself into the hole—again and again over a three-week period—and slowly scraped away vertical layers of soil to expose the inner chambers, fungus-gardens and tunnels.
This research in central Brazil is helping Rabeling better understand the evolution of the fungus-gardening ants, which have been around for 50 million years.
Rabeling and his advisor Ulrich Mueller recently discovered that another closely related fungus-gardening ant that lives throughout Brazil and Central America is completely asexual—it’s the only ant species in the world known to have dispensed with males entirely. He estimates that the asexual ants, Mycocepurus smithii, evolved only one to two million years ago.
Given past trends, it’s unlikely the species will survive very long (relative to sexually reproducing species), says Mueller. Without the genetic recombination that helps animal species adapt, they are more likely to go extinct. Whether or not this ant’s asexual strategy will become an exception to the rule is a question for an evolutionary biologist many million years from today.
Until then, Rabeling will use molecular genetic tools to understand the origin and maintenance of asexuality in this fascinating ant species.
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