Flight of the Cockroach

June 12, 2019 • by Nicole Elmer
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 Middle photo and right photo: the Atta roach in a fungus garden and on the wing of a queen leaf cutter ant (Photos: Alex Wild). Left photo: Zach Phillips at BFL


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Zach hard at work. (Photo: Jessica Lee)

Wheeler observed that these roaches are often invisible to their hardworking hosts, likely due to the roaches’ mimicry of the ants’ chemical profile. Ants do not “see” the way people do. What they lack in vision they make up for in their sense of smell. Ants have a remarkably sophisticated sense of smell which allows them to pick up odors that in turn dictate their behavior and social organization. The Atta roach capitalizes on this by mimicking the odor of the leaf cutter ants, but this mimicry may be imperfect, and the roaches still seem to regularly be recognized by some of the ants as intruders. This could explain one of Wheeler’s other interesting observations about the roaches. He noticed that the Attaphila he collected all had incomplete antennae, possibly having been clipped off by ants continually tending the fungal garden, or possibly by ants actively attacking the roaches. In addition to their chemical mimicry,” Zach says, “the roaches, like Peter Rabbit, are especially good at running through and hiding in the garden.”

The Atta roach may have it made in the shade, literally, as it can spend its entire life inside the ant colony. Some leave only when the virgin leaf-cutter queens are ready to depart home for good and mate mid-air with male ants from other colonies. The wingless roaches ride the virgin queens during their mating flights, which has led to the assumption that after flights the roaches remain with queens beginning new colonies. However, early in his PhD work, Zach observed that new leaf-cutter queens (termed “foundresses”) and roaches don’t get along in the lab, which led him to test other possible modes of roach “between-colony transmission.” He’s just finished this spring’s field season at Brackenridge Field Lab.

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 Queen leaf-cutter ant and her smaller daughter workers. (Photo: Alex Wild)

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