DECEPTION IN NATURE - CATERPILLARS SING LIKE ANTS TO SNEAK INTO ANTS' NESTS

Before they become butterflies, some caterpillars transform themselves into ants. Rather than living out in the open and braving predators while they grow up, these caterpillars sneak into ant nests for free food and lodging — or they just eat the ants. Either way, scientists have found, part of the caterpillars’ disguise involves mimicking the sounds of an ant queen. When worker ants hear this tune, they drop everything to tend to the mooching invaders.

 At the beginning of its life, a caterpillar of the genus Maculinea hangs out on its favorite plant and munches away, like any other future butterfly. Its food plants are within the foraging grounds of Myrmica ants, the caterpillar’s targets. Once it finishes growing, the caterpillar waits until an evening between 6 and 8 PM—prime foraging time for the ants—then lets go of its perch and falls to the ground. There, it waits.

 

When a Myrmica ant that’s out searching for food stumbles across the caterpillar, it stops and feels it with its antennae. This assessment may take only a few sends, or may be an hours-long “adoption ritual,” explains University of Turin biologist Luca P. Casacci. Then the ant picks up the giant baby (“Whoops, how did one of our larvae get out here?”) and carries it back to the ant nest.

 

Ants rely mostly on chemical cues to recognize each other, communicate, and coordinate their activities. Parasitic caterpillars take advantage of this system, Casacci says. The caterpillars use chemicals on the outsides of their bodies to imitate the smell of the ants; this hastens their adoption and lets them safely hang around the nest.

 

But scientists recently discovered that Myrmica ants also communicate with sound. They make noise by dragging their hind legs across spikes on their abdomens. Ants that have different ranks within the colony make different sounds. One study found that Maculinea caterpillars could mimic these sounds, in addition to mimicking the ants’ smell. So Casacci brought caterpillars and their host ants into the lab for some recording sessions.

 

Casacci and his coauthors made recordings of queens and worker ants, as well as cuckoo and predatory caterpillars—both before and after they were adopted by the ant colony. Analyzing the components of the insects’ sounds, they found that caterpillars sound more like ant queens than like worker

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http://blogs.discovermagazine.com/inkfish/2014/04/11/caterpillars-sneak-into-ant-nests-by-singing-like-queens/

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