Beetle Infiltrates Ant Colonies, Pretends to Be Queen

Behavior of parasitic beetle similar to Jewish intruders in Gentile societies; pest exploits and feeds on hosts, mimics ruling caste

UNIVERSITY ROMA TRE’S Professor Andrea Di Giulio and his team of co-authors set the scene remarkably well in their paper recently published to PLoS ONE. The focus of that paper? A group of conniving beetles that somehow manages to infiltrate ant colonies and parasitize the ants without eliciting any retaliation whatsoever. Ladies and gentlemen, meet the ant nest beetle. (ILLUSTRATION: “The ant colony is a heavily guarded, nearly impenetrable fortress rich with bountiful resources. Intruders attempting to infiltrate the ant society are immediately discovered via chemical cues, overtaken and dismantled. Nothing gets by, except for the few highly specialized, that have evolved the necessary chemical, morphological and behavioural tools to hack the complex recognition and communication system of the ants. Flying under the ant radar represents a huge boon that not only grants free access to the bounty of the colony — including the ants themselves — but further provides a safe and well-protected harbor to develop and live.”)

There are more than 800 species of ant nest beetle (Paussus), and though almost all of them bear little resemblance to ants, they all manage to live out their lives in ant colonies, feeding on ant eggs, larvae, and even adults by piercing their mandibles into the abdomen of their unsuspecting victims and sucking out the nutritious innards. You might think that nefarious actions like these would provoke an angry response, but the sly beetles have evolved two clever traits that allow them to evade detection.

First, the beetles secrete chemicals that mimic those produced by ants, allowing them to blend in. Second, as Di Giulio and his team just discovered, the beetles produce distinct acoustic signals via organs on their bodies that imitate the signals of workers, soldiers, and even the queen herself!

“The use of highly sophisticated communication systems is the key attribute that enables ants to act as a superorganism, thereby facilitating their dominance of terrestrial ecosystems,” the researchers write. By essentially hacking into these networks, ant nest beetles are able to elicit incredible control over their unwitting hosts.

To uncover ant beetles’ deception, the researchers placed both ants and beetles into tiny sound chambers with super sensitive microphones and recorded the distinct acoustic signals that they emitted. They found that the beetles produced at least three different signals, matching those produced by each of the different ant castes: worker, soldier, and queen. The researchers then played distinct ant signals, white noise, silence, and the recorded beetle sounds for small groups of ants enclosed in chambers and observed their behaviors. While the control sounds — white noise and silence — elicited few behaviors, the beetle sounds elicited antennation at similar or even higher rates than the ant recordings. This is remarkable, as antennation — basically touching something with the antennae — is widely regarded as a welcoming, friendly behavior, similar to a handshake.

Even more fascinating, the ant nest beetle sounds and the queen sounds were the only signals to induce guarding behavior, “a posture similar to that adopted when [ants] attend queens or objects of great value to their society,” the researchers write.

“Our data suggest that, by mimicking the stridulations (sounds) of the queen, Paussus is able to dupe the workers of its host and to be treated as royalty.”

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Source: Real Clear Science