Monday, December 28, 2009

Higher Pitches Show Genetic Diversity

A recent study found that higher pitched notes in a male bird's song signal better genetic diversity in at least one species, the Ocellated Antbird (Phaenostictus mcleannani).
DeWoody and former Purdue graduate student Johel Chaves-Campos studied ocellated antbirds in the tropical forests of Central America. The antbirds survive by tracking army ants, which hunt in large swarms and are capable of killing just about anything in their paths. The birds flit ahead of the swarms and collect arthropods that flee for their lives....

The antbirds have several calls, some to let fellow antbirds know where the army ants are heading, others to attract mates and still others that are defensive or aggressive to protect turf. DeWoody's research involved recording those calls and matching them to DNA samples of the birds. The results suggest that genetic diversity in antbirds affects their physical abilities to produce certain sounds.

"Our results are consistent with the idea that some sound frequencies are biomechanically difficult to produce. Males that are genetically diverse, and therefore expected to be in better physical condition, are able to produce sound frequencies that males with less genetic variation are unable to reach," Chaves-Campos said.

DeWoody said females can pick up on the pitch of the males' songs to decide which birds will make the best mates.
You can read the full study online at PLoS ONE.