Printer Friendly

Frog finds empty bandwidth, then croaks.

Frog finds empty bandwidth, then croaks

Like radio stations vying for crowded air waves, some singing frogs complete for broadcast frequencies. Alejandro Purgue, a herpetologist at the University of Utah in Salt Lake City, suggests that the South American frog Leptodactylus ocellatus evolved an underwater mating call in response to airwave competition from another frog that uses the same frequency above water.

Scientists have suspected that a few frog species might, through some unknown mechanism, produce underwater calls. Purgue appears the first to document it thoroughly, using U.S. Navy hydrophones and computer analysis. He interprets L. ocellatus' underwater calls as a previously unrecognized dimension of "niche partitioning" -- the means by which species living close to each other minimize competition.

The male L. ocellatus produces calls in the frequency range of 250 to 500 hertz, presumably to maintain territoriality and to attract mates. But the frog Physalaemus cuvieri calls in a similar range at many of the same ponds, and its song is about 40 decibels louder. Taking advantage of the fact that very little sound crosses the air-water interface, L. ocellatus apparently avoids competition by channeling its call underwater. "This underwater channel has no other species calling in a close frequency range, providing an excellent alternative way of communication," Purgue says.
COPYRIGHT 1990 Science Service, Inc.
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1990, Gale Group. All rights reserved. Gale Group is a Thomson Corporation Company.

Article Details
Printer friendly Cite/link Email Feedback
Title Annotation:frogs compete for broadcast frequencies
Author:Weiss, Rick
Publication:Science News
Date:Aug 11, 1990
Words:212
Previous Article:Polka-dot chemistry and zebra stripes: scientists claim first sighting of elusive Turing structures in chemical landscapes.
Next Article:Cultivating weeds for pest control.
Topics:


Related Articles
Making sense of animal sounds; scientists studying animal sounds are finding common threads to the barks, growls and whines of different species.
The body ear: to pinpoint a sound's direction, coqui frogs may lend not only an ear but a lung as well.
Jumping gender: frogs change from she to he.
The truth is, frogs bluff and crabs cheat.
Single singing male toad seeks same.
New robot frog gets into fights.
Frogs play tree: male tunes his call to specific tree hole.
It's not easy being green: some frogs employ special tactics for desert survival.
Croak!

Terms of use | Copyright © 2016 Farlex, Inc. | Feedback | For webmasters