Navigation Links
Stanford researchers discover the African cichlid's noisy courtship ritual
Date:6/13/2012

African cichlids enjoy an alien, exotic courtship routine. A dominant male attracts choice females to his territory by dancing seductively. If the female is sufficiently impressed, she lays her eggs and immediately collects them in her mouth, where the male fertilizes them. And, in some species, every once in a while, a lower-ranking male will dart into the scene and try to fertilize a few eggs before the dominant male knows what's happened.

At least that's what we thought was going on. But one day, while watching this nostalgic display in the lab, Stanford postdoctoral biology researcher Karen Maruska noticed something unusual. A dominant male was courting a female in one corner of the tank, at the entrance to a terra cotta pot he had claimed as his territory.

"Then, at the last minute, a subordinate male made a beeline for them from the corner of the tank behind the pot, so he could spawn at just the right time," Maruska said. "And I thought: there's no way the subordinate saw" that opportunity. In fact, he didn't see it. He heard it.

Astatotilapia burtoni's predilection for waggling its tail and quivering its body before mating is well documented. But what Maruska, undergraduate researcher Uyhun Ung and Stanford biology Professor Russ Fernald would later write in a paper published last week in PloS ONE was that males also vocalize during courtship. Not only are females responsive to these calls, but their ability to hear them improves with their sexual receptiveness. This additional courtship component may provide crucial signals used for mate choice decisions and help explain how similar-looking cichlid species avoid accidental interbreeding.

Listening fish

Using underwater microphones called hydrophones, the researchers found that males would make low-frequency sounds when confronted with receptive females. And females preferred males associated with playbacks of these courtship sounds over males that were associated with no sound, or a neutral noise.

But not all hearing thresholds were created equal. Females that were sexually receptive and had high circulating levels of sex hormones were dramatically more sensitive to the low frequencies contained in the courtship sounds than females that had already spawned and were in the mouth-brooding parental care phase of their cycle. This kind of hormone-dependent hearing has been observed in other animals, and is a reliable indicator of the importance of sounds in courtship displays.

Subordinate males were also subtly more sensitive to certain frequencies than dominant males. Although the reasons for this change are less clear, Maruska suggests the subordinate males may "use the frequency of the sound to determine which males to fight with and attempt to take over their territory." Because the frequency of the courtship sound is related to body size, subordinate males may listen to these courtship sounds to identify the smallest and most vulnerable males in their area.

A small pond

The cichlids studied by the Fernald lab are native to Lake Tanganyika in East Africa "where they co-exist with a lot of other cichlid species," said Maruska. "Each species needs to find its niche in the system."

The high level of diversity within the cichlid family is unusual, and difficult to maintain when all the relatives are in the same body of water. Researchers had previously assumed that cichlids, which tend to be brightly colored fish, only used visual cues to distinguish potential mates from out-of-species mistakes. But biologists now believe that visual cues alone can't account for the phenomenon.

Recent field studies by other scientists have shown that cichlid species that live in overlapping areas in the wild produce distinct sounds. The Stanford researchers' discovery that these sounds are an integral component of courtship rituals lends credence to the theory that the vast array of cichlid species may be a consequence of courtship displays that make use of more than one sensory system.

Still, "not a lot is known about fish sounds," said Maruska. There remains a host of unsolved mysteries in the field. "We don't even know the mechanism of sound production in this species yet."


'/>"/>

Contact: Max McClure
maxmc@stanford.edu
650-725-6737
Stanford University
Source:Eurekalert  

Related medicine news :

1. Antioxidant shows promise as treatment for certain features of autism, Stanford study finds
2. New type of retinal prosthesis could better restore sight to blind, Stanford study says
3. Invasive heart test being dramatically overused, Stanford study shows
4. Researchers determine pathway for origin of most common form of brain and spinal cord tumor
5. UCI researchers create mosquitoes incapable of transmitting malaria
6. Moffitt Cancer Center researchers develop and test new anti-cancer vaccine
7. Penn and Cornell researchers spearhead the development of new guidelines for veterinary CPR
8. VCU researchers identify changes in cholesterol metabolic pathways
9. An important breakthrough in immunology by IRCM researchers
10. Mount Sinai researchers develop a multi-target approach to treating tumors
11. Doubling down on heart failure: Researchers discover new route to disease, and drugs to match
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Stanford researchers discover the African cichlid's noisy courtship ritual
(Date:6/25/2016)... (PRWEB) , ... June 25, 2016 , ... The temporary closing of Bruton Memorial Library ... City Observer , brings up a new, often overlooked aspect of head lice: the parasite’s ... for fumigation is not a common occurrence, but a necessary one in the event that ...
(Date:6/25/2016)... ... June 25, 2016 , ... Dr. Calvin Johnson has ... he has implemented orthobiologic procedures as a method for treating his patients. The ... first doctors to perform the treatment. Orthobiologics are substances that orthopaedic surgeons use ...
(Date:6/24/2016)... Marne, Michigan (PRWEB) , ... June 24, 2016 , ... ... To deal with these feelings, many turn to unhealthy avenues, such as drug or ... Center of Marne, Michigan, has released tools for healthy coping following a traumatic event. ...
(Date:6/24/2016)... ... 24, 2016 , ... Global law firm Greenberg Traurig, P.A. announced that 20 ... by their peers for this recognition are considered among the top 2 percent of ... honors as members of this year’s Legal Elite Hall of Fame: Miami Shareholders ...
(Date:6/24/2016)... (PRWEB) , ... June 24, 2016 , ... People across ... in Genome magazine’s Code Talker Award, an essay contest in which patients and their ... award to be presented at the 2016 National Society of Genetic Counselors (NSGC) Annual ...
Breaking Medicine News(10 mins):
(Date:6/26/2016)... , June 27, 2016  VMS Rehab Systems, ... Board will take whatever measures required to build a ... stock which is currently listed on the OTC Markets-pink ... Company Chairman and CEO, "We are seeing an anomaly ... to understand, not only by the Company, but shareholders ...
(Date:6/24/2016)... , June 24, 2016   Bay ... Rehabilitation Network,s Dean Center for Tick Borne ... Medicine and Rehabilitation, MIT Hacking Medicine, University of ... Innovation, today announced the five finalists of ... Lyme disease.  More than 100 scientists, clinicians, researchers, ...
(Date:6/24/2016)... Calif. , June 24, 2016  American Respiratory Labs (ARL), ... is now able to perform sophisticated lung assessments in patients, homes, ... , Inc. Patients are no longer limited to ... EasyOne PRO ® , ARL patients like Jeanne R. of ... in the comfort of her own home. ...
Breaking Medicine Technology: