Featured Research

from universities, journals, and other organizations

Piddling Fish Face Off Threat Of Competition

Date:
December 17, 2007
Source:
BioMed Central
Summary:
Aggressive territorial male Mozambique tilapia fish send chemical messages to rival males via their urine. They increase urination, have smellier urine and store more in their bladders than less aggressive males, according to new research.

Aggressive territorial male Mozambique tilapia fish (Oreochromis mossambicus) send chemical messages to rival males via their urine. They increase urination, have smellier urine and store more in their bladders than less aggressive males, according to new research. Animal behaviourists have known for some time that the urine of freshwater fish is a vehicle for reproductive hormones that act in the water as pheromones, affecting the behaviour and physiology of members of the opposite sex. Now, this research sheds light on the role of urine in influencing members of the same sex.

"Few studies have looked at the roles of pheromones in urine during competition between individuals of the same sex. We've found that tilapia dominant males store more urine in their bladders than subordinates, actively urinate during times of confrontation and the urine's olfactory potency or smell strength is even greater," explained Eduardo Barata, who led the Portuguese research.

As a lekking species -- where males group together in the same area to breed, never leaving their nest, not even to feed -- social hierarchy is important for the cichlid fish from Africa. Males actively advertise their dominant status through urinary odorants, which are thought to control aggression in rival males and so maintain social stability within the area, or lek. By measuring male urination frequency during competition, Barata et al. found that dominant or 'resident' males increased urination frequency in the presence of 'intruder' males from once every ten minutes to once every minute.

Dominant males stopped urination when their opponent gave up, indicating a close link between aggression and urination rate. By also collecting urine and measuring the volume over five days and evaluating olfactory potency using an electro-olfactogram, it was seen that subordinate males also stored less urine and the urine was less smelly than that of dominant males.

"We know pheromones are involved in reproductive and non-reproductive behaviours of fish, for example during migration, mating and schooling," explained Barata. "While we do not yet know what these chemicals are, it is clear they play a major role in many aspects of tilapia social behaviour by providing information about the fish's aggressive capabilities for instance. This is also probably not unique to tilapia, so we're touching the tip of the urinary pheromone iceberg!" concluded Barata.

Journal reference: Male urine signals social rank in the Mozambique tilapia (Oreochromis mossambicus, Peters 1852) Eduardo N Barata, Peter C Hubbard, Olinda G Almeida, Antonio Miranda and Adelino V M Canario BMC Biology (12 December 2007)

Further Information

1. Pheromones are chemicals that trigger adaptive physiological and behavioural responses, and fish release them into the water via urine, skin and faeces.

2. Mozambique tilapia are endemic to the lakes and rivers of the east African coast. Males turn black during the breeding season and defend small territories centred on pit-like nests they dig in the sand. Females visit and spawn in these territories but brood eggs and rear young in a separate area.

Article: Male urine signals social rank in the Mozambique tilapia (Oreochromis mossambicus, Peters 1852). Eduardo N Barata, Peter C Hubbard, Olinda G Almeida, Antonio Miranda and Adelino V M Canario BMC Biology (12 December 2007) (http://www.biomedcentral.com/bmcbiol/)


Story Source:

The above story is based on materials provided by BioMed Central. Note: Materials may be edited for content and length.


Cite This Page:

BioMed Central. "Piddling Fish Face Off Threat Of Competition." ScienceDaily. ScienceDaily, 17 December 2007. <www.sciencedaily.com/releases/2007/12/071212201413.htm>.
BioMed Central. (2007, December 17). Piddling Fish Face Off Threat Of Competition. ScienceDaily. Retrieved April 19, 2014 from www.sciencedaily.com/releases/2007/12/071212201413.htm
BioMed Central. "Piddling Fish Face Off Threat Of Competition." ScienceDaily. www.sciencedaily.com/releases/2007/12/071212201413.htm (accessed April 19, 2014).

Share This



More Plants & Animals News

Saturday, April 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Vermont Goat Meat Gives Refugees Taste of Home

Vermont Goat Meat Gives Refugees Taste of Home

AP (Apr. 18, 2014) Dairy farmers and ethnic groups in Vermont are both benefiting from a unique collaborative effort that's feeding a growing need for fresh and affordable goat meat. (April 18) Video provided by AP
Powered by NewsLook.com
Man Claims He Found Loch Ness Monster With... Apple Maps?

Man Claims He Found Loch Ness Monster With... Apple Maps?

Newsy (Apr. 18, 2014) Andy Dixon showed the Daily Mail a screenshot of what he believes to be the mythical beast swimming just below the lake's surface. Video provided by Newsy
Powered by NewsLook.com
First Ever 'Female Penis' Discovered In Animal Kingdom

First Ever 'Female Penis' Discovered In Animal Kingdom

Newsy (Apr. 18, 2014) Not only are these newly discovered bugs' sex organs reversed, but they also mate for up to 70 hours. Video provided by Newsy
Powered by NewsLook.com
Little Progress Made In Fighting Food Poisoning, CDC Says

Little Progress Made In Fighting Food Poisoning, CDC Says

Newsy (Apr. 18, 2014) A new report shows rates of two foodborne infections increased in the U.S. in recent years, while salmonella actually dropped 9 percent. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins