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 October 21, 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 October 21, 2014).

Share This



More Plants & Animals News

Tuesday, October 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

White Lion Cubs Born in Belgrade Zoo

White Lion Cubs Born in Belgrade Zoo

AFP (Oct. 20, 2014) Two white lion cubs, an extremely rare subspecies of the African lion, were recently born at Belgrade Zoo. They are being bottle fed by zoo keepers after they were rejected by their mother after birth. Duration: 00:42 Video provided by AFP
Powered by NewsLook.com
Traditional Farming Methods Gaining Ground in Mali

Traditional Farming Methods Gaining Ground in Mali

AFP (Oct. 20, 2014) He is leading a one man agricultural revolution in Mali - Oumar Diatabe uses traditional farming methods to get the most out of his land and is teaching others across the country how to do the same. Duration: 01:44 Video provided by AFP
Powered by NewsLook.com
Goliath Spider Will Give You Nightmares

Goliath Spider Will Give You Nightmares

Buzz60 (Oct. 20, 2014) An entomologist stumbled upon a South American Goliath Birdeater. With a name like that, you know it's a terrifying creepy crawler. Sean Dowling (@SeanDowlingTV) has the details. Video provided by Buzz60
Powered by NewsLook.com
Adorable Video of Baby Rhino and Lamb Friend Playing

Adorable Video of Baby Rhino and Lamb Friend Playing

Buzz60 (Oct. 20, 2014) Gertjie the Rhino and Lammie the Lamb are teaching the world about animal conservation and friendship. TC Newman (@PurpleTCNewman) has the adorable video! Video provided by Buzz60
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:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

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