University Park, Pennsylvania: In their article, "Behaviorally induced sex reversal of Metriaclima cf. livingstoni (Cichlidae) from Lake Malawi," researchers Jay R. Stauffer, Jr. and Renea A. Ruffling describe a rare event. While sex reversal is a well-known and well-documented phenomenon among marine reef fishes, the same cannot be said for freshwater fishes. In their experimentation utilizing wild-caught M. cf. livingstoni 
(captured while SCUBA diving off the Mazini Reef in Lake Malawi) were held in tanks with one male and multiple females. This is a typical aquarium setup familiar to thousands of cichlid aquarists around the world.
(captured while SCUBA diving off the Mazini Reef in Lake Malawi) were held in tanks with one male and multiple females. This is a typical aquarium setup familiar to thousands of cichlid aquarists around the world.M. cf. livingstoni are typical mbuna from Lake Malawi, they are maternal mouthbrooders, and the males will spawn with as many ripe females as they can entice. 
In their experiments the aquariums (75.5 L (= 20 gallons) in volume) were divided into equal compartments with sealed-in clear Plexiglas panes. The single male was placed on one side and the females remained on the other side in each tank. The males in each tank could see the females, and vice versa, but there was no physical contact between the sexes in the tanks. The populations were manipulated in different tanks and in subsequent trials. The resluts were that a total of three previously confirmed females acquired males secondary sexual characteristics. In one of the trials a reversed females sucessfully fathered three large broods of fry. In a second trial another brood of fry was fathered by a different sex-reversed female.
In their experiments the aquariums (75.5 L (= 20 gallons) in volume) were divided into equal compartments with sealed-in clear Plexiglas panes. The single male was placed on one side and the females remained on the other side in each tank. The males in each tank could see the females, and vice versa, but there was no physical contact between the sexes in the tanks. The populations were manipulated in different tanks and in subsequent trials. The resluts were that a total of three previously confirmed females acquired males secondary sexual characteristics. In one of the trials a reversed females sucessfully fathered three large broods of fry. In a second trial another brood of fry was fathered by a different sex-reversed female.The full citation is Copeia 2008, No. 3, 618-620, Stauffer and Rufling. Reprints can be requested from Jay R. Stauffer, Jr., Pennsylvania State University, School of Forest Resources, 420 Forest Resoirces Building, University Park, PE 168802 (e-mail: vc5@psu.edu).
1 comment:
Thank you for the article, it was very interesting. Who would have though sex reversal did exist with freshwater fishes. I look forward in reading interesting topics like these in the future. This is something that we aquarium hobbyist look forward to. I do wonder if other Cichlid fish would have the same behavior such as this one:
http://www.aquariumfishexperts.com/tropical-fish-fish/cichlids/american-cichlids/apistogramma-hongsloi-redstripe-dwarf-cichlid/
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