nochel hump, is it a dominance thing?

[dan518]

Hi, i have three male cons, the most dominant has the biggest nochal hump, the least dominant does not have one.
if the one lowest in the pecking order became the boss, would he grow one.

 

[dan518]

sorry about the bad pics, need a better phone i think

 

[dan518]

or is it the most dominate fish naturally have the bigger humps threw better dna

 

[duanes]

According to Dr George Barlow in The Cichlid Fishes Natures Grand Experiment in Evolution,
"Mature males of many species of cichlids develop a swollen forehead. The throat also expands."
"the nuchal hump is one way the male reveals his gender to the female, and at the time it is needed most, right at pair formation. The cause of the distention is a local edema: Fluid floods the tissues.

 

[dan518]

Thanks, so the size of the nuchal hump can increase or decrease depending mood/breeding opportunities of the fish.

 

[duanes]

From the same book
"Using dummy Midas cichlids, Paul Siri and I established that females best respond to a dummy having a hump that agrees with the normal size, which is fairly small compared with huge heads some overfed males in captivity develop. Contrary to predictions made by sexual selection hypothesis, the largest humps drew the least response from females.

 

[duanes]

Again from the same cichlid researchers book
"In the Midas cichlid, the swelling normall occurs during the time of pair formation, then subsides around the time of spawning."

Thanks, so the size of the nuchal hump can increase or decrease depending mood/breeding opportunities of the fish.