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RE: Sex change in fish
I am not a man of scientific method or background but I have learned this
about Notho's: when I bring a young pair to auction at the Chesapeake Club,
I need to be prepared to have the buyer call me a month or two later and ask
if there is another female available because both fish have turned out be
males. I check both fish with a magnifying glass before pronouncing a pair
"a pair".
I find this situation to quite humorous as who knows how our societies would
have developed and settled if we homo sapiens did not know for sure what we
were going to be...
-----Original Message-----
From: owner-killietalk at aka_org [mailto:owner-killietalk at aka_org]On
Behalf Of Doug Karpa-Wilson
Sent: Friday, February 04, 2000 8:57 AM
To: killietalk at aka_org
Subject: Re: Sex change in fish
BizEcology at aol_com wrote:
> I have read in the past about apparent sex changes in a number of fish.
One
> of the theories is that female beyond breeding age have changing to male
> appearances serves two purposes:
>
> 1. The female gets left alone, since males will not be chasing her for
> spawning
>
> 2. Males will not waste effort in a futile attempt to mate with a female
> incapable of producing viable offspring.
>
In an evolutionary sense neither would make much sense, since if she's past
breeding age, there's no way selection could ever operate on a sex change.
However, if being female requires more energy investment, switching to being
male when worn out may help squeeze the last bits of potential reproductive
success out of a long life. More likely sex switching derives from the
simple
fact that the rarer sex has the higher fitness except in some situations,
such
as when one sex keeps harems.
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