Re: [RML] Hermaphroditism - was Kubutu

Mach T. Fukada (fukada at hawaii.edu)
Sat, 14 Mar 1998 19:54:34 -1000

It seems to make sense that animals that live in environments prone to
great catastropic perturbations would have evolved that there are a
percentage of the population are hermaphoditic, with the ability to switch
to one sex or the other depending on the need. Someone suggested to me that
the sex change we see in the Desert Gobies is a result of such an
adaptation although as far as I know nobody has done the work necessary to
say that the "females" that change to males are actually females,
hermaphodites, or submissive males displaying female color to avoide the
dominant male (there is an evolutionary advantage to this i.e. the pseudo
female male fish are probablly able to sneak into a dominant male's
territory and mate with females, etc...). I can think of a few killies,
livebearers, parot fish, damselfish that seem to show similar things. On
the other hand in very stable environments all female parthenogenic
populations seem to appear (I can only think of a gecko in Hawaii
(immigrant) that is an all female population that might have sex
(female<>female) but not have any males to fertilize eggs...

MTF

>I recall discussing sex-change in Desert Gobies, sex ratios in fry (and in
>fish keepers) and even remember mentioning my Flat Rock Creek Inornata
>female with the pointed fins and great colour that successfully produced
>fry. But I must have missed the one on the fish that is "self-satisfied"
>;-)
>
>Regards,
>Bruce.
>
>Bruce Hansen, ANGFA, caring for our aquatic ecosystems.
>
>Please visit us at http://www.ozemail.com.au/~fisher/angfa.htm
>
>
>
>----------
>> From: Adrian R. Tappin <atappin at ecn.net.au>
>> To: rainbowfish at pcug.org.au
>>
>> An interesting subject is hermaphroditism in rainbowfishes. Gerald Allen
>> noted that Chilatherina fasciata are sometimes hermaphroditic; that is
>both
>> male and female reproductive organs are present in the same individual.
>Nick
>> Romanowski in the ANGFA Journal 'Fishes of Sahul' reported his
>observations
>> of apparent hermaphroditism in Melanotaenia fluviatilis.
>>
>> I raised this subject some time ago on this list but it never received
>any
>> feedback. However, this could well indicate that hermaphrodism may be
>more
>> widely deployed in rainbowfishes than previously thought.

Mach T. Fukada, Web Master
fukada at hawaii.edu
Honolulu Aquarium Society
http://www.geocities.com/Heartland/Meadows/2948/HASF.html