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Bettas are weird.

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#13 Synirr


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Posted 08 February 2012 - 02:22 PM

I wonder if the influence that smaller/larger or younger/older males have on the sex ratios of their offspring has to do with the father excreting sex-determining pheromones into the water around the developing fry. Many species experience a drop in hormone/pheromone production as they age, so if such a mechanism were in place, it could provide a possible explanation for why a younger male would produce more male offspring.

#14 Solitarianknight


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Posted 08 February 2012 - 02:28 PM

thats cuz ovaries are analogous to testes. they are the same structure with minor changes (same goes for the clit and penis, hand and foot, etc). the change from female to male wouldnt be absurd, it happens to human embryos; all fertilized eggs grow as females until the first surge of testosterone occurs and ovaries start to descend and turn into testes. what makes it so bizzare is that they change genders after the sex organ is removed entirely, not altered. it seems to imply that bettas can regenerate organs, or have more then 2 sex organs in a given individual.

i dont think it is normal for bettas to change gender, i think the mechanism is meant for gender determination rather then alteration. there are fish that change gender, the most common example would be marine damselfish (of which clownfish are members). but they go from asexual to male to female, and can never go in reverse of female to male.

doubtfull, and if you could it would have to be very very early. just because you cant sex a fry doesnt necessarily mean it doesnt have a sex.

...Thats what i said isnt it, i said its common that overies turn into testies and that it was odd that they were able to form testies without them, also, i understand that the fry might have a sex even that young, the question was DO THEY, is it possible that their sex is determined after they hatch out and start swimming.

#15 Maryanne


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Posted 09 February 2012 - 08:43 AM

Found on bettas4all.

Effect on growth and reproduction of hormone immersed and masculinized fighting fish Betta splendens.
Kirankumar S, Pandian TJ.

To produce all-male progenies in the fighting fish, Betta splendens, six groups of fry were subjected to discrete immersion treatment at different 17alpha-methyltestosterone (MT) doses (viz. 100, 200, 500, 700, 900, and 1,000 microg/l) for a constant duration (3 hr/day) and frequency (second, fifth, and eighth day after hatching). The treatment at 900 microg/l led to 98% masculinization and 71% survival at sexual maturity. Treated groups, which showed significant deviation from the 1:1 sex ratio, were classified into two different series: S1 and S2. The groups that showed nearly cent-percent masculinization were classified as S1, and the other groups were classified as S2. The S1 males showed remarkably slower growth and attained 3.5 cm total length compared to 6.0 cm attained by a normal male. The S2 males attained 5.4 cm total length. Apart from these morphological defects, both S1 and S2 males suffered functional (decreased sperm count and sperm motility) and behavioral defects (incomplete embracing during mating) in their reproductive ability, leading to approximately 50% and 30% reduction in fecundity per mating, respectively. The cumulative fecundity loss suffered by the S1 male during its active reproductive phase is discussed. When normal and sex-reversed males were presented, a female preferred the former. Progeny testing of the sex-reversed males showed the occurrence of 12.75% males, indicating the possible role of autosomal genes in the sex determination mechanism of this species. Discrete immersion treatment at optimal/super-optimal doses ensured not only a higher percentage of masculinization, but also a higher frequency of homogametic males (XX).

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