A small fish in the Pacific Ocean has
developed an extremely interesting adaptation.
When beneficial, bluebanded goby fish can change their sex. These fish
grow from about 2 to 2.5 inches in length and are orange and luminescent blue
in appearance. They usually live around,
and feed on, grayish-green algae. The
evolutionary advantage to their unique ability derives from the social
structure of these fish. Bluebanded
gobies live in groups called harems consisting of a dominant male and 4-5
females. If this male dies, one female physically
changes into a male to lead the harem and reproduce with the remaining
females.
Recently, at a lab at Georgia State
University, Matthew Grober has very closely studied the behavior of bluebanded
gobies. Along with physical indication
of a fish’s sex, he observed behaviors, such as the tendency for males to move
in rapid zig-zag movements referred to as “jerks” and for females to be less
active and more submissive. Grober stated
that within minutes he is aware of sex-change, but that the process takes 1-2 weeks
to be finished.
Grober designed an experiment in which
a group of males was in its own tank. He
discovered that in this type of environment, all but one of the gobies would
change their sex to female to restore the social order and allow for the opportunity
to reproduce. This remaining male was the
sole dominant fish in the group, while the rest of the group showed submissive
behaviors. This showed that the behavior
of the fish was determined by the social hierarchy.
I believe that these fish provide parallels to human society. People are greatly shaped by the social hierarchy surrounding them, just as these fish are, which illustrates the importance of having a positive environment for as many children and adolescents as possible.
That's one of the most interesting things i've heard in awhile, great article. What a useful adaptation, and it is really interesting to see how these animals are able to change the whole structure of their bodies in order to help their social hierarchy. I wonder if scientists are doing any tests or have learned the exact body process and see if any other animals could sustain such a change.
ReplyDeleteWow that is very strange but interesting. It seems like that would help keep the population booming. That is a really amazing way of adapting. I wonder if its only these fish that can do this?
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