| MadSci Network: Zoology |
There is no clear answer to your questions. There is a little known about hormones which can induce different dominant/ submissive behaviors in cichlids. For instance, treatment with testosterone or cortisol can increase aggressive behaviors, while treatment with estradiol or metatyropone can increase submissive behaviors. However, these experiments only show that introduction of these hormones can elicit such effects - it does not prove that they are the hormones responsible for such behaviors in untreated animals. Also, the production of these behaviors upon drug treatment may be a toxic response and not a normal reaction. Additionally, behavior can be greatly affected by social or environmental conditions, so extreme behaviors may not be due just to spontaneously high hormone levels. So while there are hints of what might be controlling dominant/submissive behaviors, we can not yet point a sure finger at any one hormone. The question of hormone-regulated growth control is not nearly as clear. While hormones surely play a role in growth control, I am not aware of any obvious candidates. Additionally, environmental conditions can greatly affect growth rate within a tank. For instance low food levels, poor water quality, crowded conditions, and other factors can reduce overall growth rate within a tank. I would guess that your stunted tank is due to an environmental factor such as this, and not a direct result of unusual hormone levels. I welcome you to look for yourself in the primary literature for further information on these topics. (try: www4.ncbi.nlm.nih.gov/entrez/query.fcgi)
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