Mustafa noted that in tanks with thousands of shrimp he sees very few berried females at any given time (I am paraphrasing).
Is this a common observation among the rest of you who have large populations of shrimp? If this is the case, how is this apparent limiting accomplished? Do the females give off a pheromone of some sort to limit/regulate reproduction? Does anyone know if this is true for wild populations?
I'm trying to figure out why this limited reproduction (if true) would be a darwinian or evolutionary advantage to the organism, or if the males should rise up (so to speak), and demand more parties.
Brad
Supershrimp and the Matriarchal Society
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KenCotigirl
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Re: Supershrimp and the Matriarchal Society
Brad I have only one tank a ten gallon that is close to thousand shrimp. At any given time i see five or six berried shrimp. I also have 75 +/- larvae floating. This has been going on for two years with a only a three month pause. I started with 158 shrimp in 2008. Breeding did not take off till 2012 due to my constant changes to the tank. I finally stopped making changes in sept, oct 2011.
Sorry got off the subject. I think this seems normal. They have limited pressure from predators. They are long lived. Almost all the larvae survive as compared to other low order shrimp. There is not a need to reproduce as quickely as possible. I think a better question is do they produce as many eggs over their lifetime as cherry shrimp? While a cherry shrimp lives two years she can produce a clutch of 30 eggs nearly every month for say 18 clutches thats 540 shrimp. H. rubra I am guessing she berries twice a year for 18 years with a clutch of 15 eggs that is also 540 shrimp. The twice a year berrying is based on one tank with 25 shrimp where i have seen no more than 3 berried shrimp at any time. Obviously this is not scientically based.
Now that i read what i wrote the twice a month maybe only for low populations. At thousands of shrimp per tank you should see hundreds of berried shrimp a month. That is not happening. This may be a topic for graduate study. Pheromones are used by bees to control populations so why not shrimp. Food, space and other environmental conditions effect bees and the pheromones they produce. Hmmm. Interesting.
Funny everything you read about wild populations, berried shrimp and larvae have not been caught. The experts have no idea of their densities. That is one reason they are not on the endangered species list. Nice thoughtful question.
Ken
Sorry got off the subject. I think this seems normal. They have limited pressure from predators. They are long lived. Almost all the larvae survive as compared to other low order shrimp. There is not a need to reproduce as quickely as possible. I think a better question is do they produce as many eggs over their lifetime as cherry shrimp? While a cherry shrimp lives two years she can produce a clutch of 30 eggs nearly every month for say 18 clutches thats 540 shrimp. H. rubra I am guessing she berries twice a year for 18 years with a clutch of 15 eggs that is also 540 shrimp. The twice a year berrying is based on one tank with 25 shrimp where i have seen no more than 3 berried shrimp at any time. Obviously this is not scientically based.
Now that i read what i wrote the twice a month maybe only for low populations. At thousands of shrimp per tank you should see hundreds of berried shrimp a month. That is not happening. This may be a topic for graduate study. Pheromones are used by bees to control populations so why not shrimp. Food, space and other environmental conditions effect bees and the pheromones they produce. Hmmm. Interesting.
Funny everything you read about wild populations, berried shrimp and larvae have not been caught. The experts have no idea of their densities. That is one reason they are not on the endangered species list. Nice thoughtful question.
Ken
Re: Supershrimp and the Matriarchal Society
I think it's much simpler than one would think. Not enough food for hundreds of shrimp to be berried in a tank with thousands of shrimp. And they don't have all that much food in nature anyway. Egg production is very energy intensive and requires lots of protein. If it were possible to feed them more without messing up the water I would guess that more shrimp would be berried. The other day I saw the highest number of berried shrimp ever out in the open feeding on food I threw in: 13-15 of them. I didn't look for any hiding females, so if we add a few more to account for hiding shrimp we can say that probably about 20 shrimp were berried in that tank of 1000+ (maybe even 2000+).