I've finally located a spawning known-male RBTA that I'll be bringing in to hang out with my egg bearing female RBTAs.  I assume the three major things I can vary, to encourage gamete developement and spawning are food, temperature and lighting.  Do you have any recommendations as to what to vary, by how much, and for how long?

One other question: What influence, if any, does color have on the ability of E. quadricolor or S. haddoni anemones to reproduce?  In other words, can a green BTA successfully sexually reproduce with a rose BTA?

Thanks!

Mark

You asked:"Do you have any recommendations as to what to vary, by how much, and for how long?"

For temperature: I would go to Google Earth, zoom in to a reef of your choice.  Get the latitude and longitude.  Then I would go to one of the NOAA/NASA sites that deals with Sea Surface Temperatures (SST), and find the records for the lat/long.  Go back to the records for the mid-80s to eliminate the recent effects due to global warming.  Get the average monthly temperatures and adjust your system accordingly changing the value each month for that month. 

Then go to an online almanac or such, and get day lengths for the same latitude (longitude won't matter with that).  And adjust the lighting for the same.  Make sure they are synchronized.

The feed the animals the maximum they can/will eat. 

Within a year, you should get spawing.  One of my friends with a male has noted hers spawns in the spring.  So - perhaps next year.  This project should be at least a year long, maybe more.

There is information about raising larvae, etc, in several issues of AHABS.  You might find them useful.

These animals are brooders, I think.  I have seen images of larvae maintained within the females after spawning.  This is not uncommon in anemones.  So, when the males spawn, that triggers egg release and spawing by the female, but she will maintain the eggs inside her coelenteron.  They will, in a short time, be visible as smudgy dark dots inside tentacles and such.  Eventually she will release them to settle as crawl away babies.

"One other question: What influence, if any, does color have on the ability of E. quadricolor or S. haddoni anemones to reproduce?  In other words, can a green BTA successfully sexually reproduce with a rose BTA?"

That is a good question.  If those two color forms are different species, there may be little or no reproduction.  If they are the same species you should get normal reproduction.  In other words, color shouldn't make any difference.  I don't think they are separate species, so the cross should be fine.  The first generation may be all of one color - it would be interesting to know which - and then the second generation (crossing the offspring of the first when they mature) should show some interesting color variations. 

Good luck!!! 

Cheers, Ron

"The difference in mind between man and the higher animals, great as it is, certainly is one of degree and not of kind. The love for all living creatures is the most noble attribute of man." Charles Darwin (1809-1882)

And, one more question:  I've read a number of sources that indicate various coral spawnings occur X number of days after a full moon at particular times of the year.  Do you have any idea if the moon's influence is a gravitational thing or if it's related to luminosity?  Would you expect that it's necessary/beneficial to go to the trouble of trying to simulate the varying levels of nighttime light that correspond with the phases of the moon?

Mark

I think that it is more than likely related to the tides or some other physical attribute related to the moon than to moonlight.  It has only been recently that a chemical system was found in some coral that could even respond to moonlight, and there is not experimental evidence linking gamete release to any sort of illumination changes.  While there is a correlation with moon phase and natural spawning, I think that correlation has nothing to with the moon's light. The old saw... "Correlation doesn't imply causation,"is relevant here.  If you think about this, variations in moon light are very "dubious" things to base a species' spawning on.  If it gets cloudy for a few days/weeks with a storm pattern --- phfft.  There goes this year... Spawning IS correlated to lunar periodicity.  But, I don't think lunar light has any causative response.  I think the lunar connection is with regard to tidal influences and these act to trigger animals whose spawning condition has been "set" by several months of associated changes in temperatures and day lengths.

Spawning synchrony is especially spectacular with regard to corals, because there are a lot of them doing their thing simultaneously and there are a lot of corals in a small area.  However, it is not unique. Many temperate species spawn with the synchrony seen in corals, but their spawnings are cued by a combination of events - temperature changes, day length changes, and tidal events.  In some temperate species I have worked with (sea cucumbers), whole populations can spawn in few minutes.  Enough eggs are released in the water to change the color of bays from dark blue to green.  These animals spawn on the first sunny afternoon after the sping equinox on an ebbing or outgoing tide. 

The cues:

1. Day length (equinox),
2. Temperature (spring - three months of progressively warmer temperatures following six months of progressively dropping temperatures), and
3. lunar influences (outgoing tides). 
4. Why it has to be sunny, I haven't a clue, but it does.  Perhaps, that is a built-in safety check so that it isn't raining (lowering the salinity - as most echinoderms are sensitive to lowered salinity).

One other thing... Anemones, while related to corals, ain't corals.  And their spawnings are not necessarily cued to the same things.

If this was my experiment, I would concentrate on getting the appropriate variations and synchrony in temperature and day length down pat.  Then I would work on getting currents to mimic the appropriate tidal regimes.  Then, after all of those mallards were in a linear array - and only then-  would I even start to concern myself with lunar light.  Personally, I think that part of the game is a waste of time.  Frankly, for any anemone in water more than a few meters deep, I doubt that moonlight is intense enough to cause any sort of neural stimulation. 

It takes several months or more of good feeding and appropriate conditions for the animal to grow the gametes.  Typically the animals will spawn about 30% of their mass, sometimes more.  They need a LOT of food for a LONG TIME prior to spawning.  When my Stichodactyla haddoni female spawned, she would release 250,000,000 to 500,000,000 eggs per spawning event.  These events occurred within a week or so after the spring equinox (day length influence from a nearby window).  The female didn't start to have visible gametes in her septa until about 3 months before the equinox, but it is likely the gamete production started well before that time.

The animal has at least two things going on in it.  First, there is the meiosis resulting in the production of the gametes.  In the females, this stops at the end of first reduction division.  That forms the haploid nucleus.  After that, cells surrounding the oocyte pump nutrients into it.  In effect, that grows the egg until it is "ripe."  When spawning is triggered, second reduction division is completed and the egg follicle ruptures and the egg is released.  In nature, the proximate - actual - cause of spawning in the female anemones (at least in the temperate species that have been studied) is usually the presence in the water of spawn from another spawning individual, typically a male.  In any normal spawning invert population, with "ripe and ready"  individuals, the first spawner is ALWAYS a male.  That first spawn releases chemicals as well as sperm, as these move down current, one can watch other animals spawn - bang - bang - bang - as the male's spawn hits them.  As they spawn, the chemical load of spawning critters can turn clear water a milky color - with my cukes it was a greenish "mist"...  and every animal that is ripe in the population is triggered to go.  

When spawning occurs, things will happen fast - and be over fast, and you will be one busy boy...  Water change after water change will be needed.  Once the males spawn, the problem is one of diluting the males' spawn to an acceptable level.  Fertilization by more than one sperm does occur, particularly in aquaria, and it always kills the embryo.  So... when these events start to appear imminent, you will have to watch the animals like the proverbial predatory avian dinosaur (a hawk).  You will really need to control sperm abundance.  You will have to have a good compound microscope available, etc....

Happy Trails... 

Cheers, Ron

"The difference in mind between man and the higher animals, great as it is, certainly is one of degree and not of kind. The love for all living creatures is the most noble attribute of man." Charles Darwin (1809-1882)

It sounds like having just the one male anemone and many females is a good arrangement then.

I'm not sure how the animals would sense tidal events?  Would that just be a matter of the frequency and vigorousness of the waves they're subjected to?

As to the compound microscope, I've got a decent one here... now all I need is an observer who has a clue what to look for.

Thanks again.

Mark

You asked, "I'm not sure how the animals would sense tidal events?  Would that just be a matter of the frequency and vigorousness of the waves they're subjected to?"

1) By and large these animals seldom subjected to waves.  Most of the populations are too deep to have waves affect them unless there is a very serious storm.  As a rule of thumb, waves cause no net water movement, only cyclic back and forth water movement on the bottom, and the depth to which that movement is felt is related to the height of the wave.  The movement extinguishes at depth that is about 7 times the height of the wave.  So, if the wave passing over the bottom is 3.3 feet (1 m) high, at a depth of 23 feet (7 m), there is really no net movement from the wave, and below about 10 feet the movement is really puny...  In other words, wave makers for aquaria are another of those wonderful pieces of aquarium equipment designed to mimic some water flow that exists only in a marketer's imagination. 

2)You really should read my AHABS issue devoted to anemones to learn about them.  In any case, the animals surface is covered with sensory cells - these cells respond to tactile stimulation.  What is water movement, but tactile stimulation?Additionally, tidal flux causes changes in all sorts of chemical concentrations - they might be responding to that as a secondary stimulus. 

Cheers, Ron

"The difference in mind between man and the higher animals, great as it is, certainly is one of degree and not of kind. The love for all living creatures is the most noble attribute of man." Charles Darwin (1809-1882)