Cowrie reproduction - questions

[palmerc]

I have what I think is either a Cypraea annulus or moneta. It is just over one inch long.

My question: I got it from the sea when on holiday recently. It has been in my tank for 2 weeks now and has laid a clutch of eggs and has been brooding them for about 6 days by sitting on top of them. The eggs were white initially but are now quite a dark purple. Does this mean that they are fertile and will hatch?

Are cowries single sex or hermaphroditic? Can they store sperm to be used later, or do they carry fertilised eggs around for a while before laying them?

How long will the eggs take to hatch approximately? And to develop into little cowries?

Would really like to know more about these little creatures.

Here are some pics. If anyone can confirm the ID it would be appreciated.

Just after laying the eggs.

Six days later

Regards,
Clinton

Johannesburg, South Africa

 

[graveyardworm]

Your id is correct, I believe it takes two to reproduce. I'm not 100% on this, but I'm pretty sure the cowries larvae are pelagic, meaning their young go through a planktonic stage which makes them more challenging to raise. More than likely they will become food for your corals, or get removed by your skimmer.

 

[greenbean36191]

It looks to me like C. moneta. They are dioecious (seperate sexes). They can take as long as 6 weeks between copulation and laying the eggs. It then takes as long as 4 more weeks for the eggs to hatch. Then the larvae are planktonic for a few days up to two weeks. I think that period is toward the shorter end for this species, but I don't have any good numbers. As David pointed out, that planktonic stage will make them almost impossible to raise in a reef tank.

 

[nYgel]

I'm going to go ahead and point out they are the coolest snail (ish) thing ever, I had two in my tank for a good while until the smaller one died, and now i have a huge one that roams my tank at night, they're great.

 

[650-IS350]

I have 4 of em in my tank.. I like them..

 

[palmerc]

Thanks for all the replies. Pity about the pelagic life-cycle phase, but maybe a few will survive being eaten long enough to reach adulthood. here's hoping

Found this info:

Reproduction

In the wild the sexes are separate with fertilization being internal. The female will lay a cluster of white, parchment-like eggs, and then stands guard over them by covering the eggs with her foot. Once the embryos develop into the swimming veliger larvae, they enter into the plankton to drift to develop further. This planktonic larval stage is relatively long, and could be the reason that captive breeding was nowhere to be found in my research.

 

[greenbean36191]

Even if they don't get eaten there is still a lack of appropriate food for the larvae to eat. I don't know that she raised them to adulthood, but IIRC a researcher in Hawai'i raised some of the larvae. Unfortunately it was her dissertation, so it's not available in an easily accessible journal.

 

[BrianPlankis]

<a href=showthread.php?s=&postid=9011347#post9011347 target=_blank>Originally posted</a> by greenbean36191
Even if they don't get eaten there is still a lack of appropriate food for the larvae to eat. I don't know that she raised them to adulthood, but IIRC a researcher in Hawai'i raised some of the larvae. Unfortunately it was her dissertation, so it's not available in an easily accessible journal.

Mike,

If you can PM me the dissertation details our library has a really fabulous inter library loan guy, I might be able to get it.

Brian

 

[greenbean36191]

I'll try to remember to get the citation for you on Tues. when I go to the library. Just FYI, the disseration is about snail larvae in Kaneohe Bay, HI, not about cowries in particular, so I don't know how much specific info it contains.

 

[greenbean36191]

Taylor, J. B. 1975. Planktonic prosobranch veligers of Kaneohe Bay. Ph.D. dissertation, University of Hawai'i. Honolulu, Hawai'i.

I also found this one which I do have access to, but I haven't had time to get ahold of:
Katoh, M. 1989. Life history of the golden ring cowrie, Cypraea annulus, (Mollusca: gastropoda) on Okinawa Island, Japan. Marine Biology. 101(2), 227-234.

 

[Malifluous]

I got some snakehead cowries from a guy on ebay. They lay eggs all the time but I have never seen a baby develop. One day the eggs just dissappear.