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How do Portugese-man-o-war jellyfish reproduce?The syphonophore, the Portuguese man of war: This is a collection of jelly fish each having its own individual function, catching food, digestion, movement, reproduction. I can understand that the digestive jelly fish can feed the other jelly fish but if only one of the jelly fish reproduce, then how do the other jelly fish in the colony come about? Have I got the facts wrong, or does the reproducing jelly fish produce all of the jelly fish? Nazer |
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Helen - Wonderful creatures indeed! Although keep your distance, of course, because they are nasty stingers, but they're beautiful things to look at. I think this question is based on the fact that our listener knows that these animals are not in fact jellyfish. They're not single living creatures like that but they're colonies of lots of little creatures that live together. They belong in the same phylum, the Cnideria, as jellyfish and they look similar but they are in fact different. Portuguese man of wars are called siphonophores and they're made up of three main different types of little animals that live together. There are dactylozoids which make up the tentacles, there are gastrozoids which are the bits that eat the food, and there are gonozoids, and they are the bits of these creatures that reproduce. They produce sperm and they produce eggs. In fact, you get female and male Portuguese man of war, even though they’re called “Men”. The sperm will fertilize eggs in the water colum to produce larvae which grow into bigger Portuguese man of war. And the way that they grow from those individual cells is by asexual division of those cells and they produce all those individual three types of animals that live in this one colony and drift around the oceans, stinging things and eating things as they go. |
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March 2010 |
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Nazer, Mr D - (NAZ ) - Science asked the Naked Scientists:
The syphonophore, the Portuguese man of war:
This is a collection of jelly fish each having its own individual function, catching food, digestion, movement, reproduction.
I can understand that the digestive jelly fish can feed the other jelly fish but if only one of the jelly fish reproduce, then how do the other jelly fish in the colony come about?
Have I got the facts wrong, or does the reproducing jelly fish produce all of the jelly fish?
What do you think?
- Nazer, Mr D - (NAZ ) - Science - 9th Jan 10
Your post interested me so I searched for info. It seems you are right. I found that man o wars arent jelly fish at all (they just resemble them) and are in fact a colony of organisms-Siphonophora-each are so specialized that most lack the ability to survive on their own.They are considered on a border between a colony and a multicellular organism.The siphonophores, are an order of the Hydrozoa, a class of marine invertebrates belonging to the phylum Cnidaria. They are colonial, but the colonies can superficially resemble jellyfish; although they appear to be a single organism, each specimen is actually a colony of Siphonophora. The best known species is the dangerous Portuguese Man o' War (Physalia physalis). Siphonophores are especially scientifically interesting because they are composed of medusoid and polypoid zooids that are morphologically and functionally specialized. Siphonophores have been known to grow up to 130 feet in length. Each zooid is an individual, but their integration with each other is so strong that the colony attains the character of one large organism. Indeed, most of the zooids are so specialized that they lack the ability to survive on their own. Siphonophorae thus exist at the boundary between colonial and complex multicellular organisms. Also, because multicellular organisms have cells which, like zooids, are specialized and interdependent, siphonophores may provide clues regarding their evolution. - jazzderry - 30th Aug 10
Well blow me I never knew that!! I always thought they were a jelly fish not a colony, nice info thanks! - Variola - 31st Aug 10
surprised me too! - jazzderry - 5th Sep 10
i just realized i misread your question. from what i read i was geting two different explanations of their reproduction process but i think what you wish to know is that after reproduction/fertilization, budding or miotic division takes place: 1- The Portuguese Man-O-War are hermaphrodites, so each individual gonozooid consists of male and female parts. The gonozoids of the man o’ war are the polyps that are responsible for reproduction. The adult medusa releases sperm which fertilizes an egg.(i believe one site said it releases the sperm into the open ocean toward another swarm) The egg forms a larva, which finds a place to form into gonozooids. These polyp gonozooids eventually release a medusa form by asexual budding that grows into the adult medusa which started the cycle. 2-Physalia reproduction takes place mostly in the fall. Physalia are dioecious, meaning that each “individual” is either male or female. The polyps responsible for reproduction are the gonozooids, which are comprised of gonophores; sacs containing either ovaries or testes. Fertilization occurs externally when the men of war shed their gametes into the open ocean; sperm from one colony fuses with the eggs of another colony. It is unknown what causes this spawning cycle to begin. However, the release of gametes may be triggered by a chemical response due to the presence of men of war in large quantities in a single locality. This critical density is probably needed for successful fertilization. Physalia physalis also reproduces a sexually by means of budding or mitotic division. - jazzderry - 6th Sep 10
Nobody has answered the question, which I'll try to reformulate. The Man of War comprises four separate organisms (polyps): the sail and three zooids. Only one of these, the gonozooid, is responsible for reproduction. The gonozooid can presumably only reproduce more gonozooids, and not gastrozooids, because those are different organisms. So how exactly do more gastrozooids form? Also, how do all four polyps initially assemble to make a Man of War?
- Kevin - 1st Aug 11
I got this off of the Waikiki Aquariums website:
See the whole discussion | Make a comment"The life cycle of the Portuguese man-of-war involves both sexual and asexual reproduction. A colony is started by a small swimming stage, called a larva, which is the product of the fusion of an egg and sperm from mature parent colonies. The larva produces a colony itself through a process called budding (asexual reproduction). The original individual divides and divides, producing more individuals, until the colony is formed. In a mature colony, specialized individuals (gonozooids) produce the eggs and sperm which will lead to more larval forms." My understanding is that the sperm and egg come together and from that an organism forms that grows all four zooids into one larger organism.Thus, while only the gonozooid actually reproduces, from the egg and sperm union all of the zooids are formed similar to how an egg and sperm form all of the cells of multi-cellular organisms except each is its own organism. An interesting animal colony to say the least. - Daniell - 9th Jan 12
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