One mind many bodies.

Slime Mould Fruiting Bodies - Photo hosebirdwatcher.livejournal.com

Slime Mould Slug and Fruiting Bodies - Photo Copyright, M.J. Grimson & R.L. Blanton



I first came across Dycostelium in Maturana and Varela's mind-bending book (which I hope to revisit here one day) "The Tree of Knowledge". This creature/s is fascinating due to its amazing ability to exist for much of the time as individual one celled amoebae but then, when conditions get tough, thousands of separate individuals come together and coalesce to form a large slug (all the amoebae now inside one sheath) which moves off to fresh pastures. Finding a likely site the slug stands up to form a tall fruiting body the head of which matures to disperses thousands of spore which become individual amoebae again. For the mostpart the amoebae are happy going their own separate way foraging for bacteria on the moist forest floor only assuming the slug form when food runs out or conditions get dry.


The Youtube clip is an old film by Prof. John Bonner - the grandfather of slime molds - showing the individual amoebae coalescing to form the slug then forming the fruiting body.




Some photos of the fruiting bodies of different slime moulds:
(hosebirdwatcher.livejournal.com)

Vaguely plant-like, the slime moulds used to be classified as fungi but as taxonomy is now based more on molecular RNA they have been placed further out to the right in the Kingdom Amoebozoa (There are now six Kingdoms of life: Animal, Plant, Fungi etc...). Whatever, how amazing that apparently separate individuals can just come together and form one organism!

Another example of composite creatures and far more impressive due to their size and complexity are the Siphonophora - mostly deep-sea living animals of which some have been found 40 meters in length. Although they appear to be a single organism they are in fact made up from a vast colony of thousands of zooids - free-swimming, self-supporting individuals - which have become fully integrated to operate as a single entity. The seperate organs of the siphonophore responsible for feeding or swimming or reproduction can be considered as sub colonies of specialised zooids. The siphonophora prey on crusteaca and small fish using tentacles to poison and ensnare. A surface living example is the Blue bottle or Portuguese-man-of-war.

Above photos Claire Nouvian.

The following description of Siphonophore is from Eugene Marais' wonderful book "The Soul of the White Ant" where this South African Lawyer/Poet/Natural Scientist likened the termite community to a composite animal. While looking for community analogies in other fields of biology he wrote of Siphonophore:

"The great peculiarity of these creatures is that every full-grown specimen is a composite animal composed of hundreds of individuals. The single individual is born by a budding process from the generative group of the composite animal. These newly born individuals swim around freely and are able to continue life singly and reproduce themselves. Each is a perfect marine creature with mouth, stomach, swimming apparatus and sexual organs. If by chance a group of siphonophora happens to meet, they cling to each other. In some species organic union takes place immediately, in others something less than this. But apart from this small difference the final result is the same. Immediately after the union the single individuals undergo a curious change. One group forms a complicated swimming apparatus; another group becomes the stomach and digestive system; and yet another group develops into the sexual organs of the composite animal. One group even takes on the hepatic functions and becomes the liver. Each individual of such a group loses all its separate organic functions. Those of the stomach group for instance, forget they ever sought food or had a sexual life of their own. The new organisim is a perfect whole animal. Were you to see it in its perfect stage you would not dream that it had been formed in this way from separate individuals. Yet one can break it up again ! One can tear apart each individual until the whole animal has been disorganised. One might suppose death would be the result, but not at all. Each little part begins to stir in the water. Slowly it repairs its lost organs and functions until at last it once again is a perfect individual, as different from the composite Siphonophore as the camel from the whale." 1973 Penguin p 79.


Video of Siphonophore from CreatureCast.org