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Scottnema lindsayae

is a Top Predator in Some Ecosystems

Usually the top predator in an ecosystem is a large carnivore.  For example, the lion is the top predator in some parts of Africa and various sub species of Tiger are top predators in parts of Asia.  In the Arctic it is the mighty Polar bear, largest of all the current land carnivores.

Of course, the ecosystems in parts of Africa have a top herbivore as well.  The Elephant plays a very important part in the ecosystem.

Antarctica

In some places in the Antarctic, the top predator is an omnivore. It is the nematode worm known by its scientific name of Scottnema lindsayae.   This worm grows to about 1 millimetre (0.04 Inches) long.  It moves through the dry soils of the Antarctic dry valleys eating both animals and plants.  Its food consists of yeasts, fungi, algae and bacteria.  In its own way it takes the roles both of Lion and Elephant.

When the upper Taylor Valley was discovered in 1903 by Robert Falcon Scott, as far as he could see it was completely lifeless, although he did see the skeleton of a seal.  Since this is a long way from the sea, the seal must have got lost.

Captain Scott was a very well educated man; the fact that he could not see any life and believed that the place could not support any is interesting.  It was not for a long time before it was discovered that he was incorrect.  The dry valleys do not have as many species as many ecosystems, but there are certainly some.

Scottnema lindsayae survives the Antarctic winters in a freeze dried state (anhydrobiosis) reviving to take advantage of better conditions when they occur.  We do not know how long it can survive in its inactive state, but it may be a very long time.

Experiments have shown that this nematode requires over 200 active days to complete its life cycle, so it must be  many years before it is ready to lay eggs since most of each year it will be inactive.