|Microscopic organisms are often very transparent. Because of this they can give unique glimpses inside their bodies. With the aid of the microscope we can study many of their internal anatomical features. One of the things we can observe is their digestive tract. It is not just the bowels we can see, it is also the content. This way it is possible to reconstruct the menu card of the diner that has been served. If you can distinguish the front and rear end of the organism you can even see in which chronological order the food was consumed.|
The first menu that I observed under the microscope was eaten by a larva of a fish. This youngster still has a lot to learn.
The micro equivalent of a fast food diner can easily be distinguished. A quick snack of water fleas (Bosmina sp.) are visible just below the shiny air sac. You may watch your diet, young friend! Especially since 2 very nutritious Volvox colonies were available.
A more healthy meal had this Oligochaete worm (an aquatic cousin of the earth worm).
After a quiet evening in a vegetarian restaurant it is full with desmids (Closterium) and diatoms (Navicula).
The real 'connoisseur' that volunteered for a close study of its intestines proved to be the Chironomid (midge) larva. Its long slender (it does watch its proteins) body was just digesting a delicious and varied meal.
I could reconstruct the following micro gastronomic diner:
Microscopic menu á la carte
as a starter - a small plate with water fleas
the main dish - a bowl with 2 species of shelled amoebae, Arcella sp. and Lesquereusia spiralis, a real delicacy we can compare with eating escargots.
as a dessert - a light salad (yes, in the micro world things tend to be quite different than in our macroscopic world) made of several algae, not just green algae but conjugating green algae, again showing the fine taste of the consumer. We can clearly see the desmid Netrium digitum and a nice filamentous alga, perhaps a Spirogyra but the chloroplast has already been digested.
Asplanchna's last supper
Not all micro organisms have such a good taste for cuisine. This victim of extensive over eating, the rotifer Asplanchna, did choose a wrong type of food. Almost like a cannibal it devoured a dish of the smaller rotifer Keratella, overlooking the fact that their loricas were armored with spines. It proved to be a fatal meal.
It would have been wiser if it had eaten that Micrasterias thomasiana!
comments to the author Wim van Egmond are welcomed.
All photographs © Wim van Egmond 2003
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