The Superorganism Concept and the Secret to a Long Life

An exception to the general rule:  termite queens live exceptionally long and, at the same time, are extraordinary fertile.

Usually the rule in the animal kingdom is: a lot of progeny means a short life – if you are less fertile, you live longer. However, it seems that social insects – that is, insects that live in societies – can escape this fate. How they do this has been revealed by a research team from the Institute of Zoology at the University of Freiburg, taking the termite species Macrotermes bellicosus as its model.

The queen of the termite species Macrotermes bellicosus lays approximately 20,000 eggs a day, yet it can live up to 20 years.

 Photo: Judith Korb

“Macrotermes queens are the most reproductively successful terrestrial animals,” says Freiburg biologist Prof. Dr. Judith Korb. Termite queens lay continuously about 20,000 eggs daily. And yet they reach ages of up to 20 years. Workers from this species have the same genome as the queen, but are infertile and only live for a few months. Judith Korb, together with her PhD student Daniel Elsner and Dr. Karen Meusemann, has found a clue to why the queen and king – unlike the workers – practically do not age. The team has published its results in the scientific journal ‘Proceedings of the National Academy of Sciences’ (PNAS).

Superorganism in Symbiosis

Korb has studied Macrotermes bellicosus since her doctoral thesis. This termite species lives in the savanna of western Africa and builds meters-high mounds. They have an organized society with division of labor, something that led to the concept of the superorganism [del: becoming established in research]: a queen and a king are responsible for reproduction, soldiers defend the colony, workers build the mound and gather grass and leaves, which are used to feed a fungus that they cultivate in specially developed “gardens”, where it decomposes complex plant compounds and thus concentrates nitrogen. This in turn is an important nutrient for the termites, and it limits the growth of the colony if insufficient quantities are available. The extreme sensitivity of the fungus means that the temperature in the interior of the mound must always be around 30 degrees Celsius.

This species of termite lives in the savanna of western Africa and builds meters-high mounds.

 Photo: Judith Korb

Now, in order to track down the secret of a long life, the Freiburg team first compared the genetic information that is active in young and old animals and used bythe cells – separately for queens, kings and workers. “We were very surprised by the result,” reports Korb. “We found hardly any differences between old and young individuals in queens and kings, but for the workers they were enormous.”