The World’s Smallest Gardeners: Primitive Agriculture in the Tardigrade Hypsibius dujardini?

I ran a microbiology and art workshop at the Eden Project earlier this week for around 400 members of their team. The event was a prelude to Eden’s groundbreaking Invisible Worlds Project which will explore the world, that we now know, lies beyond our limited human senses. Please follow this link for more information on this unique and important project Invisible Worlds.

As part of this,  I brought a culture of tardigrades (Water Bears/Moss Piglets) to show to the participants using a microscope. The name tardigrade equates to “slow walker”,  and the colloquial name “water bear”  comes from the way they walk, reminiscent of a bear’s gait. Tardigrades are microscopic creatures, usually less than 0.5 mm in length, that by being quite plump, bilaterally symmetrical, segmented,  and having four pairs of legs with bear-like claws, are undeniably and microscopically cute. Having said this, tardigrades are the only animal that can survive in the harsh environment of space. When encountering desiccation, these creatures can lose body water and enter a dehydrated and reversible ametabolic state. This dehydrated form of the tardigrade can withstand a wide range of physical extremes that normally kill other organisms, such as extreme temperatures (from −273 °C2 to nearly 100 °C), high pressure (7.5 GPa), immersion in organic solvents and exposure to high doses of radiation.

The tardigrade I brought to the Eden Project, was Hypsibius dujardini,  a freshwater tardigrade commonly found in the sediments of lakes, rivers, and streams and often in association with microscopic algae on which it feeds.

During the workshop, and over periods of 1-3 hours,  I noticed that the uniform and green soup of tardigrade culture and their green algae food had begun to “coagulate” into green clots. Please see images below.

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A uniform culture of tardigrades and their microscopic green algal food at the beginning of a demonstration.

 

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A culture after 1-3 hours, in which the tardigrades and their microscopic green algal food have “coagulated”.

 

Now this is just a hypothesis at the moment, and I’m happy to be proved either wrong or right but I have a strong  suspicion that the tardigrades here are actually farming or herding their algal food, and may be even moving it towards conditions of optimal growth. In the time-lapse videos below, the tardigrades appear to be “herding” the algae into clumps with their claws, and even moving the algae towards a source of light to better enable the algae to grow.

Below, Tardigrades “herding” algae into clumps?

 

Below, Tardigrades “herding” algae into clumps and moving these?

 

Again, this is just a hypothesis at the moment,  but if correct,  this would add an additional layer to the cuteness of these intriguing creatures,  if they were indeed microscopic farmers or gardeners.

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