P Polycephalum appears aware of food location

[Jeremiah Blondin]

During an experiment designed to study the foraging techniques of Physarum Plycephalum slime mold, I adhered an oat flake to the lid of the petri dish.  The result was surprising in that the mold did not spread uniformly up the walls, retracting the unnecessary mass only upon encountering food.  Rather, it extended a vein directly up the petri dish wall, climbing the wall only in the location of the untouched oat flake. (See attached photos.)  The organism is somehow aware of the location or at least the direction of food.  This will be followed by additional experiments to deduce the distance at which P. Polycephalum becomes aware of previously unencountered food.

[Heather Barnett]

Hello Jeremiah, I have observed similar behaviour, where there appears to be some intentionality in the direction and movement towards a food source. This hasn't been documented to my knowledge in published research. There is no known mechanism for the organism to be able to know that food is there, as it operates through chemotaxis and obviously has no sense organs (smell or sight) to inform it of the presence of food. But empirically I have observed the appearance of directed growth in some of my animations. Factors that may affect the spread and size/shape of plasmodium growth include moisture levels, the environment (if old oats are starting to go mouldy) and space available to explore.

I can send your query out to the slimoco membership, I'm sure others will have experience and knowledge to share.

Best, Heather

PS: better to add photos and link to them rather than add as attachments that need to be downloaded. the ning photo tool resizes and is easy to use. feel free to set up albums of your experiments. 

[Jeremiah Blondin]

Upon removal of the oat flake from the dish lid, the plasmodium retracted, apparently losing interest in the foodless lid. Two more oat flakes have been adhered to the lid on the opposite side of the dish. Growth is already occurring toward one flake and I suspect I will soon see growth below the other as well. Photos to follow as growth become more pronounced. My hypothesis at this point is that the slime mold is essentially "smelling" through chemotaxis, collecting particles from the air as they hit the plasmodium and moving from the area of lowest food particle concentration to the area of highest food particle concentration. This would also explain why directed growth is observed more readily when the oat flakes are secured above the plasmodium. There are likely more particles falling from above than would be possible if situated horizontally. I may attempt to publish the results if this turns out to be correct. I am preparing to drill an air current path into a new dish to see if oats placed in the path of an air current will alter the growth of the plasmodium. Does this sound sensible to you or do you think I'm wasting my time? Thank you for your response and for creating this group. This is a pretty fascinating little creature you've introduced me to. :-)