Came across this lovely, bright yellow lump on a walk recently – a quick prod with a stick sent a gust of what looked like custard powder on the breeze. I knew immediately I’d come across something interesting.
Fuligo septica or the “Scrambled Eggs” slime mold (studiously avoiding a much more… unpleasant name) is a slime mold in the class Myxogastria: as Wikipedia puts it, “the plasmodial or acellular” slime mold class. Typically I try to write my posts from my own knowledge, with perhaps one or two facts from outside sources. However, at university the focus seems to be very much on the animal, plant, (some) fungal and bacterial life – all the lovely Archaea, slime molds, protists etc. are swept under the rug of “they don’t fit, just know they’re there, yeah?”. To this end, I know very little about slime mold life cycles and taxonomy from my studies, but I’ll do my best to lay the groundwork of understanding here.
Life Cycle
There are elements reminiscent of the fungal and algal life cycles (my mind harkens back to an examination in which I had to outline the polyphasic life cycle of Puccinia graminis) in those of the slime molds. Fertilisation occurs when two haploid (n) amoeboid gametes fuse. Initial cell fusion (plasmogamy) is followed by nuclear fusion (karyogamy) and final development into a diploid (2n) amoebozygote. Fascinatingly, however, the cell does not split in the mitosis that follows, instead the single cell expands its cytosol and membrane (along with its territory) and becomes a multinucleate 2n mass. This mass is never truly “finished” dividing following fertilisation, and continues to take in outside nutrition and increasing its nuclear count. Frutification occurs due to a complex set of conditions, the exacts of which differ between species and are not thoroughly understood. A hypothallus is generated on a substrate, on which the fruit body sits, sending forth many millions of meiotically-derived haploid spores. These then establish elsewhere, and may asexually multiply via mitosis, develop into motile flagellar gametes, or fuse with a partner to begin the process again.
Slime molds are absolutely bizarre. Studies have shown that they can efficiently link food sources together into living networks of overstretched plasmodium, showing one of the potential “simplest routes” between points. This can be exploited to help solve numerous problems, such as the “minimum spanning tree”, or the linkage diagram between any set of points that takes the least effort (path length). If you haven’t watched the (in my circles at least) constantly referenced video of a slime mold linking strategically placed oat flakes together into an almost 1-for-1 map of the Tokyo Rail Network, I highly recommend it.
sploopst 