Can you separate slime mold facts from fiction? Test yourself with these true-or-false statements about Physarum polycephalum.
Printable version
These statements also come on paper, with every answer explained, in the slime mold quiz booklet (PDF, 14 pages), handy for a classroom or a family evening.
The full answer key, question by question. Expand a question to see the correct answer and why.
Answer : True
TRUE. A slime mold plasmodium, even when it covers an entire dinner plate, is a single cell (a coenocyte) with billions of nuclei sharing one continuous cytoplasm, with no internal walls separating them.
Answer : True
TRUE. In 2016, Audrey Dussutour's team showed that Physarum polycephalum learns to ignore bitter but harmless substances such as quinine or caffeine after a few days of exposure. The same year, they showed that this learned behavior can be passed to another slime mold through cell fusion.
Answer : False
FALSE. Slime mold actually avoids light (a behavior called negative phototaxis). It thrives in darkness and is typically grown in the dark or under very dim red light in laboratory settings.
Answer : True
TRUE. Each fragment carries thousands of nuclei and its share of cytoplasm, so a piece that is not too small regenerates into a complete organism. If the pieces of the same slime mold are put back together, they can fuse into one again.
Answer : False
FALSE. Although slime mold was historically classified with fungi due to its spore-producing structures, molecular analysis has placed it among the protists (Amoebozoa). It is no more related to mushrooms than you are.
Answer : True
TRUE. In 2010, Atsushi Tero and colleagues placed oat flakes on a map at the positions of the cities around Tokyo. The network the slime mold built between them was comparable to the real rail network in cost, efficiency and resistance to breakdowns.
Answer : False
FALSE. Slime mold is harmless to humans. It produces no toxins and does not parasitize animals. At most, the spores released by wild species when they fruit can bother people with asthma or mold allergies.
Answer : True
TRUE. As a sclerotium, slime mold enters deep dormancy. If it was dried slowly and kept dry and in the dark, it reliably revives after two years and more, waking within a day or two once moisture and food return.
Answer : False
FALSE. Physarum polycephalum has 720 mating types, produced by combining three genes: matA (16 versions), matB (15) and matC (3). Two reproductive cells can only pair if their combinations differ.
Answer : True
TRUE. In 2021, four slime molds traveled to the ISS as dry sclerotia. Astronaut Thomas Pesquet woke them on 2 September, and all four grew in orbit while thousands of French classes ran the same experiment on Earth.
