slimemold

Slime mold, or slime molds, refers to a group of mostly soil-dwelling protists in the Amoebozoa that are not true fungi, though they can resemble molds. The two main lineages are plasmodial slime molds (myxomycetes) and cellular slime molds (dictyostelids). Notable species include Physarum polycephalum, a well-studied plasmodial slime mold, and Dictyostelium discoideum, a widely used cellular model organism.

Plasmodial slime molds form a single, multinucleate mass called a plasmodium that crawls through decaying vegetation and feeds by engulfing bacteria and other microbes. The plasmodium moves via waves of cytoplasmic streaming and can become very large. When nutrients become scarce, it differentiates into sporangia that produce and release spores, which can disperse and give rise to new individuals.

Cellular slime molds consist of individual diploid amoebae that live separately while feeding. Under starvation they can aggregate into a cohesive slug-like pseudoplasmodium that migrates and eventually forms a fruiting body with spores. Some species also exhibit sexual cycles that produce resting zygotes and later meiosis.

Ecology: Slime molds thrive in moist, shaded environments such as leaf litter, rotting wood, and mulch. They play roles in decomposition and nutrient cycling by feeding on microorganisms in these microhabitats.

Research significance: Physarum polycephalum is noted for displaying collective, problem-solving behavior, including maze navigation and network optimization, which has inspired unconventional computing ideas. Dictyostelium discoideum serves as a major model for studying chemotaxis, cell signaling, differentiation, and development in a simple multicellular system.

Human relevance: They are generally harmless to humans and crops. They are cultivated in laboratories and by hobbyists, and are viewed as safe educational and research organisms.