Scrambled egg slime
Fuligo septica
The scrambled egg slime is a globally distributed slime mold primarily found on dead wood and bark mulch. It forms a conspicuous yellow, foamy plasmodium that is capable of active movement across the substrate to ingest food. For reproduction, this mass transforms into a solid, crusty aethalium where the dark spores mature. Despite its fungus-like appearance, the organism taxonomically belongs to the group of Amoebozoa.
Details
Identification
Bright yellow color, cushion-like shape (aethalium), foamy structure in the active stage, dark spore powder under a calcareous crust when mature.
Social behavior
Lives as a single-celled, multinucleated giant cell (plasmodium) formed by the fusion of numerous individual cells.
Diet
Feeds heterotrophically through phagocytosis of bacteria, fungal spores, and organic particles.
Hunting strategy
Engulfs and digests food particles through the amoeboid movement of the plasmodium.
Spawning substrate
Moist dead wood, bark mulch, leaf litter, or occasionally living plants.
Overwintering
Survives unfavorable weather periods as spores or by forming a hardened sclerotium.
Ecology
Ecological role
Important decomposer of organic matter and regulator of bacterial populations in soil and wood ecosystems.
Natural predators
Specialized beetle species (e.g., Agathidium species) and various slugs.
Competitor species
Other myxomycetes and saprobic fungi compete for substrate and microorganisms.
Ecosystem service
Contributes to the nutrient cycle by consuming microorganisms and breaking down organic remains.
Threats
No significant threats at present; the species benefits from anthropogenic bark mulch.
Scientific profile
Profile
Distinguishing features
Distinctive, cushion-shaped aethalium with a usually bright yellow (rarely white or reddish), calcareous, and brittle crust (cortex). The internal spore mass is dark brown to black. The preceding plasmodium is typically bright yellow and slimy-fluid. Microscopically, the species is characterized by a calcareous capillitium (physaroid type) and finely warted spores (6–9 µm).
Habitat
Saprobic on decaying wood (especially conifers), bark mulch, leaf litter, and occasionally on living plants or grass. Frequently found in forests, gardens, and clear-cuts. Cosmopolitan distribution ranging from the Arctic to the tropics.
Diet
Phagotrophic; the plasmodium feeds by engulfing (endocytosis) bacteria, fungal spores, yeasts, and dissolved organic matter from the substrate.
Reproduction
Complex life cycle: Spores germinate into myxamoebae or myxoflagellates, which fuse to form a diploid zygote. This develops into the multinucleate plasmodium. Upon light stimulus or nutrient depletion, sporulation into an aethalium occurs. Spore dispersal is mediated by wind, rain, or insects (e.g., beetles of the family Leiodidae).
Ecological role
Important decomposer in the nutrient cycle; contributes to the regulation of bacterial populations. Notable for its extreme tolerance to heavy metals (especially zinc); Fuligo septica can tolerate zinc concentrations toxic to other organisms by sequestering them as fuligopyrone complexes within the plasmodium.
Protection & threats
Status not on standard scale
Main threats
No threats currently known. The species is considered very common, widespread, and adaptable to anthropogenic habitat changes (e.g., gardening, forestry).