Slime molds live independent lives, but during food shortages, they will come together and form into an enormous single cell called a slug.
Slime molds have traits similar to both fungus and animals. Their life cycles can be very strange as they go through different stages. When times are good, they live independently, but if conditions change and the food supply disappears or conditions gets too hot or dry or any other big change, the individual cells will begin to gather together to form a single structure. The individual cells will send out a chemical signal directing all of them to gather together.
This new structure is the slug, so-called because it really resembles a slug. The slug will creep along seeking out food. When the communal cells sense that they’ve come across more food, the slug stops, cells in the mold now begin to do different things. Some of the cells will go about creating an anchor, others begin creating a stalk with a spore cap, while others become spores in that cap.
When a drop of rain hits the spore cap hard enough, the spores will fly out. They are a bit like plant seeds. Each of them will become a independent cell when they land and begin a new life cycle.
Slime molds were at one time thought to be fungi, but unlike fungi, they can move almost like an animal making them very different from fungi. Slime molds are made up of individual cells that can come together to form a single mass. They can be orange, red, yellow, brown, black, blue, or white and are usually quite bright.
These large masses act like giant amoebas, moving along slowly while searching for food. They can navigate around obstacles and if a food source is nearby, they head straight for it. Slime molds are very interesting. You can chop up a slime mold and the pieces will just pull themselves back together again.
There are 2 kinds of slime molds, one is the plasmodial slime molds, they consist of a big cell wall that surrounds thousands or millions of nuclei. They contain proteins called microfilaments that act like tiny muscles, these muscles allow the mass to crawl along at about 2.5 cm a day. The other type is the cellular slime molds, these also produce spores, but these spores form into amoeba-like cells. The cells live individual lives and never form into larger structures.
When nutrients and moisture are scarce, individual cells send out a chemical beacon to attract other cells of the same species. The cells join up to form a mass that looks and acts like a slug to take them to a more favorable location.
Slime molds feed on decaying vegetation, bacteria, fungi, and even other slime molds. They are most commonly found in forest settings but can be seen in gardens.