Final answer:
Slime molds swarm as a response to food scarcity, with acellular types forming a multinucleate single cell and cellular types aggregating into a slug-like mass that behaves as a single unit.
Step-by-step explanation:
Slime molds, which are fungus-like protists, display fascinating behaviors when food resources are scarce. Swarming in slime molds can be observed in two distinct types: acellular and cellular. Acellular slime molds swarm by fusing together to form a single large cell with multiple nuclei, while cellular slime molds swarm by aggregating as individual amoeboid cells into a mass which then functions as a unit.
For acellular slime molds, swarming allows them to move as a plasmodial blob, engulfing organic matter for nutrition. During times of stress, such as during food scarcity, this adaptation enables them to form sporangia and thus spread their spores to potentially more favorable environments. Conversely, cellular slime molds like Dictyostelium form a slug-like structure when they swarm, eventually creating a fruiting body to disperse spores when conditions are unfavorable.