What Does “A Swarm of Ants” Mean?
“Swarm” applies most precisely to one specific ant event: the nuptial flight. On warm, humid days, usually after rain, mature colonies release their winged reproductive ants, queens and males, all at once, in a synchronized mass mating flight often called a “flying ant day.” These swarms can be dense enough to show up on weather radar.
Outside of nuptial flights, “swarm” is also used more loosely for any large, dense mass of foraging or relocating ants, though “army” or “colony” are more common for everyday, non-flying gatherings. After mating, males die within hours, and each newly fertilized queen sheds her wings and attempts to found a brand-new colony of her own.
Example: “A swarm of ants filled the sky over the backyard, a sure sign that flying ant season had arrived.”
Related: Collective Nouns for Insects · What Is a Group of Ants Called? · An Army of Ants · A Colony of Ants · A Nest of Ants