Locust

The locust is a unit spawned by the swarm host.

Overview
Locusts are short-lived, ferocious, parasitic symbiotes. Powerful for their size, they are spawned from the millions of larvae that inhabit the swarm host's bloodstream. When the swarm host is threatened or engaged in combat, subtle chemical signals instruct the larvae to head for its incubator, where they are evolved into locusts.

Originally, locusts attacked any nearby enemy with volleys of acidic saliva. Since evolving pressurized air glands, locusts can attack aerial targets, and have developed the ability to fly themselves.

Game Unit
The swarm host creates 2 locusts manually, with a cooldown of 60 seconds. It is not autocast, but can be used whether the swarm host is burrowed or not.

Heart of the Swarm Campaign
In the StarCraft II: Heart of the Swarm campaign, swarm hosts can be upgraded to produce locusts faster. The carrion strain can produce flying locusts.

Legacy of the Void
In Legacy of the Void, locusts can be spawned every 60 seconds. Spawning locusts is no longer auto-cast, and no longer requires the swarm host to be burrowed. Locusts are also able to fly, and must be ordered to land at a targeted area using "Swoop" in order to attack.

Co-op Missions
Locusts are available to Abathur in Co-op Missions. They can be spawned via his swarm hosts, and can be upgraded at the infestation pit. In addition, Abathur unlocks an upgrade that gives him and his ally the random chance to spawn locusts from the bodies of dead enemies at Level 13.

Portrait
A variant locust portrait is available to zerg players via Heart of the Swarm's leveling system. It is unlocked at level 11.

Development
Locusts used to be able to target air units.

Flying Locusts had to be researched at the infestation pit in the beta version of Legacy of the Void.

Heroes of the Storm
Locusts appear in Heroes of the Storm, and are naturally spawned from the body of Abathur.

Special Locust Strains

 * Flying locust