Harvest Mission

The harvest mission represents the alien's main avenue of gathering resources to build new soldiers and conduct UFO missions. Every UFO you send out on a mission requires Alien Food in order to be conducted. Alien Food essentially represents the upkeep of an alien crew while they are away from the base. As such, larger UFOs which have a larger crew will require more Alien Food in order to operate. You should always keep an eye on the amount of Alien Food you have in storage as if you run out, you effectively lose the game as you cannot send out any more UFOs.

In addition to gathering Alien Food, the harvest mission will also gather organs. Organs are used in the breeding process to build additional soldiers for your invasion. Each unique alien type has its own associated organ value, with early game units such as Sectoids being very cheap to produce, while more late game units such as Mutons requiring substantially more organs per unit produced.

The most effective ship to utilize when running harvest mission is the Harvester. Available from fairly early in the game, this UFO will provide a substantial boost to the amount of Alien Food and Organs gathered from a single harvest. As such, the Harvester should be one of the first ships the alien side researches as the amount of resources you have in storage will skyrocket once one is in your fleet.