Crickets. They’re not just for reptiles anymore. They’ve been widely touted for being high in protein with a smaller environmental footprint than chicken, pork, or beef. That means they could account for a chunk of the increase in food production that will be necessary to sustain an earthly population that’s projected to reach nine billion by the year 2050.

But researchers at the University of California at Davis published a study this past spring that suggests the story on crickets may be more complicated than at first it seemed.

To be truly sustainable, they need to be fed something more efficient than the same kind of grain-based feed we use for conventional livestock, which uses large amounts of water and fertilizer.

Crickets