Seed spitter

A desert plant has a neat way to coerce spiny mice in its native Negev Desert to spread its seed. The plant sweet mignonette, or taily weed, releases a toxic “mustard oil bomb” containing isothiocyanates when the mouse eats the plant's fruit making the critters spit out the seeds. The chemical weapon not only protects the plants' seeds from being ingested but any delay in the mouse reaction means that it allows the nocturnal rodents to spread the seed farther than they would otherwise reach if the fruit were simply to root at the foot of the parent plant. “It’s fascinating that these little mice are doing analytical chemistry, assaying the fruit for toxic compounds” and learning not to bite into the seed, explains team member Denise Dearing of the University of Utah. “It's not that these mice have poor table manners,” Dearing says. “They deliberately wiggle the seed out of the pulp of the fruit like a person does when eating watermelon. This removal of the seed keeps the toxins in the pulp from being activated.”