Flea beetles outwit their host plant’s mustard oil bomb and
use it for their own purposes
Almost all herbivorous insects are specialized to feed on
specific host plants and have adapted to their chemical defenses. Flea beetles
are important pests of cabbage and other cruciferous plants, such as mustard,
horseradish and rapeseed. These plants use a sophisticated defense system,
known as the mustard oil bomb, to get rid of their enemies : If plant tissues
are wounded, glucosinolates and an enzyme known as myrosinase come into
contact, and, as a result, toxic metabolites are formed which deter most
insects. This defensive mechanism, however, has no negative effect on flea
beetles, according to scientists from the Max Planck Institute for Chemical
Ecology in Jena, Germany. Flea beetles are even able to sequester
glucosinolates without the mustard oil bomb being set off by the plant’s
enzyme. Moreover, the insects use their own myrosinase and can utilize the
plants’ defensive chemicals for their own purposes. The beetles’ mustard oil
bomb is likely to fend off predators.