Horseradish flea beetles use plant defense compounds, so-called glucosinolates, from their host food plants for their own defense. Like their hosts, they have an enzyme which converts the glucosinolates into toxic mustard oils. A research team at the Max Planck Institute for Chemical Ecology in Jena, Germany, has now found that these glucosinolates are present in all life stages of the horseradish flea beetle; however, the enzyme required to convert these into toxic substances is not always active. Although larvae are able to successfully fend off attack from a predator, such as the harlequin ladybird, pupae are predated because they lack enzyme activity. These findings have been published in Functional Ecology, in February 2020.
Click here for original story, Whether horseradish flea beetles deter predators depends on their food plant and their life stage
Source: Phys.org