Slug herbivory on hybrids of the crop ce:italic>Brassica napus/ce:italic> and its wild relative ce:italic>B. rapa/ce:italic>

摘要

Some plant species can cross with each other but stay nevertheless distinct with little gene flow between them. Selective herbivory could explain this pattern when hybrids are more susceptible or intermediate between their parents. We performed choice and no-choice experiments with the slugArion lusitanicusto test this hypothesis for the cropBrassica napus, wildB. rapaand their backcross hybrids. In both experiments slugs greatly preferredB. napusoverB. rapawhile average herbivory on backcross hybrids was intermediate. Concentrations of aliphatic glucosinolates in the hybrids were intermediate between the parental species. Slug herbivory potentially reduces establishment of backcross hybrids. This hypothesis needs to be tested in the field.