Incorporation of an invasive plant into a native insect herbivore food web

Abstract

The integration of invasive species into native food webs represent multifarious dynamics of ecological and evolutionary processes. We document incorporation ofPrunus serotina(black cherry) into native insect food webs. We find thatP. serotinaharbours a herbivore community less dense but more diverse than its native relative,P. padus(bird cherry), with similar proportions of specialists and generalists. While herbivory onP. padusremained stable over the past century, that onP. serotinagradually doubled. We show thatP. serotinamay have evolved changes in investment in cyanogenic glycosides compared with its native range. In the leaf beetleGonioctena quinquepunctata, recently shifted from nativeSorbus aucupariatoP. serotina, we find divergent host preferences onSorbus- versusPrunus-derived populations, and weak host-specific differentiation among 380 individuals genotyped for 119 SNP loci. We conclude that evolutionary processes may generate a specialized herbivore community on an invasive plant, allowing prognoses of reduced invasiveness over time. On the basis of the results presented here, we would like to caution that manual control might have the adverse effect of a slowing down of processes of adaptation, and a delay in the decline of the invasive character ofP. serotina.