PLANT POLYPLOIDY AND INSECT PLANT INTERACTIONS/

We used flow cytometry and extensive geographic surveys of herbivore a ttack to test whether repeated evolution of autotetraploidy in the per ennial herb Heuchera grossulariifolia Rydb. (Saxifragaceae) has create d evolutionary barriers to attack by the specialist moth herbivore Gre ya politella (Prodoxidae). We found that the moth has colonized tetrap loid as well as diploid populations, has colonized tetraploids of sepa rate evolutionary origin, and, at least under some conditions, is more likely to attack tetraploids than diploids. Plant polyploidy therefor e provides a potential route out of specialization as an evolutionary dead end in phytophagous insect taxa as well as a potentially importan t route to subsequent phylogenetic and geographic diversification of p lant/insect interactions.