Phylogenetics and phylogeography of the oak treehopper Platycotis vittata indicate three distinct North American lineages and a neotropical origin.

Ecological differences including habitat, pollinators, and temporal separation between species and populations are important isolation barriers that can impede gene flows among evolving lineages, and subsequently lead to population divergence or speciation (Coyne and Orr, 2004). Temporal or allochronic speciation occurs when members of co-existing species or populations differ in breeding period that causes reproductive isolation as in the famous example of 13and 17-year periodical cicadas, Magicicada (Cooley et al., 2003). For insects like the apple maggot, Rhagoletis pomonella (Bush et al., 1989), the green lacewing, Chrysoperla plorabunda and C. downesi (Tauber and Tauber, 1977), and the treehopper, Enchenopa binotata (Wood, 1993a), the timing of reproduction can be greatly modified by their host-plant usage and the insect’s reproduction is strongly correlated with the plant phenology. Host shifting that changes life history timing thus plays an important role in reproductive isolation and speciation of phytophagous insects (Berlocher and Feder, 2002; Drès and Mallet, 2002). Treehoppers (Insecta: Hemiptera: Membracidae) are phytophagous insects that use their piercing and sucking mouthparts to feed on the phloem or xylem of plants (Wood, 1993b; Lin, 2006). The North American oak treehopper, Platycotis vittata (Fabricius) displays an extensive frontal horn dimorphism and color polymorphism in various life stages, between sexes, and throughout its geo-