 She heads a team of researchers who found that five "Timema" species ("T. douglasi", "T. monikense", "T. shepardi", "T. tahoe" and "T. genevievae") have used only asexual reproduction for more than 500,000 years, with "T. tahoe" and "T. genevievae" reproducing asexually for over one million years.The geographic range of "Timema" is limited to mountainous regions of western North America between 30° and 42° N. They are found primarily in California, as well as in a few other neighboring states (Oregon, Nevada, Arizona) and in northern Mexico.All are herbivores, primarily feeding on host plants found in chaparral.