In 2008, researchers studying the presence or absence of a dorsal stripe suggested that it has independently evolved several times in "Timema" species and is an adaptation for crypsis on needle-like leaves. All of the eight "Timema" species with a dorsal stripe have at least one host plant with needle-like foliage. Of the thirteen unstriped species, seven feed only on broadleaf plants. Four ("T. ritense", "T. podura", "T. genevievae", and "T. coffmani") rest during the day on the host plant's trunk rather than its leaves and have bodies that are brown, gray, or tan. Only two species ("T. nakipa" and "T. boharti") have green unstriped morphs that feed on needle-like foliage; both are generalist feeders that also feed on broadleaf hosts.