Kāhuli (Partulina anceyana) on 'ōhi'a original

Original 6"x8" illustration.

Pūpū kani oe (Partulina anceyana) and ʻōhiʻa (Metrosideros polymorpha).

Partulina is a genus in the endemic Achatinellinae subfamily (family Achatinellidae). Unlike the O’ahu tree snails (genus Achatinella), Partulina are distributed on multiple islands in the Hawaiian archipelago. Partulina is sister to Achatinella, and share similarities in life history, including live-born young, long lives, low fecundity, and slow maturation.

Kāhuli were once abundant in Hawaiian forests. These tree snails, which had little in the way of natural predators, were so prevalent that that collectors could bring home thousands of snails on a single hike—an act no doubt contributing to their decline.

While we often think of snails as garden pests, kāhuli were friends of the forest. These colorful gems did not prey on native plants, but instead grazed algae and fungus on the surface of leaves, keeping native plants healthy and assisting in natural processes such as photosynthesis. This must have been an important ecological role considering how many snails there used to be!

Threats to Hawaiian tree snails include introduced predators (primarily rats, Euglandina rosea, and chameleons), climate change, habitat loss, invasive species, and naturally low reproductive rates.