Coleotichus blackburniae as they develop. This insect occurs on all the main islands of Hawaii. They are found on `a`ali`i ("Dodonaea viscosa") bushes and koa ("Acacia koa") trees. Also found on Formosan Koa (Acacia confusa) which is native to Southeast Asia. It has been commonly used in Hawaii as an ornamental landscape tree that has been deemed invasive. A. confusa and A. koa both have distinctive phyllodes that differentiate each species but since its introduction C. blackburniae has been recorded to associate with the invasive Formosan koa. Common to all true bugs, this species has no mouth parts with which to bite,
Acacia koa survives best in pasture when planted under koa. This is because koa trees reduce radiative cooling, preventing frost damage to ōhia lehua seedlings. Koa is the preferred host plant for the caterpillars of the green Hawaiian blue ("Udara blackburni"), which eat the flowers and fruits. Adults drink nectar from the flowers. Koa sap is eaten by the adult Kamehameha butterfly ("Vanessa tameamea"). The koa bug ("Coleotichus blackburniae") uses its rostrum to suck the contents out of koa seeds. Koa is vulnerable to infection by koa wilt. Acacia koa Acacia koa is a species of flowering tree in the pea family,