Ambrosia Beetle (Coleoptera: Curculionidae) Communities and Frass Production in 'Ōhi'a (Myrtales: Myrtaceae) Infected With Ceratocystis (Microascales: Ceratocystidaceae) Fungi Responsible for Rapid 'Ōhi'a Death.

Rapid 'Ōhi'a Death (ROD) is a deadly disease that is threatening the native Hawaiian keystone tree species, 'ōhi'a lehua (Metrosideros polymorpha Gaudich). Ambrosia beetles (Curculionidae: Scolytinae) and their frass are hypothesized to play a major role in the spread of ROD, although their ecological niches and frass production within trees and across the landscape are not well understood. We characterized the beetle communities and associated frass production from bolts (tree stem sections) representative of entire individual 'ōhi'a trees from multiple locations across Hawai'i Island by rearing beetles and testing their frass for viable ROD-causing fungi.

Invasive rat control is an efficient, yet insufficient, method for recovery of the critically endangered Hawaiian plant hau kuahiwi (Hibiscadelphus giffardianus).

Biological invasions of rodents and other species have been especially problematic on tropical islands. Invasive Rattus rattus consumption of Hibiscadelphus giffardianus (Malvaceae; common Hawaiian name hau kuahiwi) fruit and seeds has been hypothesized to be the most-limiting factor inhibiting the critically endangered tree, but this has not been experimentally tested, and little is known about other factors affecting seed dispersal, germination, and seedling establishment. Thus, we do not know if rat removal is sufficient to increase hau kuahiwi recruitment.