Life History and Host Range of Hawaii’s Endangered Blackburn’s Sphinx Moth (Manduca blackburni Butler)

Abstract

Manduca blackburni, Blackburn’s sphinx moth (BSM), is a federally listed endangered species endemic to Hawaii. Originally found throughout the main Hawaiian Islands, it has disappeared from most of its range, and is now restricted to small localized populations on the islands of Maui, Hawaii, and Kahoolawe. While the adult and last instar larvae are described, the early life stages of BSM have not previously been figured. Further, the host range of the moth is not known, though it is suspected to feed on a wide range of solanaceous plants. Eggs and larvae of M. blackburni were collected from East Maui and reared on both native and invasive solanaceous hosts to examine host specificity in the context of habitat restoration and the importance of new invasive hosts to BSM populations. Larvae developed on several native and introduced solanaceous species. We present the first published descriptions of the early larval instars, and confirmation of several suitable hosts, both native and exotic. Low rates of parasitism in our field collections suggest that, at least in some areas, parasitoids may not severely impact populations, and these areas could be important refugia for BSM. Rearing efforts confirm that at least two species of native Solanum, in addition to Nothocestrum, can be used in site restoration as potential host plants.