Long-Distance Movement of Bactrocera dorsalis (Diptera: Tephritidae) in Puna, Hawaii: How far can they go?

Abstract

The oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), is considered a major economic threat in many regions worldwide, including the island of Hawaii in the Hawaiian archipelago. The need to control large populations over large areas helped initiate the USDA-ARS (United States Department of Agriculture–Agricultural Research Service) area-wide program. There is some discussion concerning the feasibility of eradication of the oriental fruit fly in areas on the island of Hawaii. An important aspect of population suppression is concerned with the ability of a species to move long distances. Suppression of an area may be futile if source populations outside of that area are capable of moving into and re-establishing populations within the suppression area. While most movement studies focus on the short-distance dispersal of flies from a single release point, this study aimed to explore the longer tails of the dispersal distribution suspected for many tephritids. Four releases of double-marked, sterile, laboratory-reared oriental fruit flies were completed. The releases took place at four different distances from an experimental fruit fly suppression zone within the Puna District on the island of Hawaii. Flies captured in methyl eugenol traps and protein bait traps were collected and examined for the mark. Many flies were recovered at unprecedented long distances (between 2–11.39 km) from the release point. Studies of this nature are notoriously difficult, as replication is not feasible and countless variables complicate procedures. However, we feel extremely fortunate to have collected data confirming results that, to our knowledge, have not been previously observed. These long-distance recaptures aid in understanding the long tails of spatial distribution of fly movement that have been suspected of this species, and will benefit consideration of dimensions for buffer zones that would be needed for the establishment of infestation-free or low-prevalence zones.