Assemblages of fruit flies (Diptera: Tephritidae) along an elevational gradient in the rainforests of Papua New Guinea

Abstract Papua New Guinea (PNG) has the greatest diversity of dacine fruit fly species (Diptera: Tephritidae: Dacinae) in the world, many of which are significant agricultural pests. Although their taxonomy is relatively well known, there is limited research on their geographical and elevational distribution. We undertook a survey of PNG's fruit fly fauna along a complete elevational gradient on Mt Wilhelm (175–3700 m a.s.l.) to determine the elevational species distribution and turnover of fruit fly communities. Fruit flies were sampled using a selection of male parapheromone lures, including Zingerone, a new and promising male attractant. In total, we collected 10 700 fruit flies representing 77 species. The total abundance and species richness of fruit flies decreased with increasing elevation. Species richness was similarly high at 175 and 200 m a.s.l. (30 and 27 species) and at 700 and 1200 m a.s.l. (16 and 20 species, respectively) but dropped suddenly to only two species at 1700 m a.s.l. and to zero at all four sites above this elevation. There were no flies attracted exclusively to Zingerone. One species (Bactrocera recurrens) exhibited dramatic, temporal changes in abundance during the study period. Fruit fly assemblages were significantly influenced by both the lure type and elevation. Similarity of fruit fly communities decayed linearly with increasing elevational distance. We concluded that the upper limit of fruit fly distribution in PNG occurs between 1700 and 2200 m a.s.l. and the centre of diversity occurs between 0 and 700 m a.s.l