Pheromone Communication inAnastrepha obliqua(Diptera: Tephritidae): A Comparison of the Volatiles and Salivary Gland Extracts of Two Wild Populations

Abstract

The West Indian fruit fly Anastrepha obliqua Macquart (Diptera: Tephritidae) is one of the major pests on mango (Mangifera indica L.; Sapindales: Anacardiaceae) and starfruit (Averrhoa carambola L.; Oxalidales: Oxalidaceae) crop plantations in Brazil. Pheromone communication inter alia plays an important role in fruit-fly courtship behavior. In order to highlight the site of pheromone synthesis, we identified and compared the volatiles from the aeration extracts of calling males with the volatiles produced by their salivary glands in 2 wild populations of A. obliqua collected from mangoes and starfruits. In addition, we performed a series of bioassays to compare the biological significance of both extracts. In total, 36 volatile compounds were identified, with 8 of them being shared by the 2 populations and the 2 extract types. Linalool and α-copaene were exclusively found in the aeration extract while ethyl heptanoate, methyl octanoate, and 1-nonanol were detected only in the salivary-gland extracts. The chemical profiles of the volatiles from the aeration extracts and from the salivary-gland extracts differed significantly between the 2 populations as well as the chemical profiles of both extracts within each population. The quantities of the 8 shared compounds generated a variability of more than 60% in the mango population and 80% in the starfruit population. The similarities observed between the chemical profiles of the aeration extracts and the salivary-gland extracts suggest that the latter could be the storage site and probably also the production site of some pheromone components in this fruit-fly species. This hypothesis is supported by the comparable biological activities of both extracts in terms of their attractiveness for conspecific females.