Yeast Species, Strains, and Growth Media Mediate Attraction of Drosophila suzukii (Diptera: Drosophilidae)

Abstract

Specific ecological interactions between insects and microbes have potential in the development of targeted pest monitoring or control techniques for the spotted wing drosophilid, <i>Drosophila suzukii</i> (Matsumura), an exotic invasive pest of soft fruit. To evaluate <i>D. suzukii</i> attraction to yeast species from preferred types of fruit, three yeasts were isolated from blackberry fruit and two yeasts from raspberry fruit and used to bait simple plastic bottle traps. <i>Saccharomyces cerevisiae</i> and <i>Hanseniaspora uvarum</i> were identified from blackberries, whereas a different <i>H. uvarum</i> strain was identified from raspberry. Yeast identification was based on sequence analysis of the D1/D2 domain of the large subunit 26S rRNA gene. Commercial baker's yeast (<i>S. cerevisiae</i>) was similar or more effective for the capture of <i>D. suzukii</i> males and females than yeasts isolated from blackberry or raspberry when grown in sucrose. However, when grown in corn syrup, a strain of <i>S. cerevisiae</i> from blackberry captured the highest number of females and a strain of <i>H. uvarum</i> isolated from raspberry captured high numbers of males and females. Species of <i>Candida</i>, <i>Hanseniaspora</i>, and <i>Pichia</i> from a laboratory yeast collection did not outperform baker's yeast in pairwise tests when grown in sucrose solution or yeast-peptone-dextrose medium. The raspberry strain of <i>H. uvarum</i> grown in corn syrup outperformed <i>S. cerevisiae</i> grown in sucrose, in terms of captures in baited traps under laboratory conditions. We conclude that yeast species, strain, and growth medium can have a marked influence on <i>D. suzukii</i> attraction to baited traps, a finding that could assist in the development of yeast-related monitoring or control techniques targeted at this pest.