Mind the Wound!—Fruit Injury Ranks Higher than, and Interacts with, Heterospecific Cues for <i>Drosophila suzukii</i> Oviposition

• Main Authors: Renate Kienzle, Marko Rohlfs
• Format: Article
• Language: English
• Published: MDPI AG 2021-05-01
• Series: Insects
• Subjects: host selection; host cues; preference hierarchy; avoidance
• Online Access: https://www.mdpi.com/2075-4450/12/5/424

<i>Drosophila suzukii</i> is a globally distributed insect that infests many economically important fruit varieties by ovipositing into ripening fruits. The mechanisms underlying host selection, in particular the fly’s preference for fresh, intact, and competitor-free fruits, are only partially understood. We hypothesize that <i>D. suzukii</i> females use cues of different fruit properties to rank potential host fruits in a hierarchical manner. We created four naturally occurring fruit (blueberries) categories: (1) intact; (2) artificially wounded; (3) wounded + containing eggs of different <i>Drosophila</i> species; and (4) intact + exposed to <i>D. melanogaster</i>. Individual <i>D. suzukii</i> females were offered several fruits in different two-way combinations of the fruit categories. Females showed a robust oviposition preference for intact vs. wounded + infested fruits, which was even stronger compared to the intact–wounded combination. Females preferred ovipositing into intact vs. intact + exposed blueberries; however, they preferred intact + exposed over wounded blueberries. This implies a hierarchical host preference in <i>D. suzukii</i>, which is determined by heterospecific cues (possibly fecal matter components) and an unknown “wounding factor” of fruits.