Environmental ethanol as a reproductive constraint on spotted wing drosophila and implications for control in Rubus and other fruits

Spotted wing drosophila (SWD), Drosophila suzukii Mat. (Diptera: Drosophilidae), is a recent fruit pest of the Americas whose destructiveness stems from its subcutaneous insertion of eggs into cultivated berries via the female’s prominent double bladed and serrated ovipositor.
Atypical of most other Drosophila, D. suzukii adults and larvae are non-saprophagous and therefore do not have to contend with fermented substrates containing toxic levels of ethanol.
Here, we test whether D. suzukii can safely ingest environmental ethanol, which could have important implications for host selection, reproductive potential, chemical control, and the need for crop sanitation.
We designed a series of laboratory experiments to measure critical life history traits of D. suzukii feeding on Rubus and Vaccinium in an ethanolic environment.
These life history traits included adult survivorship, sex ratio, and optimal reproductive output. D. suzukii were quite sensitive to ethanol when compared with D. melanogaster. Ethanol concentrations >2.5% reduced both pupal and adult production of SWD and increased adult mortality.
Male SWD were 2 to 3 times more sensitive to ethanol than were females with sex ratios increasingly favoring females at higher concentrations.
These results suggest that little if any overlap between the niches of SWD and native D. melanogaster will enable these species to coexist.
In fact, SWD may create more habitat for wild Drosophila at the expense of both wild and cultivated fruit species.

XI International Rubus and Ribes Symposium

B.J. Sampson, E.T. Stafne, D.A. Marshall-Shaw, S.J. Stringer, T. Mallette, C.T. Werle, D. Larson

spotted wing drosophila, Drosophila suzukii, Drosophila melanogaster, ethanol, intolerance, niche breadth, ecotoxicology, IPM

https://doi.org/10.17660/ActaHortic.2016.1133.64