D3204: Does domestication matter? Comparing Drosophila suzukii oviposition and adult emergence between wild and cultivated blueberries

Spotted-wing drosophila (SWD), Drosophila suzukii, is a highly polyphagous and economically
significant pest of small fruits. SWD is a challenging pest because females have a serrated
ovipositor which allow them to lay eggs in the skin of many ripening fruits, like blueberries.
Wild blueberries that grow in non-crop habitats surrounding cultivated blueberry fields can
potentially serve as an alternate host to SWD. Because blueberries were first domesticated about
a century ago mainly for large fruit size, we hypothesized that cultivated blueberry fruits are
more susceptible to SWD than wild blueberry fruits. To test this, in June-July 2023, we collected
cultivated and wild blueberry fruits from bushes across four commercial blueberry farms in New
Jersey (USA); this state was the center of blueberry domestication (N = 40 wild and 40 cultivated
bushes). Fruits were taken to the lab and their size (volume) was measured. Following, we
exposed each fruit to gravid SWD. After 24 h of exposure, the number of eggs per fruit was
counted. Each infested fruit was incubated individually until adult emergence and the number of
emerged male and female flies was recorded. Results show that cultivated fruit were 3.4 times
bigger than wild fruit and got 1.8 times more SWD eggs. The number of eggs laid was positively
correlated with adult emergence but only for cultivated fruit, indicating a reduced capacity for
SWD offspring development in wild fruit. Findings from our study highlight the potential effects
of crop domestication on frugivorous pests.