African fig fly: Does a secondary invader have the potential to become a primary pest?

The African fig fly (AFF) (Zaprionus indianus) is an understudied invasive fly that is a primary pest of figs and a secondary pest of other small fruit crops. It invaded Florida in 2005, but it wasn’t until the spread of another invasive drosophilid, spotted wing drosophila (SWD) (Drosophila suzukii), that it was found throughout the country. Current hypotheses suggest that SWD facilitates the spread of the AFF by damaging fruit, providing a suitable niche for AFF to lay eggs. Previous work has demonstrated that the incision from the SWD ovipositor allows AFF to infest fruits with thicker skin (e.g., grapes and persimmons). However, for a majority of crops that are potential hosts for AFF, the extent to which AFF can oviposit into fruit on its own or requires damage from SWD (or other sources) has not been assessed. Here, we tested the ability of AFF to lay eggs in and develop in three different economically important berry crops (blackberry, raspberry, and blueberry) at different stages of ripeness and with levels and sources of damage. We found that for blackberry and raspberry, AFF can lay eggs and fully develop in fruit without any external damage. These results suggest that AFF could be a primary pest of some berries, and that its relationship with SWD is more complicated than originally thought.