16S of control and park25 flies and their feces
We prepared and analyzed DNA samples for 16S rRNA marker gene analysis as done previously28,30. Sequencing libraries were prepared by extracting DNA from a single fly using the Zymo Quick-DNA fecal/soil microbe kit (D6011, Zymo, Irvine, CA). Then, the V4 region of the extracted DNA was amplified and sequenced using a dual-barcoding method described by Kozich37, with the exception of substituting Accuprime PFX DNA polymerase reagents for Accuprime PFX Supermix. The Invitrogen SequalPrep Normalization kit was used to normalize samples into pools of 96 samples (in some cases, the samples were normalized as part of a pool with samples not published in this study). Then, fragments in the size range of 250-450 nucleotides were size-selected using a BluePippin (BYU DNA Sequencing Center). Finally, samples in this study were sequenced on partial lanes of a MiSeq using 500 cycle chemistry (paired-end 2 x 250, BioDesign Institute at Arizona State University)