Male flies were harvested at indicated time point and heads were removed by freezing the flies in liquid nitrogen followed by five rounds of vortexing and freezing. Purified nuclei were obtained using an immunoenrichment protocol (Jauregui-Lozano, 2021) Omni-ATAC libraries were made with Illumina Tagment DNA TDE1 Enzyme and Buffer kit and "IDT for Illumina" Nextera DNA UD Indexes Set A