Contribution of neurons that express fruitless and Clock transcription factors to behavioral rhythms and courtship

Animals need to integrate information across neuronal networks that direct reproductive behaviors and circadian rhythms. The Drosophila master regulatory transcription factors that direct courtship and circadian rhythms are co-expressed. We find sex differences in the number of these <i>fruitless</i> (<i>fru</i>) and <i>Clock</i> (<i>Clk</i>)-expressing neurons (<i>fru</i> ∩ <i>Clk</i> neurons) regulated by male-specific Fru. We assign the <i>fru</i> ∩ <i>Clk</i> neurons to the electron microscopy connectome and to subtypes of clock neurons. We discover sex differences in <i>fru</i>-expressing neurons that are post-synaptic targets of <i>Clk</i>-expressing neurons. When <i>fru</i> ∩ <i>Clk</i> neurons are activated or silenced, we observe a male-specific shortening of period length. Activation of <i>fru</i> ∩ <i>Clk</i> neurons also changes the rate a courtship behavior is performed. We examine male courtship behavior over 24 h and find courtship activities peak at lights-on. These results reveal how neurons that subserve the two processes can impact behavioral outcomes in a sex-specific manner.