Asexuality in Drosophila juvenile males is organizational and independent of juvenile hormone

Abstract

Sexuality is generally prevented in newborns and arises with organizational rewiring of neural circuitry and optimization of fitness for reproduction competition. Recent studies reported that sex circuitry in Drosophila melanogaster is developed in juvenile males but functionally inhibited by juvenile hormone (JH). Here, we find that the fly sex circuitry, mainly expressing the male‐specific fruitless (fruM) and/or doublesex (dsx), is organizationally undeveloped and functionally inoperative in juvenile males. Artificially activating all fruM neurons induces substantial courtship in solitary adult males but not in juvenile males. Synaptic transmissions between major courtship regulators and all dsx neurons are strong in adult males but either weak or undetectable in juvenile males. We further find that JH does not inhibit male courtship in juvenile males but instead promotes courtship robustness in adult males. Our results indicate that the transition to sexuality from juvenile to adult flies requires organizational rewiring of neural circuitry.

Where does mating drive come from?

“…Ji et al (2023) perform these same stimulation experiments, also finding that juvenile males have the latent capacity to perform courtship behaviors. But Ji et al remain proponents of the organizational hypothesis, arguing that male‐like sexual behaviors have been observed in female mice and flies undergoing optogenetic stimulation, so an artificial evocation of mating behavior may be misleading.…”