Previous studies have shown that male courtship performance may be weakened under conditions wherein visual cues are absent 7, 9, 10. Sensory cues play key roles in initiating and maintaining courtship behaviour in Drosophila 7, 8.
Together, these findings indicate that DA plays an essential role in regulating Drosophila sex responses, including those involved in male-male homosexual behaviour. In addition, DAergic neurons have been associated with alcohol-induced male-male courtship behaviour 6. Interestingly, a decrease in DA levels is observed when males experience enhanced attractiveness toward other males during inter-male courtship 5. A previous study has also shown that increasing DA levels in most dopaminergic (DAergic) cells may induce intense inter-male courtship in Drosophila 4. On the other hand, down-regulation of DA levels in PPL2ab neurons significantly decreases the sustainment of courtship 2. Moreover, an increase in DA levels in a subset of PPL2ab neurons is sufficient to enhance courtship sustainment in both young and aged males 2. It has been determined that dopamine (DA) modulates the intensity of male courtship in Drosophila 1, 2, and that DA is associated with the regulation of female sexual receptivity 3. Our study provides insight for subsequent studies focusing on sexual circuit modulation by PPL2ab neurons.Ĭourtship is an instinctive behaviour whereby animals utilize their sensory perception to recognize a conspecific and suitable partner. This is interesting evidence that courtship responses in male individuals are controlled by PPL2ab neurons in the CNS. Moreover, the observed male-male courtship is triggered primarily by target motion, yet chemical cues can replace visual input under dark conditions. Intriguingly, the DA-synthesizing abilities of these neurons appear to affect both the courting activities displayed by male flies and the sex appeal of male flies for other male flies. Here we report that changes in the ability of the PPL2ab in the central nervous system (CNS) to produce DA strongly impact male-male courtship in D. Previous studies have revealed that alterations in DA synthesis in dopaminergic neurons can induce male-male courtship behaviour, while increasing DA levels in the protocerebral posteriolateral dopaminergic cluster neuron 2ab (PPL2ab) may enhance the intensity of male courtship sustainment in Drosophila. Dopamine (DA) is essential for both physiological and behavioural responses, including the regulation of sexuality.
The neurology of male sexuality has been poorly studied owing to difficulties in studying brain circuitry in humans.