On May 21 2008, Journal of Neuroscience published an online paper from ION entitled "Increased dopamine level enhances male-male courtship in Drosophila". This work was done by graduate students Tong Liu and colleagues, under the supervision of Dr. Aike Guo, and in collaboration with Dr. Jean-Fran？ois Ferveur in France.

Courtship behavior is fundamental to the propagation of animal species and their adaptations to changes in the environment. Male courtship in Drosophila is complex, consisting of a stereotypic set of behaviors, including orientation towards a female, tapping with its forelegs, following the female, singing courtship song, licking the female's genital, attempting copulation, and final copulation. While male flies generally court female flies, an intense male homosexual courtship behavior can be induced by gene mutation or ectopic gene expression. Dopamine, as an important neuromodulator, is involved in the regulation of many simple and complex behaviors. The role of dopamine in sexual behavior has been extensively studied in mammals. Some studies indicated that the dopaminergic system play a role in regulating the receptivity of female and sexual arouse of the male in fruit fly courtship behavior. This current study showed that elevation of dopamine level induced male-male courtship behavior in fruit flies. In this study, genetic, pharmacological, behavioral and surgical methods were used to show that male flies with increased dopamine level tend to have enhanced propensities to court other males, without affecting overall male heterosexual courtship, their attractiveness to other males, their short-term spontaneous locomotor activity, or their general olfactory/gustatory abilities. Furthermore, visual and chemosensory inputs played a positive role in this enhancement, indicating that the high intensity of male-male interactions shown by males with higher dopamine levels is related to their altered sensory perception of other males. These findings indicate that increased dopamine level is correlated with a more intense male-male courtship towards other mature males. Although, at this moment, it is still unknown that how high-level dopamine can induce male-male courtship behavior in fruit flies and whether these results can be generalized to other species, further dissections of fly male-male courtship may help us understand the fine mechanisms underlying sensory communication regulating inter- individual behaviors.