For past 100 years, a lot of work had been carried out on the overt courtship behaviours that male flies direct toward females. But in the end, it is up to the female fly to decide whether to reject the male or copulate with him.

The question remains as what drives the female to make this decision?

In a paper published in Neuron, researchers report that “they have identified two small groups of neurons in the female brain that function to modulate whether she will mate or not with a male based on his distinct pheromones and courtship song.”

In the latest work came up in the journal Current Biology. Dr Leslie Vosshall of The Rockefeller University in New York City and her team discovered a small group of neurons in the abdominal nerve cord and reproductive tract known as Abdominal-B neurons. These are required by the female “to pause her movement and interact with a courting male. When the neurons are inactivated, the female ignores the male and keeps moving, but when the neurons are activated, the female spontaneously pauses. "Pausing to interact with a male, rather than avoiding him, is a crucial step in any female's behavior leading to copulation.”

In another work that appeared in Neuron, scientists studied the effect of a small protein known as sex peptide. It gets transferred along with sperm from males to females and is detected by sensory neurons in the uterus. Sex peptide alters the female's behaviour in a way so that she turns reluctant to mate again for about 10 days.

"Thanks to our work, we think the sex peptide signal goes to a region of the fly's brain that is the homolog of the hypothalamus, which has been know for many years to be central in controlling sexual receptivity in vertebrates," explained co-lead author Dr Mark Palfreyman of the Research Institute of Molecular Pathology in Vienna, Austria.

Every researcher associated with these findings strongly hope that further investigation will help them to have a better and clearer understanding of sexual receptivity in vertebrates.