It seems that being a great looking female is just not enough – for her to be attractive, she has to “smell” and “taste” like one too.
When it sees a female fruitfly, a male fruitfly tries to attract her, but when it encounters a male fruitfly, he will fight – but why? A new research by scientists at Harvard Medical School tried to unravel the mystery behind these sex-specific responses in fruitflies.
The team focused on a particular gene called transformer, which is active in females but not in males. Through blocking transformer expression in a variety of different tissues in females, the researchers could specifically alter the “femaleness” or “maleness” of the pheromones, which in turn altered the patterns of aggressive behaviour encoded in the fly’s brain.
When they changed pheromone profiles so that females “tasted” like males, the researchers found that males would attack them – showing that pheromonal cues alone could label another fly as a competitor.
But the researchers were surprised to discover that males also attacked “aggressive females”—flies that still looked, smelled and tasted female but had been genetically altered to display male-like patterns of behaviour.
When the researchers turned the tables by triggering the expression of transformer in males so as to feminize both the pheromonal and behavioural profiles, males began to court them.
“Future studies will aim at unravelling the neuronal circuitry that governs this type of decision-making behaviour, as such decisions are essential for survival,” said Edward Kravitz, the George Packer Berry Professor of Neurobiology at Harvard Medical School.
“This study addresses a classic question in animal behaviour: What motivates an individual to do X rather than Y, or vice versa,” said Laurie Tompkins at the National Institutes of Health.
“Because the general principles of how behaviours are controlled are conserved among species, Kravitz”s conclusions about how flies make simple choices may illuminate how humans and other animals make more complex decisions.”
The research is published in the November 23 issue of PLoS Biology. (ANI)
Fernández MdlP, Chan Y-B, Yew JY, Billeter J-C, Dreisewerd K, et al. (2010) Pheromonal and Behavioral Cues Trigger Male-to-Female Aggression in Drosophila. PLoS Biol 8(11): e1000541. doi:10.1371/journal.pbio.1000541