Flies pre-programmed for fruit, reported by ABC News in Science, 24 April 2007. The Tahitian Noni shrub has a fruit that smells so bad it has been nicknamed “vomit fruit”. The fruit produces both hexanoic and octanoic acids, which not only puts people off, but repels most insects. However, one species of fruit fly, named Drosophila sechellia, is attracted to the fruit, where it feeds and lays its eggs. Japanese scientists have studied the genes that determine the fly’s sense of smell and found two genes that are different to corresponding genes in other fruit flies. To test the theory that these genes made the fruit attractive to such flies, they replaced the olfactory genes in a different species of fly with those D. sechellia. The genetically modified flies were attracted to the fruit. Takashi Matsuo, one of the scientists involved in the study commented, “We found, for the first time, the genes that determine the insects’ preference [for] their host plants.”


Editorial Comment: These findings are a challenge to the theory that insects and plants co-evolved, particularly when we have just proved that insects will be attracted to whatever smell we have creatively implanted a smell gene for. Shades of designer gene creation don’t you think? (Ref. ecology, genetics, olfaction)

Evidence News 13 June 2007