Crickets Falling Silent It’s not unusual to see evolutionary change in response to threats to an animal. The crickets on the islands of Kauai and Oahu, in the Hawaiian archipelago, have begun to fall silent. Normally, crickets rub their wings together to produce their distinctive ‘chirping’ noise. This is used to attract mates, but it also attracts predatory flies. These flies track down the chirping crickets and use them as hosts for their larvae, leaving the unfortunate cricket to be eaten alive by the growing maggots. In order to avoid this gruesome fate, some crickets have developed modified wings. Known as “flatwing” males, these crickets are mute. As such, they can effectively hide from the threat of the flies. The cost of this, though, is that they can no longer chirp to attract females themselves. The innovative solution to this is for the “flatwing” males to simply hang around those males that are still capable of chirping. The flatwings will then attempt to intercept those females that are drawn to the song. This adaptation has proven wildly successful, with over 90% of the crickets on Kauai now no longer capable of chirping. This drastic change began appearing in 2003, the adaptations occurring as a response to the predatory flies arrival on the island from the mainland of the United States. When the same adaptation was found in crickets two years later on the island of Oahu, some 100km from Kauai, it was assumed that the Kauai crickets had hitchhiked there with a little help from humans. Dr. Nathan Bailey, a member of the group that have led the most recent study on the phenomenon, noted that "An egg laid by a female in some soil could hitch-hike on someone's boot". However, a recent study throws doubt on that idea. The team noticed that the wing shapes of the flatwing crickets on the two islands were different, hinting that something unusual was happening. When they ran genetic analysis, they discovered that the flatwing mutation had, apparently, developed twice. The flatwing mutation was confirmed to be due to a mutation on a single gene of the X chromosome, and a multitude of other genetic markers were used to demonstrate the two distinct groups. It was this that finally convinced the team that the mutation had managed to develop in two isolated cases. "Up until my post-doc Sonia showed me the diagram of nearly non-overlapping genetic markers from each island...” Dr. Bailey explained, “I was unconvinced either way about what we were dealing with". This is not the first time the same trait has appeared convergently in two different groups. The projectile tongue of certain salamanders have evolved in isolated populations on more than one occasion. This particular case, however, is notable for the rapidity with which the adaptation occurred. In Dr. Bailey’s own words, "This is an exciting opportunity to detect genomic evolution in real time in a wild system, which has usually been quite a challenge, owing to the long timescales over which evolution acts." - Dale Read More - http://www.bbc.co.uk/news/science-environment-27592656 http://www.cell.com/current-biology/abstract/S0960-9822%2814%2900524-7 http://www.sciencedaily.com/articles/c/convergent_evolution.htm Image Credit – http://bishopmuseum.org/