Love Chemical for Species Survival

David - My last paper this month ties into the Valentine's day themes of love and sex with some findings from a collaborative paper from German and American researchers about the evolution of sex pheromones, the chemicals released by organisms wanting to attract a mate. Now while the effectiveness of human pheromones has long been debated by scientists, the value of pheromones in other animals is clear. Males release chemicals that specifically attract females of the appropriate species. This signal attracts coupling between compatible animals.

Hannah - A fascinating system for attraction, but how did this system evolve to produce coupling between specific species?

David - That is the exact question that the authors of this paper, published online in Nature this month, aimed to work out. They studied the pheromones produced by members of the parasitic wasp genus Nasonia. What they found was that the Nasonia vitripennis wasp produces a novel pheromone, different from other pheromones produced by other species.

Hannah - So this wasp species produces a pheromone different from other species. What did the researchers do with this information?

David - They were able to show that the new pheromone was intitially ignored by potential mates if it was presented alone. If however the new pheromone was mixed with a blend of the old pheromones, the female wasps became responsive to the new signal. They used wasps from a sister species, Nasonia giraulti, to show that this effect was specific to the Nasonia vitripennis wasps.

Hannah - So if the pheromone was ignored by these wasps, how did it eventually become detected and why is that important, in evolutionary terms?

David - Well the data indicate that while a new pheromone is initially ignored by its intended recipient, evolutionary mechanisms will eventually develop a new olfactory receptor for the female wasps. This gives the new wasps a way of detecting their potential mates in a more specific way, making it more likely that they will mate with the right type of wasp.

Hannah - Ever evolving love, beautiful!