Seminar announcement 16. Apr 2014
Dr. Johannes Stökl
Pheromone evolution in insects: Lessons learnt from Leptopilina, a parasitoid of Drosophila
The evolution of chemical communication and the origin of pheromones are among the most challenging issues in chemical ecology. Current theory predicts that chemical communication can arise from compounds primarily evolved for non-communicative purposes but experimental evidence for this hypothesis is scarce. The parasitic wasp Leptopilina heterotoma gives an outstanding example for the evolution of a non-informative compound into a cue and a true signal. The wasp does use its defensive compound (‑)‑iridomyrmecin in two communicative functions: (-)-iridomyrmecin is used as a semiochemical cue to avoid interference with con- and heterospecific females and as main component of a species-specific sex pheromone. While competition avoidance is mediated by (-)-iridomyrmecin alone, several minor compounds are necessary for mate attraction and recognition. The chemical ecology of Leptopilina wasps provides novel insights into the evolution of insect pheromones by demonstrating the increase in specificity in both the sender and the receiver during the putative evolution of a defensive compound into a competition avoidance cue and sex pheromone.