April 1, 2014
Different Scents Used To Attract Or Repel Insects
Flowering plants attract pollinating insects with scent from their flowers and bright colors. If they have become infested with herbivores like caterpillars, they attract beneficial insects like parasitic wasps with the help of scent signals from their leaves. The wasps then lay their eggs in the caterpillars and kill the parasites. Floral and foliar scents can, however, mutually reduce their attractiveness. That's why flowering plants face a dilemma: should they use their resources to attract pollinating insects and, by extension, for reproduction or should they invest in defence against herbivores? A Swiss-Italian research team headed by Florian Schiestl from the University of Zurich has now demonstrated that plants are able to adjust their scent bouquet to their needs at any given time and, in this way, to attract partner or useful insects in a more targeted manner.
The results illustrate important ecological interactions when a plant attracts partner insects. Schiestl is of the opinion that the new findings may be relevant for the organic cultivation of useful plants. "One could try to optimise the attraction of parasitic wasps with less fragrant varieties and the attraction of pollinators with more fragrant ones."
"Herbivory and floral signaling: phenotypic plasticity and trade-offs between reproduction and indirect defense" is published in New Phytologist. Authors are Florian P. Schiestl, Heather Kirk, Laurent Bigler, Salvatore Cozzolino, Gaylord A. Desurmont