|Title||The spatial range of parasitoid recruitment: do more attractive cabbage varieties attract parasitoids from a larger distance?|
|Author(s)||Aartsma, Y.S.Y.; Leroy, B.; Werf, W. van der; Dicke, M.; Poelman, E.H.; Bianchi, F.J.J.A.|
|Event||4th International Entomophagous Insects Conference, Torre del Mar, Malaga, 2015-10-04/2015-10-09|
Farming Systems Ecology
Crop and Weed Ecology
Laboratory of Entomology
|Publication type||Abstract in scientific journal or proceedings|
|Abstract||Plants under attack by insect herbivores can produce volatile organic compounds
which are known to attract parasitoids searching for hosts. While these interactions have been well-studied under laboratory or small scale field conditions, little is known about the spatial scale to which these interactions extend. Since volatile blends can differ between and within plant species, parasitoids search for hosts in a chemically complex landscape. Selection of
crop varieties with elevated levels of volatile emission has been proposed as an component of more sustainable pest control. However, to predict whether these more attractive varieties are successful on field scale, communication between tri-trophic levels via plant volatiles has to be studied in a landscape context.
We investigated the host finding success of the parasitoid wasp Cotesia glomerata in a series of large scale experiments. Parasitoids were released in an arrangement of white cabbage plants (Brassica oleracea var. alba L.) and the parasitism rate of experimentally
inoculated Pieris brassicae larvae on cabbage plants was assessed. Experimental set-ups differed between (1) two white cabbage cultivars with dissimilar attractiveness to the wasps, and (2) distance between cabbage plants. Additionally, in a semi-field set-up, we studied more detailed wasp behavior when plants were at different distances from release point. Parasitism of experimentally inoculated Pieris brassicae was affected differently by a
combination of plant spacing and plant cultivar used. The highly attractive cultivar recruited wasps equally at both distances, while the less attractive cultivar showed a large decrease in parasitism incidence when spacing was increased. Results of this study indicate that distance between host-infested plants matters for
parasitoid host searching success and that emission of herbivore induced plant volatiles by different cultivars affects recruitment of parasitoids.