ICE3

Host Recognition in Insect Herbivores

Insect herbivores use blends of airborne volatile chemicals to recognize and to efficiently locate plants from a distance. Female and male insects use these signals to discriminate food sources, rendez-vous sites and larval host plants from the background chemical environment. Plants release hundreds of compounds, both host and non-host plants plants release partly the same compounds, and the volatile emissions of neigbouring plants intermix. In addition, the volatile release from individual plants is not constant, but changes during phenological development and in response to abiotic and biotic stress.

How does the insect make sense of this changeable and nosiy multidimensional signal? Deciphering the perceptual odour space and the mechanisms underlying host recognition is a current frontier in biology.

The host-finding and egg-laying behaviour of the cotton leafworm Spodoptera littoralis is to be studied in wind tunnel, olfactometer and servosphere bioassays. Chemical analysis of volatiles released from two hosts plants, alfalfa and cotton, will be done in parallel. Identification of key plant stimuli enables comparative studies of mating and oviposition signals, pheromones and plant volatiles, and their interaction. Related topics of interest are larval perception of plant stimuli, and the question whether larval experience modulates adult host choice.

Behavioural studies are integrated with the work done by colleagues within the IC-E3 initiative. This concerns signal processing of pheromones and plant volatiles, from peripheral olfactory neurons to higher brain centers, and an investigation of the plasticity and neuromodulation of the induced behavioural responses.

Funding
The Linnaeus initiative "Insect Chemical Ecology, Ethology and Evolution" IC-E3.

Personnel
Seniors: Marie Bengtsson, Peter Witzgall
Postdocs: Paul Becher, Nimal Punyasiri (partly financed by Phero.net)
PhDs: Ahmed Saveer, Zakir Ali

References
Bengtsson M, Jaastad G, Knudsen G, Kobro S, Bäckman A-C, Pettersson E, Witzgall P. (2006). Plant volatiles mediate attraction to host and non-host plant in apple fruit moth, Argyresthia conjugella. Entomol exp appl 118:77-85.

Knudsen GK, Bengtsson M, Kobro S, Jaastad G, Hofsvang T, Witzgall P. (2007). Discrepancy in laboratory and field attraction of apple fruit moth Argyresthia conjugella to host plant volatiles. Physiol Entomol. In press.

Tasin M, Bäckman A-C, Coracini M, Casado D, Ioriatti C, Witzgall P. (2007). Synergism and redundancy in a plant volatile blend attracting grapevine moth females. Phytochemistry 68:203-209.

Tasin M, Bäckman A-C, Bengtsson M, Ioriatti C, Witzgall P. (2006). Essential host plant cues in the grapevine moth. Naturwissenschaften 93:141-144.

Back to Projects >>>