Chemical Ecology Group

Semiochemicals mediating interactions with plant feeding (phytophagous) insects

Insect-plant interactions is an area of long-standing interest in the chemical ecology group. We hope that by improving our understanding of them we can develop sustainable and novel approaches to crop protection that provide alternative or supplementary approaches to use the use of pesticides. The multidisciplinary work carried out by our group integrates studies of insect physiology and plant chemistry to provide an understanding of how insects interact with plants. We have shown that the molecular basis of host-plant recognition by phytophagous insects involves highly specialised olfactory cell types, keyed to the detection of individual compounds.

Rhopalosiphum padi and Sitodiplosis mosellana

Spatio-temporal resolution of an olfactory signal

Recently we reviewed the use of plant volatiles for host location and have shown that the main mechanism operating here is the use of specific ratios of commonly occurring plant volatiles rather than taxonomically characteristic compounds (Bruce, Wadhams & Woodcock, 2005). The diagram on the right shows how fine spatio-temporal resolution of the olfactory signal by the insect can be used to detect whether a particular combination of volatiles was emitted from the same source or not.

As well as identifying attractant semiochemicals from host plants we have shown that there is active avoidance of non-host volatiles and volatiles released from damaged or insect-infested plants. Plants in an inappropriate physiological state may also be repellent. Winter host volatiles of host alternating aphids are often repellent to the summer morphs.

The alarm pheromone signals of crop pests can be used to disrupt colonisation of crops by the pests and insect sex pheromones are used in monitoring traps for monitoring populations of crop pests.

Publications

Bruce, T.J.A., Hooper, A.M., Ireland, L., Jones, O.T., Martin, J.L., Smart, L.E., Oakley, J., Wadhams, L.J. Development of a pheromone trap monitoring system for orange wheat blossom midge, Sitodiplosis mosellana, in the UK  (2007) Pest Manag. Sci., 63: 49-56.

Pope, T.W., Campbell, C.A.M., Hardie, J., Pickett, J.A., Wadhams, L.J. Interactions between host-plant volatiles and the sex pheromones of the bird cherry-oat aphid, Rhopalosiphum padi and the damson-hop aphid, Phorodon humuli (2007) J. Chem. Ecol., 33: 157-165.

Zhu, J., Zhang, A., Park, K.-C., Baker, T., Lang, B., Jurenka, R., Obrycki, J.J., Graves, W.R., Pickett, J.A., Smiley, D., Chauhan, K.R., Klun, J.A. Sex pheromone of the soybean aphid, Aphis glycines Matsumura, and its potential use in semiochemical-based control (2006) Environ. Entomol., 35: 249-257.

Couty, A., Van Emden, H., Perry, J.N., Hardie, J., Pickett, J.A., Wadhams, L.J. The roles of olfaction and vision in host-plant finding by the diamondback moth, Plutella xylostella (2006) Physiol. Entomol., 31: 134-145.

Bruce, T.J.A., Wadhams, L.J., Woodcock, C.M. Insect host location: A volatile situation (2005) Trends in Plant Science, 10: 269-274.

Bruce, T.J.A., Birkett, M.A., Blande, J., Hooper, A.M., Martin, J.L., Khambay, B., Prosser, I., Smart, L.E., Wadhams, L.J. Response of economically important aphids to components of Hemizygia petiolata essential oil (2005) Pest Manag. Sci., 61: 1115-1121.

Birkett, M.A., Bruce, T.J.A., Martin, J.L., Smart, L.E., Oakley, J., Wadhams, L.J. Responses of female orange wheat blossom midge, Sitodiplosis mosellana, to wheat panicle volatiles (2004) J. Chem. Ecol., 30: 1319-1328.

Campbell, C.A.M., Cook, F.J., Pickett, J.A., Pope, T.W., Wadhams, L.J., Woodcock, C.M. Responses of the aphids Phorodon humuli and Rhopalosiphum padi to sex pheromone stereochemistry in the field  (2003) J. Chem. Ecol., 29: 2225-2234.

Jones, G., Campbell, C.A.M., Hardie, J., Pickett, J.A., Pye, B.J., Wadhams, L.J. Integrated management of two-spotted spider mite Tetranychus urticae on hops using hop β-acids as an antifeedant together with the predatory mite Phytoseiulus persimilis (2003) Biocontrol Sci. Technol., 13: 241-252.

Shah, P.A., Pickett, J.A., Vandenberg, J.D. Responses of russian wheat aphid (Homoptera: Aphididae) to aphid alarm pheromone (1999) Environ. Entomol., 28: 983-985.

Agelopoulos, N., Birkett, M.A., Hick, A.J., Hooper, A.M., Pickett, J.A., Pow, E.M., Smart, L.E., Smiley, D.W.M., Wadhams, L.J., Woodcock, C.M. Exploiting semiochemicals in insect control (1999) Pesticide Sci., 55: 225-235.

Smart, L.E., Blight, M.M., Pickett, J.A., Pye, B.J. Development of field strategies incorporating semiochemicals for the control of the pea and bean weevil, Sitona lineatus L. (1994) Crop Prot., 13: 127-135.

Pickett, J.A., Wadhams, L.J., Woodcock, C.M., Hardie, J. The chemical ecology of aphids  
(1992) Annu. Rev. Entomol. 37: 67-90.

Griffiths, D.C. Laboratory evaluation of pest management strategies combining antifeedants with insect growth regulator insecticides (1991) Crop Prot., 10:145-151.