Sitophilus zeamais - Induced rice grain volatiles: Attractiveness towards the generalist parasitoid wasp,Theocolax elegans

One of the most damaging insect pests to stored grain is the maize weevil,sitophilus zeamais. current control methods are the use of fumigants and residual chemical insecticides and not ecologically friendly,leading to the development of new strategies based on its natural enemies. in this study,we evaluated the ability of theocolax elegans to discriminate s. zeamais - infested rice grains versus non-infested rice grains. we subsequently identified the active chemicals in the saliva of the maize weevil that elicit the production of rice grain volatiles. behavioral assays were conducted in a multiple-choice olfactometer. our results demonstrated that the experienced t. elegans females were apparently attracted by the odors released from rice grains induced by the saliva of the s. zeamais larvae. moreover,the active chemicals in the saliva of s. zeamais larvae that elicit the production of rice volatiles were investigated. results showed that artificially damaged grains do not emit large amounts of volatiles that attract the experienced parasitoid females emitted by the s. zeamais larvae damaged grains. further experiments revealed the experienced t. elegans females were apparently attracted by the odors released from rice induced by the saliva of the s. zeamais larvae. moreover,we compared the responses of female parasitoids to odors released from rice induced by protein substances of saliva and non-protein substances. further experiments revealed that volatiles attracting parasitoid t. elegans are possibly induced by some protein substances from s. zeamais larvae saliva. copyright 2016 zoological society of pakistan.