Effects of laboratory rearing conditions on the predatory mite Neoseiulus womersleyi (Schicha) (Acari: Phytoseiidae):: II.: Olfactory response

The olfactory response of Neosehilus womersleyi (Schicha) (Acari: Phytoseiidae) to preyinfested plant volatiles is known to exhibit plasticity according to the rearing conditions. We investigated whether genetic changes in the olfactory response of N. womersleyi could be caused by laboratory rearing. We reared five geographical populations of N. womersleyi under two conditions for 12 months: an artificial arena in which N. womersleyi significantly preferred prey-infested plant volatiles, and a detached-leaf culture in which N. womersleyi showed an equal response to the volatiles produced by prey-infested and intact plants. By offering the populations reared in the two conditions a choice between the volatiles of prey-infested and intact plants, we demonstrated that the olfactory response did not change as a function of the laboratory rearing method. These results suggested that the magnitude of the selection pressure under the two rearing conditions was too small to cause a detectable change in olfactory response within 12 months.