Feeding history affects the response of the predatory mite Typhlodromus kerkirae (Acari: Phytoseiidae) to volatiles of plants infested with spider mites Dimitris S. Koveos* and George D. Broufas Laboratory of Applied Zoology and Parasitology, Aristotelian University of Thessaloniki, 540 06 Thessaloniki, Greece (Received 19 November 1997; accepted 9 October 1998) ABSTRACT The response of adult females of the predatory mite Typhlodromus kerkirae (Acari: Phytoseiidae) to volatiles emitted from bean leaves infested with Tetranychus urticae (Acari: Tetranychidae) or from leaves of Oxalis corniculata infested with Petrobia harti (Acari: Tetranychidae) was studied in the laboratory using a Y-tube olfactometer. Typhlodromus kerkirae females reared from larvae through to adults on T. urticae and pollen of Vicia faba responded to volatiles of bean leaves infested with T. urticae , either when they had a choice between infested and non-infested bean leaves or between bean leaves infested with T. urticae and O. corniculata leaves infested with P. harti . However, they did not respond when they had been reared only on the carotenoid- deficient pollen of V. faba. Female T. kerkirae that had been reared from larva to the tenth day of adult life on T. urticae and subsequently fed for 1 week on V. faba pollen did not respond to volatiles of bean leaves infested with T. urticae . In contrast, those that had been reared on V. faba pollen to the tenth day of adult life and subsequently fed for 1 week on T. urticae responded to volatiles of infested bean leaves. Exp Appl Acarol 23: 429–436 © 1999 Kluwer Academic Publishers Key words: Typhlodromus kerkirae , olfactory responses, olfactometer, plant volatiles, spider mites. INTRODUCTION Predatory mites of the Phytoseiidae family feed on phytophagous mites, mainly of the Tetranychidae family. Certain species of this family such as Phytoseiulus persimilis and Amblyseius potentillae respond to volatiles emitted from plants infested with their prey and distinguish them from volatiles emitted from non- infested conspecifics (cf. Sabelis and Dicke, 1985; Dicke and Sabelis, 1988; Dicke, 1995; Koveos et al ., 1995). These allelochemical volatile substances are produced * To whom correspondence should be addressed at: Tel: +30-31-998845; Fax: +30-31-998853; e-mail: kovoes@agro.auth.gr Experimental & Applied Acarology , 23 (1999) 429–436 0168–8162 © 1999 Kluwer Academic Publishers