Review Flavonoid–insect interactions: recent advances in our knowledge Monique S.J. Simmonds* Royal Botanic Gardens, Kew, Richmond, Surrey, TW9 3AB, UK Received 17 January 2003; received in revised form 27 March 2003 Dedicated to the memory of Professor Jeffrey B. Harborne Abstract Recent contributions to the role of phenolics, especially flavonoids, in different aspects of insect–plant interactions are reviewed, including data on the effects of rutin on the feeding behaviour of a range of noctuid larvae. # 2003 Elsevier Ltd. All rights reserved. Keywords: Quercetin; Rutin; Sequestered flavonoids; Anthocyanins; Tricin; Isoflavonoids; Feeding behaviour; Spodoptera; Heliothis; Helicoverpa 0031-9422/03/$ - see front matter # 2003 Elsevier Ltd. All rights reserved. doi:10.1016/S0031-9422(03)00293-0 Phytochemistry 64 (2003) 21–30 www.elsevier.com/locate/phytochem Contents 1. Introduction ............................................................................................................................................................................... 22 2. Phenolics in trees ........................................................................................................................................................................ 22 3. Sequestered flavonoids ............................................................................................................................................................... 23 4. Flavonoids on the leaf surface.................................................................................................................................................... 25 5. Behavioural responses to quercetin-derivatives .......................................................................................................................... 25 6. Anthocyanins.............................................................................................................................................................................. 27 7. Isoflavonoids .............................................................................................................................................................................. 27 8. Tricin derivatives ........................................................................................................................................................................ 28 9. Other flavonoids ......................................................................................................................................................................... 28 10. Conclusions ................................................................................................................................................................................ 28 Acknowledgements ............................................................................................................................................................................ 29 References ......................................................................................................................................................................................... 29 * Tel.: +44-208-332-5328; fax: +44-208-332-5340. E-mail address: m.simmonds@rbgkew.org.uk (M.S.J. Simmonds).