Eur. J. Entomol. 110(2): 253–262, 2013 http://www.eje.cz/pdfs/110/2/253 ISSN 1210-5759 (print), 1802-8829 (online) Effects on lepidopteran herbivores of feeding on leaves of transgenic birch (Betula pendula) expressing the sugar beet chitinase IV gene LIISA VIHERVUORI, PÄIVI LYYTIKÄINEN-SAARENMAA, JINRONG LU and HANNA-LEENA PASONEN Department of Forest Sciences, University of Helsinki, FI-00014 Helsinki, Finland; e-mails:
[email protected];
[email protected];
[email protected];
[email protected] Key words. Lepidoptera, Lymantriidae, Orgyia antiqua, Notodontidae, Phalera bucephala, Betula pendula, silver birch, chitinase, herbivory simulation by leaf wounding, insect herbivore, nutritional indices, transgenic tree Abstract. Transgenic lines of silver birch (Betula pendula) carrying the sugar beet chitinase IV gene were used to study the effects of the heterologous expression of a transgenic chitinase on the performance of lepidopteran herbivores. The effect of wounding the leaves of birch on the performance of lepidopteran larvae and the growth of trees was also studied. Larvae of Orgyia antiqua L., Lymantriidae, and Phalera bucephala L., Notodontidae, were separately fed on the leaves of transgenic and wild-type birch, and their performance measured using nutritional indices. The relative growth rate (RGR) of O. antiqua larvae fed transgenic leaves was significantly lower than that of larvae fed wild-type leaves. Furthermore, there is little evidence that transgenic chitinase affects sur- vival but it was lowest for the group of larvae fed leaves with the highest expression of chitinase IV. Wounding did not have a sig- nificant effect on the performance of the larvae or on the growth of the branches of the trees.