Palatability of transgenic birch and aspen to roe deer and mountain hare

Abstract Genetic engineering of plant resistance characteristics against fungi may unintentionally influence traits that are important for plant–herbivore interactions. We studied the palatability of transgenic birch (Betula pendula), aspen (Populus tremula) and hybrid aspen (P. tremula x tremuloides) genetically modified with the aim to improve fungal disease resistance, to selective mammalian herbivores in cafeteria tests. Roe deer (Capreolus capreolus) were fed with transgenic birch carrying a sugar beet chitinase IV gene. In the experiment with roe deer, none of the six transgenic birch lines differed significantly from the wild-type control in the proportion of consumed plant biomass. Correlation analyses suggested that sugar content did not guide the feeding preferences of roe deer but revealed a positive correlation between starch content and proportion of mass consumed. However, the variation in starch content could not be related to the level of transgene expression. Mountain hares (Lepus timidus...