Figure 2. The spread of the leaf-mining moth and how the length of time it has been present in a location affects leaf damage and the level of attack by parasitoids.

(A) The larvae of the leaf-mining moth Cameraria ohridella cause distinctive damage to horse-chestnut leaves. (B) The modeled distribution of the spread of C. ohridella produced by augmenting the observed distribution after 2006 with a demographic model of spread assuming two generations per year. (C) The effect of the length of time that C. ohridella has been present on levels of attack by parasitoids (‘parasitism’) as estimated from the data (black points) and extrapolated from the model (white points) with the inter-quartile range (grey). (D) The effect on leaf damage of the length of time that C. ohridella has been present, based on expected results from an ordinal regression, with inter-quartile range (grey).