ABSTRACT 1. Plant distributions are dynamic but the role of plantÐinsect interactions in controlling
range dynamics is not well understood. Enemy release, for example could facilitate plant range
expansion under climate change. 2. We conducted a transplant experiment with the evergreen tree
Ilex aquifolium L. in both the historical and the expanding range in Denmark to study possible effects
of geographical position, small-scale distance, and plant types on presence and performance of the
monophagous insect leaf-miner Phytomyza ilicis Curtis. 3. The leaf miner was present in the entire
range of I. aquifolium in Denmark, and there were no differences in emergence success depending
on geographical position. Small-scale distance to existing adult plants inßuenced the activity of the
insect on the transplants, and oviposition density was negatively correlated with distance to adult
plants. 4. Plant type had an effect on leaf miner feeding, oviposition and mining, and the native
provenance of I. aquifolium supported higher densities than two cultivars. 5. There was no evidence
that enemy release facilitates the current range expansion of I. aquifolium.