The Middle Miocene represents a critical interval in the history of European angiosperms and insects, particularly in the Mediterranean region, where climate change has influenced these communities, as the small amount of unevenly dispersed data indicate. Here, we present new findings from the island of Kos, Greece, where a rich assemblage of fossilized angiosperm leaves from the Middle Miocene provides novel data of plant–insect interactions at this transitional time interval. Palaeobotanical analysis confirms multiple angiosperm morphotypes, likely belonging to both deciduous and evergreen lineages. These fossils exhibit a diverse array of insect-mediated damage types (DTs), including margin feeding, hole feeding, skeletonization, mining, and galling structures.

Using the established Labandeira DT classification framework, we document over 10 discrete damage types, indicating a high level of functional feeding group diversity. Interactions’ relative richness and diversity are different among different leaf morphospecies, although Quercus and Acer, which are some of the most common leaf elements found in the assemblage, exhibit the highest diversity in DTs.

This study is the first to document such detailed insect–plant interaction data from the Miocene of Greece and contributes a new regional data point to the research on Cenozoic plant–insect associations. The diversity and specificity of the interactions observed underscore the ecological complexity of Miocene forests in the Aegean region. These results offer new insight into the vegetational and insect community dynamics of the region and support the use of trace fossil evidence as a proxy for reconstructing ancient insect diversity.