Plant–insect interactions from the mid-Cretaceous at Puy-Puy (Aquitaine Basin, western France) indicates preferential herbivory for angiosperms amid a forest of ferns, gymnosperms, and angiosperms

Abstract

ABSTRACT Plants and insects are the two dominant groups in terrestrial ecosystems, and insect damage on fossil plants is the only direct evidence documenting the past ecological history between these two, hyperdiverse groups. We describe, analyze, and interpret plant–insect interactions of a lower Cenomanian paleoforest from western France – the Puy-Puy Quarry of the Nouvelle-Aquitaine Region. We examined 1605 fossil leaves, axes, and reproductive material of bennettitalean, pinalean, and ginkgoalean gymnosperms; lauralean and magnolialean angiosperms; and pteridophyte fronds. We identified functional feeding groups (FFGs) and insect damage types (DTs) preserved on this foliage and data were rarified to indicate sample completeness. By employing R, various statistical parameters were calculated. We established 71 DTs for the nine FFGs of hole feeding, margin feeding, skeletonization, surface feeding, oviposition, piercing and sucking, galling, mining, and pathogens, and 1292 feeding event occurrences. Of the specimens examined 22.2% exhibited one or more DT, with angiosperms the most affected plant group. The most diverse interactions were mining and galling, indicating a mosaic of humid and xeric habitats, respectively, for the Puy-Puy paleoforest, a conclusion consistent with previous paleontological and sedimentological interpretations. Elevated DT richness suggests long-standing ecological relationships between the plants and insects, representative of a mature forest.