Interaction and coevolution of plants and arthropods during the Palaeozoic and Mesozoic

Abstract

Fossil evidence of terrestrial vascular plant life and terrestrial arthropods exists from the Silurian. Fossil evidence suggests progressive interaction between the two groups through the later Palaeozoic and Mesozoic. In this paper we present data, particularly from plant fossils, concerning several interactions: feeding, shelter, transport and reproduction. Evidence of arthropod feeding includes eaten leaves, borings in plant tissues, wound reaction and leaf mining as well as gut contents and coprolites from the arthropods themselves. We trace the changes in leaf eating behaviour from continuous marginal feeding, common in the Palaeozoic and early Mesozoic to the more abundant interrupted-marginal and non- marginal feeding behaviour on Cretaceous angiosperm leaves. This change may reflect the evolution of chemical defence strategies by the plants but may also reflect the evolution of different mouthpart design in new insect groups. Leaf mines and leaf galls, although known from the Upper Carboniferous, only become common in the Cretaceous, coinciding with the evolution of several new insect groups and plants. Wood boring is recorded, for the first time, from the Lower Carboniferous and becomes common from the Upper Carboniferous. Data from coprolites suggest that spore feeding preceded leaf feeding. Experiments using pteridophytes and living arthropods indicate that some spores remain viable after passing through the gut and hence this feeding habit may have also been advantageous to some early plants for propagule transport. We conclude that there is much evidence in the fossil record suggesting plant-arthropod interaction, but many more observations are required before detailed interpretations concerning coevolution can be made.