Arthropod interactions with the Permian Glossopteris flora

Abstract

An extensive survey of literature on the Permian floras of Gondwana reveals over 500 discrete arthropod–herbivory– damage/plant–taxon/stratigraphic–unit associations spanning all regions of the supercontinent from the earliest Asselian to the latest Changhsingian. Margin– and apex–feeding damage is the most common style of herbivory but hole– and surface–feeding, galling, and oviposition damage are locally well represented. Evidence for skeletonization and mucivory is sparse and that for leaf mining is equivocal. Wood and root boring is recognized widely but only where depositional conditions were conducive to the permineralization of plant axes. Wood boring and detritivory may have been especially favoured arthropod feeding strategies in Permian high latitudes where living foliage was scarce during the polar winters. Herbivory damage is most strongly apparent on glossopterid remains; other groups of broad–leafed gymnosperms and sphenopsids host moderate levels of damage. Damage features are under–represented on lycophytes, ferns and spine– and scale–leafed conifers. A survey of insect body fossils from the Gondwanan Permian reveals that most records are from a small number of rich assemblages that are dominated by Blattodea, Hemiptera, Grylloblattida, Mecoptera and Protelytroptera, accompanied by significant representations of Coleoptera, Glosselytrodea, Miomoptera, Neuroptera, Odonata, Protorthoptera, Palaeodictyopteroida, Paoliida, Paraplecoptera, Plecoptera, Psocoptera, Thysanoptera and Trichoptera, which collectively adopted a broad range of feeding styles. Oribatid mites and collembolans appear to have been important components of the wood–boring and detritivorous communities. Although temporal trends in herbivory styles and diversity are difficult to resolve from mostly incidental observations and illustrations of plant damage across Gondwana, the results of this study provide a baseline of qualitative data for future studies that should adopt a quantitative approach to the analysis of herbivory, spanning the shift from icehouse to hothouse conditions through the Permian of the Southern Hemisphere.