Did the Early Cretaceous Emergence of Angiosperms Restrict or Extend Arthropod and Pathogen Herbivory?

Session: Phylogenetic and Computational Approaches in Paleobiology and Paleoecology, Part II

Presenting Author:

Conrad Labandeira

Authors:

Labandeira, Conrad C.¹, Xiao, Lifang², Chen, Liang³, Azevedo-Schmidt, Lauren⁴, Wang, Mingqiang⁵, Albrecht, Joerg⁶, Wang, Yongjie⁷, Ren, Dong⁸

(1) Smithsonian Institution NMNH Paleobiology, Washington, DC, USA; Department of Entomology, University of Maryland, College Park, MD, USA, (2) Guangdong Academy of Sciences, Institute of Zoology, Guangzhou, Guangdong, China, (3) College of Life Science, Capital Normal University, Beijing, Beijing, China, (4) Department of Entomology and Nematology, University of California, Davis, Davis, CA, USA, (5) Chinese Academy of Sciences, Chengdu Institute of Biology, Chengdu, Sichuan, China, (6) Functional Ecology and Global Change Lab, Senckenberg Biodiversity and Climate Research Centre, Frankfurt am Main, Hesse, Germany, (7) Guangdong Academy of Sciences, Institute of Zoology, Guangzhou, Guangdong, China, (8) College of Life Sciences, Capital Normal University, Beijing, Beijing, China,

Abstract:

Several hypotheses explain insect herbivore response to ecological dominance of angiosperms during the Early Cretaceous. We conducted two studies using the functional group-damage type (FFG-DT) system to quantitatively analyze relevant metadata at two temporal levels. the first was beta analysis of a 305 million-year-long interval of 134 plant assemblages from Late Pennsylvanian to recent in which turnover (replacement of some species by other species between sites) and nestedness (difference in composition when no species are replaced between sites) indicated that the modern pattern of herbivory was established during late Middle Jurassic, 60 million years before angiosperm ecological dominance. Turnover among Late Pennsylvanian and Early Permian plant groups declined whereas nestedness increased later during the Neogene. Gymnosperms exhibited a single insect feeding mode of low turnover and elevated nestedness whereas angiosperms showed a bimodal pattern. Less DT functional breadth, or "specificity", characterized ferns and angiosperms than gymnosperms, indicating major differences in links between insect herbivores and their herbivorized host plants. This shift likely was caused by the mid-Mesozoic Parasitoid Revolution in which bottom-to-up regulation of plant resources was replaced by top-to-down supression of herbivores mostly by emergent, highly efficient parasitoid lineages.

A second study was a tripartite network-web analysis using the most granular metric, feeding event occurrences, available to document herbivory, providing links (and interaction strengths) between damage types and their plant hosts. This study (including plant disease) focused on three highly-sampled, abundant, diverse, and well-preserved plant assemblages representing a 62 million-year-long interval immediately before and after the initial angiosperm radiation. They were late Middle Jurassic (late Callovian) at Daohugou (Northestern China; 165 Ma), dominated by ginkgophyte and bennettitalean gymnosperms; earlier Early Cretaceous (latest Barremian) at Dawangzhangzi (Northeastern China; 125 Ma) dominated by czekanowskialean and coniferalean gymnosperms; and latest Early Cretaceous (late Albian) at Nebraska, USA; 103 Ma), dominated by chloranthalean, lauralean, and other magnoliid-grade angiosperms. Preliminary analyses reveal distinct herbivory patterns between angiosperm- and gymnosperm-dominated assemblages, with significant differences in feeding strategies, tissue utilization, and pathogen interactions. Leaf functional traits appear to influence herbivory prevalence, though links between insect group and damage types remain unclear. These trends suggest potential shifts in plant-insect resource partitioning across this global plant transition.