Opposite macroevolutionary responses to environmental changes in grasses and insects during the Neogene grassland expansion

Gael J Kergoat (1) , Fabien Condamine (2) , Emmanuel E. Toussaint (3) , Claire Capdevielle-Dulac (4) , Anne-Laure Clamens (5) , Jérôme Barbut (6) , Paul Goldstein , Bruno Le Ru (7)

1 INRA - Institut National de la Recherche Agronomique
2 UMR ISEM - Institut des Sciences de l'Evolution de Montpellier
3 IP - Institut Pascal
4 Université Paris Sud (Paris 11)
5 UMR CBGP - Centre de Biologie pour la Gestion des Populations
6 ISYEB - Institut de Systématique, Evolution, Biodiversité
7 UMR Lab Evolut. Genomes Speciat.

The rise of Neogene C-4 grasslands is one of the most drastic changes recently experienced by the biosphere. A central - and widely debated - hypothesis posits that Neogene grasslands acted as a major adaptive zone for herbivore lineages. We test this hypothesis with a novel model system, the Sesamiina stemborer moths and their associated host-grasses. Using a comparative phylogenetic framework integrating paleoenvironmental proxies we recover a negative correlation between the evolutionary trajectories of insects and plants. Our results show that paleoenvironmental changes generated opposing macroevolutionary dynamics in this insect-plant system and call into question the role of grasslands as a universal adaptive cradle. This study illustrates the importance of implementing environmental proxies in diversification analyses to disentangle the relative impacts of biotic and abiotic drivers of macroevolutionary dynamics.

Domaines: Sciences du Vivant [q-bio]

Gael J Kergoat, Fabien Condamine, Emmanuel E. Toussaint, Claire Capdevielle-Dulac, Anne-Laure Clamens, et al.. Opposite macroevolutionary responses to environmental changes in grasses and insects during the Neogene grassland expansion. Nature Communications, 2018, 9 (5089), ⟨10.1038/s41467-018-07537-8⟩. ⟨hal-02322181⟩