Insect Herbivores Drive Real-Time Ecological and Evolutionary Change in Plant Populations

• Published in: Science (American Association for the Advancement of Science) Vol. 338; no. 6103; pp. 113 - 116
• Main Authors: Agrawal, Anurag A., Hastings, Amy P., Johnson, Marc T. J., Maron, John L., Salminen, Juha-Pekka
• Format: Journal Article
• Language: English
• Published: Washington, DC American Association for the Advancement of Science 05.10.2012; The American Association for the Advancement of Science
• Subjects: Analysis of variance; Animal and plant ecology; Animal, plant and microbial ecology; Animals; Aphididae; Aphidoidea; Arabidopsis thaliana; Autoecology; Biological and medical sciences; Biological Evolution; Chemical defense; chemical defenses; Composition effects; Divergent evolution; Ecology; Evening; Evolution; Evolutionary; Evolutionary biology; Feeding; Flowering; Fruit - genetics; Fruit - parasitology; Fruit - physiology; Fruits; Fundamental and applied biological sciences. Psychology; Genetics of eukaryotes. Biological and molecular evolution; Genotype & phenotype; Genotypes; Herbivores; Herbivory; Herbivory - physiology; Indigenous plants; Insect ecology; Insect genetics; Insects; loci; Moths - physiology; Oenothera; Oenothera biennis - genetics; Oenothera biennis - parasitology; Oenothera biennis - physiology; Pesticides; Phytophagous insects; Plant populations; Plant resistance; Plants; Plants and fungi; Population; Relative abundance; Seeds - genetics; Seeds - parasitology; Seeds - physiology; Selection, Genetic; Synecology; Taraxacum; Terrestrial ecosystems; toxic substances; Insecta; Biological evolution; Onagraceae; Genotype; Pest; Phytophagous; Animal plant relation; Arthropoda; Dicotyledones; Host plant; Insect resistance; Angiospermae; Lepidoptera; Oenothera biennis; Spermatophyta; Invertebrata; Oil plant (vegetal)
• ISSN: 0036-8075; 1095-9203; 1095-9203
• DOI: 10.1126/science.1225977

Insect herbivores are hypothesized to be major factors affecting the ecology and evolution of plants. We tested this prediction by suppressing insects in replicated field populations of a native plant, Oenothera biennis, which reduced seed predation, altered interspecific competitive dynamics, and resulted in rapid evolutionary divergence. Comparative genotyping and phenotyping of nearly 12,000 O. biennis individuals revealed that in plots protected from insects, resistance to herbivores declined through time owing to changes in flowering time and lower defensive ellagitannins in fruits, whereas plant competitive ability increased. This independent real-time evolution of plant resistance and competitive ability in the field resulted from the relaxation of direct selective effects of insects on plant defense and through indirect effects due to reduced herbivory on plant competitors.