A Long-Term Specialized Herbivory Highlights the Theory of Mutualistic Interaction

Abstract

Interactions between plants and insects stems from millions of years of co-evolution and are crucial in the trophic balance of terrestrial ecosystems. It is commonly accepted that herbivore-plant relationships are exclusively in favor of the insect and to the detriment of the plant. This study presents an insect damage found exclusively on the plant genera Parrotia (Hamamelidaceae), which is nowadays only represented by two plant species P. persica and P. subaequalis, respectively endemics from the Hyrcanian forest (Iran, Azerbaijan) and the Yangtze River Valley (China). Our study confirms that this insect damage type occurs for at least 15 million years from eastern Asia to western Europe. It suggests a decline of this damage type was likely due to the decrease of Parrotia’s populations in Eurasia during the late Cenozoic. Stability and persistence over time, despite the significant environmental changes through Eurasia, support the hypothesis whereby some herbivory patterns could be in somehow benefits to plants which is making to consider herbivory as a mutualistic plant-insect interaction.