PLANT-INSECT INTERACTIONS IN RESPONSE TO GLOBAL COOLING DURING THE QUATERNARY: EVIDENCE FROM EVERGREEN SCLEROPHYLLOUS OAK FORESTS IN SW CHINA

Plant and insect, being two largest groups in ecosystems, their associations closely relate to climate change. Until now, most studies focus on plant-insect associations under different climate conditions with contemporary samples. Whereas the other studies use fossil materials to understand how did climate changes in deep time impact on this associations. The Quaternary is a period characterized by the global cooling which largely affected the ecosystem, but the impact of environmental change on plant-insect associations during the Quaternary is still largely unknown. Herein, we studied the plant-insect interactions in the evergreen sclerophyllous oak (ESO, Quercus section Heterobalanus) forests in southwestern China by comparing contemporary samples with fossil record. The late Pliocene Longmen flora and eight modern forests which are dominated by ESO were used as the sample sites. Insect damages on leaves of all samples were scored with the standard measurements. All samples present high damage frequency although the high leaf mass per area. Comparing to modern samples, a lower damage frequency and damage types were observed from the late Pliocene Longmen flora, even a warmer and much wetter climate is concluded from Longmen flora than climate in modern sample sites. Besides, only one damage type (galling) of Longmen flora is absent in living ESO forests. Our results indicate there is low influence of climate changes during the Quaternary on plant-insect associations in ESO forests from SW China, which might be due to the complex topography in this region, playing an important role as the refuge for living creatures.