Plant–insect interactions from the Miocene (Burdigalian–Langhian) of Jiangxi, China

Abstract

The study of plant–insect interactions can provide valuable information about terrestrial ecosystems. A plant assemblage from the Toupi Formation of Jiangxi, China, provides indirect evidence of the plant–insect interactions that occurred in a Miocene forest community. A total of 123 dicot leaf specimens were examined and 25 of them showed traces of insect herbivory. Twenty-four damage types were identified and categorized into eight functional feeding groups. These traces indicate that insects interacted with these plants for various purposes, including feeding, sheltering and egg laying. To survey the responses of plant–insect interactions to climate conditions, the data on insect damage frequency and temperature variables from the Toupi assemblage and four other assemblages (from the middle Miocene to the early Pleistocene) from China were analyzed based on a linear stepwise regression analysis. The analysis suggests that there is a significant positive correlation between the damage frequency and the coldest month (mean) temperature (CMT) (R2 = 0.709 and P = .047). The present result provides additional support for the hypothesis that the CMT, rather than the mean annual temperature, could be one of the factors influencing the frequency of damage in paleoflora communities. When compared to the four other assemblages, the Toupi assemblage has the lowest damage frequency which could be due to the lowest CMT. It is possible that a low CMT could result in a low insect metabolic rate per unit area and unit time, leading to a low frequency of insect attack and a low herbivory rate.