Effects of temperature of plant cultivation on plant palatability modify species response to novel climate

Climate warming is expected to strengthen the plant-herbivore interactions and thus increase the plant consumption rate. However, indirect impacts of temperature (acting via changes in host plant quality) on herbivore performance have only rarely been studied, and therefore, the net effect of temperature change is difficult to predict. We thus tested the effects of temperature on plant palatability and assessed whether the effects can be explained by changes in leaf traits. We conducted multi-choice feeding experiments with six species of the genus Impatiens cultivated at three different temperatures in the growth chambers and in the experimental garden and also studied changes in leaf morphology and chemistry. The leaves of Impatiens species were most eaten when cultivated in the temperature predicted by climate warming scenario. We found the traits related to leaf morphology (SLA, LDMC and leaf size) partly mediated the effects of temperature on leaf herbivore damage. Herbivores preferred smaller leaves with lower SLA and higher LDMC values. Results of our study suggested that elevated temperature will lead to change in leaf traits and increase their palatability. This will further enhance the levels of herbivory caused by increased herbivore pressure under climate warming.