Title: Physiological and molecular changes under artificial and insect defoliation in Eucalyptus

Defoliator insect pests can cause significant damage in natural and planted forests. Thus, understanding the economic loss associated with and the molecular mechanisms underlying defoliation by insect pests is important for both forest managers and tree breeders. However, assessing the economic impact of natural insect defoliation as well as setting up insect defoliation experiments could be challenging, while the inherent variation in the pattern of insect feeding may affect experimental accuracy. Artificial defoliation has been considered as a good proxy to study insect defoliation. However, several factors such as season, age of the trees and the severity of mechanical stripping (defoliation) should be carefully considered as these could lead to different results. Additionally, physiological changes such as upregulation of photosynthesis have been observed upon defoliation. However, this depends on the degree of artificial defoliation. Thus, understanding the differences in the physiological changes between artificial and insect defoliation as well as the molecular basis of these differences is important as this could inform decision making towards a more effective use of artificial defoliation.