Tree defence, epiphylls and herbivorous insects

• Applicants: Professor Dr. Nico Blüthgen; Professor Dr. Sebastian Hess; Professor Dr. Thomas Schmitt; Professorin Dr. Sybille Unsicker
• Subject Area: Ecology and Biodiversity of Animals and Ecosystems, Organismic Interactions
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 444827997

Tropical rainforests are characterised by an amazing diversity of tree species and herbivorous insects. So far, we know only insufficiently what happens to the interactions between trees and herbivorous insects when rainforests fall victim to anthropogenic disturbances. Even less is known about the significance of complex interactions between herbivorous insects, the phytochemistry of trees and other tree-associated organisms such as epiphylls under highly variable environmental conditions, such as those found along a gradient of tropical rainforest recovery. In a second funding period, SP6 will investigate insect herbivore - tree interactions along the chronosequence during tropical rainforest recovery, taking into account the microclimate, phytochemistry and epiphylls. Firstly, we will investigate the temporal dynamics of insect herbivory in all planted tree species in T-REX plantations and regularly trap insects to construct tree-herbivore networks. Furthermore, we will monitor the temporal trajectories of epiphyll abundance and diversity to gain a more holistic understanding of the planted trees as meta-organisms. Morphological as well as volatile- and non-volatile leaf chemical traits will be measured in 6 selected tree species to study the mechanisms of species assembly. Secondly, we will use morphological and molecular methods to study the abundance and composition of epiphyllous communities in leaves of selected tree species. A morphological atlas as well as a phylogeny-informed system of functional epiphyll groups will be established. Thirdly, we will perform laboratory feeding experiments with individuals of selected herbivore taxa (e.g., Orthoptera, Lepidoptera or Coleoptera) to understand the specificity and distribution of herbivores across tree species and thus the tree – herbivore networks. Fourthly, the cuticular hydrocarbon composition, temperature-dependent respiration, water loss and critical thermal maximum of individuals of the same herbivore species used in the preference tests will be measured. Consequently, the objective is to ascertain whether these ecophysiological traits can elucidate the distribution and composition of the insect herbivore communities in plots along the chronosequence that surely exhibit significant disparities in microclimatic conditions. By combining descriptive-observational field studies with experimental approaches in the lab also using chemical and molecular methods, SP6 will make a significant contribution to understanding the mechanisms of the restoration of tree-herbivore networks after anthropogenic disturbance of tropical rainforests.

• DFG Programme: Research Units
• Subproject of: FOR 5207: Reassembly of species interaction networks – Resistance, resilience and functional recovery of a rainforest ecosystem
• International Connection: Ecuador
• Cooperation Partner: Dr. María-José Endara