Spurge toxins as a winder of evolution in hawkmoths: Phorbol ester detoxification by Hyles euphorbiae (Lepidoptera: Sphingidae)

• Applicant: Dr. Anna K. Hundsdoerfer
• Subject Area: Ecology and Biodiversity of Animals and Ecosystems, Organismic Interactions
• Term: from 2019 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 426481409

The larvae of Hyles euphorbiae feed on several spurge species of the genus Euphorbia (Euphorbiaceae), containing phorbol esters with numerous harmful biological activities. Accordingly, it has been shown, that H. euphorbiae is completely insensitive to high doses of the co-carcinogenic phorbol diester TPA (12-tetradecanoyl-phorbol-13-acetate). Published and preliminary experiments by the applicant indicated, that the larvae metabolise the diterpene esters, rather than sequestering them as had been previously suggested. Several putative metabolites of TPA have been detected in the faeces of TPA-fed larvae, suggesting several biological pathways involved. In this project, possible detoxification pathways of phorbol esters by H. euphorbiae shall be elucidated and identified.This interdisciplinary project combines analytical chemistry and molecular biology to gain an exhaustive insight of the enzymatic reactions involved. To understand the evolutionary relevance of this ecological trait as a key innovation within the genus Hyles, metabolites of H. euphorbiae will be compared to those of additional Hyles species with different preferences (food plant spectra, sensitivity to TPA) and enzyme candidates will be characterized.

• DFG Programme: Research Grants