HPLC-MS of lichen-derived metabolites in the life stages of Crambidia cephalica (Grote and Robinson) (Lepidoptera: Erebidae: Arctiinae: Lithosiini)

Tiger moths (Lepidoptera: Erebidae: Arctiinae) are an ideal study system for understanding plant-insect interactions, and the evolution of antipredatory behaviors, because they are known to sequester plant toxins (secondary metabolites).  Lithosiines (Arctiinae: Lithosiini), commonly called lichen moths due to their larval feeding behavior, represent the basal tribe of arctiines.   Lichens are often characterized by their secondary metabolites; therefore, lichenivory may provide clues to the phylogenetic basis for chemical sequestration within arctiines.  Yet, we lack a basic understanding of the extent of lichenivory among lithosiines and the dynamics of chemical sequestration among life stages.  The dynamics of chemical sequestration for the lichen moth Crambidia cephalica (Grote and Robinson) were investigated by testing the predictions that lichen-derived metabolites are unequally distributed among life stages and that lab-reared C. cephalica have less metabolite diversity than wild-caught individuals.  Crambidia cephalica was reared on Physcia (Schreber) Michaux, and examined using high performance liquid chromatography-mass spectrometry (HPLC-MS).  Results indicated that several putative lichen-derived metabolites were detected among the life stages of C. cephalica.  Additionally, different lichen-derived metabolites were present and/or absent when compared among the different life stages and the lichen host.  These results provide evidence that there are multiple lichen-derived metabolites sequestered by C. cephalica, some metabolites are retained through to adulthood and that others are lost after the larval and pupal stages.  The presence of lichen-derived metabolites in discrete life stages may indicate functional properties of the metabolites for C. cephalica with regards to chemical protection from antagonists and other physiological processes.