Secondary metabolite uptake by the Aristolochia-feeding papilionoid butterfly Battus polydamas

Abstract Many species of the Papilionidae are unpalatable and protected from natural enemies by aristolochic acids (AAs) sequestered from their Aristolochiaceae food plants. Battus polydamas (Papilionidae, Troidinii) is an Aristolochia -feeding papiloinoid butterfly. The uptake of AAs and other secondary metabolites by B. polydamas larvae from Aristolochia c was examined. The AA composition of larva, pupa and imago of B. polydamas was determined by HPLC-PDA, HPLC-MS-MS and comparison with authentic samples. The plant is rich in AA-II which is accompanied by minor amounts of AAs I, III, IV, Ia, IIIa, IVa and IVb. All eight AA analogs plus four O-glucosides from the phenolic AAs Ia, IIIa, IVa and IVb were present in the insect extracts. The AA-analogs IVb, Ia O-glucoside, IVb O-glucoside are described for the first time. The larval haemolymph qualitatively reflects the AA-pattern of the plant and is also rich in AA-II. Analysis of the larval tissues and the osmeterial secretion shows that the phenolic AAs are significantly O-glucosylated. Except for AA-I, all the AAs are gradually catabolized into unknown compounds throughout the life stages of B. polydamas , being therefore much less abundant or absent in the imago. In the imago AA-II becomes undetectable whereas AA-I remains as the major AA. Results suggest that predominance of AA-I in the adult may be due to repressed degradation of this acid rather than selective sequestration from the plant or de novo synthesis by the insect. Some aspects related to aristolochic acid uptake and metabolism are discussed.