Change in the aristolochic acids composition of the osmeterial secretions among different instars of Battus polydamas archidamas caterpillars reared on Aristolochia chilensis

SANTANDER R; URZÚA A; CABEZAS NJ; ECHEVERRÍA J; SOTES GJ

Viçosa

Congreso; VI Encuentro Brasilero de Ecología Química; 2009

Among papilionids, the Neotropical genus Battus is characterized by being monophagous, feeding only on plants of the genus Aristolochia at the larval stage. Battus polydamas archidamas Boise. (Papilionidae, Troidini), the only representative species of the genus in Chile, uses Aristolochia chilensis Bridges ex Lindl. as host-plant. Battus polydamas achidamas larvae reared on Aristolochia chilensis sequester aristolochic acids (AAs) selectively and independently of lipophilicity. A considerable proportion of the ingested acids can be recovered from the excreta, but the amounts which remain unaccounted for suggest metabolic detoxification. In this communication we report the aristolochic acid (AAs) composition in the osmeterial defensive secretion of B. polydamas achidamas larvae, reared on A. chilensis and correlates the AAs composition with the change in the feeding behavior of the caterpillars. A total of 30 plants of A. chilensis (Cuesta Lo Prado (33°28'S, 70°56'W), were examined and presence of egg clutches of B. polydamas archidamas recorded. Five plants of similar size and phenological stage, and bearing a single large egg clutch were chosen and marked. The plants were covered with a fine cloth mesh and monitored until larvae reached the second, third, fourth and fifth instars stage. From the osmeterium of each individual larva in each instar, the secretion was obtained quantitatively with small pieces of filter paper and analysis of HPLC-DAD. The osmeterial secretions show the presence of AA-I, AA-II, AA-IV, AA-IVa, AA-Ia and AA-IIIa. Also significant differences in the AA's concentration of the osmeterial secretion in each larval instar were found. These results could be correlated with the change in the feeding behavior of the caterpillars. Females of B. polydamas archidamas oviposited mostly on young leaves, and larvae fed on this tissue until the third instar; thereafter, larvae expanded their diet to mature leaves and stems. Young leaves contained higher aristolochic acids concentration than mature leaves.