Performance and host preference of Ascia monuste (Lepidoptera, Pieridae)

Experiments were conducted to determine the performance and host preference of Ascia monuste using kale (Brassica oleraceae, var. Acephala) and mustar d (B. juncea). These plants differ significantly in water and nitrogen cont ent, with mustard having larger amounts of water and kale larger amounts of nitrogen. The performance results confirmed that kale is a better food sou rce than mustard for the species, even when eggs were collected on mustard leaves in the field. However, when eggs were collected on mustard, the kale nutritive value was lower than the nutritive value obtained when eggs were collected on kale leaves. Furthermore, the results of oviposition preferen ce obtained in the field and in the laboratory have shown a preference for kale, indicating the presence of a positive correlation with performance. I n contrast to the data about oviposition preference, there was no immature feeding preference. These results indicate that host selection occurs durin g the oviposition process. Furthermore, it is possible that the high abunda nce of kale cultivated in the region studied and the nutritional quality of this plant are two factors that influence the positive relationship betwee n oviposition preference and performance for A. monuste. (C) 1998 Elsevier Science Ltd. All rights reserved.