Variation in phenology and nutritional quality between host plants and its effect on larval performance in a specialist butterfly, Zerynthia rumina

Abstract

AbstractThe main host plants of the butterfly Zerynthia rumina L. (Lepidoptera: Papilionidae) in southern Spain occur in different habitats and in general do not grow sympatrically. Therefore, each single local butterfly population uses the particular host available within its range. Aristolochia longa L. is a tuberous perennial herb available only in the spring, while A. baetica L. is an evergreen perennial vine with indeterminate growth. However, because of the toughness of older leaves, newly hatched larvae feed only on new leaves of A. baetica, and most of these leaves are produced well before the larvae hatch. In laboratory experiments, caterpillars feeding on either new or mature A. longa leaves grew faster and converted food into biomass more efficiently than those feeding on new A. baetica leaves. These differences are related to variation in nutritional quality among the host plants. Estimates of butterfly abundance were lower in sites where Z. rumina uses A. baetica, compared with those where the host is A. longa. The potential differential effect of these two food plants on the densities of local butterfly populations relying on them is discussed here.