Migration patterns and feeding resources of the Painted Lady butterfly, Cynthia cardui (L.) (Lepidoptera, Nymphalidae) in the northeast of the lberian peninsula

Abstract

The Painted Lady butterfly, Cynthia cardui (L.), is a subtropical species that periodically migrates frorn the edges of the desert bands to northern latitudes. Between 1988-89 and 1991-96 quantitative data on the abundance of the Painted Lady were collected from a number of fixed transect routes throughout Catalonia (northeast of the lberian peninsula) using the standard rnethodology of the Butterfly Monitoring Scherne. This area in the western Mediterranean is presumably one important migratory route connecting the African continent with central and northern Europe. C. cardui was recorded regularly in all kind of habitats but numbers fluctuated greatly depending on the season. The high synchrony of population changes from site to site was indicative of the level of rnigration that occurred throughout the whole area in a particular year. Seasonal abundance showed a clear pattern and revealed that overwintering of immature stages and adults is negligible and that populations begin to build up at the end of spring, coinciding with northward mass rnigrations. On the other hand, population levels remain quite low during the summer and autumn, and the data do not show a southward return flight as noted in other migrant butterflies. During the study data on larval foodplants and nectar sources were also systematically collected. Though C. cardui is a polyphagous species, there is a clear hostplant preference rank, and Malva sylvestris was the main foodplant at most sites. Likewise, within each site the use of nectar sources was limited toa few species that changed during the season according to their abundance and availability.