Larval foodplant efficiency and laying preferences in Parnassius apollo L. (Lepidoptera, Papilionidae)

A mountain butterfly species, Parnassius apollo is protected by the CITES convention of Washington and is threatened or extinct in many European massifs. The definition of the ecological factors which ran affect its survival in particular its relations with its larval foodplants, are important to design conservation policies. The larva of P. apollo is oligophagous and feeds on various species of Crassulaceae. The results of observations and experiments on the female laying preferences and on the efficiency of some of these plants for larval development are exposed here. The two species most cited as foodplants in literature, Sedum album and S. maximum, appeared to be the most efficient. Other species, although frequently mentioned were rejected and another one performed poorly. A comparison with other cases of foodplant specificity in butterflies is presented and the implications of these results for conservation are discussed.