Host plant specificity and feeding preferences of Morpho epistrophus argentinus (Lepidoptera: Nymphalidae) larvae in coastal woodlands of Argentina

The selection of suitable host plants for larval development is critical for most herbivorous insects. In this study, we examined host plant preferences of larvae of the Epistrophus white morpho butterfly, Morpho epistrophus argentinus (H. Fruhstorfer), a specialized butterfly that oviposits on a few plant species. In many species, the selection of host plant species for larvae development is under the control of ovipositing females and the role of larvae in host selection is minimal. Through field observations, we characterized larval host plant use in coastal woodland patches of its southernmost distribution range at eastern Buenos Aires, Argentina. All sampled M.e. argentinus larvaegroups (n = 40) were found on Scutia buxifolia trees, although the number of larval groups did not correlate with cover of this plant at patch scale. To further examine host plant preferences we performed translocation experiments and feeding choice assays. M.e. argentinus larvae translocated to unsuitable host plants had a shorter residence time than those translocated to suitable (i.e. control) hosts. Choice assays also indicated strong feeding preferences of wild larvae for S. buxifolia leaves. Our results highlight the high degree of host specificity of this butterfly, and reveal that host preference of growing larvae matches that of ovipositing females.