Host plant selection and larval performance in the Neotropical butterfly Mechanitis polymnia casabranca

Abstract

AbstractThe preference–performance hypothesis states that female insects oviposit on plants that result in optimal larval development. The objective of the present study was to evaluate the use of host plants of the genus Solanum by female butterflies of Mechanitis polymnia casabranca Haensch (Lepidoptera: Nymphalidae) and the performance of larvae reared on different species of Solanum. We performed field observations and oviposition experiments to evaluate the use of host plants. In the field, we recorded the abundance of host plants of the species Solanum robustum H. Wendl, Solanum mauritianum Scop., Solanum scuticum M. Nee, and Solanum paniculatum L. with and without oviposition by M. polymnia. In the oviposition experiment, we grew host plants representing common species in the field (S. mauritianum, S. robustum, and S. scuticum) in pots, with one plant per pot, which were then grouped in blocks of three plants, one of each species (n = 10 blocks). In the larval performance experiment, we reared larvae on leaves of one of three Solanum species and maintained them under controlled temperature and photoperiod conditions. We recorded the survival, larval development time, adult wing size, dry weight, and larval digestibility indices. In the field, females oviposited more frequently on S. robustum despite the greater abundance of S. mauritianum. In general, larvae reared on S. robustum or S. scuticum had highest larval performance. Larval mortality was higher in larvae reared on S. mauritianum (40.9%), followed by larvae reared on S. scuticum (7.5%) and S. robustum (6.8%). The adult wing size and dry weight were the highest in males and females originating from larvae reared on S. robustum. The results suggested a positive relationship between oviposition preference and larval performance in M. polymnia casabranca.