Larval performance and adult phenotypic variation of Acraea terpsicore (Lepidoptera: Nymphalidae) on congeneric Passiflora host plants.

Abstract

The introduction of exotic plants into different habitats can have varied consequences for local herbivorous insects, such as altered the nutrient profiles that induce the host plant shifting or reduced food availability by competition with native plants. Acraea terpsicore (Linnaeus, 1758), a common butterfly in Southeast Asia that uses Passiflora as a host plant, has been studied to compare larval performance and adult phenotypes on one local wild Passiflora plant, P. foetida and 3 exotic congeneric plants, P. edulis, a fruit crop plant, and P. x alata-caerulea and P. x coccinea-caerulea, both hybrid ornamental plants. Laboratory caterpillars that fed on P. edulis and P. x alata-caerulea died within 1-10 days, while caterpillars fed on P. foetida and P. x coccinea-caerulea completed their life cycle in 30.42 ± 0.25 days. Although the caterpillars differed in several food utilization indices, the relative growth rate and consumption index were not affected. Adult butterflies that hatched from caterpillars fed on these experimental plants had different phenotypes, especially wing colors. Therefore, although some congeneric exotic plants may have a negative impact on the butterfly population, some exotic plants can serve as alternative larval host plants and expand the ecological niche of butterflies. Difference in the composition and concentration of nutrients and defensive chemicals in each host plant may exert an impact on the phenotypic traits of butterflies, such as their body size, coloration, and wing shape. Whether butterflies may separate into different subpopulations in the future due to phenotypic variation should be further examined.