Seasonal polyphenism in the wild: survey of wing patterns in five species of Bicyclus butterflies in Malawi

Abstract.

• 1 For three successive years Bicyclus butterflies were caught on a daily basis at a field site in Malawi.
• 2 Over 5000 butterflies, belonging to five species, were captured. Eight characters describing their plastic wing pattern were measured and analyzed.
• 3 Broadly speaking, the plasticity is similar for all species, with the wet season forms having conspicuous wing markings (e.g. eyespots), and dry season forms lacking these markings.
• 4 However, at a more detailed level, each species has its own specific form of plasticity with especially clear differences in the number of intermediate forms.
• 5 Females generally show a higher degree of plasticity than males.
• 6 The relative frequencies of intermediate forms and the difference between the sexes are associated with differences between the species in their preference for more open habitats or forests.
• 7 The species with the most divergent plasticity is also ecologically and phylogenetically comparatively distant from the others.