The genetic and environmental basis of pupal colour dimorphism in Papilio zelicaon (Lepidoptera: papilionidae)

Abstract

The genetic and environmental basis of brown and green pupal colour dimorphism in the butterfly Papilio zelicaon was studied using univoltine, multivoltine, and selected low-diapause populations. The propensity for formation of brown pupae and the positive correlation between brown pupae and diapause show both inter- and intrapopulation variability. Reciprocal hybrids had colour frequencies and magnitude of the pupal colour-diapause correlation intermediate between parental population values with evidence for maternal effects in the latter. Colour frequencies among individual broods were normally distributed. One generation of selection increased incidence of green pupae and was most effective at a high selection differential. Selection results plus a heritability determination indicated that pupal colour dimorphism in P. zelicaon is a threshold trait with quantitative genetic variation. Short days and cool temperatures induced mostly diapause brown pupae irrespective of pupation substrate whereas long days and warm temperatures facilitated continuous development and cryptic colour matching of pupae to their substrate.