Diapause dynamics, seasonal phenology, and pupal color dimorphism of Papilio polyxenes in southern Florida, USA

Abstract

AbstractThe seasonal phenology, pupal diapause, and pupal color dimorphism of a Papilio polyxenes Fabr. (Lepidoptera: Papilionidae: Papilionini) population from subtropical southern Florida, USA, were studied. Adult eclosion from field‐collected individuals indicated that this population is primarily active from the late dry season through the wet season (March–September). Most pupae entering diapause in April eclosed the same year but one pupa eclosed the following February. In laboratory tests, larval rearing under short days (L10:D14) induced 88.6% pupal diapause. Diapause responses to relatively longer (L12:D12–L16:D8) photoperiods ranged from 35.1–51.5%, and were statistically equivalent. These results indicate greater variability in the photoresponse of subtropical P. polyxenes compared to temperate populations that generally show little diapause under long‐day conditions and complete diapause under short days. The proportions of diapause pupae and brown pupal color, among broods reared at photoperiods ≥L12:D12, were both normally distributed. Diapause pupae were sensitive to photoperiods from L10:D14 to L16:D8. Diapause duration was inversely related to the photophase length to which the pupae were continuously exposed. Four generations of selection, at L10:D14, for non‐diapause reduced pupal diapause from 88.6 to 20.6%, indicating the existence of considerable additive genetic variance for this trait. Selection for non‐diapause increased the percentage of green pupae from 21.8 to 58.8% and decreased the incidence of diapause in both green and brown pupae. Brown pupal color and liability to diapause are linked, but this linkage is weaker than that documented in temperate populations. The overriding effect of short days (L10:D14) inducing only brown diapause pupae did not occur in southern Florida P. polyxenes.