Production and sex ‐pheromonal activity of alkaloid‐derived androconial compounds in the danaine butterfly, Parantica sita (Lepidoptera: Nymphalidae: Danainae)

Close associations of certain lepidopteran taxa with pyrrolizidine alkaloids (PAs), a typical class of plant secondary metabolites, have been well documented from the perspective of evolutionary ecology. Male danaine butterflies are thought to utilize PAs as precursors for the production of dihydropyrrolizines [e.g. danaidone (DO) and hydroxydanaidal (HD)] in their two distinct androconial organs, viz. alar scent organs (sex brands) and abdominal hairpencils. However, little is known about the quantitative profiles of these compounds in danaines, the mechanism for their formation in the androconial organs, or their biological functions, particularly in mating behaviour. The present study addressed these unanswered questions posed for males of the danaine butterfly, Parantica sita. Chemical analyses of androconial extracts revealed considerable seasonal/regional and individual variations of the amounts of DO (the major dihydropyrrolizine produced) and 7R‐HD (the 7R‐enantiomer of HD detected in this study) found in the two organs. These variations seemed to depend primarily on the age of the male and the phenological traits of PA‐containing plants available. Males were found to acquire an adequate capability to produce DO ~1 week after eclosion. DO was shown to be produced exclusively in the sex brand and subsequently physically transferred to the hairpencil through a contact behaviour between the two organs, here termed ‘perfuming behaviour’. The results of behaviou...

Source: Biological Journal of the Linnean Society - August 17, 2016 Category: Research Authors: Keiichi Honda, Yasuyuki Honda, Junya Matsumoto, Yoshiaki Tsuruta, Wataru Yagi, Hisashi Ômura, Hiroshi Honda Tags: Research Article Source Type: research