Androconial Scales and the Sex Pheromone of the Pieris Male Wing: Secretory Cells in the Pupal Wing

In lepidopterans whose mating behaviors involve sex pheromones, female sex pheromones emitted from glands located at the female abdomens have been mainly reported. In some lepidopterans, however, male wings contain sex pheromones, and they have morphologically specialized scales, called androconial or scent scales, as well as common scales. This chapter addresses the sex pheromones and androconial scales in the male wing of the genus Pieris (Pieridae), mainly those of Pieris melete and Pieris rapae. Their significant features are as follows. (i) The androconial scales are distributed in large regions on the dorsal surfaces of the fore and hind wings. (ii) The male feeds on the raw materials for the sex pheromone only during the larval stage. (iii) Sex pheromone and its precursor are produced by the androconial scale forming cells during the pupal stage, and the produced substances are stored in the androconial scale. (iv) The androconial scales are much more easily detached from the wing than the common scales. (v) The sex pheromone is released concomitant with the detachment of the androconial scale. (vi) The androconial scales are differentiated in the pupal wing epithelium, and their mother cells are the daughter cells of the common scales. (vii) All common and androconial scale forming cells degenerate to death immediately before eclosion. Many of these features are fairly different from those of danaine butterflies (Nymphalidae), which is addressed in Chap. 4 . Based on these features of Pieris, the mechanisms of pheromone production, storage, and emission in male wings are discussed.