The occurrence of a sphragis and genital modification in Hypermnestra, Archon and Sericinus (Lepidoptera: Papilionoidea: Papilionidae)

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ABSTRACT In certain butterfly species males attach a large external mating plug termed a sphragis to the female abdomen during mating. This is derived from male accessory secretions and covers the female ostium bursae and surrounding areas, thus preventing or delaying remating. Specimens of the poorly studied parnassiines, Hypermnestra helios, Archon apollinus, A. apollinaris and Sericinus montela, were examined for the presence or absence of a sphragis. The morphology of the female genitalia, normally modified in sphragis-bearing species, was also examined, as was that of males. In H. helios, the female sterigma was membranous, with a fleshy projection behind the ostium bursae. The sphragis of this species was a solidified secretion deposited over the sterigma, especially thickly on the projection, so that it consistently assumed an irregular conical shape. In the Archon species, the sclerites of the sterigma are fused to form a large sclerotised plate around the ostium bursae, and a sphragis was present as an irregularly smeared male secretion covering the genital plate, associated with long scales from the male valvae attached laterally in rows on either side; this was found at low frequency in mated A. apollinus and A. apollinaris. In S. montela, the area surrounding the ostium bursae is sclerotised and deeply invaginated, forming a small cup. Mated females of S. montela bore a sphragis that formed a lid sealing the cup, being typically a thin wafer of solidified secretion and found at a somewhat low frequency, and also the inner wall of the cup often had a thin lining of a male accessory secretion. The evolutionary status of the sphragis in relation to the modification of the genitalia of both sexes in each genus is discussed.