PROC. ENTOMOL. SOC, WASH. 87(3), 1985, pp. 622-633 NUPTIAL FEEDING IN SEPEDON SPP. (DIPTERA: SCIOMYZIDAE) Clifford O. Berg .and K.arl Valley (COB) Department of Entomology, Cornell University, Ithaca, New York 14853; (KV) Bureau of Plant Industry, Pennsylvania Department of Agriculture, Har-risburg, Pennsylvania 171 10. Abstract.— Couning males of Sepedon fuscipennis fiiscipennis Loew, S. f. Jlor-idensis Steyskal, and 5. aenescens Wiedemann release a nearly clear liquid anally that the females feed on during copulation. Other observers have indicated that an opaque, semi-solid nuptial food is secreted orally by males of S. aenescens. S. senex Wiedemann, 5. phimbella Wiedemann, and 5. ferruginosa Wiedemann. Males of S. f. fuscipennis also attract and nourish potential mates with foods (e.g. dead snails) that they discover and defend, and some Sepedon males mate without offering females anything. These systems are compared with other insect mating systems in order to suggest fruitful avenues for future research. Reports in the literature suggest that mating in most species of Sciomyzidae (Diptera: Acalyptralae) is simple and direct. Published observations on a number of species in the genera Antichaeta, Dictya, Elgiva. Perilimnia, Pherbellia. Shan-nonia. and Tetanocera (see papers cited by Berg and Knutson, 1978, p. 240) all indicate that the males exhibit no distinctive courtship behavior. They simply leap onto females and quickly establish genitalic contact. Neff and Berg (1966) observed that premating behavior in some species of Sepedon is far more elaborate than that indicated above. We have confirmed and extended their observations by studying one species that they also studied and two taxa not included in their report. In all three taxa, the male liberates an almost clear liquid anally that the female feeds on during copulation. Our observations and those of others indicate that the use of attractive and/or nutritive substances, secreted anally or orally by the male, may be widespread in Sepedon and related genera. They also suggest differences in sites of origin of the nuptial food, and in nuptial uses of foods other than secretions, and indicate that matings sometimes occur without any food being transferred. This paper is written to present our observations on the sequence of premating acts of Sepedon fuscipennis fuscipennis Loew, 5. / floridensis Steyskal, and S. aenescens Wiedemann, to enter some contrasting observations of others into the published record, to discuss and try to explain the obvious diversity and puzzling paradoxes reported, and to note the remarkable convergence in mating systems between Sepedon and Panorpa scorpionflies. Courtship of Sepedon fuscipennis floridensis Although described as a subspecies (Steyskal, 1951), S. f. floridensis is easily distinguished from 5. / fuscipennis, and it probably should be recognized as a
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