Falces and clavuius, hitherto disregarded parts of the male genitalia in Eupithecia species (Lepidoptera, Geometridae)*

Transcription

1 ANNALES HISTORICO-NATURALES MUSEI NATIONALIS HUNGARICI Tomus 79. Budapest, 1987 p Falces and clavuius, hitherto disregarded parts of the male genitalia in Eupithecia species (Lepidoptera, Geometridae)* by A. M. VOJNITS, Budapest A. M. VOJNITS: Falces and clavuius, hitherto disregarded parts of the male genitalia in Eupithecia species (Lepidoptera, Geometridae). Annls hist.-nat. Mus. natn. hung : Abstract The falces, a peculiar structure originating bilaterally from the tegumen, and its clavate termination the clavuius, represent characteristic parts of the male genitalia in Eupithecia species. Besides the description of these two structures, all other parts of the male copulatory organ also discussed. With 27 photos on 3 plates. When surveying Iepidopterological literature, expecially works concerning Eupithecia species, one finds it rather striking that the several organs and parts are evaluated defined and designated in the most diverse fashion. Indeed no author has ever paid any attention to a special structure of the male copulatory organ, a part which is the best characteristic for the entire taxonomix group. Even if it is shown in the figures by far not a general feature it is nowhere discussed. In the following I propose to describe the structure in question, and to treat also the other parts of the male copulatory organ. Besides my own investigations, I refer mostly to Noth American authors. Uncus The typical Eupithecoid uncus is a structure atop of a wider, triangular base of diverse length. Apically bifid** in the majority of the species, the characteristically beakshaped uncus is formed by a dorsally stronger and ventrally weaker sclerotized hook. Among the most frequent Palaearctic species such is the satryata-group. Though in most cases the dorsal part of the more robust one, the reverse situation also occurs (cf. the Palaearctic lariciata FRR., oxycedrata RMBR., and the Nearctic nevadata-group). The dorsal part can also be quite short and thus displaying a transition towards the uniapical type. In the species representing the long type of the uniapical type, the apex of the uncus is strong (the Palaearctic denticulata TR., centaureata DEN. et SCHIFF., and the Nearctic palpata PACKARD as well as the mutata-gvoxxp). A medium long uncus, as compared to the entirety of the genitalia varies between very squat (homogrammata DIETZE) and very slender (lanceata HBN.). A special group, composed of the mainly East Palaearctic species, e.g. fragmentaria VOJNITS, acerba VOJNITS, which displays an uncus which is basically nothing more than a wide and flat, distally incised plate. The uncus of a Nearctic species (coloradensis HÜLST) is short, membranous, a nearly mdimentary structure. Tegumen A largely triangular formation, extending from the uncus to the conjointment of the valvae and the vinculum, its base varying and its lateral sides subtending diverse angles, rounded above and there bearing the uncus. Its width as well as its height rather variable, and it apparently lacks any feature applicable for classification or identification of the species. Its apparent shape depends largely on dissection technique and imbedding on the slide. *Thc genitalia of Eupithecia species I. The male copulatory organ. **A good example of terminological difficulties: there are two kinds of double uncus: with two separate branches (in Melticta, Rhopalocera), or single-branched but biapical (bifid) owing to a suture. However, the bifid one is often "translated" as "double-branched". In addition, the bifid uncus is termed "hooded" in American literature.

2 180 A. M. VOJNITS Falces The tegumen emits bilaterally a very peculiar structure, similar to which and, as characteristic of an entire taxonomic group, is not known elsewhere in the order Lepidoptera.* The two lateral and heavily sclerotized branches fuse medially to constitute an unpaired structure which still shows clearly the formerly discrete halves. On both sides of the line of fusion the surface of the plate is sculptured and is ismilar to a war hammer; actually its stalk is like a half tube which usually flattens out on the slide; its tapering apical part is more or less spinose and thereby displays, in contrast to the entire structure, a certain amount of diffcrentation per species group. I designate it as clavuius (Plate I: Figs 1-9, Plate II: Figs 10-18, Plate HI: Figs 19-27). Transtilla The dorsal arc of the anellus embracing the aedoeagus. The shape of the paired auricular lobes is largely dependent on imbedding. These too have never been discussed in detail. Vinculum The vinculum and the saccus are confused in several publications, or rather the vinculum remains unmentioned and the saccus is mistakenly cited as vinculum. The vinculum is situated between the tegumen and the saccus, effecting the articulation of the valvae. A highly uniform part of the male copulatory organ, without any special differentation excepting the two minute ampullae (elsewhere papillae) on both sides of the aedoeagus. They have not been examined in detail so far. Their shape, ratio of length and width, as well as their size and pilosity (shorter or longer, denser or scarcer) are characteristic for the speciesgroups. Saccus The antipodal part of the uncus in the male copulatory organ. It is usually short and wide, ending either rounded or truncate. In some species it appears rather elongated. In mainly the East Palaearctic species it is wide with obtuse angles (repetita VOJNITS, bohatschi STGR.). The wide base of the saccus may be incised (yiidaleppi VOJNITS). Also the Nearctic species show examples of both elongated and wide sacci. The shape of the saccus is much influenced by the imbedding process. In general, it should also be studied laterally, because it bears an androconial tuft of hairs in certain groups. Anellus So far not studied in detail. The sculpture of its median part is characteristic for certain groups. V a 1 v a The "typical" valva of the West-Palaearctic and Nearctic species is simple: the base is of varying length, the apex moderately pointed or rounded, generally more or less ear-shaped. Among the East-Palaearctic species they are more of a different shape, but such occur also among the West-Palaearctic and Nearctic species. The valva can be quite short and wide (undata FREYER and cimicifugata PEARSALL), or, in contrast, very narrow (pini RETZER and alpi nat a CASSINO). The ventral margin (= ventrum) of the valva bears appendices of diverse shape and development. Those which have a "striking" appearance are called sacculus in the American literature, and the valva itself as asymmetric (lanceata HBN., and segregata PEARSALL). Valvae which are deeply excised or rather constricted between the ventrum and the dorsal margin are generally wide (exiguata HBN., centaureata DEN. et SCHIFF., abbreviata STEPHENS, lariciata FRR). Neither these valvae nor the "typical" ones are naturally asymmetrical. No case is known among the Eupithecia species with incongruent right and left valvae. Such really dissymmetrical valvae occur among the Noctuids, as the apomorphic and allometric distortion of the symmetrical basic configuration. * A similar structure occurs also in some species belonging to the subfamily Larentiinae (Geometridae), e.g. in the genus Entephria HBN. However, its origin is quite different and thus cannot be homologus with the falces of the Eupithecia taxa.

3 References BOLTE, K. B. (1987, in print): Guide to the Geometridae of Canada (Lepidoptera). Subfamily Larentiinae. Genus Eupithecia. Ottawa, Agriculture of Canada, 283 pages and 286 figures. INOUE, H. et al. (1982) : Moths of Japan 1-H. Tokyo, Kyodo Printing Ltd. MCDUNNOUGH, H. J. (1949): Revision of the North American species of the Genus Eupithecia (Lepidoptera, Geometridae). Bull. Amer. Mus. Nat. Hist. 93: Author's address: DR. A. M. VOJNITS Zoological Department Hungarian Natural History Museum Budapest VIII. Baross utca Iungary 87/2794 Franklin Nyomda - Múzsák

4 Figs 1-9. Falces, clavuius and uncus of 1 = Eupithecia linariata D E N. et S C H I F F., 2 = E. succenturiata L., 3 E. denticulata T R., 4 E. impurata H B N., 5 = E. semigraphata B R U A N D, 6 E. icterata V I L L., 7 = E. orphnata B O H., 8 = E. millefoliata R Ö S S L R., 9 = E. distincîaria H. S.

5 Plate I I. to f\ u : :ar" 12 Figs Falces, clavuius and uncus of 10 = Eupithecia phimbeolata H A W., 11 = E. veratraria H. S., 12 = E. euphrasiata H. S 13 =. gemellata H. S., 14 = E. pusillata H B N., 15 = E. ochridata P I N K E R, 16 = E innotata H U F N., 17 = E. virgaweata P B L D., 18 = E. abbreviata S T P H.,

6 184 A. M. VOJNITS Plate I I I. Figs Falces, clavuius and uncus of 19 = Eupithecia iariciata F R E Y., 20 = E. pulchellata S T P H., 21 = E. pygmaeata H B N. 22 = E. alliaria D T G R., 23 ~ E. actaeata W L D R F F., 24 = E. intricata Z E T T., 25 = E. trisignaria H. S., 26 = E. pimpinellata H B N., 27 = E. graphata T R.