Current Research in Neuropterology. Proceedings of the Fourth International Symposium on Neuropterology. Bagntres-de-Luchon, France, 1991. Canard, M., Aspiick, H. & Mansell, M.W. (Eds). Toulouse, France, 1992. Pp. 193-202.

A preliminary survey of the possible evolutionary relationships of the gonarcus-parameres complex in some Myrmeleontidae (Insecta : ) *

Emilio INSOM & Salvatore CAW] Universith di Camerino, Italy Universith di Firenze, Italy

ABSTRACT

The authors have studied the variability of the gonarcus-parameres complex in tribes of Neuroptera. Although the results must be deemed as preliminary and subject to revision, it is clear that this complex of more or less sclerotized structures shows considerable variability. While there is no doubt as to its usefulness as a specific- and generic-diagnostic character, some evolutionary trends are also apparent at higher taxonomic levels which may be useful in determining the phyletic relationships of tribes and families. This is particularly true, since it may be assumed that the evolution of these characters was independent of the selective demands of the environment, and therefore less liable to convergent adaptation.

Key words : Myrmelwntidae, Ascalaphidae, gonarcus-parameres complex, morphology.

INTRODUCTION

Until now, the discussion of has been based on wing venation and its possible evolution (MARKL1954 ; STANGE1970). That wing nervature is often significant is certain, but there are other structures, such as the gonarcus-parameres complex, which are certainly useful in understanding the relationships among the different Myrmeleontoidea. The selective pressures which have moulded these structures are obviously different from those which operated on the wings. While the latter were selected

* This research was financially supported by grants from the Ministero dell'Universiti e della Ricerca Scientifica e Tecnologica (60 % funds).

193 for their mechanical fitness and had to keep a reticulation to support a smooth wing membrane (INSOM1991), the structures of the reproductive apparatus had to meet the requirements of a purely species-specific selection ; they were thus free to change significantly. Generally the gonarcus-parameres complex has been stu- died morphologically (TJEDER1970 ; ACKER1960 ; NEW 1989) or, usually, for identification of Neuroptera species. We have thus thought it worthwhile to study the comparative morphology of the gonarcus-parameres complex, so as to determine possible homologies between its constituent parts and to assess their possible significance in the detection of the phyletic relationships among the various genera of Myrmeleontidae.

MATERIALS AND METHODS

The genera studied are listed in Table I. The last abdominal segments of the specimens studied were investigated both by optical microscopy (OM) and by scanning electron microscopy (SEM). For the purpose of OM examination, the tip of the abdomen of the specimens was first soaked in hot water with the addition of some drops of NH40H. The last segments were then removed and : i) transferred to hot lactic acid for about 10 min, ii) rinsed with distilled water, iii) moved to a hot water solution of 10 % KOH for about 10-15 min, iv) rinsed again with dis- tilled water and v) transferred to Faure's fluid without arabic gum, where they were studied. Some specimens were lightly stained with Chlorazol black E in or- der to highlight the membranous structures. The specimens were finally stored in glycerol 84-88 %. For the SEM study, the segments were : i) rehydrated, ii) cleaned, iii) dehy- drated by the usual alcohol series, iv) moved to amylacetate, v) moved to the cri- tical point-drying Euroscop CPD 750@ apparatus, and vi) coated with gold in an Agar Aids@ sputter coater. Observations were made at lOkV with a Stereoscan 200@ (Cambridge Instruments Ltd) scanning electron microscope.

DESCRIPTIONS OF STRUCTURES

On the evidence of the material studied, we can now distinguish at least six gonarcus-parameres complex types (Table 11) : 1. Type A (, Stilbopteryginae, Ascalaphidae partim) ; 2. Type B (Myrmelontini) ; 3. Type C (Isoleontini [Nemoleontini] : Cueta (NavBs, 1911) ; 4. Type Dl (Myrmecaelurini) ; 5. Type D2 (Distoleontini) ; 6. Type E (Acanthaclisini) . Type A. This type has a well-developed and sclerotized gonarcus ( Ram- bur, 1842 ; Pseudopalpares Insom & Cafii, 1988 ; Parapalpares Insom & Carfi, 1988 ; NavBs, 1912 ; Indopalpares Insom & Cad, 1988). In only a few instances does it show a tendency to become membranaceous (Trichocercus Insom & Carfi, 1988 ; Goniocercus Insom & Ca&, 1988). Caudal to the gonarcus there Male genitalia of Myrmeleontidae are the parameres separated by the pelta, which is usually well-developed. It is suprising how very similar morphologies of this type are to be found in both the Palparini and in at least two tribes of Ascalaphidae (Suhpalacsini and Encyoposini) and in the subfamily Stilbopteryginae as shown by KJMMINS(1940), ACKER (1960) and NEW(1982).

Table I. Distribution of gonarcus-parameres complex types in some tribes of Myrmeleontidae. Genera asterisked (*) were studied by the authors ; the other genera are quoted from authoritative descriptions.

Epacanthacl~sis Okamoto. 1910 Dendroleontlnl Dendroleon Brauer. 1866 I I Afghanoleon Holzel. 1972 * Acanthaclls~s Rambur. 1842 Acanthacl~slnl * Syngenes Kolbe, 1897 * Centrocl~s~sNavbs. 1909 * Nophls Navbs, 1912 Aspoecklna Holzel, 1969 Myrmecae lurlnl * Myrmecaelurus Costa. 1855 Nohoveus Navbs, 1919 LoPezus Navbs. 1913 * Iranoleon Holzel, 1972 Maracanda McLachlan, 1875 Sol ter Navhs. 1912 * Gepus Navbs, 1912 Ge~ellaHolzel, 1968 Isoleon Esben-Petersen. 1930 * Cueta Wavhs, 1911 * Euroleon Esben-Petersen. 1918 * Hn-meleon L. 1767 I Morter Navhs, 1915 Mesonernurus Navbs, 1919 Geyra Esben-Petersen, 1920 Myrme leontinae * Macronernurus Costa, 1857 Pignatellus Navhs, 1914 Quinemeurus Kinmins. 1943 Gangui l us Navbs, 1912 Deutoleon Navbs. 1927 Distoleontini Barreja Navhs. 1915 D 2 Graonus Navbs, 1922 * Nemoleon Navhs, 1909 * Neuroleon Navbs, 1909 Nicarinus Navbs, 1914 Pseudoformi cal eo Wee 10, 1909 Creoleon Tillyard, 1918 * Distoleon Banks. 1910 Indofanes Banks, 1940 Nedrol edon Navhs, 19 14 Hegistopus Rambur, 1842 Gnmocnemia Schnelder, 1845 * Palpares Rambur, 1842 * Parapalpares Insom 6 Carfi, 1988 * Tri chocercus I nsom h Carf i , 1988 " Goniocercus Insom h Carfi, 1988 Pseudopalpares lnsom h Carfl. 1988 Indopalpares Insom b Carfl. 1988 Pamares Mansell. 1990 * Nosa Navbs. 1911 * Stenares Hagen, 1866 Table 11. Schematic arrangements of different gonarcus-parameres complex types (A-E) in

tribes and families resulting--. in groups of pseudoaedeagus structures (1-111). A = Palparini (Myrmeleontidae) ; Stilbopteryginae ; ~uh~alacsini;-~ncio~osini (~scala~hidae).- B = Dendroleontini, Myrmeleontini. C = Nesoleontini (Isolwntini partirn). Dl = Myrme- caelurini. D2 = Distoleontini. E = Acanthacliiisi. G = gonarcus ; 1.m. = lamina medialis ; L.s = lamina subterminalis ; M = mediuncus ; P = parameres ; p.a. = pro- cessus apicalis ; Pt = pelta.

The structures that form the pseudoaedeagus are : i) gonarcus (G) which is usually the larger structure, ii) parameres (P) either fused or partly fused with the gonarcus though their line of suture is usually quite clear, iii) pelta (Pt) arranged caudally between the two parameres, and covered by many setae. Male genitalia of Mynneleontidae

For us, this condition appears the most generalized. It is obvious that this structure differs in its morphological details, and therefore the gonarcus-parame- res complex can appear different from this type. However, by careful observation it can always be placed in type A, for instance : gonarcus alone (Nosa), or gonar- cus and parameres entirely fused together (Stenares Hagen) (INSOM& CARF~ 1988).

Type B. Its component parts are not fused to each other, but are united by mem- branes. The gonarcus always maintains its dorso-lateral position, while the para- meres are ventro-lateral and caudally directed ; sometimes distally there is a mediuncus (M). In Myrmeleontini the two parameres have cranially directed apo- physes that are not united with each other. The pseudoaedeagus is neither as well nor as strongly developed as in type A.

Type C. So far found only in Cueta [Tribe Nesoleontini sensu MARKL(1954), HOLZEL(1969) ; Isoleontini sensu HOLZEL(1972)l. It has a rather complicated structure. We maintain that only the gonarcus may be really homologous with the so-called structures in the two above-mentioned types ; the gonarcus can be saddle-shaped or dorsally straight, as can be clearly observed in the works of HOLZEL(1969, 1972, 1982, 1983) ; the parameris, or rather the structure so na- med by various authors, is single, without any sign of original duplication. Caudal to the gonarcus, we notice the mediuncus and another accessory structure, and we maintain that it may, instead, correspond with the true parameres. This structure has an internal apophysis, lamina medialis (l.m), which is cranially directed (Fig. 1).

Type Dl. This is typified by a well developed gonarcus, which may be either ap- proximately cylindrical, thin and with a wide base (Mymcaelurus Costa, 1855 ; Nophis NavBs, 1912 ; Nohoveus NavPs, 1919) or short and wide (Zranoleon Hijl- zel, 1968) ; in both instances, the parameres are small and end in two small sharp upwardly pointing protuberances.

Type D2. This type appears to be directly derived from Dl. The gonarcus is much reduced and dorsally becomes a thin bridge, often entirely membranaceous. The parameres are fused medially and have internal apophyses which are fused to each other for their entire length. Caudally, the parameres are continued by two more or less developed appendices which are dorsally bent ; moreover, anteriorly and dorsal to these structures there is a more or less rounded structure, lodged in an excavation, and covered by many setae. The morphological significance of this structure is unclear.

Type E. Also in this case, the pseudoaedeagus is much modified, as in type C, being formed by four pieces which are difficult to identify, except for the gonar- cus . In the Acanthaclisini we observe, proceeding backwards, gonarcus, a dorsal mediuncus, dorsal parameres, and caudally the lamina subterminalis (L. s) . POSSIBLE RELATIONSHIPS BETWEEN THE DIFFERENT GONARCUS- PARAMERES COMPLEXES STUDIED

From the foregoing descriptions we may conclude that, except for the tribe Isoleontini, the gonarcus-parameres complex is basically homogeneous within each tribe. Within the Isoleontini there are, however, three different patterns of this complex (Table I). As the evolution of this complex may safely be presumed to be species-specific, it follows that it may be useful in order to reconstruct the phylogeny of the Myrmeleontoidea. Considering their structure, we may group the different patterns of pseudoae- deagus in at least three groups (Table 11) : I) The pseudoaedeagus is formed by three pieces : gonarcus, parameres and either mediuncus or pelta (except in some instances of type B where there may, perhaps, be both mediuncus and an incipient pelta) ; 11) The pseudoaedeagus is formed by four parts : gonarcus, mediuncus, parameres (the internal apophyses which in Cueta are variously developed, and may be fused together so as to form the lamina medialis), and lamina subterminalis ; 111) Pseudoaedeagus reduced to two pieces : gonarcus and parameres (the latter being fused together, and thus f~rmingwith their fused apophyses an internal medial lamina). Within the first group we may separate two evolutionary trends : one leading to complexes where all the pieces are almost entirely fused together and eventually partly desclerotized. Samples of these trends may be found among the Suhpalac- sini and the Encioposini (Ascalaphidae), Palparini and Stilbopteryginae (Myrmelwntidae), as far as this last subfamily is concerned, see KIMMINS(1940), ACKER(1968) and NEW (1982). Among the Palparini we have genera with consi- derably reduced sclerotization (Trichocercus, Goniocercus), or even instances where the pseudoaedeagus is a single structure resulting from the fusion of all its basic pieces, which can no longer be clearly distinguished (Stenares), or even reduced to the gonarcus, which is the only clearly identifiable piece (Nosa), ob- viously in these instances, and especially in the last two, the gonarcus is the pre- vailing structure. The other trend (type B) is more conservative. We can, indeed, always distin- guish gonarcus, mediuncus and parameres. Within the Myrmelwntini, the mediuncus is not always really separated from the gonarcus, a line of suture always being seen between the two. Caudally the mediuncus is continued by a transparent, hardly desclerotized lobe. In group I1 we have, for the time being, included the tribes Acanthaclisini and Nesoleontini. The situation in these two tribes is remarkably different both with respect to the other Myrmelwntoidea and from each other : their only seemingly common feature is to have the pseudoaedeagus made up of four pieces. In the Acanthaclisini (type E), the most important character is the great reduc- tion of the gonarcus and of all the other structures, while a new one, the lamina subterminalis, becomes the prevailing one. Male genitalia of Myrmeleontidae

Within the Nesoleontini (type C), which are included by HOLZEL(1972) in the Isoleontini, the structures of the pseudoaedeagus are very different from those existing in the true Isoleontini. This is the main reason which prompts us to consider the two tribes as distinct. The only structure which may be safely compa- red with those of the Myrrneleontinae is the gonarcus. In the apical part of the pseudoaedeagus, behind the gonarcus, we find three structures. The first is roof- shaped and is membranaceous along its midline (Fig. 2B) ; it appears very delica- te and its margins and shape may be observed well only by a very careful prepara- tion. The second, caudal to the first, has been commonly called the mediuncus and, at least in the specimens studied [Cueta facile Banks, 1939 ; C. mysteriosa (Gersacker, 1893) ; Cueta sp.] shows a dorsal groove (Fig. 2C), which may be seen both by SEM and by OM (thus we exclude its being an artifact). Moreover, its outer surface is very similar to that of the parameres of the other Myrmeleonti- dae. Inside it continues as a lamina medialis, more or less developed according to species and cranially directed. The third structure, which is ventral to the previously described one, is both sclerotized and concave ; medially and on the inside, it has a crista more or less developed and cranially directed, while its ventro-caudal end is terminated by a spike-shaped bent process dorsally directed, processus apicalis (Figs 1 & 2A).

Fig. 1. Cueta facile : apical portion and internal structure of pseudoaedeagus. c = crista ; other figures as in Table 11. This structure looks superficially like the lamina subterminalis of type E, but we do not consider that the two are really homologous, the reason being that in the Nesoleontini the third structure appears as the direct continuation of the immedia- tely preceding structure. We thus propose that it may be a special modification of this structure, while the true lamina subterminalis of type E is a new structure. Thus, considering the previous descriptions, we think that the pseudoaedeagus of the Nesoleontini is really formed by three parts : gonarcus, mediuncus and pa- rameres, the last of them being considerably modified and secondarily subdivided Fi. 2. Gonarcus parameres complex of Cuefa sp. A = lateral view : B = caudal vicw ;C: = details of parameres. Figures as in Table II.

200 Male genitalia of Myrmeleontidae into a dorsal and a ventral portion. This gives the complex the appearance of being formed by four pieces. It is thus apparent that the Cueta is considera- bly isolated, in this respect, from the other Myrmeleontidae. The evolution of its pseudoaedeagus must have been very complex and its morphological interpretation unclear. Group 111 has the most specialized gonarcus-parameres complex. It may be subdivided into two types Dl (Myrmecaelurini) and D2 (Distoleontini). These are apparently closely related : the former seems intermediate between that of the Myrmeleontini and type D2, while the latter, is distinguished by a saddlebag-like gonarcus, dorsally reduced to a thin bridge which is often unsclerotized. The main feature of type D2 is its hooking system depending on a single structure, derived from fused parameres, and secondarily bifid, internally continued by a medially and cranially directed lamina.

Fig. 3. Possible alternative morphological relationships of the gonarcus-parameres complex ba- sed on suggested homologies. The foregoing discussion is clearly a preliminary analysis and thus, at this stage of our research, our sketches (Fig. 3) do not propose a phylogeny of the Myrmeleontoidea, but only the possible morphological evolution of the gonarcus- parameres complex.

REFERENCES

ACKER, T.S. 1960. The comparative morphology of the male terminalia of Neuroptera (). Microentomology 24 : 25-84. HOLZEL, H. 1969. Beitrag zur Systematik der Myrmelwniden (Neuroptera-Planipennia, Myrmeleonidae). Annalen des Narurhistorischen Museums, Wien 73 : 275-320. HOLZEL,H. 1972. Die Neuropteren Vorderasiens IV. Myrmeleonidae. Beitrdge zur Natur- kundlichen Forschung in Slldwestdeutschland 1 : 3-103. HOLZEL,H. 1982. Insects of Saudi Arabia. Neuroptera : Fam. Myrmelwnidae. Fauna of Saudi Arabia 4 : 244-270. HOEEL, H. 1983. Insects of Saudi Arabia. Neuroptera : Fam. Myrmeleonidae (Part 2). Fauna of Saudi Arabia 5 : 210-234. INSOM, E. 1991. Morpho-functional hypotheses on some structures of the wings of the Neu- roptera. In : Lanzavecchia, G. & Valvassori, R. (Eds) Form and Function in Zoology. Selected Symposia and Monographs U.Z.I. 5 : 267-279,Mucchi, Modena, Italy.

INSOM, E & CARF~, S. 1988. Taxonomic studies on Palparini (sensu Markl, 1954). I : The genus Pabares Rambur, 1842 partim (Neuroptera : Myrmeleontidae) with the proposal of its division and description of new genera. Neuroptera International 5 : 57-78. KIMMINS, D.E. 1940. The genus Stilbopteryx Newman (Neuroptera). The AnnaLs and Maga- zine of Natural History, London, Ser. 11, 5 : 449-462. MARKL,W. 1954. Vergleichend-morphologische Studien zur Systematik und Klassifikation der Mymeleoniden (Insects, ~euro~tera).Verhandlungen der Naturforschenden Gesell- schaj?, Base1 65 : 178-263. NEW, T.R. 1982. A reappraisial of the status of the Stilbopterygidae (Neuroptera : Myrme- lwntoidea). Journal of the Australian Entomological Society 21 : 71-75. NEW, T.R. 1989. Planipennia (Lacewings). In : Fischer, M. (Ed.) Handbuch der Zoologie, Eine Naturgeschichte der Sttimrne des Tierreiches IV (30) : 1-132. Walter de Gruyter, Berlin & New York. STANGE, L.A. 1970. Revision of the tribe Brachynemu~iof North America. Univer- sity of California Publications in Entomomology, Berkeley 55 : 1-92. TJEDER,B. 1970. Neuroptera. In : Tuxen S.L. (Ed.) Taxonomist's Glossary of Genitalia in In- sects. 89-99.Copenhagen, Denmark.

Addresses of authors :

Dr Emilio Insom Dr Salvatore Carfl Dipartimento di Biologia Molecolare, Dipartimento di Biologia Animale e Cellulare e Animale Genetica Universita di Camerino Universid di Firenze Via F. Camerini 2 Via Romana 17 1-62032 Camerino (MC) 1-50125 Firenze Italia Italia Bibliography of the

Bibliography of the Neuropterida Reference number (r#): 7295

Reference Citation: Insom, E.; Carfì, S. 1992 [1992.06.??]. A preliminary survey of the possible evolutionary relationships of the gonarcus-parameres complex in some Myrmeleontidae (Insecta: Neuroptera). Pp. 193-202 in Canard, M.; Aspöck, H.; Mansell, M. W. (eds.). Current Research in Neuropterology. Proceedings of the Fourth International Symposium on Neuropterology (24-27 June 1991, Bagnères-de-Luchon, Haute-Garonne, France). Privately printed, Toulouse, France. 414 pp.

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