ZOBODAT - www.zobodat.at Zoologisch-Botanische Datenbank/Zoological-Botanical Database Digitale Literatur/Digital Literature Zeitschrift/Journal: Denisia Jahr/Year: 2006 Band/Volume: 0019 Autor(en)/Author(s): Schaefer Carl W. Artikel/Article: The Genital capsule of some Aradidae (Hemiptera, Heteroptera) 215-224 © Biologiezentrum Linz/Austria; download unter www.biologiezentrum.at The Genital capsule of some Aradidae (Hemiptera, Heteroptera)1 C.W. SCHAEFER Abstract: The aradid genital capsule, and the eighth abdominal segment, differ in several important res- pects from those of other members of the heteropteran infraorder Pentatomomorpha. The eighth ster- num is unusually well developed and protects the venter of the capsule; a pair of lateral projections, the eighth hypopleurites or paratergites, arising from the eighth sternum, bear the eighth spiracles, which are often nonfunctional; internal structures of other pentatomomorphans (cuplike sclerite and median projection) are fused (as they often are in other pentatomomorphans), but in aradids are often enlar- ged, as major supports of the aedeagus. Most significantly, the internal (anterior) opening of the geni- tal capsule has been „displaced“ posteriorly; as a result, the two openings (internal and external) are very close to one another and, in the case of Aneurus (Aneurodellus) brouni, have become one. A scheme is presented to explain this displacement. Key words: Aradidae, Aradimorpha, genital capsule, Heteroptera, pygophore. Introduction etic (SCHAEFER 1977, 1978, 1980; see also SCHAEFER 1981a, 1981b). It seems reason- The heteropteran infraorder Pentato- able also to consider the genital capsule of momorpha contains two groups, the Tri- the Aradidae, to see how it differs from that chophora and the Aradoidea. The five su- of the Trichophora. What follows is merely perfamilies in the former Coreoidea, Idios- a start, a prolegomenon, to a deeper study of toloidea, Lygaeoidea, Pyrrhocoroidea, and the aradid genital capsule and its functional Pentatomoidea (HENRY 1997) all have ab- and phylogenetic meanings. dominal trichobothria (hence ”Trichopho- In early 1989 I spent several weeks at ra”), whereas the Aradoidea does not. The Christ Church College (now University) in phylogenetic relationship of the Aradidae to Canterbury, New Zealand. I dissected and the remainder of the Pentatomomorpha has took notes on the genital capsules of several been, in a sense, hesitant or tentative (see aradid species, and followed this with a day SWEET 1996). at the B.P. Bishop Museum (Honolulu, The genital capsule, or pygophore, of Hawaii), taking briefer notes on a few more male heteropterans contains the parameres species; more recently, I have looked at two (claspers) and the structures for copulation more species (Aneurus inconstans UHLER and (aedeagus). Because the capsule is a com- Dysodius lunatus (FABRICIUS)). Here I sum- plex structure, and because various of its marize these notes as a basis for further study parts have evolved in different groups inde- and suggest a highly speculative pathway for pendently of others of its parts, the capsule the development of the aradid genital cap- provides useful characters for phylogenetic sule. analysis and speculation. I have studied the genital capsules (py- gophores) of trichophoran males and dis- cussed their value in family-group phylogen- Denisia 19, zugleich Kataloge 1With enormous pleasure, I dedicate what is good here (and only what is good) to Ernst Heiss, colleague, fellow het- der OÖ. Landesmuseen eropterist, and (best of all) friend. Neue Serie 50 (2006), 215–224 215 © Biologiezentrum Linz/Austria; download unter www.biologiezentrum.at Fig. 1: Schematic diagram of evolution of capsules of the Bishop Museum specimens relationship of external and internal Methods openings of aradid genital capsule. were examined on the specimens, because of I had representatives of all eight aradid d. = dorsal, ext. = external, int. = internal, time constraints; the notes on these are per- op. = opening, r. = rim, v. = ventral, subfamilies, although for some the sample is force less detailed. Of necessity, nearly all x = dorsal rim of external opening plus dorsal edge of internal opening. very small. The genital capsules of the the species are from or near New Zealand, Christ Church specimens were dissected and because of this and because of the small out, softened in warm water, and studied un- number of species, the conclusions are high- der a dissecting microscope, as were those of ly tentative. Unless otherwise stated, one the two species most recently studied. The specimen was examined of each species. 216 © Biologiezentrum Linz/Austria; download unter www.biologiezentrum.at The scientific names have been checked in separate structures, and in many bugs in KORMILEV & FROESCHNER (1987). which they have become united, their sepa- rate origin is sometimes discernible; separate As a necessary point d’appui, I point out or composite, these structures guide the my conviction that the entire genital cap- aedeagus during copulation. A fuller de- sule is the modified ninth sterrnum, a con- scription, with my reasons for believing my viction supported by the relationships of the assertions, may be found in SCHAEFER various connecting membranes (see SCHAE- (1977, 1980). FER 1977, 1980); in my view, the dorsum (the tergum) of the ninth segment has been The eighth segment in male tricho- lost or reduced to a thin, often membranous phorous is usually a simple ring, its dorsum strip, just anterior to the proctiger (the membranous and the remainder lightly tenth segment). This ninth tergal remnant sclerotized. The spiracles, or spiracular rem- occasionally retains some degree of scler- nants, lie laterally in the membranous por- otization or, less occasionally, attains some tion. Although too membranous and poorly slight degree of secondary sclerotization sub- developed to be clearly differentiated, this sequent to the remnant’s reduction. I have region appears to be what SWEET (1996) found no reason to believe this is not true terms a hypopleurite, defined in other ab- also of Aradidae (and it is true also of Redu- dominal segments as the sclerite bearing the viidae (SCHAEFER 1999)), despite the re- spiracle. In Aradidae, unlike in other Pen- markable differences in this family. There- tatomomorpha, this spiracle-bearing sclerite fore, in what follows, “dorsal” and “ventral” of the male’s eighth segment is well devel- refer to the original state; i.e., the terms are oped, and is usually termed the eighth morphological and refer to the dorsal and paratergite. Sweet, however, believes this ventral parts of the external, originally spiracle-bearing structure of the male aradid terminal (posterior), opening of the genital to be a hypopleurite. He reaches this con- capsule. clusion after an exhaustive survey not only of Heteroptera, but of groups closely and The capsule itself may be thought of (in distantly related to Heteroptera and its original state) as a short tube, one of Hemiptera. However, in Aradidae, the pres- whose openings, the anterior one, opens in- ence of muscle scars on these structures in- to the interior of the insect; the other open- dicates they may not in fact be hypopleu- ing is posterior and opens externally, to the rites; SWEET (1996) suggests such scars in outside world; it is through the latter open- Aradidae are plesiomorphies. If they are not, ing that the anus deposits its materials and then these spiracle-bearing structures in the aedeagus deposits its materials. Because Aradidae may in fact be paratergites. How- the latter, external, morphologically posteri- ever, because only Sweet has so far consid- or, opening has these responsibilities, it is in ered this question in detail, I here use his some phyletic lines modified the better to term, while recognizing that further work fulfill them: the edges surrounding this pos- may prove it inaccurate. In Aradidae, the terior opening are the dorsal, the lateral, eighth sternum is also well developed. and the ventral rims, and extending anteri- orly from these rims are the dorsal, the lat- eral, and the ventral walls, these together Results comprising the body of the capsule itself. The genital capsules of several bugs were These rims may be modified (the ventral dissected, and the descriptions of these are rim is usually modified) the better to ac- more detailed than the descriptions of other commodate and enhance the performance bugs whose capsules were merely removed of the anus and the aedeagus – especially the from the specimens and observed. In these aedeagus. The aedeagus lies towards the descriptions, 8S and 9S and 8T and 9T ventral rim, which is infolded upon itself; stand for eighth and ninth sternum and ter- the terminus of this infolding may be turned gum, respectively. As indicated above, the up, as a transverse ridge, and from this arise posterolateral spiracle-bearing extensions two structures, the cuplike sclerite and the (projections) of the eighth segment are median projection; these originally were termed here “hypopleurites VIII”. 217 © Biologiezentrum Linz/Austria; download unter www.biologiezentrum.at Mezirinae dian region of ventral rim. No transverse Ctenoneurus myersi KORMILEV (capsule ridge. Median region posteriorly joined to dissected). Eighth segment: Broad, well much modified cuplike sclerite and median sclerotized ventrally and laterally, with nar- projection. Cuplike sclerite indistinguish- row nearly membranous strip dorsally; 8S ably fused with