Genital Sclerites Research Articles

Beaded lacewings – a pictorial identification key to the genera, their biogeographics and a phylogentic analysis (Insecta: Neuroptera: Berothidae)

The present paper comprises the first illustrated key for the genera of the Berothidae. Distribution maps for all genera are provided and distribution areas are discussed. A phylogenetic analysis based on the matrix of morphological characters of Aspöck and Nemeschkal (1998) using additional taxa and a modified approach concerning the homology of the genital sclerites (Aspöck and Aspöck 2008) yielded the following conflicting results: (i) The Trichomatinae are nested within the Nosybinae – which is considered an implausible position. (ii) Within the Berothinae, the genus Podallea appeared as the sister group of Asadeteva + Nodalla, whereas previously it was the sister group of the Isoscelipteron clade. In addition, the phylogenetic relevance of a peculiar phenomenon concerning the sclerites of the seventh abdominal segment of the females is discussed.

Nomenclature and taxonomy of Telmatoscopus Eaton and Seoda Enderlein; with a discussion of parameral evolution in Paramormiini and Pericomaini (Diptera: Psychodidae, Psychodinae).

Historically, Telmatoscopus Eaton, 1904 has been a nomenclaturally and taxonomically problematic taxon as different authors have used different type species to define their concepts of the genus. Here it is shown that Pericoma advena Eaton, 1893 is the valid type species rather than Pericoma morula Eaton, 1893. Furthermore, the genus Seoda Enderlein, 1935 is revived for the genus comprising Pericoma labeculosa Eaton, 1893, P. morula and their relatives. The differences between Telmatoscopus and Seoda are described in detail based on historical and freshly collected material of the three putative type species. Four new synonymies are proposed: Panimerus havelkai Wagner, 1975 and Telmatoscopus seguyi Vaillant, 1990 are synonymized with Telmatoscopus advena, and Telmatoscopus incanus Nielsen, 1964 and Telmatoscopus vaillanti Withers, 1986 are synonymized with Seoda morula. A potential phylogenetic pattern in the male genital sclerites is discussed in detail. In Telmatoscopus, the jointed appendages of the gonocoxally derived parameral complex are separate small sclerites found near the bases of the distiphallic lobes of the aedeagus. In Seoda, they are fused medially to form a small, moveable triangular or arrow-shaped sclerite. Medial parameral sclerite fusion in Psychodinae is otherwise known to occur only in Pericomaini and the paramormiine genus Psychomasina Ježek, 2004; however, many genera of Paramormiini show an apparently intermediate condition where the parameres are fused in one end to form a V- or U-shaped "furca". It is hypothesized that Paramormiini is paraphyletic with respect to Pericomaini, as suggested in a previous phylogenetic hypothesis based on molecular data.

Mites of the superfamily Pygmephoroidea (Acari: Heterostigmata: Neopygmephoridae, Pygmephoridae) associated with Trox cadaverinus (Coleoptera: Trogidae) from the Far East of Russia, with description of a new genus and two new species.

Three species of the superfamily Pygmephoroidea (Neopygmephoridae: Pygmephoridae), phoretic on Trox cadaverinus Illiger (Coleoptera: Trogidae) are recorded from the Far East of Russia. A new genus, Troxodania Khaustov and Trach gen. nov. (Neopygmephoridae), and 2 new species, Troxodania magnifica Khaustov and Trach sp. nov. and Pseudopygmephorellus troxi Khaustov and Trach sp. nov. (Pygmephoridae), are described. Bakerdania sinanii Sevastianov and Zahida Al Douri, 1989 (Neopygmephoridae) is considered as a junior synonym of Troxodania decumanus (Krczal, 1959) comb. nov. The key to genera of neopygmephorid females which have median genital sclerites is provided. The taxonomic significance of the median genital sclerite in females of the family Neopygmephoridae is discussed.

Cockroaches of genus Muzoa: morphology of the male genital sclerites and description of one new species (Dictyoptera, Blattodea, Ectobiidae, Nyctiborinae)

The male genital sclerites of cockroaches of genus Muzoa Hebard 1921 are described for first time and the new species Muzoa curtalata sp. n. is described and ilustrated. A dichotomous key to identify the species of genus Muzoa is given.

Morphologic study of male genitalia and female description of Schistopeltis lizeri Rehn (Blaberidae, Zetoborinae, Triboniini)

The genital sclerites of the male, the female and the mature nymph of Schistopeltis lizeri are described. The genitalia ofS. lizeri, S. microschistos and S. peculiaris are compared. The generic status of Schistopeltis is validated although it has close relationship with Tribonium.

Intra‐specific variation in the morphology and the benefit of large genital sclerites of males in the adzuki bean beetle (Callosobruchus chinensis)

Rapid evolution has led to a large diversity in the sizes and morphology of male genitals across taxa, but the mechanisms driving this evolution remain controversial. In this study, we investigated the function of male genital sclerites in the adzuki bean beetle (Callosobruchus chinensis) and compared the length and morphology of genital sclerites between two populations that vary in their degree of polyandry. We found that the length of male genital sclerites was negatively correlated with copulation duration but positively correlated with the speed of matings with multiple females. Additionally, we found that the average length and number of genital sclerite spines of males from the more polyandrous population were larger than those from the less polyandrous population. We suggest that the genital sclerite of male adzuki bean beetles evolved by sexual selection, and a larger genital sclerite has a selective advantage because it allows for rapid copulations with multiple females.

A new species of Neoblattella Shelford (Blattellidae: Pseudophyllodromiinae) from Amazonas State, Brazil

Neoblattella mista sp. nov. is described and illustrated based on male genitalia and morphological characters of a single specimen collected in the town of Coari, State of Amazonas, Brazil. By studying the literature on the genus, we determined that N. mista sp. nov. differs from the other four known complexes in the morphology of its genital structures, including the supra-anal plate, subgenital plate, right and left phallomeres, median genital sclerite and tergal modification in the abdomen, and is placed in the new "mista complex".

Myrsidea povedai (Phthiraptera: Menoponidae), a New Species of Chewing Louse From Phainoptila melanoxantha (Passeriformes: Bombycillidae)

A description and illustrations are given for Myrsidea povedai n. sp. from the black-and-yellow silky-flycatcher Phainoptila melanoxantha. The female of M. povedai is distinguished from those of other species of Myrsidea from Costa Rican passerine hosts by a unique combination of the following characteristics: (1) well-developed hypopharynx, (2) well-defined median gap in the rows of tergal setae and another gap between groups of setae on lateral side of tergites II-VII and the most central seta, and (3) enlarged metanotum with at least 23 setae. These characters place M. povedai close to Myrsidea campestris from Euneornis campestris and Myrsidea marini from Pezopetes capitalis (both from the Emberizidae). The female of M. povedai can be easily separeted from both aforementioned species by the abdomen without conspicuously enlarged tergites. Moreover, the male of M. povedai is characterized by a unique male genital sclerite, which is quite long (0.13-0.15), tapered apically, with a long median line, and without subapical processes. This is the first record of a chewing louse from this host and the first record of Myrsidea from the passerine family Bombycillidae. All 7 birds examined in Costa Rica in 2010 were parasitized with M. povedai. Mean abundance was 11.6, with intensity range 4-27 lice per bird.

Generic Revision of the Procirrina (Coleoptera: Staphylinidae: Paederinae: Pinophilini)

Abstract The paederine subtribe Procirrina is redescribed, the morphology, phylogenetic relationships, and distribution are discussed, and a key to the eight genera is presented. In the section on morphology, the female genital sclerites are discussed and terms are proposed for the fused sclerites. Neoprocirrus, Oedichirus, Oedodactylus, Palaminus, Paraprocirrus, Procirrus, and Pseudoprocirrus are redescribed and a list of the included species and examined species is included for each. Stylokyrtus, new genus, is described for Oedodactylus errans Sharp, 1876, new combination. Parapalaminus Bierig, 1943, Procirrinus Koch, 1934, and Oedichiranus Reitter, 1906, described as subgenera, are new synonyms of Palaminus, Procirrus, and Oedichirus respectively. The sister group of Procirrina is Pinophilina. The basal genus of the Procirrina is Oedodactylus; Pseudoprocirrus is the sister group to the remainder of the genera, which are clustered in two clades. Palaminus + Oedichirus comprise one of the two clades with...

The first holistic SEM study of Coniopterygidae (Neuroptera) - structural evidence and phylogenetic implications

Adults of two coniopterygid species, Aleuropteryx juniperi Ohm, 1968 (Aleuropteryginae) and Semidalis aleyrodiformis (Stephens, 1836) (Coniopteryginae), were studied using scanning electron microscopy. Interspecific differences in the ultrastructure of the integument of all the major parts of the body were identified and described, and the functional and phylogenetic implications of the differences discussed. Additionally, the enlarged terminal segment of the labial palps of the Coniopterygidae and the Sisyridae, which up to now has been used as an argument for a sister-group relationship between these two families, was subjected to a thorough comparison. The very different morphology makes independent enlargement of the terminal palpal segment in both families plausible. This finding is congruent with the earlier hypothesis of a sister-group relationship between Coniopterygidae and the dilarid clade, which was proposed on the basis of molecular data, larval morphology and male genital sclerites. Finally, a new classification of the coniopterygid subfamilies is presented based on characters of the larval head (prominence of the ocular region, relative length of sucking stylets). The following relationship is hypothesized: (Brucheiserinae + Coniopteryginae) + Aleuropteryginae, and the implications of this hypothesis for the phylogenetic interpretation of the ultrastructural differences that we found are discussed: (1) The wax glands, as well as plicatures, are interpreted as belonging to the ground pattern of the family Coniopterygidae, and (2) the wax glands are considered to have been reduced in Brucheiserinae and the plicatures in Coniopteryginae. A distinct (though reduced) spiraculum 8 was detected in Semidalis aleyrodiformis; as a consequence the hypothesis that the loss of spiraculum 8 is an autapomorphy of Coniopteryginae is refuted.

The principal structure of male genital sclerites and muscles of bombycoid moths, with special reference to Anthelidae (Lepidoptera: Bombycoidea)

Male genital structures and muscles of bombycoid moths have repeatedly been misidentified in the literature. Furthermore, the genital structures of some bombycoid families, such as the poorly known Australo-New Guinean Anthelidae, have essentially remained unstudied. Based on comparative morphology, this study details the principal arrangements of male genital sclerites and muscles in all bombycoid families, with particular focus on basic structures and their modifications in Anthelidae. Emphasis is placed on the homology of and fusions between these structures and their function, providing a basis for the interpretation of modifications in future phylogenetic and taxonomic studies. This includes the unique fusion of gnathos and valvae in several bombycoid families, the arrangement and extent of the fused tegumen and vinculum, as well as the homology of the “transtilla”. Further, a modification of the valve adductor muscle (the segment IX sternum to valva muscle, m4) widely regarded as a synapomorphy of Bombycoidea is demonstrated to be non-existent, as is the presumed presence of the valve abductor muscle (the segment IX tergum to valva muscle, m2) in Saturniidae.

Skeletomuscular development of genital segments in the dragonfly Anax imperator (Odonata, Aeshnidae) during metamorphosis and its implications for the evolutionary morphology of the insect ovipositor

The skeleton-muscular organisation of abdominal segments 7–9 in female Anax imperator L. (Anisoptera, Aeshnidae) was examined in the stages of ultimate larva, teneral imago, and mature imago, with special emphasis on the transformation of the muscle arrangement. The absence of certain muscles in the genital segments compared to the 7th pre-genital segment was noted on all studied stages. Reductions of certain muscles in adults compared to those in larvae are reported. Some of ovipositor's muscles appear already in larvae. Attachment sites of larval muscles are retained in freshly emerged females concurrently with integument transformations. This situation allows for precise determination of the borders of newly differentiated genital sclerites and, therefore, of the possible origin of certain ovipositor elements in odonates. All changes in the segmental sets of studied abdominal muscles during metamorphosis are tabulated, and displacements of muscles are documented and illustrated. Schematic figures illustrating homologies between the parts of larval and imaginal abdominal sclerites are provided. The origins of the components of the endophytic ovipositor in Odonata as well as their implications for the evolutionary morphology of the insect ovipositor are discussed.

The evolution of male genitalia: functional integration of genital sclerites in the dung beetle Onthophagus taurus

It is now widely recognized that sexual selection has been important in the rapid and divergent evolution of male genital morphology. However, distinguishing among putative mechanisms of sexual selection acting on male genital morphology represents a considerable challenge. Although there is growing evidence that variation in the size and/or shape of male genital structures can determine a male’s success in gaining fertilizations, our knowledge of the functional morphology of male genitalia remains limited. Here we examine the functional morphology of genital sclerites that are known to influence paternity in the dung beetle Onthophagus taurus. We show that three of the sclerites form a functionally integrated unit that generates the tubular-shaped spermatophore and delivers its opening to the female’s spermathecal duct. A fourth sclerite acts as a holdfast device during copulation. Our observations shed light on the mechanism by which these sclerites influence a male’s paternity, and their patterns of phenotypic and genetic (co)variation. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 93, 257–266. ADDITIONAL KEYWORDS: cryptic female choice – male genital morphology – paternity – sexual selection – sperm competition.

Phylogenetic relevance of the genital sclerites of Neuropterida (Insecta: Holometabola)

AbstractSegment 9 of male Raphidioptera, comprising tergite, sternite, gonocoxites, gonostyli and gonapophyses, is a benchmark for homologies in the male and female terminalia of the three Neuropterida orders Raphidioptera, Megaloptera and Neuroptera. The segments relating to genitalia are 9, 10 and 11 in males and 7, 8 and 9 in females. Results from holomorphological and recent molecular cladistic analyses of Neuropterida agree in supporting the sister‐group relationships between: (1) the Raphidioptera and the clade Megaloptera + Neuroptera, and (2) the suborder Nevrorthiformia and all other Neuroptera. The main discrepancy between the results of these studies is the nonmonophyly of the suborder Hemerobiiformia in the molecular analysis. The monophyly of the Megaloptera (which has been repeatedly questioned) is further corroborated by a hitherto overlooked ground pattern autapomorphy: the presence of eversible sacs within the complex of the fused gonocoxites 11 in Corydalidae and Sialidae. The recently discovered paired complex of gonocoxites 10 (parameres) inNipponeurorthus(Nevrorthidae) indicates that the curious apex of sternite 9 ofNevrorthusandAustroneurorthusis the amalgamation of the sclerites of gonocoxites 10 with sternite 9, interpreted as synapomorphic. In the molecular study, the Nevrorthidae, Sisyridae and Osmylidae branch off in consecutive splitting events, a result that is supported by the analysis of male genital sclerites reported here. Extraordinary parallel apomorphies (e.g. excessive enlargement and modification of gonocoxites 10 ending in a thread‐like ‘penisfilum’) in derived representatives of Coniopterygidae, Berothidae, Rhachiberothidae and Mantispidae corroborate the dilarid clade of the morphological analysis and leads us to hypothesize a sister‐group relationship of the Coniopterygidae with the dilarid clade. A re‐interpretation of the tignum of Chrysopidae as gonocoxites 11 means that the structure previously called the gonarcus represents the fused gonocoxites 9. In Hemerobiidae, the corresponding sclerite is consequently also homologized as fused gonocoxites 9. The enlargement of the lateral wings of the gonocoxites in both families is interpreted as a synapomorphy. Excessive enlargement of gonostyli 11 in the Polystoechotid clade and Myrmeleontiformia supports a sister‐group relationship of these two clades. The occurrence of certain serial homologues of female genitalia structures (gonocoxites and gonapophyses), such as the digitiform processus together with the flat appendices in segment 8 of certain Myrmeleontidae, or the wart‐like processus together with the flat circular sclerites in segment 7 of certain Berothidae, as well as the presence of gonocoxites 8 as pseudosternites in certain Nemopteridae and Coniopterygidae, are probably character reversals. The digitiform processus of tergite 9 (pseudogonocoxites) in Rhachiberothidae andAustroberothella(Berothidae) are either independently developed acquisitions with a function in oviposition, or are homologous sclerites, possibly of epipleurite origin.

Quantitative tests of primary homology

AbstractIn systematic biology homology hypotheses are typically based on points of similarity and tested using congruence, of which the two stages have come to be distinguished as “primary” versus “secondary” homology. Primary homology is often regarded as prior to logical test, being a kind of background assumption or prior knowledge. Similarity can, however, be tested by more detailed studies that corroborate or weaken previous homology hypotheses before the test of congruence is applied. Indeed testing similarity is the only way to test the homology of characters, as congruence only tests their states. Traditional homology criteria include topology, special similarity, function, ontogeny and step‐counting (for example, transformation in one step versus two via loss and gain). Here we present a method to compare quantitatively the ability of such criteria, and competing homology schema, to explain morphological observations. We apply the method to a classic and difficult problem in the homology of male spider genital sclerites. For this test case topology performed better than special similarity or function. Primary homologies founded on topology resulted in hypotheses that were globally more parsimonious than those based on other criteria, and therefore yielded a more coherent and congruent nomenclature of palpal sclerites in theridiid spiders than prior attempts. Finally, we question whether primary homology should be insulated as “prior knowledge” from the usual issues and demands that quantitative phylogenetic analyses pose, such as weighting and global versus local optima.© The Willi Hennig Society 2007.

Apatrobus osuzuyamanus sp. nov., a new patrobine species from Japan, with a comparative study of the male genital morphology of the tribe Patrobini (Coleoptera: Carabidae)

Apatrobus (Apatrobus) osuzuyamanus sp. nov. is described from Kyushu, western Japan (type locality: Mt. Osuzuyama [32°16'N, 131°25'E]). This species is distinguished from A. (A.) ohtsukai Morita by a larger body, a pair of small depressions on the pronotum, and the shape of the aedeagal apex. Based on a comparative study of the male genitalia of several species, the homology of the genital sclerites of the tribe Patrobini are revised and a new terminology is proposed. The implications of present results for Patrobini taxonomy are briefly discussed.

Musculature of the male genitalia of Xylophagus cinctus (De Geer) and relationships within the superfamily Xylophagoidea (Diptera, Brachycera)

There is no general agreement on relationships within Xylophagoidea (Diptera, Brachycera). The musculature of the male genitalia of Xylophagus cinctus (De Geer) (Xylophagidae, the most primitive family of Brachycera) is described and compared with that of some other Xylophagoidea: Exeretonevridae (Exeretonevra angustifrons Hardy), Coenomyiidae (Anacanthaspis biafasciata Roder), and Rhagionidae (Rhagio montanus Becker, Chrysopilus dives Loew, and Ch. helvolus Meigen) discussed earlier (Ovtshinnikova, 1989, 1998; Palmer et al., 2000). In spite of the differences in the structure of the genital sclerites, Xylophagidae possess all the muscles found in Coenomyiidae and Rhagionidae. The musculature of the male genitalia of Xylophagus cinctus includes two muscle pairs of the aedeagus sheath (M1 and M2); three muscle pairs of the ejaculatory complex (M30, M31, and M32); one muscle pair of the gonocoxites (M33); two muscle pairs of the gonostyli (M27 and M28); one muscle pair of the proctiger (M21), one muscle pair of the cerci (M29); two pairs of the tergosternal muscles (M51 and M52); and two pairs of the pregenital muscles (M18 and M19). Muscles of the family Exeretonevridae are mostly the same, except for the muscles of the cerci M29, proctiger M29, and pregenital muscles M18 and M19, that are subdivided into two parts. This fact and also a different degree of the development of muscles M32 and M52 clearly distinguish Exeretonevridae from closely related families. The attachment places of the muscles of the aedeagus sheath M2 and of the gonostyli M28, as well as the split character of the tergosternal muscle pair M51 makes it possible to distinguish two sister groups, Xylophagidae plus Exeretonevridae, versus Coenomyiidae plus Rhagionidae. It should be noted that the muscles of the male genitalia of Xylophagidae, Exeretonevridae, Coenomyiidae, and Rhagionidae possess similar plesiomorphic characters, and these families should be united into the superfamily Xylophagoidea. This superfamily is the most primitive superfamily of Brachycera Orthorrhapha and possesses the most stable set and arrangement of male genital muscles within the entire suborder. An improved dendrogram of the phylogenetic relationships between the known groups of Xylophagoidea is proposed on the basis of the structure of male genital muscles.

The evolution of male genitalia: patterns of genetic variation and covariation in the genital sclerites of the dung beetle Onthophagus taurus

Three main hypotheses, have been invoked to explain divergent genital evolution, the lock and key, pleiotropy, and sexual selection hypotheses, each of which make different predictions about how genital traits are inherited. Here we used a half-sib breeding design to examine the patterns of genetic variation and covariation between male genital sclerites, and their covariance with general body morphology in the dung beetle Onthophagus taurus. We found CV(A)'s and CV(P)'s were similar for both genital and general morphological traits and that CV(R)'s were large for both trait types. We found that male genital sclerites were negatively genetically correlated with general morphological traits. Variation in male genital morphology has direct implications for a male's fertilization success and the resulting sexual selection acting on male genitalia is predicted to maintain high levels of additive genetic variance. Contrary to this prediction, we found that individual genital sclerites all had low levels of additive genetic variance and large maternal and environmental sources of variation. Our data suggest that the genital sclerites in O. taurus are not inherited independently but as a genetically integrated unit. More importantly, the way the different sclerites function to influence male fertilization success reflects this genetic integration. Even though levels of V(A) in individual genital sclerites may be low, there may still be sufficient V(A) in multivariate trait space for selection to generate evolutionary change in the overall morphology of male genitalia.

Relative influence of male and female genital morphology on paternity in the dung beetle Onthophagus taurus

Studies of fertilization success have demonstrated that male effects are often a strong and important source of variation in P2 (the proportion of offspring that are fertilized by the second male to mate). More recently there has been emphasis on female processes that occur during and after copulation that might bias the outcome of male-male interactions. Here we used the sterile male technique to evaluate whether female genital morphology influences the repeatability of P2 when the same pair of male dung beetles, Onthophagus taurus, copulated with a series of full-sib females or unrelated females that were all unrelated to the male pair. Repeatability estimates of measures of female genital morphology showed that full-sib females varied less in their genital morphology than did unrelated females. Therefore, if female genital traits are an important source of variation in male fertilization success, P2 should be more repeatable across full-sib than unrelated females. Contrary to this prediction, we show that the repeatability of P2 did not differ between female groups. Moreover, specific dimensions of the female genitalia (sclerotized vagina and bursa) did not contribute significantly to variance in P2. In contrast, male effects had consistent and repeatable influences on paternity across females. These were partly explained by variation in the morphology of male genital sclerites.

One tool, many uses: precopulatory sexual selection on genital morphology inAquarius remigis

While congruent evidence indicates that sexual selection is the most likely selective force explaining the rapid divergence of male genital morphology in insects, the mechanisms involved in this process remain unclear. In particular, little attention has been paid to precopulatory sexual selection. We examine sexual selection for mating success on male genital components in six populations of Aquarius remigis, a water strider characterized by unique genital morphology. Multivariate selection analysis confirms previous findings that precopulatory sexual selection favours longer external genitalia, and provides new evidence that this selection acts independently on external genital components. In contrast, the size of the major internal genital sclerite is not correlated with mating success. Thus, precopulatory sexual selection acts strongly on the size of the external genitalia, but not on the intromittent organ itself. These results highlight the multiple functions of genital organs and the importance of both precopulatory and post-copulatory sexual selection in shaping the remarkable diversity of male genitalia in insects.