Eighth Sternum Research Articles

Description of the male of Rediviva steineri Kuhlmann, 2012 (Hymenoptera: Melittidae), an endemic oil-collecting bee species from South Africa

We describe the male of Rediviva steineri Kuhlmann, 2012; distinguished by the shape and the margin of the apical plate of the eighth sterna and the vestiture of metasomal terga two and three. Five males were collected at the type locality of the female (Farm Doornbosch, Western Cape, South Africa). We examined the types of three other closely related species (R. pallidula, R. brunnea and R. whiteheadi) and provide images of the eighth sterna for comparison with R. steineri and update Whitehead et al.’s (2008) identification key for the males of these species.

Morfologia externa dos cicadellinae (homoptera, cicadellidae): comparação entre versigonalia ruficauda (walker) (cicadellini) e tretogonia cribrata melichar (proconiini), com notas sobre outras espécies e análise da terminologia

The external morphology of two cicadelline species, Versigonalia ruficauda (Walker, 1851) (Cicadellini) and Tretogonia cribrata Melichar, 1926 (Proconiini), is analyzed. The head, axillary sclerites, wing venation, female genitalia, and tegumentary processes are described. Notes on other Cicadellini - Amblyscarlidia albofasciata (Walker, 1851), Tettisama quinquemacidata (Germar, 1821), Macugonalia lencomelas (Walker, 1851), and Diedrocephala variegata (Fabricius, 1775) - and Proconiini - Ciccus adspersus (Fabricius, 1803), Homoscarta superciliaris (Jacobi, 1905), Ichthyobelus sp., and Rhaphirrhinus phosphoreus (Linnaeus, 1758) - are added. A technique for dissecting the female genitalia is presented. The facial porlion of head in V. ruficauda, T. cribrata, and remaining species has a large sclerite (frons or postfrontofrons) clearly defined by the frontogenal suture. Below the frons, and separated from it by the epistomal suture, a smaller sclerite is present (clypeus). The identification of these sclerites is based on comparisons with descriptions in the literature of a generalized Pterygota, a Psocoptera, a fossil Hemipteroidea, and other Homoptera. The conclusions about the identities of frons and clypeus corroborate the hypotheses of Hamilton (1981) on the homologies of cephalic areas in Rhynchota. The facial sclerites have modifications related with the xyleniomyzous diet. The frons is swollen, providing a larger area for attachmcnt of cibarial muscles. Other modifications increasing the area of frons are observed in the Proconiini. In C. adspersus its lateral margins are distinctly pronounced and its upper portion has a pair of lateral elevations. In Ichthyobelus sp. and R. phosphoreus the upper part of frons is greatly developed, occupying 4/5 of dorsal area of head on middle line. The vertex is limited to a small portion (1/5) of that area. The clypeus is also swollen, a fact related with the greater development of cibarium. This character is more conspicuous in the Proconiini. In this tribe the clypeus has a convex projection occupied by the cibarium, which is greatly devcloped. The pronotum and forewings in T. cribrata are covered by pits, each with a seta on external margin. These pits are similar (and maybe homologous) to struetures in the abdomen of a membracid (Goniolomus tricomiger Stal. 1869). The pronotum is smooth in V. ruficauda. However, pits similar to those of T. cribrata, although smaller. oceur near the forewing veins. A strong costal vein is present in the forewings of the 10 studied species. This vein is formed by a fusion between precosta (PC), costa anterior (CA), and costa posterior (CP). Vestiges of subcosta posterior (ScP) and media (M) occur in the forewing base. A vein formed by a fusion between anal (A) and jugal (J) veins is observed along the inner margin of clavus. In the hindwings, PC, CA, and CP are also fused. The occurrence of PC can be inferred by the presence of the wing coupling lobe. which represents its final part. Jugal anterior (JA) is fused to anal posterior (AP). Jugal posterior (JP) occurs as a small rudiment at hindwing base. The characters of fore - and hindwings confirm the observations of Dworakowska (1988) on the Cicadellidae. The presence of PC and J corroborates Kukalova-Peck's (1983) model of the primitive pterygote venation. Comparisons between the Cicadellinae and a description of a fossil species of the order Diaphanopterodea (Kukalova-Peck 1992) revealed remarkable similarities in female genitalia. Such similarities (manifested in the positions of gonocoxites eight and nine, gonangulum, valvulae eight and nine, and lergite nine) permit a correct interpretation of the genital structurcs in the subfamily. The sclerites of the genital chamber described by Young (1977) in females of various Cicadellini are the reduced eighth abdominal sternite. Sclerotized plates in this sternite occur in A. albofasciata, T. quinquemaculata, T. cribrata, C. adspersus, and H. superciliaris. Comparisons carried out among these Cicadellinae, allied with data from the literature, indicate that the eighth sternum can provide useful characters for the subfamily taxonomy. Features of potential taxonomic interest in valvulae eight and nine include tegumentary processes (valvulae eight), shaft form, and teeth form and distribution (valvulae nine). Lists with the terms suggested for head, wings, and female genitalia are included, together with synonyms proposed by other taxonomists and morphologists.

The Bombycoidea: Phylogeny and higher classification (Lepidoptera: Glossata)

AbstractThis paper is chiefly aimed at reassessing the limits of four bombycoid families, namely the Eupterotidae, Saturniidae, Lemoniidae, and Brahmaeidae. An incompletely resolved cladogram is proposed for the whole 'bombycoid complex' (Mimallonoidea + Lasiocampoidea + Bombycoidea). Within the Bombycoidea, the primary dichotomy is considered to lie between the Eupterotidae + Bombycidae s.lat. + Endromidae + Mirinidae + Saturniidae, and the Carthaeidae + Lemoniidae + Brahmaeidae + Sphingidae. Sharing at least nine synapomorphies, the Lemoniidae and Brahmaeidae are regarded as reliable sister groups, and the Lemoniidae + Brahmaeidae are proposed as a sister group to the Sphingidae. Another newly proposed clade groups together the Endromidae, Mirinidae and Saturniidae. At family level, the Hibrildidae are synonymized with the Eupterotidae (syn. n.), for which the most significant autapomorphy lies in a previously unnoticed particularity of the female hind leg (distitarsus typically provided with a midventral row of spines). Sexual dimorphism in leg structure also leads to a redefinition of the Saturniidae, a family which must include, with subfamily rank (stat. rev.), the 'Oxytenidae' and 'Cercophanidae' of modern authors. A pair of distal, tooth-like structures on the fourth tarsomere of the female fore leg can thus be ascribed to the ground plan of the Saturniidae, along with a few other convincing autapomorphies. On the other hand, the 'Apatelodidae' are only tentatively placed in the 'Bombycidae sensu lato', a group provisionally resurrected insofar as the Apatelodidae sensu auct. prove to be diphyletic. As a matter of fact, the 'apatelodid' subfamily Epiinae is synonymized with the Bombycinae (syn. n.) in consideration of a rather large number of synapomorphies. When more extensively studied, the morphology of the eighth sternum of the male abdomen might lead to a slightly different, more restricted, concept of the Bombycidae (Le. excluding 'true' Apatelodidae). Often regarded as incertae sedis, the African genera Sabalia Walker and Spiramiopsis Hampson are definitely assigned to the Lemoniidae and Brahmaeidae respectively. Autapomorphies of these two families are recorded and discussed, as are those found to characterize the Sphingidae. Three subfamilies are tentatively recognized within the latter (Smerinthinae stat. rev., Sphinginae, Macroglossinae), five within the Eupterotidae (Hibrildinae, Tissanginae, Janinae, Panacelinae, Eupterotinae), and four within the Bombycidae s.lat. (Apatelodinae, Phiditiinae subfam. n., Prismostictinae [= Oberthueriinae, syn. rev.], Bombycinae). Three of these subfamilies are considered in a new sense, viz. the Panacelinae, Apatelodinae, and Bombycinae. Although the phylogeny of the Saturniidae is not fully taken into account in the present study, the composition of three saturniid subfamilies is critically examined (Oxyteninae, Cercophaninae, Ludiinae), and the Oxyteninae are viewed as the most 'primitive' member of the family.

Two Indian Bagous Weevils (Coleoptera, Curculionidae), Tuber Feeders of Hydrilla verticillata (Hydrocharitaceae), One a Potential Biocontrol Agent in Florida

Bagous affinis Hustache is redescribed and its release in south Florida as a potential biological control agent of Hydrilla verticillata is mentioned. A new species, B. laevigatus O'Brien & Pajni, is described. Included are habitus photographs, specific diagnoses, distributions, and line illustrations of the male phallus and endophallus and of the female spermatheca and eighth sternum of both species.

COURTSHIP AND COPULATION IN LYTTA NUTTALLI (COLEOPTERA: MELOIDAE)

AbstractDuring courtship in Lytta nuttalli Say the male assumes the active role. Mounted above the female, he repeats a cycle of three stereotyped, stimulatory activities: antennal manipulation, abdominal vibration, and attempted genital insertion. The male uses both his antennae together to stroke alternately the tips of the female’s antennae, which he holds upright with his fore legs. With rapid lateral vibrations of his abdomen, he brushes the ends of the female’s elytra and her eighth tergum with the long bristles on his eighth sternum. He also repeatedly probes the end of the female’s abdomen with his aedeagus, attempting to establish genital contact. Abdominal vibration is performed alternately with genital insertion attempts; antennation usually is carried out at the same time as the other activities. Courtship lasts for a few minutes to 1 hour or more. Copulation is initiated by successful genital insertion and is executed with the male and female aligned end-to-end. Its average duration is 8 to 10 hours. Abdominal vibration seems to be unique to Lytta, whereas the dorsal orientation during courtship and the genital activity are similar to those observed in many other Meloinae. Though antennal manipulation is common in Meloinae, the method employed by L. nuttalli is different from that in other meloines. Anatomical modifications related to courtship are discussed.

Musculature, nervous system and glands of metasomal abdominal segments of the male of Nomia melanderi Ckll. (Hymenoptera, Apoidea)

AbstractEach muscle of the third metasomal segment of the male of Nomia melanderi Ckll. is described in detail. The points of attachment of each muscle are compared with their homologs in other pregenital segments and with their homologs in the female. The function desgnated for each muscle describes its action alone or in conjunction with other muscle(s). New names are given to genital muscles by referring in the name to their points of attachment. Each intratergal muscle has homologous points of attachment in the pregenital segments of both sexes. The median tergo‐dorsoplical muscle of the seventh segment and the oblique tergo‐dorsoplical muscle of the eighth segment have changed their points of attachment. The intrasternal muscles are modified to suit the needs of courtship and mating, thus they are different from their homologs in the female. The spiracular muscles are well developed in all segments except the eighth, where the sterno‐spiracular muscle is absent. The extrinsic genital muscles are derived from the intrasternal muscles of the eighth and ninth segments. The parameral and volsellar muscles are reduced in number. The aedeagal muscles, except the aedeago‐phallic, have retained similar points of attachment to those found in primitive Hymenoptera. The topography of the metasomal nervous system is reported in detail by following each nerve and nervule to its termination. The study shows that (at least in Nomia) the criterion of nerve‐concentration should not be used alone to indicate evolutionary levels. To accommodate the morphological changes in the terminal segments the Anterior and Posterior Lateral Nerves have migrated to new locations. The pattern of nerve topography (even at the nervule level) is homologous both in the different pregenital segments and between the sexes. The fact that homology does not exist between the external genitalia of the male and the modified ovipositor of the female supports the thesis that the male genital capsule is of phallic rather than prephallic origin. A pair of intersegmental membrane glands located between the seventh and eighth sterna is described. These glands may be the source of a pheromon responsible for gregariousness among “sleeping” males.

Biological Study of the Rice Weevil Complex

The large and the small rice weevils are distinct, reproductively isolated species. The name Sitophilus oryza (L.) is applicable to the former, S. sasakii (Tak.) to the latter. Coloration is variable in both, their measurements overlap, and no practical external morphological distinctions were found, but the two species differ in the eighth sternum of the female and in the shape of a sclerite on the dorsal surface of the aedeagus of the male. Reproduction of both species was least in maize (corn), next in rough rice, and greatest in grain sorghum; with S. oryza reproduction was greater in unpolished rice than in wheat, but with S. sasakii the reverse was true. When both species were confined on maize or unpolished rice, the larger species proved to be the dominant form; on wheat the smaller species became dominant. Size and color in both forms was influenced by the host.

OBSERVATIONS ON THE POST-EMBRYONIC DEVELOPMENT OF THE FEMALE REPRODUCTIVE ORGANS IN LEUCINODES ORBONALIS GUEN. (LEPIDOPTERA: PYRAUSTIDAE) WITH NOTES ON THE HOMOLOGY IN THE TWO SEXES

Summary In the adult, the ovaries have four ovarioles each. The paired oviducts join to form the common oviduct which opens on the ninth sternum through the muscular vagina. The tubular spermatheca opens into the vagina dorsally and a pair of tubular accessory glands opens in it posteriorly through a reservoir. The ventrally situated bursa opens on the eighth sternum by the ductus bursae which, in turn, communicates with the vagina by the narrow ductus seminalis. The ovaries arise as paired patches in the early larva. Later, these differentiate into ovarioles and their epithelial coverings form a pair of solid cords of cells which run up to the seventh segment. These develop lumina and give rise to the mesodermal parts of the paired oviducts in the pfepupa. The uterine and spermathecal rudiments appear as unpaired invaginations towards the posterior borders of the eighth and ninth segments respectively. The wide uterine rudiment grows forward and bifurcates and, in the late prepupa, each branch joins with the mesodermal paired oviduct of its side. A pouch arises ventrally from the uterine rudiment and forms the bursa. The spermathecal rudiment also grows forward. Its anterior part forms the spermatheca while the middle part touches and communicates with the uterine rudiment. A pouch arising from the posterodorsal aspect of the spermathecal rudiment gives out two outgrowths, thus forming the reservoir and the accessory glands. The connection between the bursa and the uterine rudiment narrows down to form the ductus seminalis so that the opening of the spermathecal rudiment becomes mainly the opening of the oviduct and the opening of the uterine rudiment that of the bursa. A pair of small ectodermal longitudinal grooves appears in the anterior parts of each of the eighth and ninth sterna in the early fourth instar larva. These are not connected with the uterine or spermathecal rudiments at any stage and disappear in the prepupa. These are considered to represent the ovipositors. The homology of the male and female organs has been discussed.

Memoirs: Studies On the Development of the Genitalia and the Genital Ducts in Insects. I. Female of Orthoptera and Dermaptera

1. The anterior ovipositor lobes (ventral valves) of Orthoptera are serially homologous with the lateral ovipositor lobes (dorsal valves) and represent gonocoxites from which no telopodites, corresponding to the inner valves, are differentiated. 2. The common oviduct originates as an unpaired ectodermal (hypodermal) invagination, in Blattella from the seventh intersternal membrane, in Locustana , Colemania, and Forficula between the seventh and eighth sterna, ending blindly, internally, between the ends of the mesodermal oviducts lying near the posterior margin of the seventh sternum. 3. In Blattella and Forficula the early condition is retained up to the adult stage; in Locustana and Colemania the common oviduct is secondarily extended posteriorly along the eighth sternum in the first instar, the gonopore coming to open in later instars, and in the adult on the inner reflexed surface of the eighth sternum. 4. Grooves are present in the early stages of Locustana, Colemania, and Blattella , between the bases of the ovipositor lobes on the eighth and ninth sterna, which become tubular anteriorly, giving rise each to an accessory genital invagination. The invagination from the eighth gives rise to the spermatheca in Locustana and Colemania; in Blattella it atrophies in late nymphal stages. The invagination from the ninth gives rise to the paired colleterial gland in Blattella; in Locustana and Colemania it develops slowly and gives rise to a vestigial accessory genital invagination. In Forficula no ovipositor lobes are present, and the invagination from the eighth arises practically intersegmentally between sterna 8 and 9. It also gives rise to the spermatheca in the adult. No accessory genital invagination is developed from the ninth sternum. 5. In Blattella four spermathecae are present. They originate as two pairs of separate hypodermal invaginations from the seventh intersternal membrane, morphologically posterior to the common oviduct invagination. 6. The primitive position of the single gonopore in the Orthoptera and Dermaptera is between sterna 7 and 8, its position in present-day Locustidae, Tettigoniidae, Gryllidae on the eighth sternum being secondary. 7. The spermathecal function was ancestrally associated with the accessory genital invagination from the eighth sternum in the Orthoptera. The four spermathecae of Blattella represent secondarily developed structures which do not correspond to the spermathecae of other Blattids, e.g. Periplaneta and other Orthoptera. 8. There is no evidence that part of the common oviduct is of mesodermal derivation or that it has a paired origin in the Orthoptera and in insects in general. 9. A hypothetical ancestral condition of the oviducal system and accessory organs is deduced for insects in general. The paired mesodermal oviducts opened separately within the seventh intersternal membrane, two gonopores being present. Accessory genital invaginations, possibly paired, were present on the eighth and ninth sterna at the bases of the gonopods, a spermathecal function probably being associated with the invagination(s) on the eighth sternum. Phylogenetic specialization consisted in an early acquisition of an ectodermal common oviduct and single gonopore between the seventh and eighth sterna, possibly polyphyletic, and a later extension posteriorly of the common oviduct and single gonopore on to the eighth and on to the ninth sterna, this posterior extension having definitely taken place polyphyletically.