Non-Perturbative Green's Functions in Theories with Extended Superconformal Symmetry

The multiplets that occur in four dimensional rigidly supersymmetric theories can be described either by chiral superfields in Minkowski superspace or analytic superfields in harmonic superspace. The superconformal Ward identities for Green's functions of gauge invariant operators of these types are derived. It is shown that there are no chiral superconformal invariants. It is further shown that the Green's functions of analytic operators are severely restricted by the superconformal Ward when analyticity is taken into account.Comment: 17 pages, plain tex. Some conjectures that were in the original paper are clarifed in the light of more recent work to which we give references. See Note added for detail

Four-point functions in N=2 superconformal field theories

Four-point correlation functions of hypermultiplet bilinear composites are analysed in N=2 superconformal field theory using the superconformal Ward identities and the analyticity properties of the composite operator superfields. It is shown that the complete amplitude is determined by a single arbitrary function of the two conformal cross-ratios of the space-time variables.Comment: 36 pp LaTeX2e, uses amsfonts, amssymb. Some references adde

Partial non-renormalisation of the stress-tensor four-point function in N=4 SYM and AdS/CFT

We show that, although the correlator of four stress-tensor multiplets in N=4 SYM is known to have radiative corrections, certain linear combinations of its components are protected from perturbative renormalisation and remain at their free-field values. This result is valid for weak as well as for strong coupling and for any gauge group. Our argument uses Intriligator's insertion formula, and includes a proof that the possible contact term contributions cannot change the form of the amplitudes. Combining this new non-renormalisation theorem with Maldacena's conjecture allows us to make a prediction for the structure of the corresponding correlator in AdS supergravity. This is verified by first considerably simplifying the strong coupling expression obtained by recent supergravity calculations, and then showing that it does indeed exhibit the expected structure.Comment: 21 pages, no figure

On Non-renormalization and OPE in Superconformal Field Theories

The OPE of two N=2 R-symmetry current (short) multiplets is determined by the possible superspace three-point functions that two such multiplets can form with a third, a priori long multiplet. We show that the shortness conditions on the former put strong restrictions on the quantum numbers of the latter. In particular, no anomalous dimension is allowed unless the third supermultiplet is an R-symmetry singlet. This phenomenon should explain many known non-renormalization properties of correlation functions, including the one of four stress-tensor multiplets in N=4 SYM_4.Comment: minor corrections, references change

Buakea (Lepidoptera : Noctuidae), a new genus of African stem borers : morphological, ecological and molecular data

A new genus of African stem borers of the subtribe Sesamiina (Lepidoptera: Noctuidae), Buakea gen. n., is described as well as the three species it includes, two new, B. venusta sp. n. and B. kaeuae sp. n., and a species that until now was placed in the genus Busseola Thurau, B. obliquifascia (Hampson) comb. n. The three species are monophagous on different graminaceous host plants, and the two sister species B. kaeaue and B. obliquifascia were collected in different ecological zones and altitudes, which suggests an ecological mode of speciation. Bayesian and maximum likelihood phylogenies inferred from two mitochondrial genes showed that the genus is monophyletic and does not share a recent common ancestor with the genus Busseola. However no strongly supported phylogenetic relationship could be established with the other six genera of the subtribe included in the analysis

Systematics and molecular phylogeny of two African stem borer genera, Sciomesa Tams & Bowden and Carelis Bowden (Lepidoptera : Noctuidae)

Currently, the systematics of the African noctuid stem borers of the subtribe Sesamiina, which include major pests of cereals, is confused. In addition, their ecology is poorly known, as are the factors influencing their evolution. In this paper, we address these shortcomings for two genera of the Sesamiina, Sciomesa Tams & Bowden and Carelis Bowden. Mixed Bayesian phylogenetic analysis, which included their host plants and two mitochondrial genes, showed the genus Sciomesa to be polyphyletic. Two new genera were created, Pirateolea and Feraxinia. The genus Carelis proved to be paraphyletic and was subdivided into two sub-genera. The genera Sciomesa, Carelis and Pirateolea (named the 'Sciomesa genus group') share morphological traits, and the phylogenetic analysis showed that they had a common ancestor living on Cyperaceae and that they were distant from the genus Feraxinia belonging to another clade which had an ancestor living on Poaceae. Seven new species were described: Sciomesa gnosia sp. n., Sciomesia bua sp. n., Pirateolea nola gen. n, sp. n., Feraxinia serena gen. n., sp. n., Carelis australis sp. n., Carelis transversa sp. n. and Carelis agnae sp. n. Ten species were sunk as synonyms: Sciomesa mesoscia (Hampson) syn. n., Sciomesa mirifica Laporte syn. n., Sciomesa constantini Laporte syn. n. and Sciomesa etchecopari Laporte syn. n. are synonyms of Sciomesa mesophaea (Aurivillius); Acrapex sparsipucta Laporte syn. n. is a synonym of Sciomesa excelsa (Laporte) comb. n.; Acrapex congitae Laporte syn. n., Sesamia minuta Laporte syn. n. and Sesamia minuscula Laporte syn. n. are synonyms of Sciomesa boulardi (Laporte) comb. n.; Acrapex bryae Laporte syn. n. and Acrapex fayei Laporte syn. n. are synonyms of Feraxinia jemjemensis (Laporte) comb. n. Eleven new combinations were created: Sciomesa excelsa (Laporte) comb. n., Sciomesa boulardi (Laporte) comb. n., Sciomesa punctipennis (Kruger) comb. n., Pirateolea piscator (Fletcher) comb. n., Pirateolea argocyma (Fletcher) comb. n., Pirateolea cyclophora (Fletcher) comb. n., Pirateolea ochroneura (Fletcher) comb. n., Pirateolea funebris (Kruger) comb. n., Feraxinia nyei (Fletcher) comb. n., Feraxinia jemjemensis (Laporte) comb. n. and Carelis biluma (Nye) comb. n

Morphological reinforcement, ancient introgressive hybridization and species delimitation in African stem-borer species of the genus Sesamia Guenée (Lepidoptera : Noctuidae)

Species delimitation, an issue central to systematics and biodiversity studies, is addressed in the epunctifera group of the stem borer genus Sesamia Guenee (Lepidoptera: Noctuidae). This group is composed of four sub-Saharan species: Sesamia poephaga Tams & Bowden; Sesamia epunctifera Hampson; Sesamia penniseti Tams & Bowden; and Sesamia poebora Tams & Bowden, the taxonomic status of which was unclear. The first species was considered a possible synonym of the second, and the third species was considered a possible synonym of the fourth. An analysis combining morphological, ecological and molecular data enables us to conclude that S. epunctifera and S. poephaga are different species, and that S. poebora is a synonym of S. penniseti. Two new species were discovered: Sesamia firmata sp.n. and Sesamia veronica sp.n. Sesamia firmata sp.n. has atypical genitalic morphology, suggesting a strong selection resulting in a reinforcement of pre-zygotic isolation. Some specimens previously identified as S. penniseti on the basis of morphology are sisters to S. epunctifera on the mitochondrial tree, and are connected to S. penniseti on the nuclear tree. The mitochondrial distance from S. penniseti and S. epunctifera is 7.6% and 3.9%, respectively, suggesting an ancient mitochondrial introgression from S. epunctifera into S. penniseti. The possible causes of the reinforcement and introgressive hybridization are discussed. This case of mitochondrial introgression, uncommon in Lepidoptera, in which females are the heterogametic sex, may be an exception to Haldane's rule. The hybrid is assigned the rank of species and named Sesamia pennipuncta sp.n

Toward an understanding of the systematics and evolution of the genus Acrapex Hampson, 1894 (Lepidoptera : Noctuidae : Apameini : Sesamiina) : molecular phylogenetics of the genus and review of the species-rich Acrapex aenigma group

With a species count reaching almost 100 species, the genus Acrapex is themost diverse genus of sesamiine stemborers (Lepidoptera: Noctuidae: Noctuinae: Apameini: Sesamiina). Acrapex species are mostly distributed in the Afrotropics and consist of several large clades corresponding to distinct species complexes. In this study, 45 morphologically similar species of Acrapex from sub-Saharan Africa are reviewed, including 22 new species that are described: Acrapex alemura n. sp., A. barnsi n. sp., A. capelongo n. sp., A. congoensis n. sp., A. elgona n. sp., A. elisabethiana n. sp., A. eucantha n. sp., A. grandis n. sp., A. igominyi n. sp., A. inexpectata n. sp., A. ketoma n. sp., A. lilomwi n. sp., A. mafinga n. sp., A. makete n. sp., A. marungu n. sp., A. mazoe n. sp., A. mlanje n. sp., Acrapexmuchinga n. sp., A. ngorongoro n. sp., A. obscura n. sp., A. ruiru n. sp. and A. wittei n. sp. Supplemental descriptions for previously described species are provided as well. These 45 species are assigned to the newly defined Acrapex aenigma species group. We also conductmolecular phylogenetic analyses and molecular species delimitation analyses on a multimarker (four mitochondrial and two nuclear genes) molecular dataset encompassing 304 specimens (including 256 Acrapex specimens from 54 species of which 16 species belong to the A. aenigma group). Molecular phylogenetics analyses recover well-supported relationships within Acrapex and support the monophyly of the newly defined group. Results of molecular species delimitation analyses are mostly congruent and tend to corroborate the status of the sampled Acrapex species. Consistent with what has been previously found in other studies, the comparison of results from distinct methods and settings for molecular species delimitation analyses allows us to assess species boundaries with more confidence