Tilting chains of negative curves on rational surfaces

We introduce the notion of exact tilting objects, which are partial tilting objects $T$ inducing an equivalence between the abelian category generated by $T$ and the category of modules over the endomorphism algebra of $T$. Given a chain of sufficiently negative rational curves on a rational surface, we construct an exceptional sequence whose universal extension is an exact tilting object. For a chain of (-2)-curves, we obtain an equivalence with modules over a well known algebra.Comment: 13 page

Vers la comprehension de la systématique et de l’évolution du genre Acrapex Hampson, 1894 (Lepidoptera : Noctuidae : Apameini : Sesamiina) : phylogénie moléculaire du genre et définition du groupe Acrapex aenigma

International audienceSummary: With a species count reaching almost 100 species, the genus Acrapex is the most 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 alemuran. sp., A. barnsin. sp., A. capelongon. sp., A. congoensisn. sp., A. elgonan. sp., A. elisabethianan. sp., A. eucanthan. sp., A. grandisn. sp., A. igominyin. sp., A. inexpectatan. sp., A. ketoman. sp., A. lilomwin. sp., A. mafingan. sp., A. maketen. sp., A. marungun. sp., A. mazoen. sp., A. mlanjen. sp., Acrapex muchingan. sp., A. ngorongoron. sp., A. obscuran. sp., A. ruirun. sp. and A. wittein. 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 conduct molecular phylogenetic analyses and molecular species delimitation analyses on a multi-marker (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.Avec près d’une centaine d’espèces le genre Acrapex est le genre de noctuelles foreuses le plus diversifié de la sous-tribu des Sesamiina (Lepidoptera : Noctuidae : Noctuinae : Apameini). Les Acrapex sont majoritairement distribués dans la région Afrotropicale et sont composés de plusieurs clades correspondant à différents complexes d’espèces. Dans cette étude, 45 espèces morphologiquement proches d’Acrapex sub-sahariens sont étudiées, au rang desquelles figurent 22 nouvelles espèces que nous décrivons : 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., A. muchinga n. sp., A. ngorongoro n. sp., A. obscura n. sp., A. ruiru n. sp., and A. wittei n. sp. Nous fournissons également des descriptions supplémentaires pour des espèces déjà décrites. Ces 45 espèces sont assignées au groupe d’espèces Acrapex aenigma, que nous définissons. Nous avons également réalisé des analyses de reconstruction phylogénétique et des analyses de délimitation moléculaire d’espèces sur un jeu de données moléculaires multimarqueurs (quatre gènes mitochondriaux et deux gènes nucléaires) comprenant 304 spécimens (incluant 256 Acrapex de 54 espèces dont 16 appartiennent au groupe A. aenigma). Les analyses phylogénétiques retrouvent des topologies bien supportées au sein du genre Acrapex et soutiennent l’hypothèse de monophylie du groupe d’espèces nouvellement défini. Les résultats des analyses de délimitation moléculaire d’espèces sont majoritaitement en accord et tendent à soutenir le statut d’espèce des Acrapex échantillonnés. Conformément à ce qui a été mis en évidence dans d’autres études, la comparaison des résultats de différentes méthodes et paramétrages d’analyses de délimitation moléculaire d’espèces permet ainsi d’estimer les contours des espèces avec plus de confiance

Phylogeny and systematics of the Acrapex apicestriata (Bethune-Baker, 1911) species complex (Lepidoptera, Noctuidae, Noctuinae, Apameini, Sesamiina) with the description of eight new species from the Afrotropics

International audienceTwelve morphologically similar species of Acrapex Hampson 1894, (Lepidoptera, Noctuidae, Noctuinae, Apameini, Sesamiina), from Western, Central and Eastern Africa are reviewed. Eight of these species are new to science and are described: Acrapex akunamatatan. sp. and A. incrassata n. sp. from Kenya; A. gracilis n. sp., A. iringa n. sp., A. lukumbura n. sp. and A. rungwe n. sp. from Tanzania; A. soyema n. sp. from Ethiopia; and A. zoutoi n. sp. from Benin. All 12 species belong to a species complex that we hereby define as the Acrapex apicestriata group. Host-plants for three of the new species are recorded: Setaria incrassata (Hochst.) Hack. for Acrapex incrassata; Cymbopogon pospishilii (K. Schum.) C.E. Hubb. for A. rungwe; and Andropogon perligulatus Stapf. for A. zoutoi. We also conducted molecular phylogenetic analyses (using maximum likelihood and Bayesian inference) on a six gene multimarker molecular dataset (four mitochondrial and two nuclear gene fragments; 4581 nucleotides in length) consisting of 15 Acrapex species (including seven species from the apicestriata group) and four outgroups species from the subtribe Sesamiina (from genera Busseola Thurau 1904, Sciomesa Tams & Bowden 1953, Pirateolea Moyal, Le Ru, Conlong, Cugala, Defabachew, Matama-Kauma, Pallangyo & Van den Berg 2010 and Sesamia Boisduval & Guenee 1852). Both maximum likelihood and Bayesian inference analyses yield a similar and well-supported topology, which supports the monophyly of the apicestriata group

Updated phylogenetic and systematics of the Acrapex albivena Hampson, 1910 and A. stygiata (Hampson, 1910) species groups (Lepidoptera, Noctuidae, Noctuinae, Apameini, Sesamiina), with the description of nine new species from the Afrotropics

International audienceThe genus Acrapex Hampson, 1891 (Lepidoptera, Noctuidae, Noctuinae, Apameini, Sesamiina) constitutes a speciose group of noctuid stemborers mostly distributed in the Afrotropics. In this study nine new Acrapex species are described: Acrapex abyssinica n. sp., Acrapex dabaga n. sp., Acrapex jansei n. sp., Acrapex kifanya n. sp., Acrapex lusinga n. sp., Acrapex ngwenya n. sp., Acrapex njombea n. sp., Acrapex vetiveria n. sp. and Acrapex zima n. sp. All species are assigned to the A. albivena group with the exception of A. lusinga which is assigned to the A. stygiata group. We also provide supplemental descriptions for two previously described species of the A. albivena group, A. punctosa Berio, 1973 and A. sysciodes Berio, 1973, and for one species belonging to the A. stygiata group: A. brunneella Le Ru, 2014. Host plants of three species are recorded; A. brunneella and Acrapex jansei were reared on Cymbopogon pospischilii (K.Schum.) C.E.Hubb and A. vetiveria on Chrysopogon zizanioides (L.). We also conducted molecular phylogenetic analyses (using both Bayesian inference and maximum likelihood) on a multi-marker (four mitochondrial and two nuclear genes) molecular dataset encompassing 138 specimens (including 98 specimens from the A. albivena group and 23 specimens from the A. stygiata group) from 48 stemborer species. The results of the corresponding analyses support the monophyly of the two groups of interest and the species status of all newly described taxa, except for A. lusinga that was not sequenced. The phylogenetic analyses also unravel several evolutionary lineages whose precise status is pending because their DNA was extracted from larval stages.Actualisation des connaissances de la phylogénie et de la systématique des groupes d’espèces Acrapex albivena Hampson, 1910 et A. stygiata (Hampson, 1910) (Lepidoptera, Noctuidae, Noctuinae, Apameini, Sesamiina), avec la description de neuf nouvelles espèces de la région Afrotropicale. Le genre Acrapex Hampson, 1891 (Lepidoptera, Noctuidae, Noctuinae, Apameini, Sesamiina) est un groupe diversifié de noctuelles foreuses, majoritairement distribué dans la région Afrotropicale. Dans cette étude neuf espèces nouvelles sont décrites : Acrapex abyssinica n. sp., Acrapex dabaga n. sp., Acrapex jansei n. sp., Acrapex kifanya n. sp., A. lusinga n. sp., Acrapex ngwenya n. sp., Acrapex njombea n. sp., Acrapex vetiveria n. sp. et Acrapex zima n. sp. Toutes ces espèces sont assignées au groupe d’espèce A. albivena à l’exception d’A. lusinga qui est assignée au groupe d’espèce A. stygiata. Nous fournissons également des descriptions supplémentaires pour deux espèces, A. punctosa Berio, 1973 et A. sysciodes, Berio 1973, précedemment décrites dans le groupe A. albivena ainsi que pour A. brunneella Le Ru, 2014, une espèce qui appartient au groupe A. stygiata. Les plantes-hôtes de trois espèces sont répertoriées ; Acrapex brunneella et A. jansei ont été élevées sur Cymbopogon pospischilii (K. Schum.) C. E. Hubb et A. vetiveria sur Chrysopogon zizanioides (L.). Nous avons également réalisé des analyses de reconstruction phylogénétique (utilisant à la fois l’inférence Bayésienne et le maximum de vraisemblance) sur un jeu de données moléculaires multi-marqueurs (quatre gènes mitochondriaux et deux gènes nucléaires) comprenant 138 specimens (incluant 98 specimens du groupe A. albivena et 23 specimens du groupe A. stygiata) de 48 espèces de foreurs. Les résultats de ces analyses soutiennent à la fois l’hypothèse de monophylie des deux groupes d’intérêt et le statut d’espèces des taxa nouvellement décris, à l’exception d’A. lusinga qui n’a pas été séquencé. Les analyses phylogénétiques révèlent également l’existence de plusieurs lignées évolutives distinctes dont le statut reste à définir car leur ADN a été extrait de stades larvaire

Phylogenetic analysis and systematics of the Acrapex unicolora Hampson species complex (Lepidoptera, Noctuidae, Apameini), with the description of five new species from the Afrotropics

Ten morphologically similar species of Acrapex Hampson, 1891 (Lepidoptera, Noctuidae, Noctuinae, Apameini) from Central and Eastern Africa are reviewed, including five new species: Acrapex kafula le Ru sp. nov., A. kavumba le Ru sp. nov., A. kiakouama le Ru sp. nov., A. miscantha le Ru sp. nov. and A. simillima le Ru sp. nov. Evidence is provided to transfer the monotypic genus Poecopa Bowden, 1956 to the genus Acrapex. Host plants of five species are recorded, some of them for the first time. Acrapex kavumba sp. nov., A. miscantha sp. nov. and A. simillima sp. nov. were found on one host plant each. Acrapex mediopuncta, previously reported in West Africa from Pennisetum purpureum Schumach., Rottboellia compressa L., Setaria megaphylla (Steud) Dur. & Schinz. and Sorghum arundinaceum (Desv.) Stapf, was only found from S. megaphylla in Central Africa. Larvae of Acrapex unicolora were collected on Andropogon gayanus Kunth, Chrysopogon zizanoides (L.) Roberty, Cymbopogon schoenanthus subsp. proximus (Hochst. ex A.Rich.) Maire & Weller, Cymbopogon pospischiilii (K.Schum.) C.E.Hubb., Hyparrhenia diplandra (Hack.) Stapf and Setaria sphacelata (Schumach.) Moss. We also conducted molecular phylogenetic analyses (using maximum likelihood) and molecular species delimitation analyses on a comprehensive sample of 61 specimens belonging to eight of the studied species. Molecular phylogenetic analyses provided additional evidence of the synonymy of Acrapex and Poecopa, whereas molecular species delimitation analyses support the validity of the five newly described species and unravel another potential new species, only collected in the larval stage

Phylogenetics, integrative taxonomy and systematics of the Sesamia cretica species group (Lepidoptera: Noctuidae: Apameini: Sesamiina), with the description of 21 new species from the Afrotropical region

International audienceIn this study, 31 species of noctuid stemborers belonging to the genus Sesamia Guenee, 1852 (Lepidoptera: Noctuidae: Noctuinae: Apameini: Sesamiina) are reviewed. All these species are assigned to the Sesamia cretica group sensu Tams & Bowden (1953). Based on genitalic characters, several subgroups are hereby defined. Nine species belong to a species complex defined as the Sesamia albivena Hampson, 1902 subgroup; it consists of S. albivena, S. mocoensis Tams & Bowden, 1953, n. stat., S. sudanensis Tams & Bowden, 1953, n. stat. S. taenioleuca (Wallengren, 1863), and five new species that are described (S. aethiopica Le Ru n. sp. from Ethiopia, S. kafulo Le Ru n. sp. from Botswana and Zambia, S. kavirondo Le Ru n. sp. from Kenya and Uganda, S. maloukou Le Ru n. sp. from Republic of Congo, and S. soyema Le Ru n. sp. from Ethiopia). Four species belong to a species complex defined as the Sesamia cretica subgroup; this encompasses S. cretica, S. rufescens Hampson, 1910, and two new species that are described (S. ihambane Le Ru n. sp. from Mozambique and Tanzania and S. kikuyuensis Le Ru n. sp. from Kenya); two new synonyms are introduced for Sesamia cretica: Nonagria uniformis Dudgeon, 1905 n. syn. and Sesamia griselda Warren, 1913, n. syn. Ten species belong to a species complex defined as the Sesamia fuscifrontia Hampson, 1914 subgroup; this includes S. fuscifrontia, S. geyri (Strand, 1915) and eight new species that are described (S. babati Le Ru n. sp. from Tanzania, S. babessi Le Ru n. sp. from Cameroon and Zambia, S. mabira Le Ru n. sp. from Uganda, S. nangaensis Le Ru n. sp. from Cameroon and Republic of Congo, S. rungwa Le Ru n. sp. from Tanzania, S. simillima Le Ru n. sp. from Benin, Cameroon, Kenya and Uganda, S. taveta Le Ru n. sp. from Kenya and S. ulaukae Le Ru n. sp. from Ethiopia). One species belongs to a species complex defined as the Sesamia salama Le Ru n. sp. subgroup; this consists of S. salama Le Ru n. sp. from Kenya and another undescribed Sesamia species from South Africa. One species belongs to a species complex defined as the Sesamia viettei Rungs, 1954 subgroup. Six species belong to a species complex defined as the Sesamia wiltshirei Rungs, 1963 subgroup; this groups S. wiltshirei and five new species that are described (S. djenoensis Le Ru n. sp. from Republic of Congo, S. inexpectata Le Ru n. sp. from South Africa and Zambia, S. lefini Le Ru n. sp. from Republic of Congo, S. echinochloa Le Ru n. sp. from Botswana, Kenya, Mozambique, South Africa, Tanzania and Zambia and S. rindini Le Ru n. sp. from Tanzania). A supplemental description of the previously described species is also provided. Novel host plant records are also provided for 11 species of the S. cretica group. To complement the morphological study, both phylogenetic and molecular species delimitation analyses were carried out on a multimarker (four mitochondrial and two nuclear genes) molecular dataset encompassing 144 specimens representing 35 species (including 25 species from the S. cretica group). Molecular analyses provide a well-supported phylogenetic framework for the species of interest, which are all recovered monophyletic. Molecular species delimitation analyses also support the species status of almost all sampled species. Interestingly, the inferred tree indicates that the S. cretica group and the S. fuscifrontia subgroup are both paraphyletic; this indicates that, while highly informative, the chosen genitalic characters in Sesamia are not all synapomorphies