New insights on systematics and phylogenetics of Mediterranean Blaps species (Coleoptera: Tenebrionidae: Blaptini), assessed through morphology and dense taxon sampling

The genus Blaps is an emblematic group of large flightless beetles adapted to semi‐arid and arid environments. About 230 species have been described in the subgenus Blaps, which is the largest of the four extant subgenera. Within this subgenus, one large group of morphologically homogeneous species is of particular interest, and comprises the species formerly assigned to Seidlitz's division one. Strikingly, almost all species in this group are endemic to the Mediterranean basin, whereas the remaining Blaps species are mostly distributed in Asia. Here we present the first phylogenetic hypothesis for the Mediterranean Blaps and several taxonomic clarifications for the North African species belonging to this group. Based on careful examination of almost all type material and thousands of specimens for all known species and subspecies (initially 65 taxa), seven lectotypes are designated and six new synonymies are established: Blaps heydeni Allard, 1880 = Blaps heydenissp. taciturna Peyerimhoff syn.n. , Blaps emondi Solier = Blaps nitidula Solier syn.n. , Blaps tripolitanica Karsch = Blaps vialattei Peyerimhoff syn.n. , Blaps bifurcata strauchi Reiche = Blaps bifurcata ssp. gridellii Pierre syn.n. , Blaps cognata Solier = Blaps schweinfurhtii Seidlitz syn.n. and Blaps judaeorum Miller = Blaps pharao Seidlitz syn.n. Among the examined material, five species are also new for science and are assigned to extant species group. To infer species relationships, a morphological character matrix was assembled and analysed using both parsimony and probabilistic methods. All analyses yielded a similar and repeatable phylogenetic pattern, which allows us to discuss the systematics of the Mediterranean endemic species, the limit of extant species groups and to clarify the taxonomic status of several ambiguous taxa. We also reveal the existence of a large clade that encompasses the eastern Mediterranean species that are also mostly associated with arid regions. This clade is embedded within a second group that corresponds to western Mediterranean species, which are generally found in semi‐arid regions. Finally, we discuss the relevance of species groups in relation to their geographic distribution. This work represents a first step for further studies in taxonomy, systematics and historical biogeography of Blaps species.     

Identification and Localization of Frankia Strains in Alnus Nodules by In Situ Hybridization of nif H mRNA with Strain-Specific Oligonucleotide Probes

In situ hybridization of Frankia mRNA with specific probes wasused to localize the strains Arl3 and AcoN24d in Alnus nodulesobtained after inoculation with one or both strains. The probesconsisted of 18-mer oligonucleotides, complementary to strain-specificsequences located within the nif H gene. Sections of nodulesinoculated with only one strain revealed a specific hybridizationbetween the probe and the corresponding Frankia strain mRNA.In sections of dually-inoculated nodules the presence of thestrain AcoN24d in the nodule was clearly shown whereas thoseof the strain Arl3 could not be detected. This suggests thatthe strain Arl3 is less infective than the strain AcoN24d andis not present within the nodule. Key words: Nitrogen fixation, actinorhizae, autoradiography, histochemistry     

Analysis of cytosolic isocitrate dehydrogenase and glutathione reductase 1 in photoperiod‐influenced responses to ozone using Arabidopsis knockout mutants

Oxidative stress caused by ozone (O₃) affects plant development, but the roles of specific redox‐homeostatic enzymes in O₃ responses are still unclear. While growth day length may affect oxidative stress outcomes, the potential influence of day length context on equal‐time exposures to O₃ is not known. In Arabidopsis Col‐0, day length affected the outcome of O₃ exposure. In short‐days (SD), few lesions were elicited by treatments that caused extensive lesions in long days (LD). Lesion formation was not associated with significant perturbation of glutathione, ascorbate, NADP(H) or NAD(H). To investigate roles of two genes potentially underpinning this redox stability, O₃ responses of mutants for cytosolic NADP‐isocitrate dehydrogenase (icdh) and glutathione reductase 1 (gr1) were analysed. Loss of ICDH function did not affect O₃‐induced lesions, but slightly increased glutathione oxidation, induction of other cytosolic NADPH‐producing enzymes and pathogenesis‐related gene 1 (PR1). In gr1, O₃‐triggered lesions, salicylic acid accumulation, and induction of PR1 were all decreased relative to Col‐0 despite enhanced accumulation of glutathione. Thus, even at identical irradiance and equal‐time exposures, day length strongly influences phenotypes triggered by oxidants of atmospheric origin, while in addition to its antioxidant function, the GR‐glutathione system seems to play novel signalling roles during O₃ exposure.     

Metazoan Relationships on the Basis of 18S rRNA Sequences: A Few Years Later...

SYNOPSIS. The 18S rRNA database is continuously growing andnew tree construction methods are being developed. The presentstudy aims at assessing what effect the addition of recentlydetermined animal 18S rRNA sequences and the use of a recentlydeveloped distance matrix calculation method have on the resultsof some previously published case studies on metazoan phytogeny.When re-assessing three case studies, part of their conclusionswas confirmed on the basis of the present 18S rRNA data set:1) the monophyly of Arthropoda; 2) the monophyly of the Vestimentifera-Pogonophoraand their protostome character; 3) the doubt about the monophyleticorigin of Echiura-Sipuncula and 4) the coelomate characterofNemertea. Yet, it is also demonstrated that some of the previousresults are no longer warranted when updating the analyses:1) the monophyly of both the Annelida and the Eutrochozoa; 2)the sister-group relationship of Echiura to Vestimentifera-Pogonophoraand 3) the polyphyly of the Mesozoa and their close relationshipto Myxozoa and Nematodes. In addition, some new very preliminaryevidence is provided for: 1) a common ancestry of Platyhelminthesand Mesozoa and the monophyly of the latter group and 2) themonophyly of Clitellata, Hirudinida and Oligochaeta. Finally,doubt is casted on the monophyly of the Polychaeta and the polychaeteorders Spionida, Phyllodocida, and Sabellidae. Of course, thesehypotheses also need further testing.     

THE IMPORTANCE OF THE HOST SPECIES IN DETERMINING THE ACTION OF VIRUS INHIBITORS

Some plant species from which viruses are difficult to transmit to other species by sap inoculation contain substances that inhibit infection. The extent to which infection is inhibited by these substances depends on the species of plants to which inoculations are made and not on the identity of the virus. The inhibitors are largely ineffective in preventing infection of the species which contain them.
Infection of cucumber was less affected than any of the other species by all the inhibitors tested.     

Rides septales à organisation de type tétracoralliaire chez Trachypsammia (Tabulata, Permien)

Précédemment décrite chez Kerforneidictyum et Palaeacis I'organisation des rides septales suivant un schema de type tetracoralliaire est reconnue chez Trachypsammia monoseptata (Permien de Timor) où n'avait été signalé qu'un fort “Medianseptum”. II détermine un plan de symétrie bilatérale dans le calice; la ride cardinale forte est en position dorsale ou interne, la ride antipode également bien développée en position ventrale ou externe souvent plus courte, les rides considérées comme alaires sont identifiables au moins dam leur partie proximale. L'ensemble des rides clairement observables sont les rides majeures (protorides et métarides), les rides mineures sont à peine ébauchées. T. monoseptata pourrait représenter un stade calicinal jeune de T. dendroides. Trachypsammia dendroides (Permien de Timor) posséde un plan de symétrie bilatérale net. la ride cardinale est plus forte et plus longue que les autres rides, la ride antipode plus courte, les rides alaires sont identifiables en coupe transversale. rides majeures el mineures sont bien differenciées; le nombre total de rides est souvent de 32. Chez T. xizangensis (Permien du Tibet), seule une symétrie bilatérale a été observée en coupe. Pas de donnees pour T. mrditerranea (Permien de Sicile). Les affinités systéinatiques très étroites mises en évidence entre Polaeacis et Trachypsammia par les caractéres microstructuraux sont confirmées par Ie dispositif septal, ces Tabulés constituent-ils un groupe particulier? La question est posée A rugosan pattern of the septal ridges, formerly described in Kerforneidictyum and Palaeacis is pointed out in Trachypsammia monoseptata (Permian of Timor) for which only the ‘Medianseptum’ had been observed. T. monoseptata exhibits a strong cardinal ridge in dorsal or internal position. just opposite a shorter counter ridge, thus creating a plane of bilateral symmetry. The ridges assumed to be alar can be identified by their proximal ends being in contact with the ‘Medianseptum’. The major ridges (proto and metaridges) are obvious, the minor ones show only their very proximal ends. T. monoseptuta could be a calicinal young stage of T. dendroides. T. dendroides (Permian of Timor) shows a plane of bilateral symmetry, the cardinal ridge is stronger and longer than the others, the counter shorter, the alar ridges can be identified in transverse section. major and minor ridges are well developed; the number of ridges is often 32. In T.xizangensis (Permian of Tibet) only the bilateral symmetry is known, while there are no data for T mediterranea (Permian of Sicily). The systematic affinities between Palaeacis and Trachiypsammia pointed out on the basis of microstructural data are also supported by the septal ridges pattern. Do Palaeacis, Trochypsammia and others form a special division of Tabulate corals? That is the question     

Degradation of native and exotic riparian plant leaf litter in a floodplain pond

1. A litter‐bag experiment was undertaken in a pond on the margins of a large temperate floodplain in south‐western France to assess the potential influence of the replacement of native by exotic riparian species on organic matter degradation. We determined initial litter chemical composition, breakdown rates and the invertebrate assemblages associated with the litter for five pairs of native dominant and exotic invasive species co‐occurring at different stages along a successional gradient. 2. Litter chemical composition, breakdown rates and abundance and diversity of detritivorous invertebrates were similar for the exotic and native species overall. No overall changes in organic matter degradation can thus be predicted from the replacement of dominant natives by exotic invasives. Breakdown rates were primarily driven by the C/N ratio. 3. One invasive species (Buddleja davidii) showed significantly higher breakdown rates than its native counterpart (Populus nigra), resulting in the disappearance of leaf litter 6 months prior to the next litterfall. In some cases, therefore, invasion by exotic species may result in discontinuity of resource supply for decomposers.