Phylogeny of macrophagous leeches (Hirudinea,Clitellata) based on molecular data and evaluation of the barcoding locus

Oceguera‐Figueroa, A., Phillips, A. J., Pacheco‐Chaves, B., Reeves, W. K. & Siddall, M. E. (2010). Phylogeny of macrophagous leeches (Hirudinea, Clitellata) based on molecular data and evaluation of the barcoding locus. —Zoologica Scripta, 40, 194–203. The phylogenetic relationships of macrophagous leech species are studied using two mitochondrial [cytochrome c oxidase subunit I (COI) and 12S rDNA] and two nuclear (28S rDNA and 18S rDNA) markers. The complete dataset analysed in this study included 49 terminals and 5540 aligned characters. Phylogenetic analyses were performed under two optimality criteria: Maximum Parsimony and Maximum Likelihood. The monophyly of the two currently recognized families (i.e. Erpobdellidae and Salifidae) is confirmed and well supported. The phylogenetic position of Gastrostomobdellidea is studied for the first time and found to be sister to family Salifidae nested well within Erpobdelliformes. Previously recognized taxonomic arrangements were evaluated and discarded through successive constraint analyses. Correlation between morphology and phylogeny was notable in Salifidae but not in Erpobdellidae. Variability of COI, the barcoding locus, was examined across species leading to the recognition of the invasive Barbronia weberi in Mexico, Costa Rica, Germany, South Africa and Taiwan.     

Pollination ecology of Arum italicum (Araceae)

The pollination ecology of Arum italicum was studied in south-western France. This plant attracts olfactory dung-breeding flies through deceit. These insects are principally represented by Diptera, all belonging to saprophyte families. The volatilization of the odouriferous compounds, responsible for their attraction, is achieved through the production of heat by the appendix. The insects are trapped for 24 h in order to participate in both sexual phases of the protogynous inflorescence. The male flowers produce three heat events during flowering. These peaks of heat seem to be involved in the spathe movements, since they occur during the opening of the inflorescence and the liberation of the insects. The last male heat event may be linked with the liberation of pollen and its dispersion by stimulating trapped flies. According to their frequency and pollen-load, two Psychoda species appear to be the most efficient pollinators ( P. crassipenis and P. pusilla ). Nevertheless, each of the other attracted species could play a significant role under different spatio-temporal conditions. Experiments on self-pollination have shown that obligate cross-pollination is necessary for A. italicum to set seeds. Moreover, hand- and natural-pollinated plants showed similarly high abortion frequencies suggesting that seed set may be more constrained by resources rather than by pollination limitation.  © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 2003, 141 , 205–214.     

How did an annual plant react to Pleistocene glaciations? Postglacial history of Rhinanthus angustifolius in Europe

The impact of climate fluctuations during the Pleistocene on the geographic structure of genetic variation in plant populations is well documented, but there is a lack of studies of annual species at the European scale. The present study aimed to infer the history of the widespread European annual Rhinanthus angustifolius C. C. Gmelin (Orobanchaceae). We explored variation in chloroplast DNA (cpDNA) sequences and amplified fragment length polymorphism (AFLP) in twenty-nine populations covering the entire distribution area of the species. Five AFLP groups were identified, suggesting at least two glacial refugial areas: one area in southwestern Europe and one large eastern area in the Balkan/Caucasus. Recolonization of previously glaciated areas mainly took place from the east of Europe. Despite the difference in life-history traits, the patterns found for the annual R. angustifolius show similarities with those of perennial species in terms of genetic diversity and geographic organization of genetic variation. Although organelle markers have typically been preferred in phylogeographic studies, the cpDNA variation in R. angustifolius did not show any clear geographic structure. The absence of geographic structure in the cpDNA variation may reflect persistence of ancestral polymorphisms or hybridization and introgression with closely-related species.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 98 , 1–13.     

Leeches (Oligochaeta?: Euhirudinea), their phylogeny and the evolution of life-history strategies

Powerful tests of adaptational hypotheses can be made in the context of well-supported cladograms by investigating the most parsimonious transformation of intrinsic or extrinsic factors to explain their distribution across taxa in a cladogram. Such tests are used here to discover patterns of life-history evolution in leeches; in particular in relation to exploitation of terrestrial and aquatic habitats, parental care and resource utilization. Moreover, the relationships among leeches, acanthobdellids and branchiobdellids is reaffirmed as is their collective placement within the oligochaetes.     

Problems Determining the Phylogenetic Position of Echiurans and Pogonophorans with Limited Data

The phylogenetic position of Echiura and Pogonophora was recently reconsidered using 346 bp of elongation factor 1-alpha (EF-1α). On the basis of these results alone it was suggested that the relationships of Anne lida be reconsidered and that the systematics of the group changed accordingly. An examination of these data, however, reveals difficulties in the original analysis that relate to weighting and the relative inclusion or exclusion of available characters and of taxa. Wholesale revision of the systematics of Annelida or of groups therein awaits the availability of more comprehensive work.     

Effects of chorda tympani nerve anesthesia on taste responses in the NST

Human clinical and psychophysical observations suggest that the taste system is able to compensate for losses in peripheral nerve input, since patients do not commonly report decrements in whole mouth taste following chorda tympani nerve damage or anesthesia. Indeed, neurophysiological data from the rat nucleus of the solitary tract (NST) suggests that a release of inhibition (disinhibition) may occur centrally following chorda tympani nerve anesthesia. Our purpose was to study this possibility further. We recorded from 59 multi- and single- unit taste-responsive sites in the rat NST before, during and after recovery from chorda tympani nerve anesthesia. During anesthesia, average anterior tongue responses were eliminated but no compensatory increases in palatal or posterior tongue responses were observed. However, six individual sites displayed increased taste responsiveness during anesthesia. The average increase was 32.9%. Therefore, disinhibition of taste responses was observed, but infrequently and to a small degree in the NST At a subset of sites, chorda tympani-mediated responses decreased while greater superficial petrosal-mediated responses remained the same during anesthesia. Since this effect was accompanied by a decrease in spontaneous activity, we propose that taste compensation may result in part by a change in signal-to-noise ratio at a subset of sites.