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Selected AbstractsFaunal make-up, host range and infestation rate of weevils and tephritid flies associated with flower heads of the thistle Cirsium (Cardueae: Astaraceae) in JapanENTOMOLOGICAL SCIENCE, Issue 4 2004Akinori NAKAMURA Abstract From 1988 to 1998, we collected flower heads of 39 thistle taxa (35 taxa of Cirsium, one species each of Breea, Synurus, Saussurea and Arctium; Cardueae; Astaraceae) in Japan, mainly from Hokuriku and other parts of central Honshu, and kept them in the laboratory to breed weevils and tephritid flies, the core fauna. We report the faunal make-up, host plants, geographic distribution and the attack levels of the insects. Results indicated that (i) three Larinus species (Curculionidae) and three species of tephritid flies (Tephritis, Urophora and Xyphosia) comprised the core fauna; (ii) two insect species belonging to the same taxonomic group (either Curculionidae (Larinus) or Tephritidae) tended to use different host plant species; (iii) two sympatric Larinus species (L. latissimus and L. meleagris) segregated the host plants seasonally in central Honshu (Cirsium blooming in spring and autumn, respectively); and (iv) two tephritid fly species, Xyphosia punctigera and Urophora sachalinensis, segregated geographically (the former on the Japan Sea side and the latter on the Pacific Ocean side). In comparison with their European counterparts, the weevils and tephritids of the Japanese Cirsium are characterized by a lower species richness and a lower degree of specialization in usage of the thistle flower heads, with gall-formers being distinctly under-represented, and callus tissue-feeders being absent. This reflects the fact that Japanese thistles are so closely related that hybridization frequently occurs, and also that the thistles have had a short history of interaction with the insects since the thistles' arrival in Japan. [source] The annual cycle and interannual variability of atmospheric pressure in the vicinity of the North PoleINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 10 2003Richard I. Cullather Abstract A comparison of National Centers for Environmental Prediction,National Center for Atmospheric Research reanalysis six-hourly sea-level pressure data with former Soviet drifting station observations over the central Arctic Basin reveals high monthly correlations throughout the period 1950,91, but also a preferred winter season negative bias of about 1.4 hPa. Using the reanalysis, supplemented by Arctic Ocean Buoy Program fields and in situ observations, a generalized depiction of the annual cycle of pressure fields over the Arctic may be constructed. Above the Canada Basin,Laptev Sea side of the Arctic, the annual cycle of surface pressure is dominated by the first harmonic, which has an amplitude of about 5 hPa and maximum pressure occurring in March. Along the periphery of northern Greenland and extending to the North Pole, a weak semiannual cycle is found in surface pressure with maxima in May and November. The presence of the semiannual variation over time is highly variable. Dynamically, this progression of the annual cycle may be attributed to the transfer of atmospheric mass from Eurasia and into the Canadian Archipelago in spring and the reverse condition in autumn. Over the central Arctic Basin, springtime pressure increases result from an enhanced poleward mass transport from Eurasia. An increase of equatorward transport over the Canadian Archipelago in May and June results in central Arctic pressure decreases into summer. A less distinct temporal separation between the poleward Canadian transport and the equatorward Eurasian transport results in the weaker second pressure maximum in autumn. On interannual time-scales, atmospheric mass over the central Arctic is exchanged with the storm track centres of action in the North Atlantic and North Pacific. In particular, the large decrease in central Arctic Basin sea-level pressure during the late 1980s is due to a large transfer of atmospheric mass into the North Pacific. Copyright © 2003 Royal Meteorological Society [source] An unconformity in the early Miocene syn-rifting succession, northern Noto Peninsula, Japan: Evidence for short-term uplifting precedent to the rapid opening of the Japan SeaISLAND ARC, Issue 3 2002Kazuhiko Kano Abstract The present paper describes the newly discovered early Miocene unconformity in the northern Noto Peninsula, on the Japan Sea side, central Japan. The unconformity marks the boundary between an early Miocene non-marine to marine succession and a more extensive, late early to early middle Miocene marine succession, and contains a time gap of an order of 1 million years or less from 18 Ma or earlier to 17 Ma. The early Miocene succession likely represents an early phase of marine transgression and initial slow rifting. The overlying early to early middle Miocene succession records the climax of the opening of the Japan Sea at ca 16 Ma with widespread, rapid subsidence of the Japan Arc. The unconformity between the two transgressive successions may represent a global sealevel fall or, more likely, crustal uplifting because no upward-shallowing or regressive facies remains between the two successions. Early Miocene unconformities that are thought to be correlative with this unconformity in the northern Noto Peninsula occur in places along the Japan Sea coast of Sakhalin and Japan. They are likely to have been produced during rifting in response to upwelling of asthenospheric mantle, although more accurate age constraints are necessary to evaluate this idea. [source] Contrasting patterns of nuclear microsatellite genetic structure of Fraxinus mandshurica var. japonica between northern and southern populations in JapanJOURNAL OF BIOGEOGRAPHY, Issue 6 2010Li-Jiang Hu Abstract Aim, The aim of this study is to detect extant patterns of population genetic structure of Fraxinus mandshurica var. japonica in Japan, and to provide insights into the post-glacial history of this species during the Holocene. Location, Hokkaido and Honshu islands, Japan (including the Oshima and Shimokita peninsulas). Methods, We examined nine polymorphic nuclear microsatellite loci to assess genetic variation within and among 15 populations across almost the entire range of the species in Japan. Extant patterns of geographical structure were analysed using Bayesian clustering, Monmonier's algorithm, analysis of molecular variance, Mantel tests and principal coordinates analysis. Recent bottlenecks within populations and regional genetic variation were also assessed. Results, Northern populations (Hokkaido Island and the Shimokita Peninsula) formed a single homogeneous deme, maintaining the highest level of allelic diversity on the Oshima Peninsula. By contrast, southern populations (Honshu Island) demonstrated strong substructure on both coasts. Specifically, populations on the Pacific side of Honshu exhibited significant bottlenecks and erosion of allelic diversity but preserved distinct subclusters diverging from widespread subclusters on the Japan Sea side of this island. Main conclusions, Genetic evidence and life history traits suggest that F. mandshurica occupied cryptic northern refugia on the Oshima Peninsula during the Last Glacial Maximum, which is reflected in the species' extant northern distribution. Strong geographical structure in southern populations, in agreement with fossil pollen records, suggests geographical isolation by mountain ranges running north,south along Honshu. Given that this tree species is cold-adapted and found in riparian habitats, populations on the Pacific side of Honshu probably contracted into higher-elevation swamps during warm post-glacial periods, leading to a reduction of effective population sizes and rare allelic richness. [source] The Keiva ice marginal zone on the Kola Peninsula, northwest Russia: a key component for reconstructing the palaeoglaciology of the northeastern Fennoscandian Ice SheetBOREAS, Issue 4 2007Clas H, ttestrand One of the key elements in reconstructing the palaeoglaciology of the northeastern sector of the Fennoscandian Ice Sheet is the Keiva ice marginal zone (KIZ) along the southern and eastern coast of Kola Peninsula, including the Keiva I and II moraines. From detailed geomorphological mapping of the KIZ, primarily using aerial photographs and satellite images, combined with fieldwork, we observed the following. (1) The moraines display ice contact features on both the Kola side and the White Sea side along its entire length. (2) The Keiva II moraine is sloping along its length from c. 100 m a.s.l. in the west (Varzuga River) to c. 250 m a.s.l. in the east (Ponoy River). (3) The KIZ was partly overrun and fragmented by erosive White Sea-based ice after formation. From these observations we conclude that the KIZ is not a synchronous feature formed along the lateral side of a White Sea-based ice lobe. If it was, the moraines should have a reversed slope. Rather, we interpret it to be time transgressive, formed at a northeastward-migrating junction between a warm-based Fennoscandian Ice Sheet expanding from the west and southwest into the White Sea depression, and a sluggish cold-based ice mass centred over eastern Kola Peninsula. In contrast to earlier reconstructions, we find it unlikely that an ice expansion of this magnitude was a mere re-advance during the deglaciation. Instead, we propose that the KIZ was formed during a major expansion of a Fennoscandian Ice Sheet at a time pre-dating the Last Glacial Maximum. [source] | ||||||||||