Trophic level modulates carabid beetle responses to habitat and landscape structure: a pan‐European study

1. Anthropogenic pressures have produced heterogeneous landscapes expected to influence diversity differently across trophic levels and spatial scales. 2. We tested how activity density and species richness of carabid trophic groups responded to local habitat and landscape structure (forest percentage cover and habitat richness) in 48 landscape parcels (1 km²) across eight European countries. 3. Local habitat affected activity density, but not species richness, of both trophic groups. Activity densities were greater in rotational cropping compared with other habitats; phytophage densities were also greater in grassland than forest habitats. 4. Controlling for country and habitat effects, we found general trophic group responses to landscape structure. Activity densities of phytophages were positively correlated, and zoophages uncorrelated, with increasing habitat richness. This differential functional group response to landscape structure was consistent across Europe, indicated by a lack of a country × habitat richness interaction. Species richness was unaffected by landscape structure. 5. Phytophage sensitivity to landscape structure may arise from relative dependency on seed from ruderal plants. This trophic adaptation, rare in Carabidae, leads to lower phytophage numbers, increasing vulnerability to demographic and stochastic processes that the greater abundance, species richness, and broader diet of the zoophage group may insure against.     

Exceptionally well‐preserved brittle stars from the Pliensbachian (Early Jurassic) of the French Ardennes

Abstract: Two new genera and species of ophiuroid, Inexpectacantha acrobatica new gen. et sp. and Eirenura papillata new gen et sp., are described on the basis of 39 articulated specimens and several hundreds of arm fragments and isolated skeletal parts. The material was extracted from a lumachellic bed in a late early Pliensbachian succession of argillites at Sedan, French Ardennes. The material is unusually well preserved with even finest structures of the skeleton discernible. Despite the exceptionally detailed morphological data extractable from the material, the higher taxonomic classification in the system of recent ophiuroids could only be tentatively attained. Inexpectacantha acrobatica seems best placed within the Ophioplinthacinae inside the Ophiacanthidae whereas Eirenura papillata shares greatest similarities with the Ophioleucinae. The occurrence of articulated specimens of different sizes, with some of the most delicate skeletal structures left intact, together with completely disarticulated skeletons of the same species suggests that the ophiuroids were preserved as autochthonous faunule among an in situ population of Modiolus sp. during a period of more favourable bottom water conditions in an otherwise largely hostile near‐shore soft‐bottom environment. Based on its small size, the highly flexible arms and the presence of well‐developed hooks on distal arm segments, an epizoic way of life is inferred for I. acrobatica while E. papillata, with its rigid arm structure and the conspicuously large tentacle pores, is interpreted as mostly deposit‐feeding bottom surface dweller.     

Development and characterization of microsatellite markers for two dioecious Ficus species

Microsatellite markers for Ficus montana and Ficus septica were developed using genomic libraries enriched for di‐, tri‐ and tetranucleotide repeats. The subsets of five and three best scorable primer pairs were characterized on 24 F. montana and 36 F. septica individuals, respectively. For F. montana, loci showed five to 14 alleles per locus and expected heterozygosities ranged between 0.23 and 0.87. For F. septica, loci showed three to five alleles per locus and expected heterozygosities ranged between 0.36 and 0.49. Four primer pairs (two from each subset) cross‐amplified in the other species, indicating transportability of the markers within the genus Ficus.     

Juvenile-to-Adult Antler Development in White-Tailed Deer in South Texas

Abstract: Past studies using penned deer provide conflicting results on the age when reliable predictions about antler growth potential in white-tailed deer (Odocoileus virginianus) can be made. We captured wild whitetail males via aerial net gun on 12 ranches in 5 counties in south Texas, USA, from 1999 to 2007 to determine if a reliable juvenile-to-adult relationship in antler development existed. We individually marked and released captured animals at the trap site after we took antler and body measurements. We recaptured marked animals as possible in subsequent years or until we obtained final measurements after legal harvest. Amount of growth in the first set of antlers in whitetail males was a poor predictor of antler growth at maturity. By 4.5 years of age there were no differences (P > 0.05) in antler measurements regardless of the amount of development of the first set of antlers at 1.5 years. We concluded culling of yearling males based on number of antler points would have little positive effect on overall antler quality in future years.     

树鼩细胞周期蛋白T1 cDNA的克隆和序列分析

树鼩细胞不能感染HIV-1,但支持HIV-1进入靶细胞后的转录,可能是因为树鼩细胞周期蛋白T1(tsCycT1)能结合HIV-1的Tat蛋白。通过设计引物,用RT—PCR技术,获得全长为2175bp tsCycT1基因的cDNA。其核苷酸序列与人的CycT1(hCycT1)基因的cDNA有92．6％的相似性;由此推导出的氨基酸序列有94．1％相似性。其中,hCycT1和tsCycT1氨基端的1—272个氨基酸的相似性高达98．8％,氨基酸第261位点为半胱氨酸。这些结果提示,tsCycT1会和HIV-1的Tat结合,形成高亲和的、锌依赖的复合物,支持HIV-1转录。     

Phenotypic correlates of Clock gene variation in a wild blue tit population: evidence for a role in seasonal timing of reproduction

The timing of reproduction in birds varies considerably within populations and is often under strong natural selection. Individual timing within years is dependent on a range of environmental factors in addition to having an additive genetic basis. In vertebrates, an increasing amount is known about the molecular basis for variation in biological timing. The Clock gene includes a variable poly-glutamine (poly-Q) repeat influencing behaviour and physiology. Recent work in birds, fish and insects has demonstrated associations between Clock genotype and latitude across populations, which match latitudinal variation in breeding time. In this study, we investigated the phenotypic correlates of variation in Clock genotype within a single blue tit Cyanistes caeruleus population over two successive breeding seasons. In females, but not in males, we observed a general trend for birds with fewer poly-Q repeats to breed earlier in the season. Incubation duration was shorter in both females and males with fewer repeats at the polymorphic Clock locus. Poly-Q Clock allele-frequency was homogenously distributed within the study population and did not exhibit any consistent environment-related variation. We further tested for effects of Clock genotype on reproductive success and survival, and found that females with fewer poly-Q repeats produced a higher number of fledged offspring. Our results therefore suggest that (i) selection in females, but not in males, for fewer poly-Q repeats may be operating, (ii) the across–population associations in timing of breeding involving this locus could be linked to variation within populations, and (iii) the Clock gene might be involved in local adaptation to seasonal environments.     

Development and mapping of a public reference set of SSR markers in Lolium perenne L.

We report on the characterization and mapping of 76 simple sequence repeat (SSR) markers for Lolium perenne. These markers are publicly available or obtained either from genomic libraries enriched for SSR motifs or L. perenne expressed sequence tag (EST) clones. Four L. perenne mapping populations were used to map the SSR markers. A consensus linkage map of the four mapping populations containing 65 of the SSR markers is presented, together with primer information and a quality score indicating the usefulness of the SSR marker in different populations. The SSR markers identified all seven L. perenne linkage groups.     

Type I microsatellite markers from Atlantic salmon (Salmo salar) expressed sequence tags

The detection of simple sequence repeats (SSRs) within expressed sequence tags (ESTs) connects potential microsatellite markers with specific genes, generating Type I markers. Using an in silico approach, we identified 1975 SSRs from the Genome Research on Atlantic Salmon Project EST database. We designed primers to amplify 158 SSRs, of which 65 amplified 76 loci (including 11 duplicated loci). Sixty‐one of the 76 loci were variable in 24 Atlantic salmon from seven populations, and 96% of these markers also amplify DNA from other salmonids. Functions for 16 of the SSR associated ESTs have been determined, confirming them as Type I markers.     

Carbon allocation in boreal black spruce forests across regions varying in soil temperature and precipitation

A common hypothesis for northern ecosystems is that low soil temperatures inhibit plant productivity. To address this hypothesis, we reviewed how separate components of ecosystem carbon (C) cycling varied along a soil temperature gradient for nine well-drained, relatively productive boreal black spruce ( Picea mariana Mill. [B.S.P.]) forests in Alaska, USA, and Saskatchewan and Manitoba, Canada. Annual soil temperature [expressed as soil summed degree days (SDD)] was positively correlated with aboveground net primary productivity (ANPP), while negatively correlated with total belowground carbon flux (TBCF). The partitioning of C to ANPP at the expense of root processes represented a nearly 1 : 1 tradeoff across the soil temperature gradient, which implied that the amount of C cycling through these black spruce ecosystems was relatively insensitive to variation in SDD. Moreover, the rate at which C accumulated in the ecosystem since the last stand replacing fire was unrelated to SDD, but SDD was positively correlated to the ratio of spruce-biomass : forest-floor-mass. Thus, plant partitioning of C and the distribution of ecosystem C were apparently affected by soil temperature, although across regions, precipitation co-varied with soil temperature. These two factors likely correlated with one another because of precipitation's influence on soil heat balance, suggesting that a soil temperature–precipitation interaction could be responsible for the shifts in C allocation. Nonetheless, our results highlight that for this boreal ecosystem, ANPP and TBCF can be negatively correlated. In tropical and temperate forests, TBCF and ANPP have been reported as positively correlated, and our results may reflect the unique interactions between soil temperature, forest floor accumulation, rooting depth, and nutrient availability that characterize the black spruce forest type.