Long-term spatio-temporal expansion of the native-invasive Retama monosperma on coastal dunes: Importance of land-use and natural dispersal vectors

Expansion of invasive species inducing sands stabilization is becoming an important ecological problem in coastal dunes in some parts of the world. Retama monosperma, an endemic to coasts of SE Spain and NE of Morocco, late-colonizing shrub occurring in sandy coastal areas, was planted along the coast of SW Spain during the 20th century to stabilize dunes. In recent decades, the species has spread rapidly, becoming invasive, and sometimes incurring notable changes in its environment and plant community. The expansion patterns of R. monosperma from 1956 to 2001 were described and quantified at the landscape scale within a protected dune system, using GIS. The differential effects on expansion patterns of the main factor controlling the population spread, grazing by domestic livestock and the abundance of wild rabbits, were analyzed comparatively. R. monosperma displays an exponential, invasive-type expansion trend, presenting a mean annual coverage increase of 15% and a mean lateral spread rate of 65.5 m yr⁻¹ from the original population nucleus to the Western and Eastern ends of the study area. The dispersal activity primarily of rabbits and the absence of competing woody species contribute to this rapid expansion. The highest local increases in plant coverage could be related to increased rabbit abundance and to the improved germination rates of seeds which have passed through the rabbit gut. In contrast, areas highly grazed by livestock present the lowest increases, and an open-type plant community is maintained there for a longer time.     

First Record of Bourgelatia diducta (Nematoda: Chabertiidae) from Wild Boars in the Republic of Korea

This study describes the first record of Bourgelatia diducta (Nematoda: Chabertiidae) from wild boars in the Republic of Korea (=South Korea). Gastrointestinal tracts of 87 Korean wild boars (Sus scrofa coreanus) hunted in mountains in the south-western part of South Korea between 2009 and 2012 were examined for their visceral helminths. B. diducta, as identified by morphological characteristics of the head and tail, were recovered from the large intestine of 47 (54%) wild boars. The average length of adult female worms was 11.3±0.87 mm and the thickest part of the body measured 0.54±0.04 mm in maximum width, while those of males were 9.8±0.72 and 0.45±0.03 mm, respectively. The characteristic J-shaped type II ovejector was observed in females, and the type II dorsal ray with 2 rami on each side of the median fissure was uniquely seen in males. The buccal capsule was small, relatively thin-walled, cylindrical, very short, and ring-shaped. The externodorsal ray arose from a common stem with the dorsal ray. The cervical groove was absent. The anterior extremity was equipped with 20-22 external corona radiata, 4 cephalic papillae and 2 lateral amphids around the mouth. The eggs were 66.0×38.9 µm in average size. By the present study, B. diducta (Nematoda: Chabertiidae) is recorded for the first time in South Korea. Additionally, morphological characteristics and identification keys provided in the present study will be helpful in the faunistic or taxonomic studies for strongylid nematodes related.     

Diversity and abundance of wild host plants of lepidopteran stem borers in two different agroecological zones of Kenya

A survey was carried out between 2004 and 2005 in two ecologically different locations, Kakamega and Muhaka to assess diversity and abundance of wild host plants of lepidopteran stem borers as compared to maize plots during the cropping and non-cropping seasons. Kakamega in Western Kenya is characterized by a Guineo-Congolian rain forest mosaic and Muhaka at the Kenyan coast by a Zanzibar Inhambane mosaic with secondary grassy and woody vegetation. In Kakamega, wild host plants and maize covered 2 and 43% of the surveyed area. No variation in diversity and relative abundance of wild host plants was observed between both the cropping and non-cropping seasons. In Muhaka, the diversity and relative abundance of wild host plant species differed between seasons, with the Shannon Weaver Index (H) of 1.67 and 0.95 for cropping and non-cropping seasons, respectively. Similarly in this location, wild host plant cover varied between cropping (23%) and noncropping (17.9%). During both seasons, this was higher than the maize cover, with 10.7% and 0% for the cropping and non-cropping seasons, respectively. For both localities, the implication of the differences found in the abundance and diversity between the cropping and non-cropping seasons is discussed.     

Farm and management characteristics associated with boar taint

Pig farms in the Netherlands producing boars have different levels of boar taint prevalence, as assessed by sensory evaluation with the human nose at the slaughter line. With a questionnaire to 152 Dutch pig producers (response rate 59%), farm and management characteristics were identified that are potentially associated with farm-level boar taint prevalence. Lower farm-level boar taint prevalence was associated with a smaller group size, a smaller pen surface per boar, newer housing equipment, not practicing restricted feeding in the last period before delivery, a longer fasting period before slaughter, a higher stocking weight and a lower fraction of boars from purebred dam line sows or from Pietrain terminal boars. These characteristics can be used to develop farm-level intervention strategies to control boar taint. More research effort is needed to establish causal relationships.     

荞麦野生种的核型及进化特征分析

荞麦起源于我国西南地区,该地区分布着丰富的荞麦野生种,剖析野生荞麦的核型特征对荞麦进化和育种研究具有重要的意义。本研究以甜荞近缘种、硬枝万年荞、疏穗小野荞、细柄野荞、齿翅野荞为试验材料,采用常规压片法进行核型鉴定。结果表明:甜荞近缘种、硬枝万年荞和疏穗小野荞都为二倍体,核型公式分别为2n=2x=16=12M+4m(2SAT)、2n=2x=16=16M、2n=2x=16=14M+2m(2SAT),而细柄野荞和齿翅野荞为四倍体,核型公式分别为2n=4x=32=32M、2n=4x=32=30M+2m(2SAT)。甜荞近缘种和硬枝万年荞核型属1A型,疏穗小野荞、细柄野荞和齿翅野荞核型属1B型,并且甜荞近缘种、疏穗小野荞和齿翅野荞都有1对随体染色体。研究证明,荞麦野生种染色体的基数为8,有二倍体和四倍体野生荞麦。通过比较分析,硬枝万年荞在进化地位上比较原始,齿翅野荞是比细柄野荞较进化的四倍体荞麦野生种。     

Complete Genome Sequence of a Novel Wild tomato mosaic virus Isolate Infecting Nicotiana tabacum in China

Virus particles of approximately 740–760 nm in length and 13 nm in diameter were observed from a diseased Nicotiana tabacum (tobacco) plant in Sichuan Province, China. The complete genomic sequence of the virus isolate XC1 was determined to contain 9659 nucleotides without 3′ terminal poly(A) tail. XC1 has a genome typical of members of the genus Potyvirus, encoding a large polyprotein of 3075 amino acids. Putative proteolytic cleavage sites and a number of well characterized functional motifs were identified by sequence comparisons with those of known potyviruses. Sequence comparison revealed that XC1 shared the highest level of nucleotide sequence identity (76.5%) with Wild tomato mosaic virus (WTMV). Phylogenetic analysis showed that XC1 was closely related to the WTMV Guangdong isolate with an identity of 94.3% between CP gene sequence of the two viruses. We thus named XC1 WTMV‐XC‐1 as a novel isolate of WTMV. The full sequence of WTMV‐XC‐1 may serve as a basis for future investigations on the gene diversity of WTMV.     

Alteration of selection regime resulting from harvest of American ginseng, <Emphasis Type="Italic">Panax quinquefolius</Emphasis>

Replicate harvest simulations were conducted in a large natural population of Panax quinquefolius L.␣(Araliaceae) to determine the selective effects of harvest. We investigated how minimum size requirements and the influence of size on apparency to human harvesters could result in preferential removal of large plants. To determine which plants were encountered in the large population, harvesters were tracked using GPS as they searched for every legally harvestable, adult plant they could find. Plants were assigned stage-specific fitness measures based on their contributions to population growth rate (λ) under three demographically based harvest regimes: no harvest, harvest and harvest removing seeds. Plant size was codified into a size-index equal to the product of total leaf area and stem height. Heterogeneity of slopes was tested to determine if the selection gradients (β) describing the relationship between fitness and size varied among the three harvest regimes. Harvest differentially reduced the fitness of larger plants in one of four individual harvest simulations. The combined harvest simulation significantly altered the selection regime for size in the population of juvenile and adult (harvestable) plants. Seed removal by harvesters intensified fitness declines for larger plants. Because larger plants contribute most to population growth, the selective effects of harvest could result in a shift in the evolutionary dynamics of this species with significant conservation implications.     

云南省爬行动物名录和地理区划更新

云南省作为中国生物多样性最高的省份, 其详实的物种本底资料对我国生物多样性研究和保护具有重要意义。本文在前期研究的基础上, 结合实体标本, 汇总编制了云南省现生、原生爬行动物更新名录。截至2021年12月31日, 云南省记录爬行动物25科82属235种, 其中龟鳖目4科12属16种, 有鳞目蜥蜴亚目6科20属72种, 蛇亚目15科50属147种。较《云南两栖爬行动物》确认新增82种, 存疑收录21种, 移除23种。基于先前云南省爬行动物区划和更新后的物种分布信息, 将云南省爬行动物地理分为6个动物地理区, 即滇西北横断山区、滇西山地区、滇南山地区、滇东南山地区、滇中高原区以及滇东北山地区; 其中滇西北横断山区、滇西山地区、滇中高原区和滇东南山地区的范围与先前研究相比有所调整。结合调整后的爬行动物地理区划, 对物种分布、物种特有性、受威胁状况等给出了统计结果。云南省爬行动物特有物种、国内仅见于云南的非特有物种数量较多, 受威胁等级高。建议今后继续加大分类学研究投入, 对滇西北、滇中特有爬行动物分布集中的区域积极开展栖息地保护工作, 同时在最新调整的《国家重点保护野生动物名录》基础上, 定期组织专家研讨, 对《云南省省级重点保护动物名录》提出更新建议。     

Quantitative and qualitative differences in morphological traits revealed between diploid Fragaria species

BACKGROUND AND AIMS: The aims of this investigation were to highlight the qualitative and quantitative diversity apparent between nine diploid Fragaria species and produce interspecific populations segregating for a large number of morphological characters suitable for quantitative trait loci analysis. METHODS: A qualitative comparison of eight described diploid Fragaria species was performed and measurements were taken of 23 morphological traits from 19 accessions including eight described species and one previously undescribed species. A principal components analysis was performed on 14 mathematically unrelated traits from these accessions, which partitioned the species accessions into distinct morphological groups. Interspecific crosses were performed with accessions of species that displayed significant quantitative divergence and, from these, populations that should segregate for a range of quantitative traits were raised. KEY RESULTS: Significant differences between species were observed for all 23 morphological traits quantified and three distinct groups of species accessions were observed after the principal components analysis. Interspecific crosses were performed between these groups, and F2 and backcross populations were raised that should segregate for a range of morphological characters. In addition, the study highlighted a number of distinctive morphological characters in many of the species studied. CONCLUSIONS: Diploid Fragaria species are morphologically diverse, yet remain highly interfertile, making the group an ideal model for the study of the genetic basis of phenotypic differences between species through map-based investigation using quantitative trait loci. The segregating interspecific populations raised will be ideal for such investigations and could also provide insights into the nature and extent of genome evolution within this group.