Consequences for seed distributions of intra-crop variation in wing-loading of wind-dispersed species

We used a computer simulation to quantify how intra-crop variation in wing-loading in a wind-dispersed species affects the seed distribution around a parent plant. We used a data set of seed distributions generated from a previous field study using artificial fruits varying in seed mass or fruit area dispersed from a tower into a tropical forest. For this study, the spatial distribution from each hypothetical parent's fruit crop of 1000 was calculated by randomly drawing locations of dispersed fruits from the previous data base. Three parents with contrasting fruit crops were used to test two hypotheses: 1) Increasing within-parent variance in wing-loading (= weight/area), while maintaining the mean, will lead to an increase in the area and uniformity of the seed distribution, without changing the mean dispersal distance. 2) Decreasing within-parent mean wing-loading, (which also decreases variance), will lead to an increase in mean dispersal distance, area, and uniformity of the seed distribution. The hypotheses were tested under four wind speeds.Increasing variance in wing-loading resulted in increasing the area and uniformity of density of the seed distribution without changing mean dispersal distance. Decreasing mean and variance in wing-loading resulted in increasing the area and uniformity of density of the seed distribution, as well as increasing the mean dispersal distance. Similar results occurred whether the differences in wing-loading arose by altering seed mass or fruit area. The effect of wind speed was consistently greater than the effect of parent. Generally, the same pattern of parent effects on seed distributions occurred, regardless of wind condition.The effects on seed distributions differed for alterations in mean versus variance, specifically in whether mean dispersal distance was increased. How selection may act on intra-crop mean and variance in wing-loading will depend on additional factors, e.g. the relative importance of distance, area, and density on seedling recruitment and the relative costs for crop size and seedling establishment of making fruit crops of a given mean and variance.     

辽宁革螨的生态地理分布

辽宁省已知的革螨46种,分属于5科19属.本文依据四个不同地理景观区内革螨的优势种、常见种和罕见种,对其生态地理分布作了讨论.(1)辽西低山丘陵及沿海平原区:本区共有革螨20种,其中仓鼠真厉螨、格氏血厉螨为优势种;塔山巨刺螨、长毛鞘厉螨为罕见种.(2)辽东山地及半岛丘陵区:本区共有革螨22种.半岛丘陵革螨优势种为仓鼠真厉螨、格氏血厉螨;辽东山地革螨优势种为耶氏厉螨与东方真厉螨.本区罕见种为赛氏血革螨、达呼尔血革螨、大连肪刺螨、三角血厉螨等.(3)辽河平原区:本区共有革螨20种.优势种为耶氏厉螨与厩真厉螨;乌苏里土厉螨为罕见种.(4)努鲁儿虎山脉北麓黄土丘陵台地及西辽河沙地区:本区共有革螨26种.优势种为东北血革螨、仓鼠真厉螨及格氏血厉螨.巨腹赫刺螨、鼬赫刺螨、拟小赫刺螨、半漠血厉螨、乌苏地厉螨、北野血革螨、楠本血革螨等为罕见种.     

Occurrence of 15-cis-violaxanthin in Viola tricolor

A new cis isomer in the violaxanthin series has been isolated from the blossoms of Viola tricolor and identified by MS, IR and UV as the central-monocis form. It was converted to all-trans-violaxanthin by stereomutation. The CD correlation between 15-cis-violaxanthin and natural violaxanthin (5,6,5′,6′-diepoxy-5,6,5′,6′-tetrahydro- β,β-caroten-3,3′-diol) provided the basis for assignment of the absolute configurations 3S, 5R, 6S, 3′S, 5′R, 6′S. Trans—cis isomerization of all-trans-violaxanthin also resulted in 15- cis-violaxanthin. In addition a quantitative determination of the carotenoids was conducted.     

Substratum as a factor in the distribution of two prosobranch freshwater snails,Viviparus bengalensis and Melania scabra

Laboratory experiments were conducted to ascertain the substratum preferendum of Viviparus bengalensis and Melania scabra. When the food (Spirogyra) was offered both on stones and sand, the average distribution of V. bengalensis and M. scabra was 19% and 10% on stone and 52% and 80% on sand respectively. In the absence of food from both stone and sand and also when sand alone was baited, both snails flocked principally towards sand. When stone alone was provided with food, V. bengalensis and M. scabra displayed 16% and 15% distribution on stone and 49% and 45% on sand respectively. Ecological significance of these results is discussed.     

宁夏宁南山区红庄林场甘肃鼢鼠分布密度与危害研究

通过对红庄林场不同立地条件随机抽样调查,结果表明：山间谷地甘肃鼢鼠平均密度为33只/hm^2;草甸山坡甘肃鼢鼠平均密度为13．3只／hm^2;林地甘肃鼢鼠平均密度为6．3只／hm^2。由于鼢鼠破坏活动,幼林受害率轻者为10％～20％,重者达到70％-80％。鼢鼠危害已制约当地造林工程的发展。     

辽宁省蜱类的生态地理分布

辽宁省已知的蜱类共13种, 分属于2科6属.本文依据不同地理景观区内蜱的种类与数量, 并结合其不同生境类型, 对蜱类的生态地理分布问题作了讨论.四个地理景观区内蜱种类与数量情况如下:(1)黄土丘陵台地干草原与西辽河风沙草原区:黄土丘陵台地干草原区蜱种类少, 但数量多.草原血蜱为优势种, 草原硬蜱数量较少.西辽河沙地草原区有草原血蜱、草原革蜱、草原硬蜱, 前两种均为优势种.(2)辽西山地疏林灌从区:本区有森林革蜱、长角血蜱、全沟硬蜱及日本锐缘蜱, 前两种为优势种.(3)辽东山地森林及林缘草地区:本区蜱种较多, 林区以日本血蜱、嗜群血蜱、全沟硬蜱为多见;林缘草地以长角血蜱、森林革蜱为优势种, 另外还有钝跗硬蜱、血红扇头蜱.(4)平原丘陵农区:木区蜱种虽然不少, 但分布局限, 数量小.有长角血蜱、草原血蜱、森林革蜱、微小牛蜱, 波斯锐缘蜱.     

Some rotifers from Republic of Korea

The author gives account of rotifers found at ten locations in the Republic of Korea, and elaborates some detail of specimens encountered with remarks and drawings. Thirty-seven different rotifer species were found, mostly belonging to the Order Monogononta. Twenty-two are new to the species list compiled by Yamamoto (1953). Keratella hiemalis was found for the first time in Asia. To date, one-hundred and two species of rotifers have been found in Korea.     

Distribution of acetylenic thiophenes in the pectidinae

The distribution and quantitative significance of biosynthetically related di- and ter-thiophenes from 27 species representing seven genera of the Pectidinae (Heliantheae) was investigated by reverse-phase HPLC. Adenophyllum, Chrysactinia and Nicolletia, three previously unstudied genera, were found to contain thiophenes for the first time. Four derivatives, 5-(4-hydroxy-1-butenyl)-2,2′-bithiophene (1), 5-(4-acetoxy-1-butenyl)-2,2′-bithiophene (2), 5-(3-buten-1-ynyl)-2,2′-bithiophene (3) and 2,2′:5′,2″-terthiophene (4) were common constituents in most species of Adenophyllum, Chrysactinia, Dyssodia, Hymenatherum, Nicolletia and Porophyllum. One additional compound, 5-methyl-2,2′:5′,2″-terthiophene (5), was also present in extracts of Adenophyllum, Dyssodia and Hymenatherum, but was not detected in any other genus. Acetylenic thiophenes were not found in any of the 18 species of Pectis examined.     

Distribution, mechanisms and evolutionary significance of clonality and polyploidy in weevils

Abstract 1 Genetical mtDNA relationships of 41 taxa of weevils were examined using cladistics. Ingroup taxa belong to Otiorhynchus scaber and O. nodosus and outgroup comparison was made with O. singularis. All three species are minor forest pests. 2 Otiorhynchus scaber specimens are either diploid sexuals or diploid, triploid and tetraploid clones, from two different populations (Slovenia and Austria) that belong to two different evolutionary lineages. Otiorhynchus nodosus specimens are tetraploid clones. Both species show geographical parthenogenesis, as do many other Otiorhynchus species. 3 Mitochondrial data indicate that O. nodosus clones are more closely related to Slovenian sexuals of O. scaber than these are to sexuals from Austria. It also shows that almost all clones of O. scaber collected in one of the two regions where sexuals are found are more closely related to sexuals from the other region. 4 Three different hypotheses that may explain the distribution of O. scaber, mechanisms important for the evolution of the clones and implications of the presence of Wolbachia are discussed. 5 We conclude that parthenogenesis is likely to be linked to hybridization in O. scaber and that hybridization events between ancestors of O. nodosus and O. scaber are the probable cause of the presence of O. nodosus in the ingroup. We also find that polyploid clones are superior colonizers compared to sexuals and diploid clones, in O. scaber. 6 The results suggest that systems where both sexuals and clones exist are more complex than previously suggested. The mapping of genetic variation in clonal complexes and the tracing of clonal origins may be useful in pest management.     

Some Approximations of the Borel-Tanner or the Generalized Poisson Distribution

This paper considers some approximations for the Borel-Tanner (Generalized Poisson) sums by using (i) Gram-Charlier Poisson expansion, (ii) Mixture of two Poisson distributions, (iii) Variance stabilizing technique, and (iv) negative binomial distribution. It has been found that the approximation obtained by using the negative binomial distribution seems to be more efficient than the other approximation.     

虫草蝠蛾幼虫空间分布型的研究

空间分布型的研究是现代理论生态学的重要基础工作之一,它在实际应用上亦具重要意义。它不仅可揭示出种群的空间结构特征,而且还是确定抽样技术、资料代换和正确估计种群数量的基础。 目前,国内外有关昆虫空间分布型的研究多限于农林业害虫,对其它昆虫的空间分布研究甚少。虫草蝠蛾是我国名贵中药材冬虫夏草的寄主昆虫,主要分布在青海、西藏、四川、云南四省境内的高山草甸。近年来,冬虫夏草产量逐年下降,远远不适应市场的需求,更因自然资源日趋减少,大有枯竭之势。为挽救这一珍贵资源昆虫,急待尽