Use of host plants by Troidini butterflies (Papilionidae, Papilioninae): constraints on host shift

Molecular phylogenetic analyses were conducted to determine relationships and to investigate character evolution for the Troidini/Aristolochia interaction, in an attempt to answer the following questions: (1) what is the present pattern of use of Aristolochia by these butterflies; (2) is the pattern we see today related to the phylogeny of plants or to their chemical composition; (3) can the geographical distribution of Aristolochia explain the host plant use observed today; and (4) how did the interaction between Troidini and Aristolochia evolve? Analyses of character optimization suggest that the current pattern of host plant use of these butterflies does not seem to be constrained by the phylogeny of their food plants, neither by the secondary chemicals in these plants nor by their geographical similarity. The current host plant use in these butterflies seems to be simply opportunistic, with species with a wider geographical range using more species of host plants than those with a more restricted distribution. © 2007 The Linnean Society of London, Biological Journal of the Linnean Society, 2007, 90 , 247–261.     

中国热带粒毛盘菌属的物种多样性研究

本文在对我国盘菌资源调查的基础上,分析研究了热带地区粒毛盘菌属真菌的物种多样性。本研究共分析451份标本,属于35个分类单位,其中Lachnum abnorme var. abnorme, L. brasiliense, L. flavidulum, L. pteridophyllum, L. sclerotii和L. virgineum 6个种的个体数量均在总数的6 %以上,占已观察标本总数的73.4 %,是我国热带地区的常见种。物种多样性分析表明,海南的物种丰富度（S=22）和多样性指数（H′=2.6696）最高,云南与广西的物种丰富度相似。采用群落系数（coefficient of community,cc）比较了不同地区的物种分布相似性。本文还试图探讨物种分布与海拔高度、生境、基物间的关系。粒毛盘菌属真菌在海拔60～2700 m的地带均有分布,由于调查和取样的局限性,物种随海拔高度变化的规律不明显;地理分布上大致可分为世界性分布、间断性分布和地方特有三种分布型。     

Mitochondrial genome nucleotide substitution pattern between domesticated silkmoth, Bombyx mori, and its wild ancestors, Chinese Bombyx mandarina and Japanese Bombyx mandarina

Bombyx mori and Bombyx mandarina are morphologically and physiologically similar. In this study, we compared the nucleotide variations in the complete mitochondrial (mt) genomes between the domesticated silkmoth, B. mori, and its wild ancestors, Chinese B. mandarina (ChBm) and Japanese B. mandarina (JaBm). The sequence divergence and transition mutation ratio between B. mori and ChBm are significantly smaller than those observed between B. mori and JaBm. The preference of transition by DNA strands between B. mori and ChBm is consistent with that between B. mori and JaBm, however, the regional variation in nucleotide substitution rate shows a different feature. These results suggest that the ChBm mt genome is not undergoing the same evolutionary process as JaBm, providing evidence for selection on mtDNA. Moreover, investigation of the nucleotide sequence divergence in the A+T-rich region of Bombyx mt genomes also provides evidence for the assumption that the A+T-rich region might not be the fastest evolving region of the mtDNA of insects.     

New Australian butterfly genus Jameela gen. nov. (Lepidoptera: Lycaenidae: Polyommatinae: Polyommatini) revealed by morphological, ecological and molecular data

This paper proposes to split the Australian Polyommatini genus Erysichton Fruhstorfer, 1916 into two genera on the basis of molecular, morphological and early stage behavioral attributes. The utility of reflective eye pattern as a taxonomic character is discussed and a neotype of Lycaena lineata Murray, 1874 is designated.     

The Origin and Identity of the Calyculus in Loranthaceae: Inferred From the Floral Organogenesis of Loranthus tanakae Franch. & Sav.

The flowers of the hemiparasitic family Loranthaceae are always subtended by a rimmed structure known as the calyculus. The origin and identity of the calyculus have been disputed for more than a century. Various hypotheses have been proposed, for example, an outgrowth of the axis, a reduced calyx, and a bracteolar (prophyllar) origin, but controversies remain. To obtain a plausible explanation of the origin of the calyculus, we investigated the flowers of Loranthus tanakae using scanning electron microscopy and light microscopy to observe the entire developmental process of the floral parts. Our results show that bracts are not present in L. tanakae. The calyculus, which lacks serving vascular bundles, initiates as a semicircular primordium and then develops into a circular structure by an adnation at both sides. The flower primordium usually cleaves into six petals from its centre along a whorled pattern in two series with three petals each, before or after the calyculus closed. Isomerous stamen primordia probably follow the same initiation pattern as petals do. Several carpels of different sizes initiate simultaneously as a united primordium. We support the hypotheses that the calyculus is of bract or bracteole origin due to its independent initiation from the inflorescence rachis, its similar morphology and positioning as the bract or bracteole, and that having no developmental relationship with the petals. We suggest keeping the usage of the term “calyculus”. Loranthus flowers should be considered monochlamydeous with three whorls of floral parts, namely petal, androecium, and gynoecium.     

青岛崂山青山湾人工鱼礁区及附近海域鱼卵仔稚鱼种类组成与数量分布

为研究人工鱼礁对产卵鱼类的诱集效果和庇护效应,2014—2015年对青岛崂山青山湾海域人工鱼礁区及附近海域鱼卵和仔稚鱼的种类组成和数量分布进行了水平和垂直拖网调查. 2014年春、夏、秋3个季节的7个航次调查中,共采集鱼卵7306粒、仔稚鱼52尾,隶属于4目9科11属12种;2015年同期进行的13个航次调查中,共采集鱼卵10373粒、仔稚鱼159尾,隶属于6目11科14属15种.2年间鱼卵和仔稚鱼样品均以鲈形目数量最多,鲽形目次之,其中鱼卵样品中仅有少鳞鱚和短吻红舌鳎构成优势种;仔稚鱼样品以少鳞鱚优势度最高,但不存在仔稚鱼优势种.鱼卵和稚鱼的高优势度物种的季节间演替明显.春、夏、秋季鱼类浮游生物群落Margalef丰富度指数、Shannon多样性指数和Pielou均匀度指数平均值均较低,说明该海域鱼类浮游生物群落结构稳定性较低.2年间所采集物种对应的成鱼平均营养级分别为3.71和3.78,均属第三营养级中的低级肉食性鱼类,绝大多数为暖温种,无冷温性种类,表现出明显的暖温带特点.综合分析认为,人工鱼礁区鱼类浮游生物群落的多样性相对较高,这与鱼礁区流速和流场特征及复杂的空间异质性有关.     

Point pattern analysis of different age-classes of Larix principis-rupprechtii in Luya Mountain Reserve, Shanxi Province, China

Larix principis-rupprechtii forest is an important vegetation formation and has a large distribution area in Luya Mountain Reserve, China. Spatial pattern analysis on individual trees in different age-classes of Larix principis-rupprechtii was made in this paper. Here, we employed the technique of point pattern analysis, which could analyze patterns under all scales along a gradient. It was based on spatial mapped points of individual distribution. The results of this study showed that the densities of the five age-classes varied in the order: age-class 3 > age-class 4 > age-class 5 > age-class 2 > age-class 1. Although age-classes 1 and 2 have much fewer individuals than other three age-classes do, the population was stable at present. However, it would be necessary to take some measures for improving population regeneration for a long-time view. The individuals of all age-classes focused on clumping distribution in space; however, their distribution pattern varied with the change of scale. This mainly depended on biological features of Larix principis-rupprechtii and forest environments, but it also meant that the scale was an important factor in controlling spatial distribution pattern of tree individuals. The feature of clumping distribution became more significant with the increase of age. The relationships between individuals in different age-classes were almost all significantly correlated with each other. These associations became more significant within the older age-classes. This suggested that the individuals of different age-classes were interdistributed, by which the population could get benefits in resource utilization. The technique of point pattern analysis is effective and easy to be used in species pattern study. Its results are more closer to the reality, especially for community structure. Translated from Acta Ecologica Sinica, 2004, 24(1): 35–40 [译自: 生态学报]     

五种温带森林土壤微生物生物量碳氮的时空格局

土壤微生物是森林生态系统中的重要分解者,在碳和氮循环中起着重要作用,同时也是对环境变化的敏感指示者。采用氯仿熏蒸浸提法测定了我国东北地区5种温带森林土壤微生物生物量碳(Cmic)和氮(Nmic)的季节动态及其在土壤中的垂直变化。结果表明:林型之间Cmic和Nmic差异显著(P0.01)。落叶松林、红松林、蒙古栎林、杨桦林、硬阔叶林的Cmic的变化范围依次为:278937mgkg-1、2181020mgkg-1、313891mgkg-1、5101092mgkg-1、4401911mgkg-1;其Nmic的变化范围依次为:1872mgkg-1、18103mgkg-1、2495mgkg-1、43125mgkg-1、40208mgkg-1。所有林型的Cmic和Nmic均随土壤深度的增加而下降。Cmic和Nmic基本上呈现出生长季开始之前下降、生长季结束时上升、其中出现12个峰值的季节变化格局,但峰值大小和出现时间随林型和土壤层次而变。010cm土层的Cmic和Nmic季节变化较大。Cmic和Nmic与凋落叶量、土壤有机碳含量和土壤总氮含量呈显著正相关。Cmic与土壤含水量呈正相关,而与土壤温度呈负相关。不同林型凋落物数量和组成、土壤理化性质的差异是导致其土壤微生物生物量时空格局差异的主要因素。     

Multispecies coexistence of trees in tropical forests: spatial signals of topographic niche differentiation increase with environmental heterogeneity

Neutral and niche theories give contrasting explanations for the maintenance of tropical tree species diversity. Both have some empirical support, but methods to disentangle their effects have not yet been developed. We applied a statistical measure of spatial structure to data from 14 large tropical forest plots to test a prediction of niche theory that is incompatible with neutral theory: that species in heterogeneous environments should separate out in space according to their niche preferences. We chose plots across a range of topographic heterogeneity, and tested whether pairwise spatial associations among species were more variable in more heterogeneous sites. We found strong support for this prediction, based on a strong positive relationship between variance in the spatial structure of species pairs and topographic heterogeneity across sites. We interpret this pattern as evidence of pervasive niche differentiation, which increases in importance with increasing environmental heterogeneity.