华南大戟科植物的增补

作者清理采自中国南部大戟科标本过程,发现一些需增补的分类群,现报道其中２个新种：分布于广东封开县的印禅铁苋菜Ａｃａｌｙｐｈａｗｕｉ和印禅三宝木Ｔｒｉｇｏｎｏｓｔｅｍｏｎｗｕｉ;２个新纪录种：分布于云南勐海县的短序白桐树Ｃｌａｏｘｙｌｏｎｓｕｂｓｅｓｓｉｌｉｆｌｏｒｕｍ和生长于海南南沙群岛的南沙大戟Ｅｕｐｈｏｒｂｉａｒｅｎｉｆｏｒｍｉｓ;１个近代生长于广东、贵州和四川的归化种－桃叶猩猩草Ｅｕｐｈｏｒｂｉａｈｅｔｅｒｏｐｈｙｌｌａ,而将依据四川渡口的标本命名的柳叶大戟Ｅ．ｅｐｉｌｉｂｉｉｆｏｌｉａ作为它的新异名．     

南亚和东南亚巨蜥居群的种间亲缘和越南─新种描述

１９９２年１１月１５日从云南省河口县城自由市场的一位越南人手中买得一雌性巨蜥,经鉴定为一新种,定名为越南巨蜥Ｖａｒａｎｕｓｖｉｅｔｎａｍｅｎｓｉｓ。鉴别特征：新种背部鳞片光滑,仅在后半部插有极少的起棱鳞片,不同于Ｖ．ｎｅｂｕｌｏｓｕｓ（Ｂｏｕｌｅｎｇｅｒ,１８８５,１８９０;Ｔａｙｌｏｒ,１９６３）;新种不同于Ｖ．ｓａｌｖａｔｏｒ在于其背部没有眼斑状横斑带（ｏｃｅｌｌｉｍａｒｋｓ）（Ｇｕｅｎｔｈｅｒ,１８６４;Ｈａｒｒｉｓｏｎ等,１９５７;Ｐｏｐｅ,１９３５）;不同于Ｖ．ｉｒｒａｗａｒｄｉｃｕｓ（Ｙａｎｇ等,１９８７）,Ｖ．ｇｒｉｓｅｕｓ和Ｖ．ｍｏｎｉｔｏｒ（Ｓｍｉｔｈ,１９３５）在于有６─７个横向扩大的眼上鳞。文中运用了１５个外部性状对产于南亚,东南亚大陆及岛屿共９个种（含新种）的种间亲缘关系进行了研究,结果认为,种间亲缘关系的亲疏与分布地区相距的远近成正相关。     

云南小孢发属地衣的分类

报道了云南小孢发属地衣１３种,其中中国新记录种６个,它们是：喜马拉雅小孢发,尼泊尔小孢发,光滑小孢发,光亮小孢发,多叉小孢发,波氏小孢发,另外７种的形态及分布也在文中进行了讨论。     

中国樟科新分类群

描写了西藏墨脱县的９个新种和两个新变种,它们是墨脱油丹、西藏球楠、扁果木姜子、勃生木姜子、少花木姜子、树志木姜子、柔毛长蕊木姜子（变种）、西藏新木姜子（变种）、纤枝钓樟等。     

Distribution and prevalence of the predatory planarian Artioposthia triangulata (Dendy) (Trieladida: Terricola) in Scotland

The distribution of the New Zealand flatworm (Artioposthia triangulata) in Scotland was surveyed between July 1991 and February 1993. There were 348 records from domestic gardens, 56 from botanic gardens, garden centres and nurseries, with only 13 from farms. Although most of the records came from around the major cities the flatworm was found to have become established throughout the Scottish mainland and some of the Islands, e.g. Bute, Gigha, Orkney and Skye. The impact of the flatworm on earthworm populations in agricultural land in Scotland was, as yet, found to be minimal but the fact that seven adjacent farms near Dunoon were infected suggested it could be spread from farm to farm and that in the West of Scotland it could become widespread in agricultural land.     

EVOLUTIONARY ECOLOGY OF DATURA STRAMONIUM L. IN CENTRAL MEXICO: NATURAL SELECTION FOR RESISTANCE TO HERBIVOROUS INSECTS

It has been assumed that herbivores constitute a selective agent for the evolution of plant resistance. However, few studies have tested this hypothesis. In this study, we look at the annual weed Datura stramonium for evidence of current natural selection for resistance to herbivorous insects. Paternal half-sib families obtained through controlled crosses were exposed to herbivores under natural conditions. The plants were damaged by two folivorous insects: the tobacco flea beetle Epitrix parvula and the grasshopper Sphenarium purpurascens. Selection was estimated using a multiple-regression analysis of plant size and of damage by the two herbivores on plant fitness measured as fruit production for both individual phenotypes and family breeding values (genetic analysis). Directional phenotypic selection was detected for both larger plant size and lower resistance to the flea beetles, whereas stabilizing phenotypic selection was revealed for resistance to S. purpurascens. However, performing the same analyses on the breeding values of the characters revealed directional and stabilizing selection only for plant size. Thus, no agreement existed between the results of the two types of analyses, nor was there any detectable potential for genetic change in the studied population because of selection on herbivore resistance. The narrow-sense heritability of every trait studied was small (all <0.1) and not different from zero. The potential for evolutionary response to natural selection for higher resistance to herbivores in the studied population of D. stramonium is probably limited by lack of genetic variation. Natural selection acts on phenotypes, and the detection of phenotypic selection on resistance to herbivores confirms their ecological importance in determining plant fitness. However, evolutionary inferences based solely on phenotypic selection analyses must be interpreted with caution.     

The influence of riparian vegetation on macroinvertebrate community structure and functional organization in six new Guinea streams

Information on the ecology of New Guinea streams is meagre, and data are needed on the trophic basis of aquatic production in rivers such as the Sepik in Papua New Guinea which have low fish yields. This study investigates the relationship between riparian shading (from savanna grassland to primary rainforest), algal and detrital food, and macroinvertebrate abundance and community structure in 6 Sepik River tributary streams. A particular aim was to elucidate macroinvertebrate community responses to changes in riparian conditions. All streams supported diverse benthic communities, but morphospecies richness (overall total 64) was less than in streams on the tropical Asian mainland; population densities of benthic invertebrates, by contrast, were similar to those recorded elsewhere. Low diversity could reflect limited taxonomic penetration, but may result from the absence of major groups (Plecoptera, Heptageniidae, Ephemerellidae, Psephenidae, Megaloptera, etc.) which occur on the Asian mainland. Population densities of all 19 of the most abundant macroinvertebrate taxa varied significantly among the 6 study streams, but community composition in each was broadly similar with dominance by Baetidae and (in order of decreasing importance), Leptophlebiidae, Orthocladiinae, Elmidae and Hydropsychidae. Principal components analysis (PCA) undertaken on counts of abundant macroinvertebrate taxa clearly separated samples taken in two streams from the rest. Both streams contained high detrital standing stocks and one was completely shaded by rainforest. Stepwise multiple-regression analysis indicated that population densities of the majority of abundant taxa (11 out of 19) across streams (10 samples per stream; n = 60) were influenced by algae and/or detritus, although standing stocks of these variables were not clearly related to riparian conditions. When regression analysis was repeated on mean counts of taxa per stream (dependent variables) versus features of each stream as a whole (thus n = 6), % shading and detritus were the independent variables yielding significant regression models most frequently, but pH, total-nitrogen loads and algae were also significant predictors of faunal abundance. Further regression analysis, undertaken separately on samples (n = 10) from each stream, confirmed the ability of algae and detritus to account for significant portions of the variance in macroinvertebrate abundance, but the significance of these variables varied among streams with the consequence that responses of individual taxa to algae or detritus was site-specific.Community functional organization — revealed by investigation of macroinvertebrate functional feeding groups (FFGs) — was rather conservative, and streams were codominated by collector-gatherers (mean across 6 streams = 43%) and grazers (36%), followed by filter-feeders (15%) and predators (7%). The shredder FFG was species-poor and comprised only 0.4% of total macroinvertebrate populations; shredders did not exceed 2% of benthic populations in any stream. PCA of FFG abundance data was characterized by poor separation among streams, although there was some evidence of clustering of samples from unshaded sites. The first 2 PCA axes accounted for 84% of the variation in the data suggesting that the poor separation resulted from the general similarity of FFG representation among streams. Although stepwise multiple-regression analysis indicated that algae and detritus accounted for significant proportions of the variations in population density and relative abundance of some FFGs, the response of community functional organization to changes in riparian conditions and algal and detrital food base was weak — unlike the deterministic responses that may be typical of north-temperate streams.     

Aquatic bird densities in two coastal lagoon systems in Chiapas State,Mexico, a preliminary assessment

Six bodies of water in two coastal lagoon systems were investigated in Chiapas State, Mexico between July, 1990 and February, 1991. The size of water bodies ranged from 102.5 to 847.5 ha. Salinity varied seasonally being the lowest in July during the rainy season (1.0) and highest in February (35.8). The waters are hypertrophic with total phosphorus concentrations as high 900 mg m^–3.The number of bird species was the highest in February (N = 9 to 23) and the lowest in July (N = 2 to 15). The majority of birds present are resident species of Mexico but several species of northern birds were present in February (e.g. Lesser Scoup, Osprey, Peregrin Falcon).The number of birds observed in the waterbodies varied during the study period being as high as 2800 Cormorants, 2300 White Pelicans and 681 Limpkins, at a particular time, or expressed in terms of units surface area of each lagoon 8.0, 2.7 and 1.9 individuals per hectare respectively. The daily food requirements of White Pelicans at such a high density is about 4.1 kg ha^–1 d^–1.The hypertrophic state of Cerritos Lagoon allows a sufficient level of production to support such a high food requirement. Considering the limited survey time spent on the lagoons the bird population numbers are probably underestimated.     

Allozyme differentiation within and between red drum (Sciaenops ocellatus) from the Gulf of Mexico and Atlantic Ocean

Nine polymorphic nuclear-gene (allozyme) loci were surveyed among 491 red drum ( Sciaenops ocellatus ) sampled in 1988 and 1989 from nearshore localities in the northern Gulf of Mexico (Gulf) and the Atlantic coast of the southeastern United States (Atlantic). Data were combined with those from a previous study to generate a data set of 762 individuals representing 11 sample localities in the Gulf and 175 individuals representing five sample localities in the Atlantic. The combined data set included individuals from the 1986 and 1987 year classes and permitted rigorous testing of both temporal and spatial genetic heterogeneity. Average heterozygosity-per-locus values (estimated using 33 assumed monomorphic loci) were 0·048 (Gulf red drum) and 0·046 (Atlantic red drum). Tests of heterogeneity in allele frequencies between year classes at individual localities and across regions (Gulf and Atlantic) were non-significant. Tests of spatial (geographic) heterogeneity indicated that red drum are weakly subdivided: genetically-differentiated subpopulations occur in the northern Gulf and along the south-eastern Atlantic coast. Genetic data were consistent with the hypothesis that red drum within the Gulf and along the Atlantic coast comprise singie subpopulalions. Genetic differences between Gulf and Atlantic red drum seem likeiy to stem from historical or recent interactions between dispersal and impediments to gene flow.     

鱼类寄生毛细科线虫－新属新种的研究

作者在武陵山地区的鱼类寄生线虫调查工作中,发现一种毛细线虫,经研究,为一新种,定名为岁新毛细线虫,新种（Ｎｅｏｃａｐｉｌｌａｒｉａｐｈｏｘｉｎｉｓｐ．ｎｏｖ．）。根据其特征,为此建立一新属──新毛细线虫属。