GENETIC VARIATION AND COVARIATION FOR CHARACTERISTICS ASSOCIATED WITH CADMIUM TOLERANCE IN NATURAL POPULATIONS OF THE SPRINGTAIL ORCHESELLA CINCTA (L.)

Heavy metals can be strong and stable directional selective agents for metal-exposed populations. Genetic variation for the metal-tolerance characteristic “cadmium excretion efficiency” was studied in populations of the collembolan Orchesella cincta from a reference- and a metal-contaminated forest soil. Previously it has been shown that “excretion efficiency” influences tolerance through midgut-mediated immobilization and excretion of toxic metal ions, and that an increased mean excretion efficiency is present in animals inhabiting metal-contaminated litter. In the present research, offspring-parent regressions showed that additive genetic variation for cadmium excretion efficiency was present in the population from the reference site. The heritability estimate was 0.33. In the natural population exposed to heavy metals from an industrial source, additive genetic variation was not significantly different from zero. Differences in the heritability between the reference and the exposed population were not significant. Genetic variation for cadmium excretion efficiency allows for a response to selection in the reference population. Such a response has probably occurred in the metal-exposed population. Half-sib analysis with animals from the reference population was used to estimate genetic variation and maternal effects for excretion efficiency, relative growth rate and molting frequency, and to determine genetic correlations between these characteristics. Additive genetic variation was demonstrated for all three characteristics, heritability estimates were 0.48, 0.75 and 0.46, respectively. Maternal effects were low for excretion efficiency and molting frequency, but may be present for relative growth rate. Phenotypic and genetic correlations among these characteristics were positive. The environmental correlation between relative growth rate and molting frequency was positive, others were negative. Direct selection for any of the characteristics, or genetic correlations between tolerance characteristics and growth characteristics, or both may have caused the responses previously observed in field populations.     

中国长属一新种(弹尾目:长科)

本文记述了长虫兆属西藏１新种：黄氏长虫兆Ｅｎｔｏｍｏｂｒｙａｈｕａｎｇｉ,ｓｐ．ｎｏｖ．（图１～１７）。本种与Ｅ．ｍａｒｇｉｎａｔａＴｕｌｂｅｒｇ,１８７１和Ｅ．ｌａｎｕｇｉｎｏｓａＮｉｃｏｌｅｔ,１８４２在体色上很相似,但它们可从第４腹节与第３腹节的长度比、上唇乳突、生殖板等特征相区别。正模♀,西藏错美,海拔４２００米,１９７４－ＶＩ－２６,采集号８１００;副模：２♀♀,同正模;５♀♀,２♂♂,西藏错美哲古湖附近,海拔４６００米,１９７４－ＩＶ－２８,采集号８１１７。除部分副模保存于南京大学生物系外,模式标本均保存于中国科学院动物研究所。     

中国白裸长角属一新种(弹尾目:长科)(英文)

本文记述了采自安徽省石台县篷莱洞的Sinella（s．s．）亚属一新种。模式标本保存于南京大学生物系。Sinella（Sinella）christianseni,新种（图1-12）,体长最大1．95mm,体色白至淡黄色,无眼,本种和Sinella（s．s．）browniChenandChristiansen1993很相似,主要区别在于眼,粘毛（tenenthairs）,下唇刚毛等特征。     

中国江西省刺齿属一新种(弹尾目: 长角科)

本文描述了中国刺齿属１新种—李氏刺齿（Ｈｏｍｉｄｉａｌｅｅｉ，ｓｐ．ｎｏｖ．），它的体色斑纹与Ｈ．ＳａｕｔｅｒｉＢｒｎｅｒ，１９０９极为相似，但上唇乳突，下唇刚毛Ｅ，腹管毛序以及弹器基上刺的数量可区分两者     

MATERNAL INHERITANCE AND ITS EFFECT ON ADAPTIVE EVOLUTION: A QUANTITATIVE GENETIC ANALYSIS OF MATERNAL EFFECTS IN A NATURAL PLANT POPULATION

A mother can influence a trait in her offspring both by the genes she transmits (Mendelian inheritance) and by maternal attributes that directly affect that trait in her offspring (maternal inheritance). Maternal inheritance can alter the direction, rate, and duration of adaptive evolution from standard Mendelian models and its impact on adaptive evolution is virtually unexplored in natural populations. In a hierarchical quantitative genetic analysis to determine the magnitude and structure of maternal inheritance in the winter annual plant, Collinsia verna, I consider three potential models of inheritance. These range from a standard Mendelian model estimating only direct (i.e., Mendelian) additive and environmental variance components to a maternal inheritance model estimating six additive and environmental variance components: direct additive and environmental variances; maternal additive and environmental variances; and the direct-maternal additive () and environmental covariances. The structure of maternal inheritance differs among the 10 traits considered at four stages in the life cycle. Early in the life cycle, seed weight and embryo weight display substantial , a negative , and a positive . Subsequently, cotyledon diameter displays and of roughly the same magnitude and negative . For fall rosettes, leaf number and length are best described by a Mendelian model. In the spring, leaf length displays maternal inheritance with significant and and a negative . All maternally inherited traits show significant negative . Predicted response to selection under maternal inheritance depends on and as well as . Negative results in predicted responses in the opposite direction to selection for seed weight and embryo weight and predicted responses near zero for all subsequent maternally inherited traits. Maternal inheritance persists through the life cycle of this annual plant for a number of size-related traits and will alter the direction and rate of evolutionary response in this population.     

中国安徽省刺齿珧属一新种(弹尾目:长珧科)(英文)

本文记述弹尾目刺齿属一新种,即安徽刺齿Homidiaanhuiensisspnov．。该种有些特征与H.speciosaSzeptycki1973相似,但第4腹节毛序,上唇无乳突及下唇三角区刚毛E纤毛状可与后者区分。     

中国西藏地区刺齿属一新种(弹尾目:长科)(英文)

本文记述刺齿属一新种──西藏刺齿Homidiatibetensissp．nov．该种有些特征与H．heugsanicaLeeetPark,1984相似,但第1,3,4腹节毛序,下唇基部毛式和上唇无乳突可与后者区分。     

印度尖瘤(虫兆)属一新种(弹尾纲,长角(虫兆)科)

描述尖瘤属Acrocyrtus印度1新种,陈氏尖瘤A.cheni sp.nov.。     

MEASURING THE PLASTICITY OF DEVELOPMENTAL RATE ACROSS INSECT POPULATIONS: COMMENT ON ROCHA AND KLACZKO (2012)

Rocha and Klaczko emphasize the general complexity of reaction norm shape and caution that ignoring such complexity can be misleading when forcing nonlinear reaction norms into linear shapes. They refer to our article on differences in plasticity of Drosophila serrata populations along a latitudinal gradient as an example of a misleading simplifying approach. However, their claim that an artifact is introduced into our analyses by calculating developmental rate as the reciprocal of development time (rate = time^?1) is based on a misunderstanding of the mathematical properties of the thermal developmental rate reaction norm. Here we discuss why developmental rate is a suitable measure for our study and under which circumstances it is appropriate to describe developmental rate by a linear model.     

INHERITANCE OF ENVIRONMENTAL VARIATION IN BODY SIZE: SUPERPARASITISM OF SEEDS AFFECTS PROGENY AND GRANDPROGENY BODY SIZE VIA A NONGENETIC MATERNAL EFFECT

Maternal effects provide the most common mechanism by which environmental variation in one generation affects the phenotype of individuals in subsequent generations. In egg-laying animals, however, we typically observe that maternal effects can have large influences on early growth (egg size and early development), but these effects gradually disappear and become undetectable by the time progeny mature due to developmental plasticity in progeny. We describe a system in which an environmentally induced reduction in body size is inherited by progeny via a nongenetic maternal effect. The seed beetle, Callosobruchus maculatus, completes development inside a discrete resource package (a seed) selected by its mother. Due to superparasitism in response to low host availability, progeny frequently develop at high densities, resulting in intense larval competition and pupation at a smaller body size. Females reared at higher density (and thus emerging smaller) lay smaller eggs than females reared at lower density. Progeny from these smaller eggs mature at a smaller size than progeny reared from the larger eggs laid by females reared at lower density. Crosses between high and low density lines demonstrated that treatment differences in body size are maternally inherited, confirming that the inheritance of body size variation in part involves an environmentally based maternal effect.     

EFFECTS OF MATERNAL AND PATERNAL ENVIRONMENT AND GENOTYPE ON OFFSPRING PHENOTYPE IN SOLIDAGO ALTISSIMA L.

To predict the possible evolutionary response of a plant species to a new environment, it is necessary to separate genetic from environmental sources of phenotypic variation. In a case study of the invader Solidago altissima, the influences of several kinds of parental effects and of direct inheritance and environment on offspring phenotype were separated. Fifteen genotypes were crossed in three 5 × 5 diallels excluding selfs. Clonal replicates of the parental genotypes were grown in two environments such that each diallel could be made with maternal/paternal plants from sand/sand, sand/soil, soil/sand, and soil/soil. In a first experiment (1989) offspring were raised in the experimental garden and in a second experiment (1990) in the glasshouse. Parent plants growing in sand invested less biomass in inflorescences but produced larger seeds than parent plants growing in soil. In the garden experiment, phenotypic variation among offspring was greatly influenced by environmental heterogeneity. Direct genetic variation (within diallels) was found only for leaf characters and total leaf mass. Germination probability and early seedling mass were significantly affected by phenotypic differences among maternal plants because of genotype ( genetic maternal effects ) and soil environment ( general environmental maternal effects ). Seeds from maternal plants in sand germinated better and produced bigger seedlings than seeds from maternal plants in soil. They also grew taller with time, probably because competition accentuated the initial differences. Height growth and stem mass at harvest (an integrated account of individual growth history) of offspring varied significantly among crosses within parental combinations ( specific environmental maternal effects ). In the glasshouse experiment, the influence of environmental heterogeneity and competition could be kept low. Except for early characters, the influence of direct genetic variation was large but again leaf characters (= basic module morphology) seemed to be under stricter genetic control than did size characters. Genetic maternal effects, general environmental maternal effects, and specific environmental maternal effects dominated in early characters. The maternal effects were exerted both via seed mass and directly on characters of young offspring. Persistent effects of the general paternal environment ( general environmental paternal effects ) were found for leaf length and stem and leaf mass at harvest. They were opposite in direction to the general environmental maternal effects, that is the same genotypes produced “better mothers” in sand but “better fathers” in soil. The general environmental paternal effects must have been due to differences in pollen quality, resulting from pollen selection within the male parent or leading to pre- or postzygotic selection within the female parent. The ranking of crosses according to mean offspring phenotypes was different in the two experiments, suggesting strong interaction of the observed effects with the environment. The correlation structure among characters changed less between experiments than did the pattern of variation of single characters, but under the competitive conditions in the garden plant height seemed to be more directly related to fitness than in the glasshouse. Reduced competition could also explain why maternal effects were less persistent in the glasshouse than in the garden experiment. Evolution via selection of maternal effects would be possible in the study population because these effects are in part due to genetic differences among parents.     

EFFECT OF EDTA ADDITIONS ON NATURAL TRICHODESMIUM SPP. (CYANOPHYTA) POPULATIONS1

Despite nearly two decades of intensive research, many questions regarding the physiology and ecology of the marine, non‐heterocystous cyanobacterium, Trichodesmium, remain unresolved. We note here the effect of EDTA (ethylenediaminetetraacetate) on N₂ fixation by Trichodesmium, and the use of EDTA as a means of extending the viability of natural Trichodesmium spp. populations. We examined nitrogenase activity (NA) as a function of EDTA concentration, time of collection, light level, and iron addition. Samples collected early in the day and treated with EDTA maintain a steady rate of activity for hours longer than controls. Furthermore, samples preincubated through the night with EDTA were active the next morning, compared with controls that were inactive. The discovery that (10–50 μM) low concentrations of EDTA prolong the duration of NA of Trichodesmium during experimental manipulations without affecting the rate of acetylene reduction allows for longer term manipulative experiments to be conducted.     

中国长颚属二新种(弹尾目:长颚科)

长颚(虫兆)属(Neanura)1893年由Mac Gillvary所建立,模式种为N.muscorum(Templeton)。该属为一大属,至1964年已记录了75种,5亚种。1967年底,massaud根据口器的结构,对该属进行了订正。他将该属中下颚呈简单的尖刺状,无缨状叶,上颚仅3—4端齿的种保留在该属内,而将上颚6齿以上,下颚复杂,有缨状叶的种列入别的属。经Massaud订正后的长颚(虫兆)属Neanura(s.str)共48种。目前该属已知种已超过55种。     

温度对前齿肖蛸(Tetragnatha praedonia),实验种群增长的影响

本文根据前齿肖蛸(Tetragnatha praedonia)在20℃、23℃、26℃、29℃、32℃和35℃6种恒温条件下的发育历期、幼蛛存活率、成蛛产卵率、产卵量和孵化率组建了前齿肖蛸在不同温度条件下的实验种群增长表。结果表明前齿肖蛸在所试验的6种恒温条件下其种群数量可保持上升趋势,其中以在29℃的条件下种群数量增长最快,繁殖一代种群数量可增加74.28倍;以在20℃的条件下种群数量增长最慢,繁殖一代种群数量可增加20.74倍。     

陕西长安及汉中两地中华稻蝗的比较。

通过对采自陕西长安及汉中地区的中华稻蝗Oxya chinensis(Thunberg)之11个数量性状进行了多元分析。在主成分分析的第1、2主轴所构成的平面上,生活在两个地区的稻蝗个体被明显分成两个集团。此外,两地稻蝗在卵囊平均含卵量、卵粒大小及有效积温等生物学特性上均有显著的差异,这意味着长期的地理阻隔(秦岭山脉)致使两地的稻蝗演化成两个地理宗。由于使用传统的形态方法无法准确区分这两个地区的稻蝗,我们为这两个居群的雌性和雄性成虫分别建立了线性判别函数,以便为今后进一步的小进化研究奠定一个基础。V(雌性)＝-11.67+195.44H+1.91E/F+8.663MX+22.80F/C+0.34P一3.50MZ-102.76H/C-42.51F;y(雄性)＝-17.06+30.183MZ+4.313F,这里,当v(雌性或雄性)<0时,个体属于长安县的居群,否则,属于汉中的居群。     

A PRELIMINARY BIOCHEMICAL GENETIC STIJDY OF TWO POPULATIONS OF LITHOGNATHUS AURETI (PERCIFORMES: SPARIDAE)

Summary

Two populations of Lithognathus aureti were electrophoretically analysed to determine the extent of genetic divergence between, and variation within them. Gene products of 35 protein coding loci showed no fixed allele differences between these populations. However, significant genotypic differentiation between the populations was found at two loci, which indicates that effective barriers exist to isolate them. This is substantiated by catch-and-release data. The limited gene flow between the populations from Meob Bay and Rocky Point, and the enviromnental barrier in the vicinity of Meob Bay, indicate that they are effectively isolated. This is the first account of the genetic variation of these populations, and the results are important for the effective management of these recreationally and commercially exploited, fishes.     

EFFECT OF TEMPERATURE ON TWO ENZYMES FROM A PSYCHROPHILIC CHLOROMONAS (CHLOROPHYTA)1

A psychrophilic green alga belonging to the Chloromonas genus and here named ANT1 was collected in Antarctica. The activities of two enzymes, nitrate reductase and argininosuccinate lyase, were measured at various temperatures and compared to the corresponding enzyme activities in the mesophilic species Chlamydomonas reinhardtii Dangeard. For both enzymes, the temperature for apparent optimal activity was about 20°C lower in ANT1 than in C. reinhardtii. The enzymes were also submitted to various heat treatments before measuring their activities. Both psychrophilic enzymes were more sensitive to heat than the corresponding mesophilic enzymes. It is worth stressing, however, that in both species nitrate reductase was much more sensitive to heat than argininosuccinate lyase, which probably indicates that the peculiar structure of each protein primarily determines its dependence to temperature. Secondary adaptations to low temperatures should then occur to confer the psychrophilic character.