Diversity and beyond: plant functional identity determines herbivore performance

1. Recent biodiversity studies have addressed various community-level effects of biodiversity change, but the number of studies on specific biotic interactions is still rather limited. An open question in the context of plant-insect-herbivore relationships is how diversity impacts the population ecology of individual species. 2. In the present study, we explored the relationship between plant species diversity and the performance and fitness of a generalist herbivore, the meadow grasshopper Chorthippus parallelus Zetterstedt (Orthoptera, Gomphocerinae). A total of 1620 fourth-instar nymphs of this insect were captured and transferred to cages (10 females and 10 males per cage) on 81 experimental grassland communities in plots containing one to 60 plant species within the Jena biodiversity experiment. 3. Median survival of grasshoppers in the experiment was 14.5 days. Survival was independent of plant species richness and number of plant functional groups in the communities, but increased if plant communities contained grasses. Plant species richness and plant functional group richness had no effect on the number of oothecae laid by females or the number of hatchlings in the next generation. 4. Functional group composition of the plant communities affected most fitness measures. Grass presence increased the number of oothecae laid by females from 0.78 +/- 0.21 to 3.7 +/- 0.41 per female, and the number of hatchlings in the next generation from 4.0 +/- 1.3 to 16.6 +/- 2.4. Certain combinations of plant functional groups increased grasshopper survival. 5. The findings indicate that the fitness of C. parallelus is influenced more by plant functional group identity than by plant species richness. In the absence of grasses, grasshoppers performed better if more than just one functional group of plants was present. We call this a 'rescue effect' of plant functional group richness.     

一株功能型益生菌对肉鸡生产性能的影响

实验选用3日龄AA肉鸡14 000只,随机分成2组,实验组口服功能型微生态制剂,空白对照组不饲喂任何微生态制剂,全程跟踪监测。结果表明,肉鸡在口服功能型益生菌制剂后表现出三大特点:(1)肉鸡生长加快,鸡群整齐度与均匀度有所改善,出栏平均重提高9.5%;(2)肠道环境有所改善,饲料利用率提高,实验组比对照组料肉比降低2.16%;(3)实验组鸡群可提前3~5 d出栏。     

高体近红鲌的生长与繁殖

高体近红鲌为长江上游的特有鱼类,以2008年5—11月从赤水河赤水市江段采集的540尾高体近红鲌标本为材料,对其生长与繁殖特性进行了研究和分析。结果表明:高体近红鲌鳞片年轮结构呈疏密切割型,年龄特征显著。种群由1—4龄共4个年龄组组成,其中以2龄个体为主。体长分布主要集中在100—160 mm;体重分布主要集中在20.0—50.0 g。总性比为♀∶♂=1.30∶1。体长与鳞径呈直线关系,体长和体重呈幂函数关系且幂指数接近3,基本符合匀速生长类型,体长和体重Von Bertalanffy方程分别为Lt=217.38(1-e-0.2867(t+0.757))和Wt=118.151-e-0.2867(t+0.757)2.8103;生长拐点为2.85龄,拐点对应的体长和体重分别为Lt=140.09 mm,Wt=34.37 g。雌雄初次性成熟年龄均为1龄;繁殖高峰期为6—7月。Ⅳ期雌鱼的绝对繁殖力为950—8655粒,平均值(3087.90±1602.15)粒;体长相对繁殖力FL为10.00—56.20粒/cm,平均值(24.26±10.16)粒/cm;体重相对怀卵量FW为66.08—197.67粒/g,平均值(116.49±32.05)粒/g;卵径频率分布显示高体近红鲌为一次产卵类型。       

桂西北典型喀斯特区生态服务价值的环境响应及其空间尺度特征

Study on ecosystem service values (ESVs) is the bridge of understanding ecosystem and economic decision-making. To investigate the response of ESVs to ambient environment and their spatial scales is an urgent work in the process of ecological restoration and sustainable development in southwest China. Based on the previous research results, the remote images, and weather data of 31 years (1975-2005), the response of ESVs to ambient environment and their spatial scales in a typical karst area of northwest Guangxi, China were evaluated with the method of empirical mode decomposition (EMD) in this paper. The results showed that ESVs had obvious variations with changes in elevation, rocky types and soil types, and had corresponding characteristics of spatial scales. The ESVs in middle and low elevation areas were higher, but they decreased due to human activities such as deforestation. The ESVs in peak-cluster depression areas were lower, and they would increase as influenced by policies such as returning farmland to forestland. The ESVs were influenced by rocky types, showing lower values but an increasing trend in the typical karst regions while higher values but a decreasing trend in non-karst regions. The average ESVs in the west part of the study region, which is not only the main nature reserve for rare wildlife species in Guangxi, but also one of the best preserved natural vegetation regions in China, were more than 15,000 RMB Yuan ha-1,. Comparatively, the ESVs were less than 10,000 Yuan ha-1 in the middle part of the region attributed to low vegetation coverage, serious peak-cluster depression and karst rocky desertification. After about 20 years, that is from 1985 to 2005, the ecosystem conditions had been improved and the ESVs had increased in the middle and eastern part of this study region. On the contrary, in most western part, which was dominated by subtropical evergreen broad-leaved forest, they had been worsened, and the balance values of ESVs were negative. As for the relationships of ESVs with rocky types and soil types, lime soil and red soil were the two main soil types that contributed to ESVs (The total contribution was above 60%, and it is 63.77%,64.37%,64.56%,64.91% respectively in the four years of 1985, 1990, 2000 and 2005.). The variance contribution of intrinsic mode function (IMF) and trend (R) showed that there were obvious special sales for ESVs in this study area, and the main spatial scales were about 2.7 km, 5.5 km, and 11.6 km. The variance contribution ratio was 12.29%, 11.26%, 11.49% respectively, and the trend (R) was high (17.74%). In conclusion, this study indicated that ecosystem conditions in the typical karst area were improved owing to the application of rocky desertification control policies, such as ecological migration and returning farmland to forestland. Besides, the main spatial scales of ESVs in the study area were the interactions of terrain, physiognomy, land use / land cover and human activities.     

Rare, threatened and alien species in the gastropod communities in the clay pit ponds in relation to the environmental factors (The Ciechanowska Upland, Central Poland)

The objectives of the present survey were to formulate a zoocenological analysis of the gastropod communities in clay pit ponds, as well as to determine the relationships between the gastropods and their environments, and to evaluate the water habitats in terms of their ecological-conservation value. The physical and chemical parameters of water, gastropod species and macrophytes occurring in the ponds indicate mesotrophic conditions. Principal Component Analysis (PCA) reveals a correlation between gastropod density and nitrates, a correlation between gastropod density and alkalinity, and additionally shows a correlation between gastropod density and chlorides. The pond surface area, nitrates, chlorides concentrate, alkalinity, and substratum have all affected these gastropod communities. The occurrence of the first permanent population of Ferrissia clessiniana (Jickeli, 1882) was recorded in Poland. Valvata naticina Menke 1845 has become a critically rare species (CR) due to the pollution of water environments. Five other species, e.g. Anisus vorticulus (Troschel, 1834) and Planorbis carinatus O.F. Müller, 1774 are recorded on the Polish Red List of Species. The clay pit ponds of the Ciechanowska Upland, because of their distinctive environmental features, provide a refuge where a number of rare, threatened and alien gastropod species live.     

Prey-capture in the African clawed toad (Xenopus laevis): comparison of turning to visual and lateral line stimuli

Separately delivered visual and lateral line stimuli elicit similar but not identical orientation and approach by intact, sighted Xenopus. Response frequencies for visual stimuli declined sharply for distant or caudal stimuli while those for lateral line stimuli changed little. Turn angles correlated highly with stimulus angles but were smaller on average, so regression slopes were less than one. Regression slopes were smaller for visual than for lateral line stimuli, but this apparent difference was due to different distributions of stimulus distance interacting with the toad’s rotation center. Errors in final headings, most often under-rotations, did not differ by modality. Frequencies of lunges and arm capture movements were higher for visual stimuli both overall and especially for rostral proximal stimuli. The results demonstrate accurate orientation by sighted Xenopus to visual and lateral line stimuli; they are consistent with expectations based on in-register tectal maps. Orientation to lateral line stimuli is similar to previous results with blinded animals, revealing no heightened acuity in the latter. Modality differences indicate that the lateral line system is better for omnidirectional orientation and approach to distant stimuli whereas the visual system is more attuned to nearby rostral stimuli and more apt to mediate strikes.Electronic Supplementary Material Supplementary material is available to authorised users in the online version of this article at .     

Bilateral similarity function: A novel and universal method for similarity analysis of biological sequences

Bilateral similarity function is designed for analyzing the similarities of biological sequences such as DNA, RNA secondary structure or protein in this paper. The defined function can perform comprehensive comparison between sequences remarkably well, both in terms of the Hamming distance of two compared sequences and the corresponding location difference. Compared with the existing methods for similarity analysis, the examination of similarities/dissimilarities illustrates that the proposed method with the computational complexity of O(N) is effective for these three kinds of biological sequences, and bears the universality for them.     

The Interaction between Polynucleotide Kinase Phosphatase and the DNA Repair Protein XRCC1 Is Critical for Repair of DNA Alkylation Damage and Stable Association at DNA Damage Sites

XRCC1 plays a key role in the repair of DNA base damage and single-strand breaks. Although it has no known enzymatic activity, XRCC1 interacts with multiple DNA repair proteins and is a subunit of distinct DNA repair protein complexes. Here we used the yeast two-hybrid genetic assay to identify mutant versions of XRCC1 that are selectively defective in interacting with a single protein partner. One XRCC1 mutant, A482T, that was defective in binding to polynucleotide kinase phosphatase (PNKP) not only retained the ability to interact with partner proteins that bind to different regions of XRCC1 but also with aprataxin and aprataxin-like factor whose binding sites overlap with that of PNKP. Disruption of the interaction between PNKP and XRCC1 did not impact their initial recruitment to localized DNA damage sites but dramatically reduced their retention there. Furthermore, the interaction between PNKP and the DNA ligase IIIα-XRCC1 complex significantly increased the efficiency of reconstituted repair reactions and was required for complementation of the DNA damage sensitivity to DNA alkylation agents of xrcc1 mutant cells. Together our results reveal novel roles for the interaction between PNKP and XRCC1 in the retention of XRCC1 at DNA damage sites and in DNA alkylation damage repair.     

Oceanimonas smirnovii sp. nov., a novel organism isolated from the Black Sea

A slightly creamy, melanogenic, gram-negative, aerobic bacterium was isolated from seawater sample collected in the Karadag Natural Reserve of the Eastern Crimea, the Black Sea. The novel organism was chemoorganotrophic, had no obligate requirement in NaCl, tolerated to 12% NaCl, grew between 10 and 45 degrees C, was slightly alkaliphilic, and was not able to degrade starch, gelatin, agar, and Tween 80. 16S rRNA gene sequence-based analyses of the new organism revealed that Oceanimonas doudoroffii ATCC 27123T, Oceanimonas baumanii ATCC 700832T, and Oceanisphaera litoralis DSM 15406T were the closest relatives (similarity around 97%-96%). The G + C content of the DNA of the strain 31-13T was 55.5mol%. Phosphatidylethanolamine (49.0%), phosphatidylglycerol (41.8%), and diphosphatidylglycerol (9.2%) were the predominant phospholipids. The major fatty acids were 16:0 (24.1%), 16:1omega7 (40.3%), and 18:1omega7 (29.2%). On the basis of the significant differences demonstrated in the phenotypic and chemotaxonomic characteristics, it is suggested that the bacterium be classified as a novel species; the name Oceanimonas smirnovii sp. nov. is proposed. The type strain is 31-13T (UCM B-11076T = LMG 22147T = ATCC BAA-899T).     

不同基肥对退化坡地及牧草产量和质量的影响

探讨了不同基肥组合处理对退化坡地的改造利用和对牧草生产的影响．在相同的肥水管理条件下,以“鸡粪＋牛粪＋石灰”的基肥组合（Ａ）处理退化坡地土壤,可使皇草、杂交狼尾草、矮象草和墨西哥玉米的年产量比“猪粪＋牛粪＋石灰”的组合（Ｂ）处理分别高出９．７％、１２．８％、４３．０％和９．９％,前者（Ａ）生产出的牧草的粗蛋白含量略高于后者（Ｂ）,粗纤维含量略低于后者,而粗灰分含量显著高于后者．