Historical relationships of the Mesoamerican highlands,with emphasis on tropical montane cloud forests:a temporal cladistic biogeographical analysis

The historical relationships of nine areas of endemism of the tropical montane cloud forests(TMCFs)were analysed based on a temporal cladistic biogeographical approach.Three cladistic biogeographical analyses were conducted based on 29cladograms of terrestrial taxa by partitioning them into three time-slices,namely,Miocene,Pliocene,and Pleistocene.The results showed different area relationships over time.For the Miocene and Pliocene time slices,the Isthmus of Tehuantepec acted as a geographic barrier that fragmented the TMCFs into two portions:west of the Isthmus and east of the Isthmus.In the case of the Pleistocene,the TMCFs were broken into two portions,one related to the Neotropical region and the other to the Nearctic region.Furthermore,the analyses allowed us to detect the influences of different geological and paleoclimatological events on the distribution of the TMCFs over time.Therefore,the TMCFs current distribution might have been driven by geological events during the Miocene-Pliocene,whereas climatic fluctuations have the highest impact during the Pleistocene.

Integrative taxonomy of the Plain-backed Thrush(Zoothera mollissima)complex(Aves,Turdidae)reveals cryptic species,including a new species

Background: The Plain-backed Thrush Zoothera mollissima breeds in the Himalayas and mountains of central China. It was long considered conspecific with the Long-tailed Thrush Zoothera dixoni, until these were shown to be broadly sympatric.Methods: We revise the Z. mollissima–Z. dixoni complex by integrating morphological, acoustic, genetic(two mitochondrial and two nuclear markers), ecological and distributional datasets.Results: In earlier field observations, we noted two very different song types of "Plain-backed" Thrush segregated by breeding habitat and elevation. Further integrative analyses congruently identify three groups: an alpine breeder in the Himalayas and Sichuan, China("Alpine Thrush"); a forest breeder in the eastern Himalayas and northwest Yunnan(at least), China("Himalayan Forest Thrush"); and a forest breeder in central Sichuan("Sichuan Forest Thrush"). Alpine and Himalayan Forest Thrushes are broadly sympatric, but segregated by habitat and altitude, and the same is probably true also for Alpine and Sichuan Forest Thrushes. These three groups differ markedly in morphology and songs. In addition, DNA sequence data from three non-breeding specimens from Yunnan indicate that yet another lineage exists("Yunnan Thrush"). However, we find no consistent morphological differences from Alpine Thrush, and its breeding range is unknown. Molecular phylogenetic analyses suggest that all four groups diverged at least a few million years ago, and identify Alpine Thrush and the putative "Yunnan Thrush" as sisters, and the two forest taxa as sisters. Cytochrome b divergences among the four Z. mollissima sensu lato(s.l.) clades are similar to those between any of them and Z. dixoni, and exceed that between the two congeneric outgroup species. We lectotypify the name Oreocincla rostrata Hodgson, 1845 with the Z. mollissima sensu stricto(s.s.) specimen long considered its type. No available name unambiguously pertains to the Himalayan Forest Thrush.Conclusions: The Plain-backed Thrush Z. mollissima s.l. comprises at least three species: Alpine Thrush Z. mollissima s.s., with a widespread alpine breeding distribution; Sichuan Forest Thrush Z. griseiceps, breeding in central Sichuan forests; and Himalayan Forest Thrush, breeding in the eastern Himalayas and northwest Yunnan(at least), which is described herein as a new species. "Yunnan Thrush" requires further study.

Cost-Effective Discovery of Nucleotide Polymorphisms in Populations of an Allopolyploid Species Using Pool-Seq

Population genetics studies of allopolyploid species lag behind those of diploid species because of practical difficulties in analysis of homeologs-duplicated gene copies originating from hybridized parental species. Pool-Seq, i.e. massive parallel sequencing of pooled individuals, has high potential for detecting nucleotide polymorphisms within and among multiple populations;however, its use has been limited to diploid species. We applied Pool-Seq to an allopolyploid species by developing a bioinformatic pipeline that assigns reads to each homeolog as well as to each polymorphic allele within each homeolog. We simultaneously sequenced eight genes from twenty individuals from each of 24 populations, and found over 100 polymorphic sites in each homeolog. For two sites, we estimated allele frequencies using the number of reads and then validated these estimations by making individual-based estimations. Pool-Seq using our bioinformatic pipeline allows efficient evaluation of nucleotide polymorphisms in a large number of individuals, even in allopolyploid species.

中国胸横刻瘿蜂一新种(膜翅目:瘿蜂科)

记述中国瘿蜂科胸横刻瘿蜂属1新种:蒲氏胸横刻瘿蜂Lithosaphonecrus puigdemonti Pujade-Villar sp. nov.,编制了该属种的检索表。

Cephalic anatomy highlights morphological adaptation to underground habitats in a minute lacewing larva of Dilar (Dilaridae) and conflicting phylogenetic signal in Neuroptera

Dilaridae are a distinctive and phylogenetically ambiguous neuropteran family.So far,the anatomy of the immature stages remains largely unknown.We examined the 1st instar larvae of Dilar montanus in detail and present results of live observations for the first time.The minute,cryptic larvae display features correlated with their underground lifestyle:for instance,a strongly flattened head,stout antennae,eyelessness,and burrowing forelegs.In contrast to molecular data,several characters suggest a‘dilarid clade’combining Dilaridae with Mantispoidea,for instance a very thin and curved or reduced tentorial bridge,and an elongated postmentum.We found intrinsic antennal muscles and Johnston's organ,the first record of these structures in holometabolous larvae.This proves that the first 2 larval antennomeres are homologous with the scapus and pedicellus.The described characters are discussed and analyzed with an updated matrix of neuropteran larval characters.Alternative scenarios of character evolution are presented.Additionally,we show how the 1st-instar larvae move and feed in the substrate,and also provide a high-resolution video recording of the function of the elongate tubular ovipositor and the egg-laying behavior in an adult female under natural conditions.

Positive effects of tree species diversity on litterfall quantity and quality along a secondary successional chronosequence in a subtropical forest

Aims Litterfall,as an important link between aboveground and belowground processes,plays a key role in forest ecosystems.Here,we test for effects of tree species richness on litter production and litter quality in subtropical forest.The study further encompasses a factorial gradient of secondary succession that resulted from human exploitation.Given that a large percentage of subtropical forests are in secondary successional stages,understanding the role of biodiversity on forest re-growth after disturbance appears critical.Methods From January 2009 to December 2014,we monitored forest litterfall in 27 Comparative Study Plots that spanned a gradient of tree species richness(3-20 species)and secondary successional ages(~20 to 120 years)in Gutianshan Natural Nature Reserve,Zhejiang Province,China.The experiment is part of the biodiversity-ecosystem functioning research platform‘BEF-China’.Tree litterfall was collected in monthly intervals using litter traps.Samples were separated into leaf and non-leaf components.Leaf litter was further sorted into dominant and other species.Community level monthly leaf litter C and N contents were analysed through a full year.General linear mixed-effects models were applied to test for effects of tree species richness and successional age on litter quantity and leaf litter C/N.Important Findings Litterfall increased with species richness among and within successional age and this effect was consistent across years.Successionally older stands had higher litterfall and this effect was related to increased tree species richness.However,species richness did not change the intra-and inter-annual temporal stability of litterfall.Increasing tree species richness increased leaf litter quality(decreased C/N),while successional age had no effect.Our study indicates that more diverse forest stands produce more leaf litter and that this litter has higher N concentrations,which could promote forest growth through accelerated nutrient re-cycling.

Tree diversity increases levels of herbivore damage in a subtropical forest canopy:evidence for dietary mixing by arthropods?

Aims Plant diversity has been linked to both increasing and decreasing levels of arthropod herbivore damage in different plant communities.So far,these links have mainly been studied in grasslands or in artificial tree plantations with low species richness.Furthermore,most studies provide results from newly established experimental plant communities where trophic links are not fully established or from stands of tree saplings that have not yet developed a canopy.Here,we test how tree diversity in a species-rich subtropical forest in China with fully developed tree canopy affects levels of herbivore damage caused by different arthropod feeding guilds.Methods We established 27 plots of 30×30 m area.The plots were selected randomly but with the constraint that they had to span a large range of tree diversity as required for comparative studies in contrast to sample surveys.We recorded herbivore damage caused by arthropod feeding guilds(leaf chewers,leaf skeletonizers and sap feeders)on canopy leaves of all major tree species.Important Findings Levels of herbivore damage increased with tree species richness and tree phylogenetic diversity.These effects were most pronounced for damage caused by leaf chewers.Although the two diversity measures were highly correlated,we additionally found a significant interaction between them,whereby species richness increased herbivory mostly at low levels of phylogenetic diversity.Tree species with the lowest proportion of canopy leaf biomass in a plot tended to suffer the highest levels of herbivore damage,which is in contrast to expectations based on the resource concentration hypothesis.Our results are in agreement with expectations of the dietary mixing hypothesis where generalist herbivores with a broad spectrum of food plants benefit from increased resource diversity in tree species-rich forest patches.

Positive effects of tree species richness on fine-root production in a subtropical forest in SE-China

Aims Fine roots play an important role in the biogeochemical cycles of terrestrial ecosystems and are vital for understanding forest ecosystem functioning and services.Higher plant species diversity has been largely reported to increase aboveground community biomass,but how biodiversity affects fine-root production and the related mechanisms in forests remain unclear.In this study,we aim to answer two questions:(i)does fine-root production increase with tree species richness?(ii)Can this effect be explained by niche complementarity among species?Methods We analyzed data from a large forest biodiversity experiment(BEF-China)with 5-year-old trees.Fine-root growth was measured as standing biomass and annual fine-root regrowth was estimated using ingrowth cores.Moreover,relative yield was calculated to test whether over-or under-yielding occurred when mixtures were compared with the average monoculture of the species included in the mixtures.We calculated functional diversity for fine-root(≤2 mm in diameter)traits by Rao’s quadratic entropy index for each species mixture.The effects of manipulated tree species richness and identity on fine-root traits were analyzed with linear mixed-effects models.Mixed models were also used to test the relationships between tree species richness and fine-root standing biomass,annual regrowth and vertical heterogeneity.Important Findings Fine roots of more than one species were found in half of the soil cores in mixtures indicating that belowground interactions in these young forest stands occurred much earlier than canopy closure.We found significant differences among species in fine-root traits such as diameter and specific root length(SRL),which suggested different resource-use strategies and niche partitioning among species.Mean fine-root diameter of species ranged from 0.31 to 0.74 mm,mean SRL ranged from 12.43 m·g^(−1)to 70.22 m·g^(−1)and mean vertical distribution indexβranged from 0.68 to 0.93.There was a significant positive relationship between species richness and the evenness of the vertical distribution of fine-root standing biomass.Moreover,marginally significant positive relationships existed between species richness and standing biomass as well as annual regrowth of fine roots.Relative yields and Rao’s quadratic entropy index were both not significantly affected by species richness.However,the relative yield of fine-root standing biomass was marginally correlated with Rao’s quadratic entropy index,implying that belowground niche complementarity between species does contribute to diversity effects.In conclusion,our study showed positive effects of species richness on the filling of soil volume by fine roots in the studied experimental forest communities.This has positive effects on fine-root standing biomass and may also lead to increased aboveground biomass.

Family-level leaf nitrogen and phosphorus stoichiometry of global terrestrial plants

Leaf nitrogen(N) and phosphorus(P) concentrations are critical for photosynthesis, growth, reproduction and other ecological processes of plants. Previous studies on large-scale biogeographic patterns of leaf N and P stoichiometric relationships were mostly conducted using data pooled across taxa, while family/genus-level analyses are rarely reported. Here, we examined global patterns of family-specific leaf N and P stoichiometry using a global data set of 12,716 paired leaf N and P records which includes 204 families, 1,305 genera, and 3,420 species. After determining the minimum size of samples(i.e., 35 records), we analyzed leaf N and P concentrations, N:P ratios and N^P scaling relationships of plants for 62 families with 11,440 records. The numeric values of leaf N and P stoichiometry varied significantly across families and showed diverse trends along gradients of mean annual temperature(MAT) and mean annual precipitation(MAP). The leaf N and P concentrations and N:P ratios of 62 families ranged from 6.11 to 30.30 mg g–1, 0.27 to 2.17 mg g–1, and 10.20 to 35.40, respectively. Approximately 1/3–1/2 of the families(22–35 of 62) showed a decrease in leaf N and P concentrations and N:P ratios with increasing MAT or MAP, while the remainder either did not show a significant trend or presented the opposite pattern. Family-specific leaf N^P scaling exponents did not converge to a certain empirical value, with a range of 0.307–0.991 for 54 out of 62 families which indicated a significant N^P scaling relationship. Our results for the first time revealed large variation in the family-level leaf N and P stoichiometry of global terrestrial plants and that the stoichiometric relationships for at least one-third of the families were not consistent with the global trends reported previously. The numeric values of the family-specific leaf N and P stoichiometry documented in the current study provide critical synthetic parameters for biogeographic modeling and for further studies on the physiological and ecological mechanisms underlying the nutrient use strategies of plants from different phylogenetic taxa.

Long-term overlap of social and genetic structure in free-ranging house mice reveals dynamic seasonal and group size effects

Associating with relatives in social groups can bring benefits such as reduced risk of aggression and increased likelihood of cooperation.Competition among relatives over limited resources,on the other hand,can induce individuals to alter their patterns of association.Population density might further affect the costs and benefits of associating with relatives by altering resource competition or by changing the structure of social groups;preventing easy association with relatives.Consequently,the overlap between genetic and social structure is expected to decrease with increasing population size,as well as during times of increased breeding activity.Here,we use multi-layer network techniques to quantify the similarity between long-term,high resolution genetic,and behavioral data from a large population of free-ranging house mice(Mus musculus domesticus),studied over 10years.We infer how the benefit of associating with genetically similar individuals might fluctuate in relation to breeding behavior and environmental conditions.We found a clear seasonal effect,with decreased overlap between social and genetic structure during summer months,characterized by high temperatures and high breeding activity.Though the effect of overall population size was relatively weak,we found a clear decrease in the overlap between genetic similarity and social associations within larger groups.As well as longer-term within-group changes,these results reveal population-wide short-term shifts in how individuals associate with relatives.Our study suggests that resource competition modifies the trade-off between the costs and benefits of interacting with relatives.

Seasonal dynamics of foliar antioxidative enzymes and total anthocyanins in natural populations of Iris pumila L.

Aims Plants in their natural habitats frequently cope with a multitude of abiotic stresses,such as high light intensity,extreme temperatures and water deficit,which often co-occur during periods of drought,especially in semi-arid and arid regions.Exposure of plants to stressful environmental conditions usually induce overproduction of reactive oxygen species(ROS)that,as highly toxic derivatives of O_(2),can assault all cell macromolecules,leading to the disruption of cellular homeostasis and,consequently,the uncoupling of major metabolic processes,the photosynthesis and photorespiration.In order to minimize ROS-mediated cellular damage,plants have evolved highly efficient antioxidative defense systems that include both enzymatic and non-enzymatic components.Since abiotic stress can also operate as a strong evolutionary force that shapes adaptations in natural plant populations,the aim of this study was to examine the seasonal variation patterns of two distinct antioxidative systems,ROS-scavenging enzymes and anthocyanin pigments,in the leaf tissue of a steppe plant,Iris pumila,as expressed under contrasting light conditions that the species regularly experiences in the wild.Methods We selected two natural populations of I.pumila inhabiting the alternative radiation environments in the Deliblato Sands,a sunexposed dune site and a woodland understory.The specific activity of three antioxidative enzymes,superoxide dismutase(SOD),catalase(CAT)and peroxidase(POD)and the content of total anthocyanins were examined in leaves of I.pumila plants collected from each of the 31 Iris clones(17 in the exposed population and 14 in the shaded population)once during each of the three seasons,spring,summer and autumn in 2004.Specifically,a fully expanded leaf was cut from each clonal plant between 15:00 and 16:00 h,immediately frozen in liquid nitrogen and stored at-70℃until preparation.Important Findings Generally,all three antioxidative enzymes were up-regulated in summer-harvested leaves compared to their spring or autumn counterparts,as was observed for the concentration of foliar anthocyanins,indicating that strengthening of antioxidant systems was the key mechanism for long-term acclimatization of I.pumila plants to stressful environmental conditions within their natural ecological niches.When plants from contrasting radiation environments were compared,SOD and CAT activities appeared to be greater in shade-exposed than in sun-exposed leaves.Conversely,POD activity and the content of foliar anthocyanins were notably higher in foliage experiencing full sunlight relative to those developed under vegetation canopy,suggesting the synergistic function of these two molecules in protecting leaf cells against photoinhibitory and photooxidative effects of strong light.

The role of soluble sugars during drought in tropical tree seedlings with contrasting tolerances

非结构碳水化合物(NSCs)是植物的贮藏化合物,用于代谢、运输、渗透调节和叶片脱落后的再生。即使在最适宜生长的条件下,植物也会继续储存NSCs。这种储存可能是由于生长受到抑制而产生的被动积累,也可能是由于以生长为代价而产生的主动储备。前者暗示NSCs可能是碳汇有限生长的副产物,而后者则表明NSCs在植物适应逆境中具有的功能作用。本研究中,利用13C脉冲标记,我们追踪了具有不同干旱耐受性的两种热带树种的幼苗在干旱和常湿条件下茎和根器官中可溶性糖的来源,以估计干旱前储存的NSCs与干旱期间同化的NSCs的相对分配。我们监测了生长、气孔导度、茎干水势和NSC储存以评估对干旱的全碳响应。结果表明,与对照幼苗相比,不耐旱树种生长速度减慢,在叶片、茎和根器官中储存NSCs,在茎和根器官中可溶性糖(源于干旱前的储存)的比例更大。相反,与对照幼苗相比,耐旱树种则能保持生长和茎根NSCs浓度,但叶片NSCs浓度降低,茎和根可溶性糖的比例更大,这些可溶性糖来自于新同化的光合产物。这些结果表明,不耐旱树种由于缺水导致生长受限而被动积累NSCs,而耐旱树种则通过分配NSCs到茎和根器官来积极响应缺水。这些策略似乎与基线最大生长速率相关,并且支持了以前的研究结果,表明在生长和耐旱性之间存在一种权衡关系,同时也为NSCs分配的可塑性在干旱中的重要性提供了新的证据。

An optimised sequential extraction scheme for the evaluation of vanadium mobility in soils

Reviewing the current state of knowledge about sequential extraction applied for soil vanadium （V） fractionation, we identified an urgent requirement of an sequential extraction （SE） specified for V. Namely, almost all previous SE extracted only 8.4%-48% of total V in soils （excluding residue）. Thus, we proposed an eight-step SE for V fractionation in soils according to the knowledge gained from literature and our own dissolution experiments with model minerals. After extracting the mobilisable and adsorbed V with de-ionised water and 5 mmol/L phosphate, I moVL pyrophosphate was applied to gather organic matter bound V which minimised the artefact dissolving AI and Fe （hydr）oxides occurred when using HNO3-H202 for extraction. Extraction with 0.4 mol/L NH2OH. HCI was highly selective toward manganese oxides. Fractionation of different crystalline A1 and Fe （hydr）oxides associated V with 1 mol/L HCI, 0.2 mol/L oxalate buffer and 4 mol/L HCI at 95℃especially improved the extractability of V incorporated with crystalline phase associated V. The suitability of our new SE scheme was confirmed by its higher selectivity against the target phases and higher extraction efficiencies （55%-77% of total V） with model minerals and 6 soils of different properties than previous SE.

Heterosis in age-specific selected populations of a seed beetle： Sex differences in longevity and reproductive behavior

We tested mutation accumulation hypothesis for the evolution of senescence using short-lived and long-lived populations of the seed-feeding beetle, Acanthoscelides obtectus （Say）, obtained by selection on early- and late-life for many generations. The expected consequence of the mutation accumulation hypothesis is that in short-lived pop- ulations, where the force of natural selection is the strongest early in life, the late-life fitness traits should decline due to genetic drift which increases the frequency of mutations with deleterious effects in later adult stages. Since it is unlikely that identical deleterious mutations will increase in several independent populations, hybrid vigor for late-life fit- ness is expected in offspring obtained in crosses among populations selected for early-life fitness traits. We tested longevity of both sexes, female fecundity and male reproductive behavior for hybrid vigor by comparing hybrid and nonhybrid short-lived populations. Hybrid vigor was confirmed for male virility, mating speed and copulation duration, and longevity of both sexes at late ages. In contrast to males, the results on female fecundity in short-lived populations did not support mutation accumulation as a genetic mechanism for the evolution of this trait. Contrary to the prediction of this hypothesis, male mating ability indices and female fecundity in long-lived populations exhibited hybrid vigor at all assayed age classes. We demonstrate that nonhybrid long-lived populations diverged randomly regarding female and male reproductive fitness, indicating that sexually antag- onistic selection, when accompanied with genetic drift for female fecundity and male virility, might be responsible for overriding natural selection in the independently evolving long-lived populations.

Pollination interactions reveal direct costs and indirect benefits of plant-plant facilitation for ecosystem engineers

作为生态系统工程师的植物通过对非生物条件和生物区系的影响而显著地改变环境,从而促进了原本在这些环境下无法存活的伴生物种的生长。然而,很多研究缺乏对互惠效应的了解,因为对植物-植物相互作用的研究通常只估计了对伴生物种的益处,而很少考虑一个营养水平如何直接和间接调节植物的反馈作用。我们对两个植物物种(Arenaria tetraquetra和Hormathophylla spinosa,他们或单独开花,或与伴生植物一起开花)进行了一项田间试验用以分解净效应并验证以下假设:授粉者介导的相互作用提供益处用来平衡植物产生促进作用的成本。我们发现,促进作用的净成本伴随授粉介导的益处而存在。尽管两种植物单株植物上的产花更少,但与单独开花相比,他们在与伴生植物一起开花时,每朵花上的授粉者多样性增强。尽管这两种植物单独开花时,单株种子产量较高,但坐果和结实的产量存在种间差异。四叶蕨属的植物(Arenaria tetraquetra),伴生植物对其坐果和结实有负面效应,而刺山蕨属的植物(Hormathophylla spinose),当其与伴生植物一起开花时,坐果更高,结实则不受影响。我们的研究表明,除了承受直接成本外,植物还可以从伴生物种的促进作用中受益,通过提高其对传粉者的可见性。因此,我们强调授粉的相互作用可以补偿物种促进作用的成本,这些促进作用依赖于作为生态系统工程师的植物。本研究阐明了植物-植物间直接相互作用的结果如何被包括第三方在内的间接相互作用来调节的。

Storytelling and environmental information: connecting schoolchildren and herpetofauna in Morocco

Northwestern Morocco is undergoing a sudden change in the level of infrastructure growth and pressure on the environment from increased tourism.The ongoing changes are raising questions about how the ecosystem will react,and the relevant drivers of these changes.The Oued Laou valley in north-west Morocco hosts high landscape,species and human cultural diversity.The Talassemtane National Park has been established to preserve the envi-ronment in this region;however,what information tools are available to children regarding this environment?The ecosystem is illustrated here using three components:herpetofauna(representing ecosystem components),prob-lems related to water quantity and quality(representing interactions within ecosystem components)and Talassemtane National Park(representing a case of ecosystem management).A children’s book was written on this topic,and when the book was delivered to pupils,a questionnaire was included,aimed at determining their sources of environ-mental information.The results identified major changes in the sources of information utilized by children in this part of Morocco,a clear role of schools in explaining ecosystem components,and an increasing role of TV in environmental information supply.The role of the family was found to be less important than TV or school.Another major source of pupils’environmental knowledge is personal observation and hands-on experience,both for rural and urban children.Children are willing to discover and understand complex systems,and researchers should be encouraged to supply children with correct and up-to-date information on environmental systems,focusing at first on the local environment,as a background for sustainable development.

Condition-dependence and sexual ornamentation： Effects of immune challenges on a highly sexually dimorphic grasshopper

Sexual ornaments contribute substantially to phenotypic diversity and it is particularly relevant to understand their evolution. Ornaments can assume the function of signals-of-quality that the choosy sex uses to evaluate potential mating partners. Often there are no obvious direct benefits and investment into mate choice is primarily rewarded by beneficial alleles that are inherited to the offspring. Inter-sexual communication via sexual ornaments requires honesty of the sexual signal, yet the question of what maintains honesty remains only partially solved. One solution is that honesty is maintained by trait expression being dependent on individual condition, since condition-dependent trait expression offers an effectively inexhaustible source of genetic variability. Here we test in the highly sexually dimorphic club-legged grasshopper Gomphocerus sibiricus if putative sexual ornaments, in particular the striking front-leg clubs, are more strongly affected by a lipopolysaccharide （LPS） immune challenge than putatively not sexually selected traits. Our results show overall little condition-dependent expression of morphological and song traits, with sexually selected traits exhibiting effects comparable to nonsexually selected traits （with the possible exception of stridulatory file length and syllable-to-pause ratio in advertisement songs）. Interestingly, field observations of individuals of lethally parasitized individuals suggest that a very strong environmental challenge can specifically affect the expression of the front-leg clubs. The presence of 1% of males in natural populations with missing or heavily deformed clubs plus 5% with minor club deformations furthermore indicate that there are risks associated with club development during final ecdysis and this might act as a filter against deleterious alleles.

Spatial patterns and determinants of common root-associated fungi in a subtropical forest of China

Aims Spatial patterns of fungal populations are affected by plant distribu-tion,abiotic factors,fungal dispersal ability and inter-species interac-tions.While several studies have addressed spatial patterns of some mycorrhizal,saprotrophic and pathogenic fungi,the method based on fruit-body surveys is not efficient and unreliable to study the spa-tial pattern of root-associated fungal species because most fungi in plant roots do not have sporocarps and cannot be identified based only on morphological traits.Our aims are(i)to determine the spa-tial pattern of common root-associated fungi;(ii)to evaluate whether the abundance and spatial pattern of root-associated fungi and cat-egories of fungi,reflect their biotic and abiotic niche constraints.Methods About 828 soil cores were collected from a 24-ha plot in a sub-tropical forest and Illumina Miseq was carried out to determine fungal composition in root samples and spatial patterns of 1009 common fungal Operational Taxonomic Units(OTUs)were studied using point pattern analyses.Biotic(plant community composition)and abiotic niche constraints on the presence/abundance of a fun-gal OTU was assessed as the n-dimensional niche hypervolumes of biotic and abiotic characteristics.Important Findings Our results showed that(i)most fungal OTUs were highly spa-tially aggregated at small scales(less than 30 m),but that the aggregated pattern decreased,while regular and random patterns increased,with the increasing distance;(ii)A significant positive correlation was found between fungal abundance and aggrega-tion intensity of fungal OTUs,indicating that the dominant fungi tended to be more aggregated in natural forests;(iii)Mean abun-dance and spatial aggregation intensity of ectomycorrhizal and pathogenic fungi were relatively higher than those of saprotrophic fungi,indicating that host plants may play an important role in determining spatial pattern of root-associated fungi;(iv)Spatial patterns of root-associated fungi depended on fungal abundance,fungal functional group,fungal taxa,biotic and abiotic niche hypervolumes of fungal OTUs.