The influence of sex, line, and fight experience on aggressiveness of the Siamese fighting fish in intrasexual competition

We examined the influence of sex, line, i.e., broods from different parents, and previous fight experience on the aggressiveness of the Siamese fighting fish Betta splendens in intrasexual competition. The innate aggressiveness of the fish against their mirror images was measured on the day prior to the direct fight with other individuals, and it was found to be influenced by the line type but not by the sex. In the direct fight with other individuals, the males invested more effort in the fight than the females. In addition, the individuals of a particular line that exhibited a lower innate aggressiveness spent less time in the direct fight and were often losers when compared with those of other lines. After the direct fight with other individuals, the aggressiveness of the fish against their mirror images was remarkably influenced by the outcome of the direct fight, i.e., the winners exhibited more aggressive behavior, whereas the losers exhibited a lesser degree of aggressive behavior. This influence of the previous fight experience on subsequent aggressiveness was the greatest in the individuals of the line that have exhibited the lowest innate aggressiveness. However, the positive effect of the winning experience or the negative effect of the losing experience on subsequent aggressiveness decreased following several days after the previous fight increased.     

Parameters of rewards on choice behavior in Siamese fighting fish (Betta splendens)

Five experiments were conducted with Siamese fighting fish (Betta splendens) to investigate how choices in a T-maze were affected by parameters of a social reward (aggression display to another male): presence or absence, amount, delay and distance traveled. Bettas showed a preference for the side associated with the presence of another male rather than the side associated with nothing (Exp 1), a greater length of time of the reward (Exp 2) and shorter delay (Exp 3). The animals were indifferent when one side offered a longer delay to a longer reward time compared with a shorter delay to a shorter reward time (Exp 4). What was most surprising, however, was that fish preferred to choose the side that was associated with swimming a greater distance to reach an opponent male (Exp 5). These experiments demonstrate that, while some parameters of a visual reward affect behavior in predicable ways (greater amount, shorter delay), the complex motivations underlying inter-male aggression can produce what appear to be paradoxical results.     

内蒙古典型草原区芨芨草群落适生生境

芨芨草群落是干旱与半干旱地区重要的植被资源,内蒙古典型草原区常在地形稍低的部位镶嵌有芨芨草群落,且芨芨草群落常与低洼湿草甸群落相连。为了探究芨芨草群落的适生生境,在锡林郭勒盟典型草原区选取了4个代表性调查区,从芨芨草群落及其相邻群落分布的地形特征、调查区的地下水埋深、1 m深土层的土壤电导率、土壤pH值和土壤质地等指标上对芨芨草适生生境进行探究,结果表明,芨芨草群落在内蒙古典型草原区常分布在河漫滩和丘间蝶形洼地地区,呈现出由高程梯度导致的与地带性针茅群落、湿草甸群落带状分布的特点,导致这种成带分布的原因与地下水埋深及地表径流有关,芨芨草群落生境的地下水埋深一般在1-3 m且有地表径流的补充;芨芨草群落耐盐碱性强,其生境也与反映土壤盐分含量的土壤电导率和土壤pH值有关;但芨芨草群落生境的形成不是由土壤机械组成所致。     

Group size, sex and age composition of chital (Axis axis) and sambar (Rusa unicolor) in a deciduous habitat of Western Ghats

Knowledge of the social structure of a population is important for a range of fundamental and applied purposes. Group characteristics and population structure of chital (Axis axis) and sambar (Rusa unicolor) were studied in a deciduous habitat of Mudumalai Tiger Reserve, Western Ghats, India, during 2008-2009. Vehicle transects were monitored monthly to gather information on group-size and age-sex composition of chital and sambar. The average mean group size and crowding for chital and sambar was 13.1 ± 0.5 (n = 1020), 3.6 ± 0.2 (n = 377) and 33.3, 11.0 respectively. The average adult male:adult female:fawn ratio was 63.4:100:22.3 (n = 9391) and 43.9:100:23.7 (n = 1023) in chital and sambar respectively. The mean group size of chital and sambar varied significantly between seasons (Kruskal-Wallis test, p = <0.001). Peak fawning season was observed from February to May for chital and May to August for sambar. Group's sex-age composition influenced group formation in both species between seasons at different level. Adult male and fawn were the important predicting variables of change in group size. Skewed female sex ratio was probably due to selective male predation by large predators. Although fawning occurred throughout the year, both species showed seasonality in fawning. The above mentioned patterns differed between species depending upon their ecological adaptation in foraging strategies and habitat preference.     

Rapid assessment of female preference for male size predicts subsequent choice of spawning partner in a socially monogamous cichlid fish

Although size-assortative mating in convict cichlids, Amatitliana nigrofasciata, is supposed to result from mutual mating preference for larger individuals, female choice in relation to male size remains ambiguous. We revisited the evidence for directional preference for larger males in female convict cichlids using a classical two-way choice apparatus in which each female could decide to spend time in front of a small male or a large one. We found evidence for female preference for large males, as assessed from association preference during a 4-hour period following encounter. Furthermore, females decided to spawn in front of the initially preferred male more often than expected by chance. Our results thus confirm the existence of a directional preference for large males in female convict cichlids, and indicate that association preference measured over a short period of time can provide a quick and reliable proxy for reproductive preference in this species.     

Shoaling in juvenile guppies: the effects of body size and shoal size

While factors affecting shoal mate choice have been examined extensively in adult guppies (Poecilia reticulata), few studies have focused on the shoaling behavior of juveniles. In this study, juvenile guppies were tested for their ability to shoal as well as their response to shoal mates of different body size and to shoals with different numbers of individuals. In dichotomous choice tests, 10-day-old guppies (mean body length=8.83 mm), 30-day-old guppies (13.17 mm) and 50-day-old guppies (18.6mm) were given the opportunity to swim near shoals of five fish or an empty chamber. In most cases, the juvenile fish demonstrated shoaling behavior, swimming near a group of fish rather than an empty chamber, regardless of the age of the stimulus shoal. When presented with two shoals, one of similar age and body size and one of dissimilar age and body size, only the 50-day-old guppies showed a significant preference for the age-matched shoal. Similarly, when choosing between a large shoal and a small shoal, only the 50-day-old guppies spent significantly more time near the larger shoal. Thus, while juveniles at each age shoaled, only 50-day-old fish demonstrated the shoal mate discrimination seen in adult fish.     

Interactive effects of sublethal predation and body size on siphon production of the bivalve Nuttallia olivacea

This paper is intended to reveal effects of siphon cropping on siphon production of a tellinacean bivalve Nuttallia olivacea, an important prey for juvenile stone flounder. We carried out a two-way field experiment in which bivalves of three treatments (3-times siphon removal, 1-time removal, no removal) and four size classes (9-50 mm shell length) were caged and placed in the field for 3 mo. Growth of repeatedly-removed bivalves was inhibited, indicating reduced siphon growth (natural increase of siphon size according to somatic growth). However, siphon production of removed bivalves was larger than non-removed bivalves, possibly because of siphon regeneration. Juveniles (N. olivacea < 20 mm shell length) showed high growth performance. Their siphon growth was greater than their siphon regeneration. In all bivalves except juveniles, siphon regeneration was greater than siphon growth and engendered high siphon production. Siphon growth was dependent on bivalve size and was only slightly reduced by siphon loss, but siphon regeneration seemed to be dependent mostly on the extent of siphon loss. Greater siphon removal enhanced larger siphon production. These results indicate that intensive siphon cropping by juvenile stone flounder induces high siphon production without serious impact on N. olivacea.     

Flavonoid profiles in the Heliohebe group of New Zealand Veronica (Plantaginaceae)

The Heliohebe group of Veronica (sect. Hebe) consists of five species occurring in the South Island of New Zealand. These species and a hybrid were analysed for their flavonoids. Five flavone glycosides were isolated and identified by NMR spectroscopy and three additional glycosides were detected by LC–UV–MS. Luteolin 7-O-, 3′-O- and 4′-O-glucosides and apigenin 7-O-glucoside were present in all six taxa investigated, 6-hydroxyluteolin glycosides were found in five and a luteolin caffeoylglycoside in four taxa, while a hypolaetin 7-O-glycoside was detected only in Veronica pentasepala. The 3′-O- and 4′-O-glucosides of luteolin are also common in other species of Veronica sect. Hebe (restricted to the Southern Hemisphere), but are rare in Northern Hemisphere species of Veronica and thus act as good chemotaxonomic markers for the section. The relatively simple flavonoid profiles found in the Heliohebe group are plesiomorphic and consistent with the group's status as sister to the Hebe clade. Based on the detected flavonoids, two groups could be distinguished within the Heliohebe clade: (1) Veronica hulkeana, Veronica lavaudiana and Veronica raoulii, characterised by luteolin caffeoylglycoside, and (2) V. pentasepala and Veronica scrupea, where this compound is replaced by a 6-hydroxyluteolin dihexoside.     

鲶鱼和胡子鲶的两性异形与雌性个体生育力

检测了鲶鱼(Silurus asotus)和胡子鲶(Clarias fuscus)繁殖期18个形态特征的两性异形以及雌性个体生育力。结果表明,鲶鱼和胡子鲶雌雄性别比例均符合1∶1。One-way ANOVA显示,鲶鱼雌雄个体体长差异不显著,胡子鲶雌性个体体长显著小于雄性个体(P0.05)。以体长为协变量的One-way ANCOVA显示,特定体长的鲶鱼雌性个体的眼间距和体高显著大于雄性个体(P0.05),两性间其它局部特征不存在显著的两性差异;特定体长的胡子鲶雌性个体的体高、腹鳍基前距和腹鳍臀鳍间距显著大于雄性个体,雌性个体的臀鳍基长、尾柄高和尾鳍长显著小于雄性个体(P0.05),两性间其它局部特征不存在显著的两性差异。Two-way ANOVA显示,胡子鲶体长显著大于鲶鱼(P0.05),性别及物种与性别两因素的相互作用对体长影响不显著。以体长为协变量的Two-way ANCOVA显示,胡子鲶的头长、头宽、吻长、眼间距、尾柄高、尾鳍长、背鳍基前距、背鳍基长、腹鳍基前距、腹鳍臀鳍间距、体重和去内脏体重显著大于鲶鱼,头高、体高、臀鳍基长显著小于鲶鱼(P0.05),物种间的其他形态特征变量差异不显著;雌性个体的体高、背鳍基前距、腹鳍基前距、腹鳍臀鳍间距显著大于雄性个体,臀鳍基长、尾柄高、尾鳍长、背鳍基长显著小于雄性个体(P0.05),两性间的其他形态特征变量差异不显著;物种与性别两因素的相互作用对体高、臀鳍基长、尾柄高、尾鳍长、背鳍基长和腹鳍臀鳍间距影响显著,对其余的形态特征变量影响不显著。15个形态特征变量的主成分分析(Eigenvalue≥1)发现,前2个主成分共解释68.4%的变异。头宽、眼间距、尾柄高、尾鳍长、背鳍基前距、背鳍基长、腹鳍基前距和腹鳍臀鳍间距在第一主成分有较高的正负载系数,臀鳍基长在第一主成分有较高的负负载系数(解释51.2%变异);眼后头长在第二主成分有较高的负负载系数(解释17.2%变异)。胡子鲶在第一主成分和第二主成分的分值均显著大于鲶鱼,雌雄两性的差异以及两因素的相互作用对分值的影响均不显著。实验检测的鲶鱼、胡子鲶的怀卵数量与体长和体重回归关系显著。One-way ANCOVA及矫正平均值Tukey's检验显示,特定体长的胡子鲶的产卵数量显著大于鲶鱼。性选择是胡子鲶大个体雄性形成的主要原因,同时影响与运动相关的尾部特征。生育力选择更多的影响与雌性胡子鲶较大腹腔容积相关的形态特征变异。环境因子、食物可得性和营养状况同时影响了个体大小两性异形的形成。     

Correlated evolution of conspicuous coloration and body size in poison frogs (Dendrobatidae)

Conspicuous coloration is often used in combination with chemical defenses to deter predators from attacking. Experimental studies have shown that the avoidance inducing effect of conspicuous prey coloration increases with increasing size of pattern elements and with increasing body size. Here we use a comparative approach to test the prediction from these findings, namely that conspicuous coloration will evolve in tandem with body size. In our analysis, we use a previously published mitochondrial DNA-based phylogeny and comparative analysis of independent contrasts to examine if evolutionary shifts in color pattern have been associated with evolutionary changes in body size in aposematic poison frogs (Anura: Dendrobatidae). Information on body size (snout to vent length) and coloration were obtained from the literature. Two different measures of conspicuousness were used, one based on rankings by human observers and the other based on computer analysis of digitized photographs. The results from comparative analyses using either measure of coloration indicated that avoidance inducing coloration and body size have evolved in concert in poison frogs. Results from reconstruction of character change further indicate that the correlated evolution of size and coloration has involved changes in both directions within each of the different clades of the phylogenetic tree. This finding is consistent with the hypothesis that selection imposed by visually guided predators has promoted the evolution of larger body size in species with conspicuous coloration, or enhanced evolution of conspicuous coloration in larger species.     

crm-1 facilitates BMP signaling to control body size in Caenorhabditis elegans

We have identified in Caenorhabditis elegans a homologue of the vertebrate Crim1, crm-1, which encodes a putative transmembrane protein with multiple cysteine-rich (CR) domains known to have bone morphogenetic proteins (BMPs) binding activity. Using the body morphology of C. elegans as an indicator, we showed that attenuation of crm-1 activity leads to a small body phenotype reminiscent of that of BMP pathway mutants. We showed that the crm-1 loss-of-function phenotype can be rescued by constitutive supply of sma-4 activity. crm-1 can enhance BMP signaling and this activity is dependent on the presence of the DBL-1 ligand and its receptors. crm-1 is expressed in neurons at the ventral nerve cord, where the DBL-1 ligand is produced. However, ectopic expression experiments reveal that crm-1 gene products act outside the DBL-1 producing cells and function non-autonomously to facilitate dbl/sma pathway signaling to control body size.     

性别、季节和体型大小对吐鲁番沙虎巢域的影响

2008年6月份至2009年5月份对吐鲁番沙虎的巢域进行调查:2008年6月份至2008年8月份为繁殖季节(RS),2008年9月份至2009年5月份(冬眠期除外)为非繁殖季节(NRS)。利用截趾标志重捕法研究吐鲁番沙虎的巢域,共标记283只吐鲁番沙虎,累计繁殖季节24只,非繁殖季节43只重捕超过3次(其中13只个体在繁殖季节和非繁殖季节均够3次以上捕捉次数,为重复个体),可以用于计算个体巢域面积数据。利用软件MapGis计算最小凸多边形法(MCP)巢域面积,并分析性别、体型大小、季节等因素对巢域的影响。结果表明:吐鲁番沙虎非繁殖季节雄性、雌性与幼体各组间的巢域面积差异均显著,繁殖季节巢域面积差异不显著;雌雄个体不同季节或全年合并比较巢域面积差异性均不显著;非繁殖季节面积与吻肛长(SVL)显著相关、全年成体组的巢域面积与吻肛长显著相关;成体巢域面积季节差异显著(U=41,P=0.046),幼体则没有季节差异(U=159,P=0.537)。因而,吐鲁番沙虎的巢域大小受性别因素影响不大,体型大小对巢域面积有显著影响,由于繁殖、食物资源等的季节变化是影响吐鲁番沙虎巢域最重要的因素。     

Septal pore complex morphology in the Agaricomycotina (Basidiomycota) with emphasis on the Cantharellales and Hymenochaetales

The ultrastructure of septa and septum-associated septal pore caps are important taxonomic markers in the Agaricomycotina (Basidiomycota, Fungi). The septal pore caps covering the typical basidiomycetous dolipore septum are divided into three main phenotypically recognized morphotypes: vesicular-tubular (including the vesicular, sacculate, tubular, ampulliform, and globular morphotypes), imperforate, and perforate. Until recently, the septal pore cap-type reflected the higher-order relationships within the Agaricomycotina. However, the new classification of Fungi resulted in many changes including revision of existing and addition of new orders. Therefore, the septal pore cap ultrastructure of more than 325 species as reported in literature was related to this new classification. In addition, the septal pore cap ultrastructures of Rickenella fibula and Cantharellus formosus were examined by transmission electron microscopy. Both fungi have dolipore septa associated with perforate septal pore caps. These results combined with data from the literature show that the septal pore cap-type within orders of the Agaricomycotina is generally monomorphic, except for the Cantharellales and Hymenochaetales.It appears from the fungal phylogeny combined with the septal pore cap ultrastructure that the vesicular-tubular and the imperforate type both may have arisen from endoplasmic reticulum. Thereafter, the imperforate type eventually gave rise to the perforate septal pore cap-type.     

Phylogenetic reassessment of Hyaloscyphaceae sensu lato (Helotiales, Leotiomycetes) based on multigene analyses

Hyaloscyphaceae is the largest family in Helotiales, Leotiomycetes. It is mainly characterized by minute apothecia with well-differentiated hairs, but its taxonomic delimitation and infrafamilial classification remain ambiguous. This study performed molecular phylogenetic analyses using multiple genes including the ITS-5.8S rDNA, the D1–D2 region of large subunit of rDNA, RNA polymerase II subunit 2, and the mitochondrial small subunit. The primary objective was to evaluate the phylogenetic utility of morphological characters traditionally used in the taxonomy of Hyaloscyphaceae through reassessment of the monophyly of this family and its genera. The phylogenetic analyses inferred Hyaloscyphaceae as being a heterogeneous assemblage of a diverse group of fungi and not supported as monophyletic. Among the three tribes of Hyaloscyphaceae only Lachneae formed a monophyletic lineage. The presence of hairs is rejected as a synapomorphy, since morphologically diversified hairs have originated independently during the evolution of Helotiales. The true- and false-subiculum in Arachnopezizeae are hypothesized to have evolved through different evolutionary processes; the true-subiculum is likely the product of a single evolutionary origin, while the false-subiculum is hypothesized to have originated multiple times. Since Hyaloscyphaceae sensu lato was not resolved as monophyletic, Hyaloscyphaceae sensu stricto is redefined and only applied to the genus Hyaloscypha.     

Real-time PCR detection of Holophagae (Acidobacteria) and Verrucomicrobia subdivision 1 groups in bulk and leek (Allium porrum) rhizosphere soils

In the light of the poor culturability of Acidobacteria and Verrucomicrobia species, group-specific real-time (qPCR) systems were developed based on the 16S rRNA gene sequences from culturable representatives of both groups. The number of DNA targets from three different groups, i.e. Holophagae (Acidobacteria group 8) and Luteolibacter/Prosthecobacter and unclassified Verrucomicrobiaceae subdivision 1, was determined in DNA extracts from different leek (Allium porrum) rhizosphere soil compartments and from bulk soil with the aim to determine the distribution of the three bacterial groups in the plant-soil ecosystem. The specificity of the designed primers was evaluated in three steps. First, in silico tests were performed which demonstrated that all designed primers 100% matched with database sequences of their respective groups, whereas lower matches with other non-target bacterial groups were found. Second, PCR amplification with the different primer sets was performed on genomic DNA extracts from target and from non-target bacteria. This test demonstrated specificity of the designed primers for the target groups, as single amplicons of expected sizes were found only for the target bacteria. Third, the qPCR systems were tested for specific amplifications from soil DNA extracts and 48 amplicons from each primer system were sequenced. All sequences were > 97% similar to database sequences of the respective target groups. Estimated cell numbers based on Holophagae-, Luteolibacter/Prosthecobacter- and unclassified Verrucomicrobiaceae subdivision 1-specific qPCRs from leek rhizosphere compartments and bulk soils demonstrated higher preference for one or both rhizosphere compartments above bulk soil for all three bacterial groups.