Age Structure of Two Species of Odorous Frogs(Odorrana margaretae and Odorrana grahami)

Variation in age structure and body size benefits are identified to understand the evolution of life history. Here, we estimated the age structure and body size of two species of odorous frogs(Odorrana margaretae and Odorrana grahami) by using skeletochronology. The ages at sexual maturity of O. grahami and O. margaretae in both sexes were 1 and 2 years, respectively. For both sexes, the maximum age observed in O. margaretae was six years. For O. grahami, the maximum age observed in males and females were 4 and 5 years, respectively. Males and females did not differ in mean age in the two species.The average body size of both species considerably differed between sexes, with females being larger than males. The body size of females was also larger than that of males when the effect of age was removed. We also found positive correlations between body size and age within each sex in O. margaretae, but only for female in O. grahami. The female-biased sexual size dimorphism of the two species suggested that fecundity selection for larger female size may increase the reproductive output.     

Past climatic fluctuations are associated with morphological differentiation in the cloud forest endemic tree <Emphasis Type="Italic">Ocotea psychotrioides</Emphasis> (Lauraceae)

Pleistocene glacial periods have had a major influence on the geographical patterns of genetic structure of species in tropical montane regions. However, their effect on morphological differentiation among populations of cloud forest plants remains virtually unexplored. Here, we address this question by testing whether geographical patterns of morphological variation in Ocotea psychotrioides can be explained by the intensity of climate change occurring during 130,000 years. For this, we measured vegetative and reproductive traits for 96 individuals from 36 localities registered across the species’ distribution range. Species distribution models and multivariate statistics were used to investigate geographical patterns of morphological variation and test their association with current and past climatic conditions. Leaf size and pubescence in O. psychotrioides showed a latitudinal pattern of clinal variation that does not fit the geographical gradient of increasing leaf size towards lower latitudes observed globally among plants. Instead, the observed clinal variation conforms to a pattern of increasing leaf size towards higher latitudes. However, our analyses showed weak to non-significant association between morphology and current climate. Interestingly, our analyses showed that predicted shifts in the distribution range of O. psychotrioides during the last 130,000 years were accompanied by significant changes in climatic conditions, particularly temperature seasonality and precipitation. Accordingly, climatic instability showed a better fit to the observed patterns of leaf size and pubescence variation than current climate conditions. These results suggest that climatic instability during the Pleistocene glacial periods might play a key role in promoting morphological differentiation among populations of cloud forest plants.     

Geographically Distinct Expression Profile of Host Defense Peptides in the Skin of the Chinese Odorous Frog,Odorrana margaretae

Odorrana margaretae （Anura： Ranidae） is widely distributed in the southern provinces of China. Previously, 72 antimicrobial peptides （AMPs） belonging to 21 families were identified from the skin of O. margaretae, which were captured in the Hunan province. In the present study, five O. margaretae frogs were captured from the Guizhou province and a total of 28 cDNAs encoding 17 host defense peptides （HDPs） belonging to 14 families were cloned from the skin cDNA library of O. margaretae. Among the 17 HDPs, only one （brevinin-1-Omar5） had been characterized. The distinct HDP expression profiles for O. margaretae in the previous and present study may be attributed to the environmental differences between the sampling locations and the genetic divergence among O. margaretae populations. Besides, 11 of the 17 HDPs identified in the present study were novel for ranids. In order to understand their roles in host defense reactions, three HDPs （odorranain-H-OM1, odorranain-M-OM and ranatuerin-2-OM）, which possess low sequence similarity with the known amphibian HDPs, were selected for further chemical synthesis and functional analysis. Odorranain-H-OM1 showed direct antimicrobial activity against bacteria and fungi. Odorranain-M-OM exhibited concentration-dependent anti-oxidant activity. Ranatuerin-2-OM showed lectin-like activity and could strongly hemagglu -tinate human intact erythrocytes with or without the presence of Ca2＋. The diverse activities of HDPs implied that they may play different roles in host defense reactions of O. margaretae.     

Microsatellite analysis of the phylogeography, Pleistocene history and secondary contact hypotheses for the killifish, Fundulus heteroclitus

The mummichog, Fundulus heteroclitus, exhibits extensive latitudinal clinal variation in a number of physiological and biochemical traits, coupled with phylogeographical patterns at mitochondrial and nuclear DNA loci that suggest a complicated history of spatially variable selection and secondary intergradation. This species continues to serve as a model for understanding local and regional adaptation to variable environments. Resolving the influences of historical processes on the distribution of genetic variation within and among extant populations of F. heteroclitus is crucial to a better understanding of how populations evolve in the context of contemporary environments. In this study, we analysed geographical patterns of genetic variation at eight microsatellite loci among 15 populations of F. heteroclitus distributed throughout the North American range of the species from Nova Scotia to Georgia. Genetic variation in Northern populations was lower than in Southern populations and was strongly correlated with latitude throughout the species range. The most common Northern alleles at all eight loci exhibited concordant latitudinal clinal patterns, and the existence of an abrupt transition zone in allele frequencies between Northern and Southern populations was similar to that observed for mitochondrial DNA and allozyme loci. A significant pattern of isolation by distance was observed both within and between northern and southern regions. This pattern was unexpected, particularly for northern populations, given the recent colonization history of post-Pleistocene habitats, and was inconsistent with either a recent northward population expansion or a geographically restricted northern Pleistocene refugium. The data provided no evidence for recent population bottlenecks, and estimates of historical effective population sizes suggest that post-Pleistocene populations have been large throughout the species distribution. These results suggest that F. heteroclitus was broadly distributed throughout most of its current range during the last glacial event and that the abrupt transition in allele frequencies that separate Northern and Southern populations may reflect regional disequilibrium conditions associated with the post-Pleistocene colonization history of habitats in that region.     

Using Age-Based Life History Data to Investigate the Life Cycle and Vulnerability of Octopus cyanea

Octopus cyanea is taken as an unregulated, recreationally fished species from the intertidal reefs of Ningaloo, Western Australia. Yet despite its exploitation and importance in many artisanal fisheries throughout the world, little is known about its life history, ecology and vulnerability. We used stylet increment analysis to age a wild O. cyanea population for the first time and gonad histology to examine their reproductive characteristics. O. cyanea conforms to many cephalopod life history generalisations having rapid, non-asymptotic growth, a short life-span and high levels of mortality. Males were found to mature at much younger ages and sizes than females with reproductive activity concentrated in the spring and summer months. The female dominated sex-ratios in association with female brooding behaviours also suggest that larger conspicuous females may be more prone to capture and suggests that this intertidal octopus population has the potential to be negatively impacted in an unregulated fishery. Size at age and maturity comparisons between our temperate bordering population and lower latitude Tanzanian and Hawaiian populations indicated stark differences in growth rates that correlate with water temperatures. The variability in life history traits between global populations suggests that management of O. cyanea populations should be tailored to each unique set of life history characteristics and that stylet increment analysis may provide the integrity needed to accurately assess this.     

Anthropometric variationin the Yanadi: Population structure and sex differences

Anthropometric variation and sex differences were investigated among the Yanadi tribe, who live in different regions and show differences in population structure variables and form regional breeding populations. In case of within population variation in anthropometric characters, both males and females show greater variation in a few specific characters (e.g., HB, LL) and almost no variation in FB, but least variation in HL and NB in males and in ZB, LB in females and show sex differences. Overall, females showed greater variation in more number of characters than males. In case of between population variation a few traits show clinal trend between male-female comparisons. Each character shows a specific pattern (e.g., HB, ZB, EL, GB) which vary according to the spatial distribution of the regional populations. The curves also indicate least average differences corresponding to within regional homogeneity among males and females (e.g., HB, ECD, EB) and increasing differences with males and females of other regions. A comparison of anthropometric profiles of the five populations show significant sex differences in IY subpopulation. The three mainland subpopulations show wide morphological differentiation with two coastal subpopulations, who also differ in subsistence pattern and geographically isolated. A comparison of anthropometric profiles between males and females across five populations show positive association between P1, HF and P₂ populations, whereas significant negative association with CY and HF. The correllelographs based on the male-female comparisons also indicate greater morphological similarity between sexes in cases of within regional population. They also show clinal changes of either decreasing or increasing trends of morphological variation between populations in association with spatial distribution and population structure differences. The results obtained are in agreement with the expectations from the population structure of the tribe.     

Sex-specific niche partitioning and sexual size dimorphism in Australian pythons (Morelia spilota imbricata)

Sexual dimorphism is usually interpreted in terms of reproductive adaptations, but the degree of sex divergence also may be affected by sex-based niche partitioning. In gape-limited animals like snakes, the degree of sexual dimorphism in body size (SSD) or relative head size can determine the size spectrum of ingestible prey for each sex. Our studies of one mainland and four insular Western Australian populations of carpet pythons ( Morelia spilota ) reveal remarkable geographical variation in SSD, associated with differences in prey resources available to the snakes. In all five populations, females grew larger than males and had larger heads relative to body length. However, the populations differed in mean body sizes and relative head sizes, as well as in the degree of sexual dimorphism in these traits. Adult males and females also diverged strongly in dietary composition: males consumed small prey (lizards, mice and small birds), while females took larger mammals such as possums and wallabies. Geographic differences in the availability of large mammalian prey were linked to differences in mean adult body sizes of females (the larger sex) and thus contributed to sex-based resource partitioning. For example, in one population adult male snakes ate mice and adult females ate wallabies; in another, birds and lizards were important prey types for both sexes. Thus, the high degree of geographical variation among python populations in sexually dimorphic aspects of body size and shape plausibly results from geographical variation in prey availability.  © 2002 The Linnean Society of London, Biological Journal of the Linnean Society , 2002, 77 , 113–125.     

中华菊头蝠头骨形态特征地理差异的研究

中华菊头蝠是由鲁氏菊头蝠华东亚种提升的一个种.本文测量了海南、广东以及川渝地区中华菊头蝠的23项头骨形态测量指标,应用主成分分析、判别分析和单变量分析方法对中华菊头蝠头骨测量值进行数据处理和分析.主成分分析结果表明,3个地域种群的头骨在总体形态上存在显著的差异;判别分析和单变量分析的结果亦与上述结论相符;沿海种群头骨形态的绝大部分指标比川渝种群大.     

Female masculinization and reproductive life history in the western mosquitofish (<Emphasis Type="Italic">Gambusia affinis</Emphasis>)

In this study, we explored the relationship between female masculinization and various morphological and reproductive parameters of male and female western mosquitofish (Gambusia affinis), including body size, anal fin length, testes mass and female fecundity. We detected high levels of female masculinization in the Brazos and Little Brazos Rivers (Falls County, Texas) in March 2008, but not 2009. In both populations, masculinized females were smaller, possessed shorter anal fins, and had significantly lower total fecundity (collective number of eggs and embryos) compared to non-masculinized females. In addition, 2008 non-masculinized females were smaller and less fecund than 2009 non-masculinized females in both populations. Moreover, 2008 males were smaller, had shorter gonopodia, and smaller testes than 2009 males. Our results support the hypothesis that female masculinization can have a strong influence on reproductive life history and population dynamics of livebearing fishes.     

Biogeographic variation in skull morphology across the Kra Isthmus in dusky leaf monkeys

Despite the growing literature on the underlying factors of geographical phenotypic variation, little is known about how and to what extent biogeographic barriers in South‐East Asia have shaped morphological variation in primates. We aimed to investigate the geographical variations in skull morphology in dusky leaf monkeys by decomposing them into clinal (latitudinal), non‐clinal spatial (discrete difference between regions north and south of the Isthmus of Kra), and environment‐related components. We applied geometric morphometrics to measure 53 adult male specimens from 36 localities, covering the regions both north and south of the Isthmus of Kra. A linear model was used to test the effects of region (north vs. south of the Isthmus of Kra), latitude, and environmental factors (temperature and rainfall) on the size and shape of skulls. A part of variation in skull shape differed moderately between the regions in the north and south of the Isthmus of Kra, and this difference cannot be explained by latitudinal and environmental factors. However, for size and the majority of variations in shape, we detected limited contributions of region and the two environmental factors. Shape differentiation that was unexplained by latitudinal and environmental factors suggests that dusky leaf monkeys may have experienced a population division due to habitat constriction around the Isthmus of Kra. However, this divergence probably has been obscured by subsequent gene flow between populations after habitat recovery.     

Morphological and allozyme studies of small terrestrial snails (Opeas sp., Subulina sp. and Huttonella bicolor) collected from Peninsular Malaysia

Shell morphological characters and allozyme electrophoresis were used to study the relationships among six geographical populations of land snails collected from Peninsular Malaysia. Allozyme electrophoresis was used to study the genetic variations to complement the morphological features studied that included shell lengths, numbers of whorls and shell colour. Ten loci coding for six enzymes (MDH, LAP, ALP, PGM, G6PDH and EST) could be reliably scored in samples from the six populations studied. The dendrogram showed two major clusters with one cluster comprising Subulinidae populations from Perak, Selangor, Johor, Terengganu and Pahang while the other cluster included only the Streptaxidae Huttonella bicolor (red) population. The Subulinidae populations were grouped into two subclusters: one subcluster included the Subulina sp. populations from Perak, Selangor an Johor while the other subcluster included the Opeas sp. populations from Terengganu and Pahang. Morphological features can identify the different families and therefore they can complement the allozyme genetic studies on the land snail populations. Like other reports in the literature, our results also underline the importance of a genetic approach in conjunction with a morphological approach, for discriminating land snail species. The present results suggest that small land snails, which were similar in colour but different in sizes, were not of the same family/genus.     

A geometric morphometric approach to the study of ecogeographical and clinal variation in vervet monkeys

Aim To examine and visualize clines in size and shape of Cercopithecus aethiops Linneus, 1758 (Primate, Cercopithecidae) skulls, and to investigate environmental factors which might best explain the observed variation. Location Sub‐Saharan Africa. Methods Eighty‐six three‐dimensional anatomical landmarks were used to describe 306 skulls of adult C. aethiops sampled over its entire distribution. Geometric morphometric methods for the quantitative analysis of form variation were applied. Size and shape variables were computed and regressed onto geographical coordinates and environmental variables (elevation, temperature, rainfall, moisture and Shannon rainfall diversity index) using both linear and curvilinear models. Components (geographical, environmental, spatially structured environmental and residual) of ecogeographical variation in skull form were partitioned using partial regression. A novel approach for summarizing and visualizing nonlinear patterns of clinal variation using surface rendering of three‐dimensional shapes is presented. Results Clinal variation in size and shape was highly significant, and was best described by curvilinear models. There were strong similarities between females and males. The cline in size was especially pronounced, explaining up to about 40% of observed variation, and was mainly longitudinal rather than latitudinal. A major trend of clinal shape variation also occurred from west to east, and corresponded to an expansion of the face relative to the neurocranium in the west. In the east, skulls also tended to be deeper and with narrower zygomatic arches. Geography and the spatially structured environmental component were the major contributors to the explained variance in size in both sexes, but the proportion of variance explained by the latter was smaller in females. In contrast, geography and environment explained similar amounts of variation in shape and their contribution was about twice that of the spatially structured environmental component. About 60–80% of variation in skull form was not explained by any variable in the analysis. The main factors influencing skull size differed in females and males, with rainfall being very influential in males. Both female and male skull shapes were strongly affected by average annual rainfall. Main conclusions A strong spatial and environmental basis to variations in African vervet monkey skull form was evident. However, the observed pattern did not conform to predictions based on Bergmann's rule. Rainfall consistently emerged as an important predictor, which may contribute to intraspecific variation in the size and shape of vervet monkey skulls through its effect on habitat productivity.     

Historical divergence of mechanical isolation agents in the ground beetle Carabus arrowianus as revealed by phylogeographical analyses

In the carabid genus Carabus subgenus Ohomopterus , diverged body size and genital morphology serve as mechanical reproductive barriers. To elucidate the diverging process of body and genital sizes in Carabus arrowianus , which exhibits marked morphological diversity among geographical populations and may represent an early stage of speciation, we analysed a mitochondrial gene sequence for 1051 individuals from 63 populations and male morphology for 359 individuals from 47 populations. Two discrete morphological groups segregated by geographical barriers were distinguished, one of which possessed smaller bodies and shorter genitalia ( S group) than the other ( L group), which exhibited larger bodies and exaggerated genitalia. Genetic divergence between the two groups was significant but not large. Phylogeographical and population genetic analyses indicated that the L group was derived from the S group, and a coalescent simulation revealed that the two groups diverged during the latest middle Pleistocene (0.13 million years ago), with a much larger effective population size in the L group than the S group. Because the body size divergence could not be explained by adaptation to climatic conditions and genital morphology is considered to be subject to sexual selection, we postulated that a population division and colonization in favourable habitats caused by the Pleistocene climatic and geographical change might facilitate natural and sexual selection for enlarged body and genital sizes in the L group.     

The microevolution of the Galápagos marine iguana Amblyrhynchus cristatus assessed by nuclear and mitochondrial genetic analyses

Marine iguanas may have inhabited the Galápagos archipelago and its former, now sunken islands for more than 10 million years (Myr). It is therefore surprising that morphological and immunological data indicate little evolutionary divergence within the genus. We utilized mitochondrial DNA (mtDNA) sequence analyses and nuclear DNA fingerprinting to re-evaluate the level and pattern of genetic differentiation among 22 marine iguana populations from throughout the archipelago. Both genetic marker systems detect a low level of within-genus divergence, but they show contrasting levels of geographical subdivision among the populations. The mitochondrial gene pools of populations from different regions of the archipelago are isolated, and the mtDNA pattern appears to follow the sequence in which the islands were colonized by marine iguanas. Conversely, the nuclear DNA study indicates substantial interpopulational gene exchange, and the geographical distribution of the nuclear markers seems to be determined by isolation by distance among the populations. The natural history of marine iguanas suggests that the contrasting nuclear and mitochondrial DNA patterns result from an asymmetric migration behaviour of the two sexes, with higher (active and passive) interisland dispersal for males than females. Separate genetic analyses for the sexes appear to support this hypophesis. Based on these findings, a scenario is proposed that explains the marine iguanas' low genetic divergence, notwithstanding their long evolutionary history in the Galápagos archipelago.     

Clinal variation in carapace shape in the South American freshwater crab,Aegla uruguayana (Anomura: Aeglidae)

South America has been influenced by different geoclimatic events ever since its separation from Africa. The inland water fauna has evolved in response to the changing landscape. Currently, there are indications of variations in populations, occurring to different degrees that would indicate a clinal pattern in morphology. Among South America's fauna, the freshwater anomuran, Aegla, is an enigmatic group as a result of its endemicity and is composed of only one genus. Of all the species in this family, Aegla uruguayana has the broadest distribution. Its native habitats have been influenced by several marine transgressions during the Miocene–Quaternary Periods; thus, it is likely that their current distribution has been more recent. Its habitat spreads across a number of isolated basins and sub‐basins that display distinct degrees of isolation/connection, making clinal variation patterns in the morphology of this species possible. The present study aimed to evaluate the pattern of carapace shape variation in A. uruguayana and how it relates to the isolation and/or connection of populations from different basins and sub‐basins, allowing the determination of any extant clinal patterns. The specimens studied belong to 25 separate populations, representing all areas in which the species currently exists. A total of 523 crabs were analyzed. We identified 13 landmarks and four semi‐landmarks in the carapace. The aeglids were divided into seven size intervals to avoid an allometry effect. In each size category, shape relationships analyzed by principal component analysis suggest a geographical pattern corresponding to the distribution of the populations studied. An evaluation of covariation between body shape and geographical coordinates reveals a strong pattern and shows that population distribution had a significant effect on species morphology. Additionally, according to covariance analysis, the variation in shape was not associated with the environmental variables studied. We observed a clinal pattern throughout the species distribution, which could be attributed to genetic drift. It is possible that this process is being amplified by the geographical isolation of the basins, differences in environmental characteristics, and low dispersal ability. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 113 , 914–930.     

Intra‐ and inter‐specific variation in size and habitus of two sibling spider species (Araneae: Lycosidae): taxonomic and biogeographic insights from sampling across Europe

Discriminating closely related species can become a taxonomical challenge if a clear morphological diagnosis is lacking. Two subspecies have been recognized in Pardosa agrestis (Westring, 1861); however, their validity is still debated. To resolve this dilemma, quantitative and qualitative traits were measured for 30 females and 30 males per site from ten localities throughout Western Europe (11 measurements on each individual) and compared between subspecies. Mean annual temperature and geographical coordinates from all sites were also included in the statistical models in order to test for variations in size over the distribution range of each subspecies. We found significant differences in body size and size of copulatory organs as well as accurate criteria of discrimination between P. a. agrestis and P. a. purbeckensis F.O.P. Cambridge, 1895, suggesting that these taxa are two valid morphological species, occurring sympatrically. We also showed that temperatures did not directly influence the size of individuals, but that one species had smaller individuals at higher latitudes (following the converse Bergmann's rule), and that both species had larger individuals in centrally sampled populations (fitting to the centre hypothesis). © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 113, 85–96.     

Effect of vertebrate and invertebrate kairomones on the life history of Daphnia magna Straus (Crustacea: Branchiopoda)

The history of selection of Daphnia magna populations living in North African temporary ponds may differ from populations inhabiting permanent ponds. Laboratory experiments were conducted to examine the effect of fish Gambusia holbrooki and invertebrate Notonecta glauca kairomones on the life history traits of the freshwater Cladocera Daphnia magna Straus. With fish kairomones, Daphnia reproduced early and had a significantly smaller size at first reproduction (SFR) and a smaller size of neonates compared to control. In contrast, daphnids reared in water treated with Notonecta glauca had no effect on the age at first reproduction but females were also smaller and produced smaller neonates.     

Provenance variation in morphology and leaflet anatomy of Parkia biglobosa and its relation to drought tolerance

 Measurements of morphological and anatomical characteristics made on 4-month-old seedlings from five provenances of Parkia biglobosa (Jacq.) Benth., grown in a tropical greenhouse under controlled conditions, showed significant differences between the northern provenances, which represented the Sudan savanna zone, and the southern provenances which represented the forest zone of the species distribution. Seedlings of provenances from the savanna zone showed more xerophytic characteristics than those from the forest zone. They were smaller in height, with a greater number of smaller leaflets per pinnae, a lower specific leaflet mass, smaller palisade and guard cells and a lower ratio of palisade:non-palisade tissue. There were also significant differences in the same characteristics, except palisade cell length, between provenances from the easterly and westerly extremes of the species range. Stomatal conductance measured after 2 weeks of droughting also showed that provenances from the savanna zone had higher values, indicating greater physiological activity and reduced stress, compared with provenances from the forest zone. Multivariate discriminant analysis of the morphological and anatomical characteristics showed that 98% of the seedlings were classified correctly with respect to provenance. The squared distances between provenances were closely related to the geographical distances between locations. Yet, not all variation in leaf anatomy could be explained by the difference in climatic conditions from north to south. Also drought tolerance was not always related to morphological and anatomical features. It is possible that clinal variation within the species from east to west may be interacting with climatic differences from north to south. Received: 2 June 1998 / Accepted: 29 June 1998     

Geographical distribution and phenotypic differentiation in populations of Dactylis glomerata L. in Japan

Although the perennial grass Dactylis glomerata L. has established dominant populations in Japan since its introduction in the 1870s, there have been marked reductions in its abundance in southern and northeastern regions. In order to examine the effects of climatic factors on distribution and differentiation of the naturalized populations of D. glomerata, abundance of 26 populations over a distance of 1500 km along a latitudinal gradient was recorded at each site, and life-history traits of each population were measured in a common garden. It was found that the reduction in abundance was related to the mean summer temperature in southern regions and to the lowest temperature before snow cover in northeastern regions. Recent climatic records in Japan show an increase in the mean summer temperature but no apparent changes in the lowest temperature before snow cover. These data suggest that, assuming the recent trend in climatic changes continues, the population abundance will decrease in southern regions and will change little in the northeastern regions. Germination speed, leaf width and reproductive allocations showed clinal variation over a geographical range, and the southern populations had more rapid germination, narrower leaves and lower reproductive allocation than did the northern populations. On the other hand, seed size and germination date showed margin-center differentiation. Marginal populations in both distributional borders had smaller seeds and lower germination rates than did the central populations. This revised version was published online in June 2006 with corrections to the Cover Date.