Genomic evidence of divergence-with-gene-flow in the pink shrimp Farfantepenaeus brasiliensis.

Linking intraspecific variation in plant traits to ecosystem carbon uptake may allow us to better predict how shift in populations shape ecosystem function. We investigated whether plant populations of a dominant old-field plant species (Solidago altissima) differed in carbon dynamics and if variation in plant traits among genotypes and between populations predicted carbon dynamics. We established a common garden experiment with 35 genotypes from three populations of S. altissima from either Tennessee (southern populations) or Connecticut (northern populations) to ask whether: (1) southern and northern Solidago populations will differ in aboveground productivity, leaf area, flowering time and duration, and whole ecosystem carbon uptake, (2) intraspecific trait variation (growth and reproduction) will be related to intraspecific variation in gross ecosystem CO2 exchange (GEE) and net ecosystem CO2 exchange (NEE) within and between northern and southern populations. GEE and NEE were 4.8× and 2× greater in southern relative to northern populations. Moreover, southern populations produced 13× more aboveground biomass and 1.4× more inflorescence mass than did northern populations. Flowering dynamics (first- and last-day flowering and flowering duration) varied significantly among genotypes in both the southern and northern populations, but plant performance and ecosystem function did not. Both productivity and inflorescence mass predicted NEE and GEE between S. altissima southern and northern populations. Taken together, our data demonstrate that variation between S. altissima populations in performance and flowering traits are strong predictors of ecosystem function in a dominant old-field species and suggest that populations of the same species might differ substantially in their response to environmental perturbations.

Geographic variation in diapause induction and termination of the cotton bollworm, Helicoverpa armigera Hübner (Lepidoptera: Noctuidae)

PDF HTML阅读 XML下载 导出引用 引用提醒 皱纹盘鲍南北方群体的高温应激和生长差异 DOI: 作者: 作者单位: 1. 中国水产科学研究院 南海水产研究所, 农业部南海渔业资源开发利用重点实验室, 广东 广州 510300;2. 天津农学院 水产科学系, 天津 300384 作者简介: 姚托(1984-),男,博士,助理研究员,主要从事贝类遗传育种方面研究.E-mail:yao-tuo@163.com 通讯作者: 中图分类号: S94 基金项目: 现代农业产业技术体系建设专项资金项目（CARS-48）；广东省海洋渔业科技推广专项（A201301F04）；中央级公益性科研院所基本科研业务费专项资金项目（2014TS29）. Differences in high temperature stress and growth between southern and northern populations of Haliotis discus hannai Author: Affiliation: 1. Key Laboratory of South China Sea Fishery Resources Exploitation & Utilization, Ministry of Agriculture;South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, China;2. Department of Fishery Science, Tianjin Agricultural University, Tianjin 300384, China Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为研究皱纹盘鲍（ Ino）经过杂交和南方养殖后，南方群体（杂交群体）是否与北方群体（自交群体）在适温性上是否产生了差异，从而是否更加适应南方高温环境，本研究开展了皱纹盘鲍南北方群体的高温应激和南方地区养殖实验。高温应激实验中：经过30℃应激后，南方群体恢复期所有取样组织中HSP70在0 h的表达量都显著高于北方群体（<0.05），HSP90在外套膜和肝胰脏中的表达量也高于北方群体（鳃中的表达量略低但差异不显著）；经过33℃应激后，南方群体HSP70和HSP90在足、外套膜和鳃0 h表达量都显著高于北方群体（<0.05）。养殖实验中：从12月开始至翌年2月水温不超过17.11℃，为北方群体的快速生长期，生长快于南方群体；从3月开始，水温逐渐超过20℃，北方群体生长慢于南方群体，同时北方群体开始出现死亡现象，7月北方群体大量死亡，存活数量不足30粒。综合HSP70、HSP90的高温应激表达和养殖实验结果，可以得出：皱纹盘鲍经过杂交和南方累代养殖后，适温上限有所提高，已与北方群体产生较大差异，可适应较高的水温；30℃水温刺激下南北方群体的HSP70的相对表达量与对高温的耐受性具有正相关性，可以在鲍的抗高温选育种中进行辅助筛选。 Abstract:Hybrid abalone () have been cultured in southern China for many years. Two experiments were performed (high temperature stress and culture in a southern sea area) to study whether a southern population (hybrid population) of Pacific abalone has different high temperature tolerance and is more adapted to that environment than a northern population (inbred population). After a 30℃ stress or in the high temperature stress experiment, relative expression of heat shock protein (HSP) 70 in the southern population at 0h of the recovery phase was significantly higher in the foot, mantle, gill, and hepatopancreas than those in the northern population (<0.05). At the same time, relative expression of HSP90 in the southern population was significantly higher in the mantle and hepatopancreas than that in the northern population. The relative expression levels of HSP70 and HSP90 in the southern population after the 33℃ stressor were significantly higher in the foot, mantle, and hepatopancreas at 0 h in the recovery phase than those in the northern population (<0.05). In another experiment, the most rapid growth period in the northern population occurred from December to February;abalone in the northern population grew faster than those in the southern population and water temperature was no higher than 17.11℃ at this time. Water temperature eventually exceeded 20℃ in March, when the northern population grew slower than the southern population and mortality increased. Less than 30 abalone in the northern population remained in July. Taken together, we conclude that because hybrid abalone have been cultured for many generations in southern China, they became better adapted to higher water temperature. The relative expression levels of HSP70 in the two populations were positively correlated with heat resistance after the 30℃ stressor. These data could be useful for assisted selection in an abalone high temperature resistance breeding program. 参考文献 相似文献 引证文献

Seasonal change in mitochondrial function and metabolic enzyme activity of different populations of the mud crab, Scylla paramamosain, from China

Aim A bioclimatic analysis of the giant burrowing frog was conducted to determine if the northern and southern populations have distinct climatic profiles and to determine if the disjunction in the species records is a result of a climatically unsuitable area.Location The study utilized records throughout the species range in south‐eastern Australia.Methods The bioclim package was used to examine the climatic envelope of the species, as well as envelopes for the southern and northern populations. Principal components analysis (PCA) was used in an attempt to refine the model.Results The package predicted the observed gap between the populations as climatically suitable in all of the models. The northern populations were found in warmer and wetter sites than the southern populations. River valleys and coastal lowlands were generally unsuitable climatically for the species.Main conclusions The area of the observed disjunction is climatically suitable for both the northern and southern populations. Large river valleys appear to have played a significant role in determining the distribution of the species. PCA was used successfully to alter the model, however further research is needed to determine which is the most accurate approach.

The adaptive value of correlations among phenotypic traits depends on the prevailing environmental conditions. Differences in selection pressures during species range expansions may therefore shape phenotypic integration. In this study, we assessed variation in behavioral and morphological traits, as well as their covariations, in replicated southern and northern European populations of the northward expanding dragonfly Crocothemis erythraea. Larvae from northern populations were, on average, darker in color, and therefore, better camouflaged than larvae from southern populations. However, there was no difference in activity level. Darkness and activity were positively correlated in larvae from northern populations, whereas this trait covariation was missing in southern populations. This suggests theemergence of alternative strategies in time-limited northern populations, a higher activity level that required better camouflage through darker coloration, while less active larvae benefited from an energy-saving strategy by reducing the investment in costly traits, such as body darkness. We further found that larger larvae emerged into larger adults, with a higher investment in flight morphology. Our findings imply that phenotypic integration is associated with the northward range shift, potentially differentially shaping fitness consequences, and ecological interactions in southern versus northern populations.

Age structures and spatial distribution patterns of Quercus variabilis populations were analyzed across geographical gradients (latitude, longitude and altitude) by using the size-grading method and the ratio of variance to mean. The results showed as following: Over the horizontal gradient, the northern, middle, southern and western populations of Q. variabilis exhibited an inverse-J shape, but the eastern populations declined. The spatial patterns of adult individuals were all clumped except the northern populations which were randomly distributed. Juveniles were clumped in the northern, middle and western populations, but were randomly distributed in the southern and eastern populations. The aggregation intensity of juveniles across latitude decreased with the order as the central, northern and southern populations, but as the central, southern and northern populations for adult individuals. The aggregation intensity of both juveniles and adults across longitude followed a decreased order as the central, western and eastern populations. Along the altitudinal gra-dient, the inverse-J type occurred only in the low- and middle-altitude populations, but populations in the high altitude declined. The juveniles in populations among altitude gradient all were clumped, but the adults were all clumped except the low-altitude populations which were randomly distributed. The aggregation intensities of both juveniles and adults were higher in the middle than the other altitudinal populations. Compared with adults, juveniles generally had higher aggregation intensities across various geographical gradients. Our results revealed that the age structure and spatial distribution pattern of Q. variabilis were mainly determined by environment variation across geographical gradients and the species' biological property, which supported the central-marginal hypothesis.

AimMany studies have investigated the phylogeographic history of species on the Baja California Peninsula, and they often show one or more genetic breaks that are spatially concordant among many taxa. These phylogeographic breaks are commonly attributed to vicariance as a result of geological or climatic changes, followed by secondary contact when barriers are no longer present. We use restriction‐site associated DNA sequence data and a phylogeographic model selection approach to explicitly test the secondary contact hypothesis in the red diamond rattlesnake, Crotalus ruber.LocationBaja California and Southern California.MethodsWe used phylogenetic and population clustering approaches to identify population structure. We then used coalescent methods to simultaneously estimate population parameters and test the fit of phylogeographic models to the data. We used ecological niche models to infer suitable habitat for C. ruber at the Last Glacial Maximum (LGM).ResultsCrotalus ruber is composed of distinct northern and southern populations with a boundary near the town of Loreto in Baja California Sur. A model of isolation followed by secondary contact provides the best fit to the data, with both divergence and contact occurring in the Pleistocene. We also identify a genomic signature of northern range expansion in the northern population, consistent with LGM niche models showing that the northern‐most portion of the range of C. ruber was not suitable habitat during the LGM.Main conclusionsWe provide the first explicitly model‐based test of the secondary contact model in Baja California and show that populations of C. ruber were isolated before coming back into contact near Loreto, a region that shows phylogeographic breaks for other taxa. Given the timing of divergence and contact, we suggest that climatic fluctuations have driven the observed phylogeographic structure observed in C. ruber and that they may have driven similar patterns in other taxa.

The general phylogeographical paradigm for eastern North America (ENA) is that many plant and animal species retreated into southern refugia during the last glacial period, then expanded northward after the last glacial maximum (LGM). However, some taxa of the Gulf and Atlantic Coastal Plain (GACP) demonstrate complex yet recurrent distributional patterns that cannot be explained by this model. For example, eight co-occurring endemic plant taxa with ranges from New York to South Carolina exhibit a large disjunction separating northern and southern populations by >300 km. Pyxidanthera (Diapensiaceae), a plant genus that exhibits this pattern, consists of two taxa recognized as either species or varieties. We investigated the taxonomy and phylogeography of Pyxidanthera using morphological data, cpDNA sequences, and amplified fragment length polymorphism markers. Morphological characters thought to be important in distinguishing Pyxidanthera barbulata and P. brevifolia demonstrate substantial overlap with no clear discontinuities. Genetic differentiation is minimal and diversity estimates for northern and southern populations of Pxyidanthera are similar, with no decrease in rare alleles in northern populations. In addition, the northern populations harbour several unique cpDNA haplotypes. Pyxidanthera appears to consist of one morphologically variable species that persisted in or near its present range at least through the latter Pleistocene, while the vicariance of the northern and southern populations may be comparatively recent. This work demonstrates that the refugial paradigm is not always appropriate and GACP endemic plants, in particular, may exhibit phylogeographical patterns qualitatively different from those of other ENA plant species.

Mating in plants is usually mediated by animals, yet few studies have determined whether the mating system of plant populations changes in response to variation in the taxonomic composition or to the foraging behavior of animal pollinators. Here, I investigate covariation between striking geographic variation in pollinator fauna and the mating system of a widespread self‐compatible wetland plant, Decodon verticillatus. Flower visitor surveys in two northern populations from Canada and three southern populations from the southeastern United States revealed that flowers in northern populations were visited primarily by bumblebees (30%), nonnative honeybees (39%), and small, apparently ineffective, pollinators including wasps, flies, and solitary bees (31%). In contrast, southern populations were visited by butterflies (27%), large native bees (Bombus and Xylocopa; 65%), and only rarely by honeybees (2%). The frequency of visits to inflorescences was also much higher in southern ($$\mathrm{mean}\,=3.3/ \mathrm{h}\,$$ ) than in northern populations (1.1/h). The foraging behavior of butterflies may enhance outcrossing by reducing geitonogamy, the predominant mode of self‐fertilization in northern populations. Compared to bees, butterflies moved between inflorescences more frequently (64% vs. 43% of the time) and flew longer distances between inflorescences ($$\mathrm{medians}\,=50$$ vs. 25 cm). Despite large regional differences in visitor composition and movement patterns, multilocus estimates of the proportion of outcrossed progeny did not differ between five southern populations ($$\mathrm{mean}\,\pm \mathrm{SE}\,=0.75\pm 0.04$$ ; $$\mathrm{range}\,=0.65$$ –0.87) and 10 northern populations ($$0.72\pm 0.02$$ ; 0.62–0.86). Similarly, the fixation index of mature plants did not differ from 0 in either northern or southern populations. These results indicate that variation in the pollinator fauna, including major geographic shifts in the frequency of butterflies versus bees and native versus nonnative pollinators, does not greatly affect the mating system of D. verticillatus.

Sitobion avenae (F.) is a cosmopolitan cereal pest, but geographic barriers like the Qinling Mountains in the Shaanxi Province of China may lead to isolation among its populations, thus causing allopatric speciation. We sampled S. avenae populations from areas north (mean annual temperature, ≍9°C) and south (mean annual temperature, ≍14°C) of the Qinling Mountains, and tested them at 20°C in common garden experiments. The results showed that northern populations had reduced developmental time for first-instar nymphs but prolonged for third- and fourth-instar nymphs compared with southern populations. The postreproductive time and total lifespan of adults from southern populations were longer than those from northern populations, but no significant differences were found in reproductive time or age at first reproduction. Southern populations showed higher lifetime and daily fecundities than northern ones. Significant differences were found in correlation of life-history traits between northern and southern populations. Principal component analyses (PCAs) of S. avenae's vital life-history traits showed separation of populations from three southern locations, indicating their local adaptation. The clustering patterns generated by PCA also showed divergence between northern and southern populations. Alatae of S. avenae seemed to be able to disperse across the Qinling Mountains, which was indicated by the clustering together of some individuals from one side of the mountains with those from the other side. The impacts of the Qinling Mountains on the divergence and gene flow among S. avenae populations, as well as the potential of allopatric speciation for this species, are discussed.

We sampled yellowtail snapper, Ocyurus chrysurus, from commercial and recreational fisheries and fishery-independent surveys in the Atlantic Ocean off south Florida from 1980 through 2002. Specimens were collected primarily from two areas: Palm Beach and Monroe counties; collections were divided at 26° latitude into northern and southern populations. We collected sagittal otoliths and corresponding morphometric data from each population. Fork lengths (FL) ranged from 115 to 605 mm with a mean length of 312 mm. Yellowtail snapper were aged using sagittal otoliths with a high degree of precision [average percent error (APE) <1%]. Ages ranged from 1 to 17 years, with mean ages of 3.96 years for the commercial fishery, 3.33 years for the recreational fishery, and 3.00 years for fishery-independent surveys. Yellowtail snapper entered the commercial and recreational fisheries by age 2; both fisheries were dominated by 2 and 3 year olds. The commercial fishery indicated the influence of a strong 1994 year class; this was not apparent in the recreational and fishery-independent surveys possibly due to small sample size. The von Bertalanffy growth curve parameters for all years and fishing modes combined [Lt = 410(1 - e-0.27(t+2.03))] were similar to previously published estimates for yellowtail snapper. The instantaneous total mortality rate of yellowtail snapper for all years and fishing modes combined (Z = 0.49) was also similar to previously published estimates. The total mortality rate for the northern population, Z = 0.67, was greater than for the southern population, Z = 0.45. Weight-length relationships were significantly different between northern and southern populations (P < 0.001), and yellowtail snapper from the southern population were significantly larger and older than those from the northern population (P < 0.001). Size-at-age was significantly larger for the most common ages (1--4 years) in the northern population compared to the southern population (age 1, P = 0.002; age 2--4, P < 0.001 ). This may be due in part to differential fishing pressure; additional site-specific sampling is needed to elucidate the demographic differences between populations.

Down the east coast of North America, populations of Atlantic killifish, Fundulus heteroclitus, experience wildly different thermal environments. Southern populations experience water that is, on average, 12°C hotter than northern populations annually. These northern and southern killifish populations cope with stress differently. When fish are stressed, such as when predators are nearby, they activate a suite of mechanisms that regulate the release of the stress hormone cortisol, allowing the fish to remain in good condition. Researchers found previously that killifish from southern populations had higher plasma cortisol levels than killifish from northern populations after they experienced the same stress. To figure out why some fish respond strongly to stress while others do not, Madison Earhart and co-workers from the University of British Columbia, Canada, with colleagues from the University of Manitoba, Canada, and the University of Glasgow, UK, set out to determine what genes are responsible for the differences in killifish stress responses by investigating different mechanisms that trigger cortisol release after experiencing stress.Earhart and colleagues travelled to the USA and collected adult killifish from northern New Hampshire and southern Georgia populations. Then, they brought the fish back to the lab in British Columbia. First, the team wanted to see whether the differences in population stress response changed when the fish experienced stress briefly or were exposed to the same stress repeatedly over the period of a week by either putting the fish in buckets and shaking them for half an hour or repeatedly shaking them every day for a week. After stressing the fish, the team collected samples of the fish's blood to measure their cortisol plasma levels, in addition to collecting samples of the fish's brain, head kidney – the organ that produces cortisol – and liver – the organ that produces and breaks down glucose – to measure the expression of genes important for the production and release of cortisol due to stress.After experiencing the single stressful situation, the southern killifish population had higher cortisol levels than the northern killifish population. However, when the fish were repeatedly stressed over the period of a week, there was no difference in cortisol levels between the northern and southern populations. The southern population of killifish, which had a stronger response to the individual stressful situation, expressed more of the genes involved in cortisol production in the brain and head kidney. In addition, the livers of fish from the southern population were more responsive to the cortisol stress hormone as they expressed larger amounts of the gene for the protein that triggers the protective mechanisms that are activated by cortisol when a fish is stressed.The team also measured the condition of the fish after repeated stress. They found that the southern killifish, which were more stress responsive than the northern killifish, were in better condition after experiencing repeated stress than were northern populations. This showed that responding to stress by increasing cortisol was beneficial for the southern population of fish.Earhart and colleagues noted that the answer as to why some fish respond more strongly to stress than others is more complex than simply increasing cortisol levels in the body. They showed that there are differences in the expression of genes all along the pathways that make cortisol, respond to cortisol and cease cortisol production in these two different populations of fish. Therefore, it is important to continue to study these differences in populations of the same species adapted to different environments.

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 429:291-301 (2011) - DOI: https://doi.org/10.3354/meps09126 Exploiting the closest productive area: geographical segregation of foraging grounds in a critically endangered seabird M. Louzao1,2,*, J. Navarro3, M. G. Forero4, J. M. Igual1, M. Genovart1, K. A. Hobson5, D. Oro1 1Institut Mediterrani d’Estudis Avançats IMEDEA (CSIC-UIB), Miquel Marquès 21, 07190 Esporles, Mallorca, Spain. 2Helmholtz Centre for Environmental Research-UFZ, Permoserstraße 15, 04318 Leipzig, Germany 3Institut de Ciències del Mar (CSIC), Passeig Marítim de la Barceloneta 37–49, 08003 Barcelona, Spain 4Departamento de Biología de la Conservacíon, Estación Biológica de Doñana (CSIC), Apartado 1056, 41013 Sevilla, Spain 5Environment Canada, 11 Innovation Blvd., Saskatoon, Saskatchewan S7N 3H5, Canada *Email: maite.louzao@ufz.de ABSTRACT: While breeding, seabirds are limited to exploiting resources within a restricted area around their breeding site and should exploit the closest productive marine areas within their distribution range. We investigated this hypothesis in one of the most endangered European seabirds, the Balearic shearwater Puffinus mauretanicus (ca. 3200 breeding pairs), restricted to the Balearic Islands. Our aims were (1) to assess whether isotopic evidence (i.e. stable isotopes of δ13C and δ15N) of foraging habitat partitioning occurs among northern, central and southern populations, (2) to geographically locate population-specific potential foraging grounds along the Iberian continental shelf, and (3) to assess whether oceanographic conditions could explain observed patterns of stable isotopes (SI). SI values showed a latitudinal gradient, with birds from the northern population having lower δ15N and δ13C values than central and southern populations. Potential foraging grounds of northern, central and southern populations were centred in Cape Creus, Ebro Delta and Cape La Nao, respectively, results which were supported by habitat models. Oceanographic conditions in each potential foraging ground were different; the northern population used richer, colder and deeper waters compared to the central and southern populations. Chlorophyll a was the main oceanographic variable that explained variation in SI values. We hypothesised that SI differences among Balearic shearwater populations might be a consequence of differences in baseline isotopic values among potential foraging grounds rather than real differences in diet. Our comprehensive study also provides important information for management strategies to conserve this critically endangered shearwater. KEY WORDS: Balearic shearwater · Geographical foraging ground segregation · Habitat modelling · Mediterranean Sea · Oceanography · Puffinus mauretanicus · Stable isotopes Full text in pdf format Supplementary material PreviousCite this article as: Louzao M, Navarro J, Forero MG, Igual JM, Genovart M, Hobson KA, Oro D (2011) Exploiting the closest productive area: geographical segregation of foraging grounds in a critically endangered seabird. Mar Ecol Prog Ser 429:291-301. https://doi.org/10.3354/meps09126Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 429. Online publication date: May 16, 2011 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2011 Inter-Research.

In Africa, there are two well-known subspecies of the desert locust; the Sahara subspecies, Schistocerca gregaria gregaria (Forskål, 1775), and the southern African subspecies, Schistocerca gregaria flaviventris (Burmeister). The northern locust, S. g. gregaria, extends across the Sahara desert to western Asia. The invasion area of the southern subspecies, S. g. flaviventris, extends to Namibia, Angola, South Africa, Ascension Islands and Botswana. Four different locust populations were selected, three populations for the northern S. g. gregaria (f, e, r) from different localities and one population for the southern S. g. flaviventris (s). Three characters were selected, the length of the forewing (E), the length of the posterior femur (F), and the widest part of the head capsule (C). Two ratios (E/F, F/C) were also calculated and compared for the different populations. The univariate analysis technique using the ANOVA test was performed for the four locust populations. The means of the different measured characters and the two ratios indicated significant differences between the southern population and the other three northern populations. The mean values of E, F, C, and E/F ratio were lower for the southern population compared to the three northern populations. Multivariate analysis of variance indicated that the four locust populations were highly significantly different (P < 0.0001). Standardised canonical coefficients for the three characters and the two ratios were given. The Mahalanobis distance (D2) between the centroids of the different populations for the three measured characters and the two ratios were significantly different (P < 0.0001). The distances recorded between the southern and the three northern populations were higher than the distances between the three northern populations. The results indicated that the southern males and females are more morphologically closer to each other than to either sex of the northern locusts. Also, the two sexes of the northern populations are more or less similar in their morphological features than the southern locust population. We may suggest that the southern population may categorise an evolutionary dichotomy that has arisen on the African continent and may separate the two locust populations into two distinct species.