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Reproductive Traits (reproductive + trait)
Selected AbstractsReproductive traits of stream-dwelling brown trout Salmo trutta in contrasting neighbouring rivers of central SpainFRESHWATER BIOLOGY, Issue 8 2002G. G. NICOLA 1.,Reproductive traits were studied in seven wild populations of resident brown trout in Spain. We examined whether growth, and certain environmental conditions such as water temperature or food abundance, could explain interpopulation variation in the reproductive characters. 2.,The results indicated that nearby populations subjected to a wide variation in environmental conditions exhibited a similar reproductive performance. 3.,Age distributions and sex ratios were not significantly different among populations. Age ranged from 0+ to 4+ years but the populations were dominated by the 0+ to 2+ groups. In all rivers females matured at age 2+ as opposed to age 1+ and 2+ for males. Mean length at the end of the growth period differed significantly among populations. However, annual growth rate was similar among rivers and was not significantly correlated with either biomass of the benthos or water temperature during the growth season. 4.,Reproductive effort, body condition, fecundity and egg size did not correlate significantly with either the abundance of benthic invertebrates or water temperature. Once the effect of body length on both egg size and number was removed, a significant negative correlation was found between these two traits among populations. [source] Reaction norms of life history traits in response to zinc in Thlaspi caerulescens from metalliferous and nonmetalliferous sitesNEW PHYTOLOGIST, Issue 1 2007Caroline Dechamps Summary ,,We examined phenotypic plasticity of fitness components in response to zinc (Zn) in the Zn hyperaccumulator, Thlaspi caerulescens. ,,Two populations from Zn-enriched soils (M) and two populations from normal soils (NM) were grown in pots at three Zn concentrations (0, 1000 and 8000 mg kg,1 Zn), for an entire life cycle. Growth, Zn accumulation and fitness components were assessed. ,,Based on vegetative growth, M and NM populations had similar Zn tolerance at 1000 mg kg,1 Zn. However, reproductive output was markedly decreased in NM at 1000 and 8000 mg kg,1 Zn. In M populations, Zn did not affect fitness. However, low Zn status enhanced reproductive output in year 1 compared with year 2 and decreased survival after the first flowering season. ,,M populations are able to achieve equal fitness across a broad range of Zn concentrations in soil by different combinations of fecundity and longevity. No cost of higher tolerance was demonstrated in M populations. Reproductive traits appeared to be a more sensitive indicator of tolerance than vegetative growth. [source] Reproductive traits following a parent,child separation trauma during childhood: A natural experiment during World War IIAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 3 2008Anu-Katriina Pesonen Given the ethical limitations of exposing children to experimentally manipulated adverse experiences, evidence of the effects of childhood traumas on subsequent life history are based mostly on women's retrospective reports and animal studies. Only a few prospective studies have assessed the life-long consequences of childhood trauma. We asked whether a traumatic separation from both parents during childhood is associated with reproductive and marital traits later in life, measured by age of onset of menarche, timing of menopause, period of fertile years, age at first childbirth, birth spacing, number of children, and history of divorce. We studied members of the 1934,1944 Helsinki Birth Cohort, including 396 former war evacuees from varying socioeconomic backgrounds, who were sent unaccompanied by their parents to temporary foster families in Sweden and Denmark, and 503 participants who had no separation experiences. Data on separation experiences, number of children, and divorces experienced came from national registers, and the remaining data from a survey among the participants aged 61.6 years (SD = 2.9). Former evacuees had earlier menarche, earlier first childbirth (men), more children by late adulthood (women), and shorter interbirth intervals (men), than the non-separated. A traumatic experience in childhood is associated with significant alterations in reproductive and marital traits, which characterize both women and men. The implications are relevant to the 9.2 million child refugees living throughout the world today. Am. J. Hum. Biol., 2008. © 2008 Wiley-Liss, Inc. [source] Estimates of heritability for reproductive traits in captive rhesus macaque femalesAMERICAN JOURNAL OF PRIMATOLOGY, Issue 9 2010Christine Gagliardi Abstract Records from a colony of captive Indian rhesus macaques (Macaca mulatta) were used to estimate heritability for a number of reproductive traits. Records were based on a total of 7,816 births by 1,901 females from 1979 to 2007. Heritability was estimated with a linear animal model using a multiple trait derivative free REML set of programs. Because no male parents were identified, the numerator relationship matrix contained female kinships established over six generations. Reproductive traits included female age at the birth of the first, second and last infant, age at death, inter-birth intervals, number of infants born per female and infant survival. Heritability for each trait was estimated as the ratio of the additive genetic variance to phenotypic variance adjusted for significant fixed effects. Estimates of heritability for early reproduction ranged from 0.000±0.072 for birth interval after the first reproduction to 0.171±0.062 for age of female at the first infant. Higher estimates of heritability were found for female longevity [0.325±0.143] and for productivity of deceased females born before 1991 [0.221±0.138]. Heritability for infant survival ranged from 0.061±0.018 for survival from 30 days to 1 year to 0.290±0.050 for survival from birth to 30 days when adjusted to an underlying normal distribution. Eight of the 13 estimates of heritability for reproductive traits in this study were different from zero [P<0.05]. Generally, heritability estimates reported in this study for reproductive traits of captive rhesus macaque females are similar to those reported in the literature for free-ranging rhesus macaque females and for similar reproductive traits of other species. These estimates of heritability for reproductive traits appear to be among the first for a relatively large colony of captive rhesus macaque females. Am. J. Primatol. 72:811,819, 2010. © 2010 Wiley-Liss, Inc. [source] Phytogenic resources of halophytes of Central Asia and their role for rehabilitation of sandy desert degraded rangelandsLAND DEGRADATION AND DEVELOPMENT, Issue 4 2009K. N. Toderich Abstract Based on soil characteristics, watertable level, mineral composition of plant biomass, morphological/reproductive traits and carbon discrimination values, a new concept for the classification of halophytes was developed. Six main groups of halophytes have been described within the desert flora of Central Asia. Significant changes on chemical contents of ions: Cl,, SO, HCO, Na+, K+, Ca2+ and Mg2+among 23 studied halophytic forage species were revealed. Alhagi pseudoalhagi, Poaceae spp., Artemisia diffusa containing minimum concentration of mineral ions were categorised as relatively more palatable and valuable feed for livestock on open grazing and as hay. Fresh biomass of forage species growing under highly saline soils sharply decreased with increasing of salinity gradient. Potassium concentration was found highest in Kochia scoparia, Agropyron desertorum, closely followed by Atriplex nitens, Suaeda salsa, while annuals Salsola spp., Bromus tectorum, Aeluropus littoralis, Tamarix hispida, Eremopyrum orientale, Agropyron desertorum contain low amount of mineral ions because excess of salts are exuded through salt glands present abundantly on the surface of the epidermis. Native and exotic, both C3 and C4, halophytes are suitable for reclamation of degraded lands have been proven very useful in demonstration trials. The fresh biomass of investigated C3 plants sharply decreased with the increasing of soil salinity gradient. An integrated Biosaline Agriculture model for sustainable and integrated use of marginal mineralised water resources and salt-affected soils through involvement of food,feed salt/drought tolerant crops and forage legumes to improve food security, alleviate poverty and enhance ecosystem health in smallholder crop,livestock systems has been demonstrated. Copyright © 2009 John Wiley & Sons, Ltd. [source] Selection for birth date in North Sea haddock and its relation to maternal ageJOURNAL OF ANIMAL ECOLOGY, Issue 2 2005PETER J. WRIGHT Summary 1Birth date can be important to lifetime reproductive success. However, selection for birth date has rarely been addressed in fish, despite the opportunity provided by otolith microstructure. 2This study examined the relationship between maternal age, spawning time and early survivorship in the North Sea haddock stock. Temporal changes in egg production were compared with the birth date distribution of progeny surviving to the demersal phase in 1994, 1996 and 1999, when the age structure of the spawning stock differed. 3Estimates of intra-annual variation in stock egg production indicated that first-time spawning 2-year-olds began spawning much later than older age-classes. 4The form and magnitude of selection on birth date varied between years, indicating that the production of multiple batches of eggs over an extended period has some adaptive significance to progeny survival. 5Survivorship was consistently poor from the late spawning period when age 2 females contributed most to stock egg production. This persistent selection against late hatched offspring could reflect either low parental investment, as age 2 females produce smaller eggs, or the short length of the growing season prior to settlement. 6Variability in birth date selection, particularly with respect to first vs. subsequent years of spawning, implies a strong selection pressure for a long reproductive lifespan. As such, reproductive potential in this and other exploited fish species with a similar reproductive trait may have been affected adversely by the general decline in repeat spawning females in recent years. [source] PLASTICITY IN REPRODUCTIVE PHENOTYPES REVEALS STATUS-SPECIFIC CORRELATIONS BETWEEN BEHAVIORAL, MORPHOLOGICAL, AND PHYSIOLOGICAL SEXUAL TRAITSEVOLUTION, Issue 5 2008Charlie K. Cornwallis Reproductive success is determined by a complex interplay between multiple sexual traits that promote mate acquisition and, following copulation, provide control over paternity. The intensity of sexual competition that individuals experience often fluctuates, and here we investigate how this influences the expression of reproductive traits and their relationships. We show in the fowl, Gallus gallus, that males of different social status, which experience different intensities of sexual competition, before and after copulation, have different reproductive phenotypes. Dominant males are more vigilant, feed less, and have larger sexual ornaments than subordinate males. Experimentally manipulating social status revealed that these differences were phenotypically plastic, indicating multiple sexual traits were dependent on the social environment. We integrated these data with previous published findings on changes in sperm numbers and velocity to show that relationships between traits were different for males when they were dominant and when they were subordinate. Furthermore, when males switched status a complex array of negative and positive correlations between the degree traits changed was observed. Our results suggest that variation in the intensity of sexual competition generates reversible plasticity in reproductive phenotypes and that relationships between sexual traits may be variable and influence the evolution of reproductive strategies. [source] EJACULATE DEPLETION PATTERNS EVOLVE IN RESPONSE TO EXPERIMENTAL MANIPULATION OF SEX RATIO IN DROSOPHILA MELANOGASTEREVOLUTION, Issue 8 2007Jon R. Linklater We assessed the extent to which traits related to ejaculate investment have evolved in lines of Drosophila melanogaster that had an evolutionary history of maintenance at biased sex ratios. Measures of ejaculate investment were made in males that had been maintained at male-biased (MB) and female-biased (FB) adult sex ratios, in which levels of sperm competition were high and low, respectively. Theory predicts that when the risk of sperm competition is high and mating opportunities are rare (as they are for males in the MB populations), males should increase investment in their few matings. We therefore predicted that males from the MB lines would (1) exhibit increased investment in their first mating opportunities and (2) deplete their ejaculates at a faster rate when mating multiply, in comparison to FB males. To investigate these predictions we measured the single mating productivity of males from three replicates each of MB and FB lines mated to five wild-type virgin females in succession. In contrast to the first prediction, there was no evidence for differences in productivity between MB and FB line males in their first matings. The second prediction was upheld: mates of MB and FB males suffered increasingly reduced productivity with successive matings, but the decline was significantly more pronounced for MB than for FB males. There was a significant reduction in the size of the accessory glands and testes of males from the MB and FB regimes after five successive matings. However, the accessory glands, but not testes, of MB males became depleted at a significantly faster rate than those of FB males. The results show that male reproductive traits evolved in response to the level of sperm competition and suggest that the ability to maintain fertility over successive matings is associated with the rate of ejaculate, and particularly accessory gland, depletion. [source] POSTMATING SEXUAL SELECTION: ALLOPATRIC EVOLUTION OF SPERM COMPETITION MECHANISMS AND GENITAL MORPHOLOGY IN CALOPTERYGID DAMSELFLIES (INSECTA: ODONATA)EVOLUTION, Issue 2 2004A. Cordero Rivera Abstract Postmating sexual selection theory predicts that in allopatry reproductive traits diverge rapidly and that the resulting differentiation in these traits may lead to restrictions to gene flow between populations and, eventually, reproductive isolation. In this paper we explore the potential for this premise in a group of damselflies of the family Calopterygidae, in which postmating sexual mechanisms are especially well understood. Particularly, we tested if in allopatric populations the sperm competition mechanisms and genitalic traits involved in these mechanisms have indeed diverged as sexual selection theory predicts. We did so in two different steps. First, we compared the sperm competition mechanisms of two allopatric populations of Calopteryx haemorrhoidalis (one Italian population studied here and one Spanish population previously studied). Our results indicate that in both populations males are able to displace spermathecal sperm, but the mechanism used for sperm removal between both populations is strikingly different. In the Spanish population males seem to empty the spermathecae by stimulating females, whereas in the Italian population males physically remove sperm from the spermathecae. Both populations also exhibit differences in genital morphometry that explain the use of different mechanisms: the male lateral processes are narrower than the spermathecal ducts in the Italian population, which is the reverse in the Spanish population. The estimated degree of phenotypic differentiation between these populations based on the genitalic traits involved in sperm removal was much greater than the differentiation based on a set of other seven morphological variables, suggesting that strong directional postmating sexual selection is indeed the main evolutionary force behind the reproductive differentiation between the studied populations. In a second step, we examined if a similar pattern in genital morphometry emerge in allopatric populations of this and other three species of the same family (Calopteryx splendens, C. virgo and Hetaerina cruentata). Our results suggest that there is geographic variation in the sperm competition mechanisms in all four studied species. Furthermore, genitalic morphology was significantly divergent between populations within species even when different populations were using the same copulatory mechanism. These results can be explained by probable local coadaptation processes that have given rise to an ability or inability to reach and displace spermathecal sperm in different populations. This set of results provides the first direct evidence of intraspecific evolution of genitalic traits shaped by postmating sexual selection. [source] Hormone response to bidirectional selection on social behaviorEVOLUTION AND DEVELOPMENT, Issue 5 2010Gro V. Amdam SUMMARY Behavior is a quantitative trait determined by multiple genes. Some of these genes may have effects from early development and onward by influencing hormonal systems that are active during different life-stages leading to complex associations, or suites, of traits. Honey bees (Apis mellifera) have been used extensively in experiments on the genetic and hormonal control of complex social behavior, but the relationships between their early developmental processes and adult behavioral variation are not well understood. Bidirectional selective breeding on social food-storage behavior produced two honey bee strains, each with several sublines, that differ in an associated suite of anatomical, physiological, and behavioral traits found in unselected wild type bees. Using these genotypes, we document strain-specific changes during larval, pupal, and early adult life-stages for the central insect hormones juvenile hormone (JH) and ecdysteroids. Strain differences correlate with variation in female reproductive anatomy (ovary size), which can be influenced by JH during development, and with secretion rates of ecdysteroid from the ovaries of adults. Ovary size was previously assigned to the suite of traits of honey bee food-storage behavior. Our findings support that bidirectional selection on honey bee social behavior acted on pleiotropic gene networks. These networks may bias a bee's adult phenotype by endocrine effects on early developmental processes that regulate variation in reproductive traits. [source] Biological and ecological traits of benthic freshwater macroinvertebrates: relationships and definition of groups with similar traitsFRESHWATER BIOLOGY, Issue 2 2000Philippe Usseglio-Polatera Summary 1Relating species traits to habitat characteristics can provide important insights into the structure and functioning of stream communities. However, trade-offs among species traits make it difficult to predict accurately the functional diversity of freshwater communities. Many authors have pointed to the value of working with groups of organisms as similar as possible in terms of relationships among traits and have called for definition of groups of organisms with similar suites of attributes. 2We used multivariate analyses to examine separately the relationships among 11 biological traits and among 11 ecological traits of 472 benthic macroinvertebrate taxa (mainly genera). The main objective was to demonstrate (1) potential trade-offs among traits; (2) the importance of the different traits to separate systematic units or functional groupings; and (3) uniform functional groups of taxa that should allow a more effective use of macroinvertebrate biological and ecological traits. 3We defined eight groups and 15 subgroups according to a biological trait ordination which highlighted size (large to small), reproductive traits (K to r strategists), food (animal to plant material) and feeding habits (predator to scraper and/or deposit feeder) as ,significant' factors determining the ordination of taxa. This ordination partly preserved phylogenetic relationships among groups. 4Seven ecological groups and 13 ecological subgroups included organisms with combinations of traits which should be successively more adequate in habitats from the main channel to temporary waters, and from the crenon to the potamic sections of rivers, and to systems situated outside the river floodplain. These gradients corresponded to a gradual shift from (1) rheophilic organisms that lived in the main channel of cold oligotrophic mountain streams to (2) animals that preferred eutrophic habitats of still or temporary waters in lowlands. The groups with similar ecological traits had a more diverse systematic structure than those with similar biological traits. 5Monitoring and assessment tools for the management of water resources are generally more effective if they are based on a clear understanding of the mechanisms that lead to the presence or absence of species groups in the environment. We believe that groups with similar relationships among their species traits may be useful in developing tools that measure the functional diversity of communities. [source] Co-evolution of male and female reproductive traits across the Bruchidae (Coleoptera)FUNCTIONAL ECOLOGY, Issue 5 2008P. F. Rugman-Jones Summary 1Despite the obvious importance of spermatozoa to individual reproductive success a general explanation of variation in spermatozoan form and function is still lacking. In species with internal fertilization, sperm not only have to interact with the physical and biochemical environment of the female reproductive tract, but frequently face competition from the sperm of rival males. Both sperm competition theory and adaptation to the selective environment of the female reproductive tract have been implicated in the evolution of spermatozoan morphological diversity. 2Using the comparative method, we examine variation in sperm length in relation to (i) sperm competition intensity (as measured by relative testis size) and (ii) female reproductive characters, across 15 species of beetle belonging to the family Bruchidae. 3Stepwise multiple regression within a phylogenetic framework revealed sperm length to be positively correlated with female spermathecal duct length and negatively related to spermathecal volume, but not testes size, indicating that the female reproductive environment rather than sperm competition per se exerts selection on sperm length in this taxonomic group. 4A positive association between testes volume and the volume of the female spermatheca was also evident suggesting correlated evolution of these traits. 5A number of models of sexual selection could lead to the correlated evolution of male and female reproductive characters, although the underlying mechanisms of cause and effect remain elusive. Divergence between species (and populations) in primary reproductive traits is likely to present a significant barrier to hetero-specific fertilization, and thus contribute to reproductive isolation. [source] Effects of defoliation on male and female reproductive traits of a perennial orchid, Dactylorhiza maculataFUNCTIONAL ECOLOGY, Issue 6 2000Vallius E. Abstract 1The effects of defoliation on male reproductive traits of plants have received little attention. We conducted two field experiments with Dactylorhiza maculata (L.) Soó to examine the effects of defoliation on both male and female reproductive traits. We removed 0, 50 or 100% of leaves prior to flowering. The quality of pollen was tested by transferring pollen from the differently treated plants to untreated plants of the same population. 2The non-defoliated plants did not differ from the defoliated plants in mass of pollinia. No differences were found in the weight of seed capsules or in the proportion of embryonic seeds raised by flowers receiving pollen from differently treated pollen donors. 3The non-defoliated and partially defoliated plants produced relatively more and heavier capsules than the completely defoliated plants. 4Defoliation decreased leaf area, corm mass and the probability of flowering in the following year. 5These results demonstrate that defoliation has no acute effects on male traits in the long-living perennial orchid D. maculata. In this respect, D. maculata differs from the two other polycarpic species studied so far. Availability of resources appeared to be insufficient to prevent negative effects of defoliation on the later-occurring and more costly female functions. [source] Reproductive strategies of Gammarus lacustris (Crustacea: Amphipoda) along an elevation gradientFUNCTIONAL ECOLOGY, Issue 4 2000Wilhelm F. M. Abstract 1.,The number of eggs, their size, mass and development time, and the starvation time of newly hatched young, was examined in four populations of Gammarus lacustris along an elevation gradient from prairie to alpine lakes (730 m to > 2300 m above sea level). Water temperature and ice-free season decreased with increasing altitude. 2.,Females in the alpine lake produced fewer but larger and heavier eggs than females in the prairie lake. Eggs produced by females in montane and subalpine lakes were intermediate in size, mass and number. Within populations, egg size was not related to the number of eggs or female size. 3.,The development time of eggs declined with an increase in incubation temperature. At all incubation temperatures, large eggs had a longer incubation time than small eggs. All eggs incubated at 4 °C failed to produce young. Young from large eggs were larger in size than young from small eggs. 4.,The starvation time of newly hatched young increased with decreasing temperature. However, slopes of regressions relating starvation time to temperature differed among populations. At 4 °C young from large eggs survived longer than young from small eggs. 5.,The high phenotypic plasticity in reproductive traits contributes to the success of G. lacustris in a wide range of aquatic habitats. It is predicted that in response to climate-induced warming, populations in currently cold montane and alpine lakes would shift their reproduction to produce more eggs of smaller size. However, the accurate prediction of the fate of populations between ecoregions will require knowledge of the extent to which these traits are under genetic control. [source] Unravelling the effects of temperature, latitude and local environment on the reproduction of forest herbsGLOBAL ECOLOGY, Issue 6 2009P. De Frenne ABSTRACT Aim, To investigate the effect of temperature, latitude and local environment on the reproductive traits of widespread perennial forest herbs to better understand the potential impacts of rising temperatures on their population dynamics and colonization capacities. Location, Six regions along a latitudinal gradient from France to Sweden. Methods, Within each region, we collected data from three to five populations of up to six species. For each species, several variables were recorded in each region (temperature, latitude) and population (local abiotic and biotic environmental variables), and seed production and germination were estimated. Resource investment in reproduction (RIR) was quantified as seed number × seed mass, while germinable seed output (GSO) was expressed as seed number × germination percentage. We performed linear regression and mixed effect models to investigate the effects of temperature (growing degree hours), latitude and local abiotic and biotic environment on RIR and GSO. Results, Temperature and latitude explained most of the variation in RIR and GSO for early flowering species with a northerly distribution range edge (Anemone nemorosa, Paris quadrifolia and Oxalis acetosella). Reproduction of the more southerly distributed species (Brachypodium sylvaticum, Circaea lutetiana and Primula elatior), in contrast, was independent of temperature/latitude. In the late summer species, B. sylvaticum and C. lutetiana, variation in RIR and GSO was best explained by local environmental variables, while none of the investigated variables appeared to be related to reproduction in P. elatior. Main conclusions, We showed that reproduction of only two early flowering, northerly distributed species was related to temperature. This suggests that the potential reproductive response of forest herbs to climate warming partly depends on their phenology and distribution, but also that the response is to some extent species dependent. These findings should be taken into account when predictions about future shifts in distribution range are made. [source] Fish community comparisons along environmental gradients in lakes of France and north-east USAGLOBAL ECOLOGY, Issue 3 2007Pascal Irz ABSTRACT Aim, To assess whether eight traits of fish communities (species richness, three reproductive traits and four trophic traits) respond similarly to environmental gradients, and consequently display convergence between the lakes of France and north-east USA (NEUSA). Location, 75 French and 168 north-east USA lakes. Methods, The data encompass fish surveys, the assignment of species into reproductive and trophic guilds, and environmental variables characterizing the lakes and their catchments. The analytical procedure was adapted from the recommendations of Schluter (1986) [Ecology, 67, 1073,1085]. Results, The comparison of the regional pools of lacustrine fishes indicated that NEUSA was about twice as speciose as France, mostly due to higher species turnover across lakes, although NEUSA lakes were consistently about 20% more speciose than French lakes for a given surface area. Warmer environments were consistently inhabited by a higher proportion of phytophilous and guarder species than were colder lakes. Hence there was convergence in community reproductive traits. Conversely, there was no evidence of convergence in the trophic structure of lacustrine fish communities between regions. Main conclusions, The influence of temperature on the availability and quality of spawning substrates appears to be a major constraint on present-day lacustrine fish communities. In parallel, phylogenetic constraints, past events such as the diversification of the North American fish fauna, and selective extinctions during Pleistocene glaciations and subsequent recolonizations contribute to explaining the dissimilarities between the communities of the two regions and differences in their relationship to the environment. [source] The genetic diversity of perennial Leymus chinensis originating from ChinaGRASS & FORAGE SCIENCE, Issue 1 2007Z. P. Liu Summary Leymus chinensis is an economically and ecologically important grass that is widely distributed across eastern areas of the Eurasian steppe. A better knowledge of genetic diversity of L. chinensis could be valuable in the efficient utilization, conservation and management of germplasm collections. Genetic diversity in thirty-seven morphological characters of 293 accessions was assessed in three successive years. Based on these qualitative and quantitative characters, the genetic diversity indices (Shannon indices) of traits and geographical populations were estimated, and a principal coordinates analysis and a path analysis were undertaken. Compared with the yellow-green type of L. chinensis, the grey-green type had significantly (P < 0·05) more genetic diversity. In addition, the path analysis suggested that the combined effects of genetic diversity and vegetative traits could explain 0·206 of the total variance in plant reproductive traits. The highest Shannon genetic diversity index of accessions (H = 2·252) was observed in accessions from the region of longitude of 124,128°E, suggesting the most abundant germplasm of L. chinensis in this region. [source] Linking behavior, life history and food supply with the population dynamics of white-footed mice (Peromyscus leucopus)INTEGRATIVE ZOOLOGY (ELECTRONIC), Issue 3 2007Stephen H. VESSEY Abstract In this paper we review and integrate key aspects of behavioral and life history traits, food supply and population dynamics of the white-footed mouse (Peromyscus leucopus), a species that is abundant and widely distributed across much of eastern North America. Results are based largely on a 33-year mark-and-recapture study in a forest fragment in northwest Ohio, USA. Behavioral plasticity in such reproductive traits as mating system and parental care allows this species to adjust quickly to changing environments. The species has a relatively "fast" life history, with rapid attainment of sexual maturity and high fecundity in the face of high mortality rates. Maximal reproductive effort early in life enables a rapid population response. Food supply, in the form of mast, determines the size of the reproducing population in early spring, which, in turn, influences the size of the late summer peak population. The peak population size is also affected by short-term weather events possibly acting via the food supply. The effects of weather and food on population growth are in part mediated through competition, including defense of space and suppression of reproduction. The inelasticity of female territories appears to set an upper limit to population density. [source] Estimation of genetic parameters of type traits in Asturiana de los Valles beef cattle breedJOURNAL OF ANIMAL BREEDING AND GENETICS, Issue 2 2002J. P. GUTIÉRREZ Ten type traits and a final score were analysed in 5868 records of the Asturiana de los Valles beef cattle breed. Traits were grouped into two classes: (i) traits scoring skeletal and muscular development and (ii) traits scoring adjustment to the breed standard. Heritabilities were moderate to low, ranging from 0.04 to 0.26. Genetic correlations among traits were, in general, in the same direction as, but higher than, phenotypic correlations. The genetic variability shown, in general, for the analysed traits would justify the inclusion of morphological assessment in the Asturiana de los Valles beef cattle breed sire selection programme. Main characteristics of the current type classification system are criticized. The knowledge of (co)variances among type and economically important productive and reproductive traits is recommended before revision of the classification methodology. Schätzung genetischer Parameter für Exterieurmerkmale in der Asturiana de los Valles Fleischrinderrasse 5868 registrierte Asturiana de los Valles Tiere wurden bezüglich 10 Exterieurmerkmalen und eines Gesamtwertes auf der Basis einer gewichteten Berücksichtigung dieser Einzelmerkmale untersucht. Die Merkmale wurden in zwei Klassen unterteilt: (i) Merkmale, die Skelett- und Muskelentwicklung betreffen und (ii) rassespezifische Merkmale. Die Heritabilitäten lagen zwischen 0,04 und 0,26. Genetische Korrelationen zwischen den Merkmalen waren allgemein mit den phänotypischen Korrelationen gleichgerichtet, aber mit höheren Werten. Die aufgezeigte genetische Variabilität der untersuchten Merkmale würde deren Eingliederung in die morphologische Bewertung im Rahmen des Asturiana de los Valles Fleischrinder Selektionsprogrammes für Bullen rechtfertigen. Wichtige Charakteristika der gegenwärtigen Exterieurbeurteilung werden kritisiert. Es wird empfohlen erst (Ko-)varianzen zwischen Exterieur und ökonomisch wichtigen Produktions- und Reproduktionsmerkmalen zu ermitteln, bevor die Bewertungsmethodik überarbeitet wird. [source] Age-related change in breeding performance in early life is associated with an increase in competence in the migratory barn swallow Hirundo rusticaJOURNAL OF ANIMAL ECOLOGY, Issue 5 2007JAVIER BALBONTÍN Summary 1We investigated age-related changes in two reproductive traits (laying date and annual fecundity) in barn swallows Hirundo rustica L. using a mixed model approach to di-stinguish among between- and within-individual changes in breeding performance with age. 2We tested predictions of age-related improvements of competence (i.e. constraint hypothesis) and age-related progressive disappearance of poor-quality breeders (i.e. selection hypothesis) to explain age-related increase in breeding performance in early life. 3Reproductive success increased in early life, reaching a plateau at middle age (e.g. at 3 years of age) and decreasing at older age (> 4 years). Age-related changes in breeding success were due mainly to an effect of female age. 4Age of both female and male affected timing of reproduction. Final linear mixed effect models (LME) for laying date included main and quadratic terms for female and male age, suggesting a deterioration in reproductive performance at older age for both males and females. 5We found evidence supporting the constraints hypothesis that increases in competence within individuals, with ageing being the most probable cause of the observed increase in breeding performance with age in early life. Two mechanisms were implicated: (1) advance in male arrival date with age provided middle-aged males with better access to mates. Yearling males arrived later to the breeding grounds and therefore had limited access to high-quality mates. (2) Breeding pairs maintaining bonds for 2 consecutive years (experienced pairs) had higher fecundity than newly formed inexperienced breeding pairs. 6There was no support for the selection hypothesis because breeding performance was not correlated with life span. 7We found a within-individual deterioration in breeding and migratory performance (arrival date) in the oldest age-classes consistent with senescence in these reproductive and migratory traits. [source] Interactive effects of environmental stress and inbreeding on reproductive traits in a wild bird populationJOURNAL OF ANIMAL ECOLOGY, Issue 6 2006A. B. MARR Summary 1Conservation biologists are concerned about the interactive effects of environmental stress and inbreeding because such interactions could affect the dynamics and extinction risk of small and isolated populations, but few studies have tested for these interactions in nature. 2We used data from the long-term population study of song sparrows Melospiza melodia on Mandarte Island to examine the joint effects of inbreeding and environmental stress on four fitness traits that are known to be affected by the inbreeding level of adult birds: hatching success, laying date, male mating success and fledgling survival. 3We found that inbreeding depression interacted with environmental stress to reduce hatching success in the nests of inbred females during periods of rain. 4For laying date, we found equivocal support for an interaction between parental inbreeding and environmental stress. In this case, however, inbred females experienced less inbreeding depression in more stressful, cooler years. 5For two other traits, we found no evidence that the strength of inbreeding depression varied with environmental stress. First, mated males fathered fewer nests per season if inbred or if the ratio of males to females in the population was high, but inbreeding depression did not depend on sex ratio. Second, fledglings survived poorly during rainy periods and if their father was inbred, but the effects of paternal inbreeding and rain did not interact. 6Thus, even for a single species, interactions between the inbreeding level and environmental stress may not occur in all traits affected by inbreeding depression, and interactions that do occur will not always act synergistically to further decrease fitness. [source] Phenotypic plasticity in a maternal trait in red deerJOURNAL OF ANIMAL ECOLOGY, Issue 2 2005DANIEL H. NUSSEY Summary 1Phenotypic plasticity and microevolution represent the two processes by which phenotypic traits in a population can track environmental change. While there is a growing literature documenting microevolution in reproductive traits in naturally occurring animal populations, few studies to date have examined either between-individual variation in levels of plasticity or how selection acts on plasticity. 2We present here mixed-effect linear models analysing changes in calving date in relation to autumn rainfall observed over a 30-year study of 2147 red deer on the Isle of Rum, Scotland. The study period is characterized by a phase of low and rising population density (up to and including 1980), followed by a phase of high and fluctuating population density (1981 to present). 3Variation within individual females explained a population-level trend of delayed calving dates following years of high autumn rainfall. There was significant variation between females both in their average calving dates and in their individual plastic responses of calving date to autumn rainfall. 4Females born in the low population density phase were, on average, phenotypically plastic for the calving date,autumn rainfall relationship, and showed significant variation in plasticity. Selection favoured individuals with early average calving dates among these females. 5Among females born at high population density, there was on average no significant plasticity for calving date, but variation in plastic responses was still present. Selection favoured females with increasingly positive plastic responses of calving date to autumn rainfall. 6We argue that early experience of high population density affects the physiological condition of females, making an environmental response (calving early following dry autumns) in later life physiologically untenable for all but a few high quality individuals. These same few individuals also tend to be fitter and have higher reproductive success. [source] Effect of indoor energy restriction level and management on beef production in Belgian Blue double-muscled cow-calf pairsJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 6 2009L. O. Fiems Summary One hundred and twenty-six cows were involved to investigate the impact of energy (E) restriction (100%, 90%, 80% and 70% of total energy requirements) during the indoor period and two calf management systems (CMS: suckling or rearing). An E restriction during the indoor period resulted in a loss of body weight, even for E100, which was compensated during the re-alimentation period, but body weight remained lower in suckling than in non-suckling cows. The cows yielded 213 full-term gestations and 8 abortions. Abortion was not affected by E (p = 0.187) or CMS (p = 0.804). Calving interval was neither affected by E (p = 0.775) but tended to be longer in suckled cows (p = 0.087). E reduced body weight and body condition score (BCS) at the end of the calving interval, while CMS only affected BCS. E70 resulted in a higher colostrum yield than E100 and E 90 but immunoglobulin content was not affected (p = 0.759). Cow culling was not affected by E or CMS. It increased from 12.9% to 22.2% and 32.5% for cows with a BCS at parturition lower than 1.5 or between 1.5 and 2.0, or higher than 2 respectively. Calf birth weight was neither affected by E or CMS, but there was an interaction between E and dam age (p = 0.050). Increasing the E restriction tended to reduce calf survival (p = 0.089). Performance of the surviving calves was not affected by E, but suckling calves gained faster than rearing calves (p < 0.001). Beef production by the cow-calf pair was not different between energy levels (p = 0.738), but it was 10.8% lower for E70 than for E100 cows. It is not appropriate to apply an E restriction of more than 10,20% for maximum cow reproductive traits and calf performance. [source] Intrapopulation variation in reproduction by female eastern kingbirds Tyrannus tyrannus: the impacts of age, individual performance, and breeding siteJOURNAL OF AVIAN BIOLOGY, Issue 3 2004Michael T. Murphy I used data from a 13-year study of eastern kingbirds Tyrannus tyrannus from central New York, USA, to evaluate the relative impact of female age and body size on reproduction. I also calculated repeatabilities of reproductive traits for both females and the sites where they bred in an attempt to evaluate the relative contribution of each to intrapopulation variation in reproduction. Female age had a strong influence on timing of breeding (breeding date advanced by one day for each year of life), but was not a significant source of variation for clutch size, egg mass, number of young to hatch or fledge, or total seasonal production. Repeatabilities of breeding date for females and sites were both significant (0.284 and 0.181, respectively), but the only other significant repeatabilities were for female clutch size (0.282) and female egg mass (0.746). Among-year repeatabilities of breeding date for females who bred at two or more sites over their lifetime were as high as those for females that were site faithful. Thus, breeding date was probably affected independently by the female and site. No measure of productivity exhibited a repeatable pattern in comparisons made among females or sites. All reproductive traits were entered as dependent variables in a series of stepwise multiple regression analyses in an attempt to identify female properties (size, lifespan and condition) that might be linked proximately to differences in breeding statistics. I found that (a) large birds tended to breed the earliest, (b) clutch size was independent of female size, condition and lifespan, (c) female body size and egg size were correlated positively, but (d) production of young was independent of all measured female properties. Reproduction appears to be linked more closely to the female than to the site. Body size accounts for a portion of the repeatable portion of breeding date and egg mass, but most of the intrapopulation variation in these and other traits remained unexplained. [source] The Human Ageing Genomic Resources: online databases and tools for biogerontologistsAGING CELL, Issue 1 2009João Pedro De Magalhães Summary Aging is a complex, challenging phenomenon that requires multiple, interdisciplinary approaches to unravel its puzzles. To assist basic research on aging, we developed the Human Ageing Genomic Resources (HAGR). This work provides an overview of the databases and tools in HAGR and describes how the gerontology research community can employ them. Several recent changes and improvements to HAGR are also presented. The two centrepieces in HAGR are GenAge and AnAge. GenAge is a gene database featuring genes associated with aging and longevity in model organisms, a curated database of genes potentially associated with human aging, and a list of genes tested for their association with human longevity. A myriad of biological data and information is included for hundreds of genes, making GenAge a reference for research that reflects our current understanding of the genetic basis of aging. GenAge can also serve as a platform for the systems biology of aging, and tools for the visualization of protein,protein interactions are also included. AnAge is a database of aging in animals, featuring over 4000 species, primarily assembled as a resource for comparative and evolutionary studies of aging. Longevity records, developmental and reproductive traits, taxonomic information, basic metabolic characteristics, and key observations related to aging are included in AnAge. Software is also available to aid researchers in the form of Perl modules to automate numerous tasks and as an SPSS script to analyse demographic mortality data. The HAGR are available online at http://genomics.senescence.info. [source] What does the male function hypothesis claim?JOURNAL OF EVOLUTIONARY BIOLOGY, Issue 5 2000Burd Paternal, rather than maternal, fitness consequences of reproductive traits are the lynchpin in many hypotheses about reproductive evolution in hermaphroditic angiosperms. These hypotheses often differ in their predictions, so that supporting or contradictory evidence for one hypothesis may not reflect similarly on another, even though both may be referred to as ,the male function hypothesis'. We provide graphical representations of four male function hypotheses from the recent literature in order to highlight their differences. We offer and explain two recommendations to reduce ambiguity in terminology: (1) male function hypotheses should address the evolution of excess flowers per se, rather than total flower number, which is usually highly plastic in modular organisms with open growth form; and (2) attention must be given to whole plant fitness, rather than fitness per flower or per inflorescence. In empirical studies, we recommend the use of path analysis to dissect the multiple pathways (through both male and female function) by which selection may act on excess flower number. [source] Plant traits as predictors of woody species dominance in climax forest communitiesJOURNAL OF VEGETATION SCIENCE, Issue 3 2001Fumito Koike Satake et al. (1989) Abstract. The dominance of a given tree or shrub species in a particular forest community may be determined by many ecological traits of the target species, as well as those of the surrounding species as its potential competitors. The present study was conducted to evaluate the possibility of predicting community status (species composition and dominance) on the basis of traits of local flora using statistical methods, and to visualize the mathematical function which determines species dominance. A general linear model and logistic regression were used for the statistical analysis. Dependent variables were designated as dominance and presence/absence of species in climax forest, with independent variables as vegetative and reproductive traits. Subalpine, cool-temperate, warm-temperate and subtropical climax rain forests in East Asia were studied. Quantitative prediction of climax community status could readily be made based on easily measured traits of local flora. Species composition and 74.6% of the total variance of species dominance were predicted based on two traits; maximum height and shade tolerance. Through application of this method, the capacity of an alien species to invade a climax forest community could possibly be predicted prior to introduction of the alien species. [source] How stupid not to have thought of that: post-copulatory sexual selectionJOURNAL OF ZOOLOGY, Issue 2 2010T. R. Birkhead Abstract Science progresses through ideas or hypotheses; novel ways of viewing the world. If those ideas survive testing, then they are considered ,the truth', or more crucially, truth-for-now, for the essence of science is that if a new idea provides a better explanation of the way the world is, the truth changes. Darwin's idea of evolution by natural selection, published as the Origin in 1859, replaced the earlier truth of physico- or natural-theology introduced by John Ray in 1691. Despite resistance by the church, Darwin's truth gained widespread acceptance, in part due to the efforts of T. H. Huxley, who on reading the Origin said ,How extremely stupid not to have thought of that!' Despite natural selection's enormous explanatory power, there were certain phenomena it apparently could not explain, including female promiscuity. It was only in the 1960s when natural selection was viewed as operating explicitly on individuals (rather than populations or groups), that this changed. Rather than being a cooperative venture between the sexes, sexual reproduction was now viewed in terms of conflicts of interests, and in so doing provided an explanation for female promiscuity (albeit in a male-biased sort of way). Until this point, sexual selection had been concerned exclusively with mate acquisition. With an evolutionary perspective focussing on individuals, it was recognized that sexual selection might continue after insemination, and that rather than competing for partners, males compete for fertilizations. Later it was acknowledged that females, through cryptic processes can also influence the outcome of sperm competition. Today, post-copulatory sexual selection provides explanations for many previously bewildering reproductive traits, including the extraordinary diversity in male and female genitalia, the design of spermatozoa and ova, of seminal fluid and of copulation behaviour itself [source] Host specificity, phenotype matching and the evolution of reproductive isolation in a coevolved plant,pollinator mutualismMOLECULAR ECOLOGY, Issue 24 2009ANNA G. HIMLER Coevolutionary interactions between plants and their associated pollinators and seed dispersers are thought to have promoted the diversification of flowering plants (Raven 1977; Regal 1977; Stebbins 1981). The actual mechanisms by which pollinators could drive species diversification in plants are not fully understood. However, it is thought that pollinator host specialization can influence the evolution of reproductive isolation among plant populations because the pollinator's choice of host is what determines patterns of gene flow in its host plant, and host choice may also have important consequences on pollinator and host fitness (Grant 1949; Bawa 1992). In this issue of Molecular Ecology, Smith et al. (2009) present a very interesting study that addresses how host specialization affects pollinator fitness and patterns of gene flow in a plant host. Several aspects of this study match elements of a seminal mathematical model of plant,pollinator codivergence (Kiester et al. 1984) suggesting that reciprocal selection for matched plant and pollinator reproductive traits may lead to speciation in the host and its pollinator when there is strong host specialization and a pattern of geographic subdivision. Smith et al.'s study represents an important step to fill the gap in our understanding of how reciprocal selection may lead to speciation in coevolved plant,pollinator mutualisms. [source] TIMP-1 as candidate gene for embryo survival in two divergent lines selected for uterine capacity in rabbits,MOLECULAR REPRODUCTION & DEVELOPMENT, Issue 6 2006Jordi Estellé Abstract Selection on uterine capacity has been used in animal breeding as a way to improve the litter size. A divergent selection experiment for uterine capacity was performed in rabbits during ten generations. After the first generations of selection, large differences in number of implanted embryos were obtained between high and low lines. The major part of the differences between lines was due to embryo survival. A segregation analysis suggested the presence of a major gene affecting the reproductive traits. The objective of this work was to test the TIMP-1 gene as a candidate gene for embryo survival in rabbits since it stands up as a target for the investigation of reproductive problems in humans. We have analyzed the parental generation of a F2 cross which consists of 8 and 14 animals from the high and low uterine capacity lines, respectively. The rabbit TIMP-1 gene structure and sequence has been determined, including the proximal promoter region. Despite of the absence of polymorphism between lines in the screened regions (CDS, proximal promoter, exon 1, intron 1, and exon 2), a real-time RT-PCR quantification of the TIMP-1 mRNA in oviduct has shown significant differences between high and low lines at 62 hr of gestation, just when rabbit embryos are located in the oviduct, postulating TIMP-1 as an interesting candidate gene to be involved in the phenotypic differences between the two rabbit lines. Mol. Reprod. Dev. © 2006 Wiley-Liss, Inc. [source] | ||||||||||||||||||||||||||||||||||