A test of the Acoustic Adaptation Hypothesis in three types of tropical forest: degradation of male and female Rufous-and-white Wren songs

Many animals produce complex vocalizations that show pronounced variation between populations. The Acoustic Adaptation Hypothesis helps to explain this variation, suggesting that acoustic signals are optimized for transmission through different environments. Little is known about the transmission properties of female vocalizations because most studies of the Acoustic Adaptation Hypothesis have focused on male vocalizations of organisms living at temperate latitudes. We explored the relationship between environmental variation and the transmission properties of songs of Rufous-and-white Wrens, resident Neotropical songbirds where both sexes sing. Using playback, we broadcast and re-recorded elements of male and female songs from three populations of wrens living in three different forest habitats in Costa Rica. We measured four variables of the re-recorded sounds: signal-to-noise ratio, excess attenuation, tail-to-signal ratio and blur ratio. Our results show a significant difference between transmission characteristics of both male and female song elements across the three habitats, indicating that sounds transmit differently through different types of tropical forest. The population from which the broadcast sounds were recorded (source population) had little effect on sound transmission, however, suggesting that acoustic differences between these populations may not arise through acoustic adaptation to these habitats. Male and female elements showed similar transmission properties overall, although signal-to-noise ratio of male elements was influenced by source population, whereas blur ratio and excess attenuation of female elements were influenced by source population. Our study highlights the differences in transmission characteristics of animal sounds through different habitats, and reveals some sex differences in transmission properties.     

Normal sex differences in prenatal growth and abnormal prenatal growth retardation associated with 46,XY disorders of sex development are absent in newborns with congenital adrenal hyperplasia due to 21-hydroxylase deficiency

Background

Congenital adrenal hyperplasia due to 21-hydroxylase deficiency is the most common presentation of a disorder of sex development (DSD) in genetic females. A report of prenatal growth retardation in cases of 46,XY DSD, coupled with observations of below-optimal final height in both males and females with congenital adrenal hyperplasia due to 21-hydroxylase deficiency, prompted us to investigate prenatal growth in the latter group. Additionally, because girls with congenital adrenal hyperplasia are exposed to increased levels of androgens in the absence of a male sex-chromosome complement, the presence or absence of typical sex differences in growth of newborns would support or refute a hormonal explanation for these differences.

Methods

In total, 105 newborns with congenital adrenal hyperplasia were identified in our database. Gestational age (weeks), birth weight (kg), birth length (cm) and parental heights (cm) were obtained. Mid-parental height was considered in the analyses.

Results

Mean birth weight percentile for congenital adrenal hyperplasia was 49.26%, indicating no evidence of a difference in birth weight from the expected standard population median of 50th percentile (P > 0.05). The expected sex difference in favor of heavier males was not seen (P > 0.05). Of the 105 subjects, 44 (27%; 34 females, 10 males) had birth length and gestational age recorded in their medical chart. Mean birth length for this subgroup was 50.90 cm (63rd percentile), which differed from the expected standard population median of 50th percentile (P = 0.0082). The expected sex difference in favor of longer males was also not seen (P > 0.05).

Conclusion

The prenatal growth retardation patterns reported in cases of 46,XY disorders of sex development do not generalize to people with congenital adrenal hyperplasia due to 21-hydroxylase deficiency. Sex differences in body weight and length typically seen in young infants were not seen in the subjects who participated in this study. We speculate that these differences were ameliorated in this study because of increased levels of prenatal androgens experienced by the females infants.     

贵州"过卯"水族的体质人类学研究

本文对贵州三都水族自治县“过卯”水族462人(男238,女224)进行了活体观察和测量。观察项目28个,测量项目64个。调查对象年龄20—55岁,三代均为“过卯”水族。分析结果表明:“过卯”水族属圆头型;男性狭面型,女性中面型;阔鼻型;宽手型,窄肩型,中腿型;男性瘦长体型,女性中间体型;男性亚中等,女性矮型身材。与我国南方其他24个少数民族群体聚类分析,结果显示“过卯”水族体质特征与湖南侗族、白裤瑶、贵州毛南族接近。贵州“过卯”水族属蒙古人种南亚类型,具有现代黄种人的容貌特征。     

Endocardial fibroelastosis in children to one year of age]

Out of 2398 autopsies of newborns and infants performed between 1976 and 1985, thirty two cases of endocardial fibroelastosis were found, i.e. 10.6% of the congenital heart diseases in this age group. Endocardial fibroelastosis was most frequent (44%) in infants aged between 3 and 6 months. Seventeen cases of the disease were seen in male infants and 15 cases in female infants. Twenty cases of the endocardial fibroelastosis (62.5%) were of isolated character (primary) whereas 12 cases (37.5%) were of the secondary character associated with other heart abnormalities. Nine cases (about 28%) coexisted with congenital abnormalities of joint and bone system and respiratory tract. A morphologic analysis of the endocardial fibroelastosis with particular reference to its etiopathogenesis suggest its congenital origin or (and) an effect of infection on myocardium. It was also suggested that endocardial fibroelastosis may be a symptom of collagenic disease. About 70% of autopsied infants were hospitalized over 3 days what meant that the course of the disease was severe. Endocardial fibroelastosis was diagnosed clinically only in 6 cases (18.75%).     

Effective size of fluctuating populations with two sexes and overlapping generations

We derive formulas that can be applied to estimate the effective population size N(e) for organisms with two sexes reproducing once a year and having constant adult mean vital rates independent of age. Temporal fluctuations in population size are generated by demographic and environmental stochasticity. For populations with even sex ratio at birth, no deterministic population growth and identical mean vital rates for both sexes, the key parameter determining N(e) is simply the mean value of the demographic variance for males and females considered separately. In this case Crow and Kimura's generalization of Wright's formula for N(e) with two sexes, in terms of the effective population sizes for each sex, is applicable even for fluctuating populations with different stochasticity in vital rates for males and females. If the mean vital rates are different for the sexes then a simple linear combination of the demographic variances determines N(e), further extending Wright's formula. For long-lived species an expression is derived for N(e) involving the generation times for both sexes. In the general case with nonzero population growth and uneven sex ratio of newborns, we use the model to investigate numerically the effects of different population parameters on N(e). We also estimate the ratio of effective to actual population size in six populations of house sparrows on islands off the coast of northern Norway. This ratio showed large interisland variation because of demographic differences among the populations. Finally, we calculate how N(e) in a growing house sparrow population will change over time.     

Sexual selection and natural selection in body size differentiation of subterranean mole rats

We exlored indirectly, the operation of sexual selection in subterranean mole rats of the Spalax ebrenbergi superspecies in Israel comprising four chromosomal species, 2n = 52, 54, 58 and 60. We reanalzed two previously available data sets of 1. body size differentiation (Nevo et al. 1986a) and 2. the intensity of “Total Aggression” in mole rats (Nevo et al. 1986b). We correlated the mean size difference between the two sexes, in each of the 12 populations of the chromosomal species, with the mean level of agression, and with climatic factors, both displaying significant correlations. The results indicated that for 2n = 52, 54, 58 and 60, the population averae difference in body weight between the sexes decreases southward as follows: 37.7g (30.8 % of females body weight), 39.3g(29.0%) 26.3g(22.8%) and 20.3g (19.3%), respectively. We interpret the higher body size diherential ketween the sexes in the north as due to sexual selection.     

Frequency, dynamics, and structure of congenital malformations in populations under long-term exposure to ionizing radiation]

Information on the dynamics, frequency, and structure of congenital malformations (CMs) and chromosomal diseases in two generations of rural populations from the Semipalatinsk region was obtained for the first time. The tests performed in the Semipalatinsk nuclear test site (STS) for many years were demonstrated to deteriorate the genetic health of the populations of the zones of extreme and maximum radiation risks. Mutagenic and teratogenic effects of long-term ionizing irradiation were detected. These were mainly expressed as an increase in the frequencies of strictly registered CMs (SR CMs), including the Down syndrome, multiple malformations (MMs) and microcephaly (1.45 +/- 0.11, 1.39 +/- 0.01, and 0.77 +/- 0.05 per 1000 births, respectively). SR CMs exhibited linear trends toward higher frequencies in two generations of exposed persons after surface nuclear tests in 1949-1963. Their frequency was strongly correlated with the effective population dose of radiation; the main population genetic parameters (inbreeding coefficient, endogamy index, etc.) had less pronounced effects on Cms.     

Medical genetic study of the population of Turkmenia. III. Hereditary pathology in Turkmen Nokhurlis

Medical-genetic investigations were carried out in isolated population of Nokhurlis inhabiting some villages of Ashkhabad and Krasnovodsk provinces. A high coefficient of inbreeding, high endogamy, and low coefficients of migration were found for this population. Two hereditary disorders are relatively frequent among the Nokhurlis and lacking in neighboring populations. The frequency of the autosomal dominant gene for congenital cataract is 0.26% and that of the autosomal recessive gene for a peculiar form of obesity is 2.47%. In both cases, the main factor affecting gene accumulation appears to be the result of genetical drift effect. The total load of hereditary diseases of higher in Nokhurlis than in other Turkmen populations. The connection between the population structure of Nokhurlis and the accumulation of hereditary disorders is discussed.     

Distortional meiotic segregation of a supernumerary chromosome producing differential frequencies in the sexes in the short-horned grasshopper Phaulacridium vittatum

Samples of males reveal the presence of a large, mitotically stable supernumerary chromosome in five populations examined. A stable frequency (11.22±0.3%) of male carriers has been observed over nine years in one population. The supernumerary follows closely the condensation cycle and behaviour of the sex chromosome in spermatogonial mitosis and meiosis. A structure simulating a terminalized chiasma frequently joins the precocious sex and supernumerary chromosomes during meiotic prophase; these two chromosomes move preferentially (70%) to opposite poles during the subsequent stages producing a differential transmission of the supernumerary to the two sexes. It is possible that the stable frequency in the population is maintained by a conserved balance between the two sexes without the need of an elimination system. The evidence supports the interpretation that the supernumerary chromosome is partially homologous with the sex chromosome. The possibility that the supernumerary might evolve into a neo-Y chromosome is suggested.     

Heritability of dispersal rate and other life history traits in the Glanville fritillary butterfly

Knowing the variances and heritabilities (h(2)) of life history traits in populations living under natural conditions is necessary for a mechanistic understanding of respective evolutionary processes. I estimated heritabilities of several life history traits, including dispersal rate, body mass, age at first reproduction, egg mass, clutch size and lifetime reproductive success, in the Glanville fritillary butterfly (Melitaea cinxia) using parent-offspring regression. Experiments were conducted under field conditions in a large population cage (32 x 26 m). Heritability estimates ranged from zero to almost one and several were significantly different from zero. Body size for both sexes, female age at first reproduction and egg weight were all moderately to highly heritable, whereas heritabilities were low or non-existent in clutch size and lifetime egg production. Heritability estimates for dispersal rate varied between the sexes, so that dispersal was heritable from mother to her female offspring only. This finding is consistent with previous results showing that the F1 female but not male offspring of females that naturally established new populations in the field are significantly more dispersive than butterflies in old populations.     

Age and sex affect quantitative genetic parameters for dominance rank and aggression in free‐living greylag geese

Knowledge of the genetic and environmental influences on a character is pivotal for understanding evolutionary changes in quantitative traits in natural populations. Dominance and aggression are ubiquitous traits that are selectively advantageous in many animal societies and have the potential to impact the evolutionary trajectory of animal populations. Here we provide age‐ and sex‐specific estimates of additive genetic and environmental components of variance for dominance rank and aggression rate in a free‐living, human‐habituated bird population subject to natural selection. We use a long‐term data set on individually marked greylag geese (Anser anser) and show that phenotypic variation in dominance‐related behaviours contains significant additive genetic variance, parental effects and permanent environment effects. The relative importance of these variance components varied between age and sex classes, whereby the most pronounced differences concerned nongenetic components. In particular, parental effects were larger in juveniles of both sexes than in adults. In paired adults, the partner's identity had a larger influence on male dominance rank and aggression rate than in females. In sex‐ and age‐specific estimates, heritabilities did not differ significantly between age and sex classes. Adult dominance rank was only weakly genetically correlated between the sexes, leading to considerably higher heritabilities in sex‐specific estimates than across sexes. We discuss these patterns in relation to selection acting on dominance rank and aggression in different life history stages and sexes and suggest that different adaptive optima could be a mechanism for maintaining genetic variation in dominance‐related traits in free‐living animal populations.     

Rare variants of blood proteins in human populations

Rare variants of blood proteins occur, due to mutations (mutant alleles) in monomorphic loci encoding various proteins. A number of authors studied the distribution of these variants in human populations using the method of electrophoresis. The population of USA, South America, Japan, Europe was analysed. 1334 rare variants (1.0.10(-3)) were discovered out of 1,329,558 alleles (test locus in 664,779 individuals). 7 mutant alleles (3.6.10(-6)) were found among 1,957,305 alleles. The low frequency of occurrence of mutations in the loci encoding rare blood protein variants, when testing the speed of mutagenicity and its alteration, necessitates electrophoresis of blood proteins to be done in large scales. A method was proposed, based on accounting rare variants in children with congenital disorders, which are supposed to have a heavy load of mutations. The data collected demonstrated that the majority of rare variants in a given generation were obtained from parents. Accumulation of rare protein variants at low concentrations, as neutral alleles, in conditions of low mutation frequency in monomorphic loci takes place in the population. Comparison of frequencies of rare variants among healthy newborns and the children with congenital disorders revealed their identity (1.0.10(-3)), as compared to 1.05.10(-3)). Simplification of the method for scoring mutations judging by rare blood protein variants, which is necessary for monitoring for gene mutations in human populations, stimulates development of novel approaches.     

The Frequency, Dynamics, and Structure of Congenital Malformations in Populations under Long-Term Exposure to Ionizing Radiation

Information on the dynamics, frequency, and structure of congenital malformations (CMs) and chromosomal diseases in two generations of rural populations from the Semipalatinsk region was obtained for the first time. The tests performed in the Semipalatinsk nuclear test site (STS) for many years were demonstrated to deteriorate the genetic health of the populations of the zones of extreme and maximum radiation risks. Mutagenic and teratogenic effects of long-term ionizing irradiation were detected. These were mainly expressed as an increase in the frequencies of strictly registered CMs (SR CMs), including the Down syndrome, multiple malformations (MMs) and microcephaly (1.45 ± 0.11, 1.39 ± 0.01, and 0.77 ± 0.05 per 1000 births, respectively). SR CMs exhibited linear trends toward higher frequencies in two generations of exposed persons after surface nuclear tests in 1949–1963. Their frequency was strongly correlated with the effective population dose of radiation; the main population genetic parameters (inbreeding coefficient, endogamy index, etc.) had less pronounced effects on Cms.     

基于农户尺度的陕北退耕区粮食安全

对陕北退耕区米脂县(人口高密度区)和吴起县(低密度区)农户尺度粮食生产能力进行分析,应用最小人均耕地面积和生产函数方法研究了该区粮食安全状况及影响因素.结果表明:人口低密度区的粮食生产能力可基本保障其粮食安全,而人口高密度区不能确保粮食安全;基本农田面积和农业科技投入是影响农户粮食安全的主要因素,劳动力投入、素质和粮食补贴也有正向影响,但目前的农业科技水平和劳动力素质未达到粮食生产能力的囤蓄要求.应加大基本农田和农业科学技术的囤蓄力度,达到最小人均基本农田0.14 hm2,重视农业劳动力的技术培训,并制定合理的退耕后续政策.     

Establishment success and resulting fitness consequences for vole dispersers

Dispersal is one of the most important, yet least understood phenomena of evolutionary ecology. Triggers and consequences of dispersal are difficult to study in natural populations since dispersers can typically only be identified a posteriori. Therefore, a lot of work on dispersal is either of a theoretical nature or based on anecdotal observation. This is especially true for cryptic species such as small mammals. We conducted an experiment on the common vole, Microtus arvalis, in semi‐natural enclosures and investigated the spatial and genetic establishment success of residents and dispersers in their natal and new populations. Our study uses genetic data on the reproductive success of 1255 individuals to measure the fitness trajectories of the residents and dispersing individuals. In agreement with past studies, we found that dispersal was highly male‐biased, and was most probably induced by the agonistic encounters with conspecifics, suggesting it could act as an inbreeding avoidance mechanism. There was low breeding success of dispersers into new populations. Although nearly 26% of identified dispersers reproduced in their natal populations, only seven percent reproduced in the new populations. Settlement appeared to be a pre‐requisite for reproduction in both sexes, and animals that did not spatially settle into a new population dispersed again, usually on the same day of immigration. In the event that dispersers reproduced in the new population, they did so at relatively low population densities. We also found age‐related differences between the sexes in breeding success, and male dispersers that subsequently established in the new population were young individuals that had not reproduced in their natal population, whereas successful females had already reproduced in their natal population. In conclusion, with our detailed field data on establishment and substantial parentage assignments to understand breeding success, we were able to gain an insight into the fitness of dispersers, and how the two sexes optimise their fitness. Taken together, our results help to further understand the relative advantages and costs of dispersal in the common vole.     

Sustainable Development under Population Pressure: Lessons from Developed Land Consumption in the Conterminous U.S.

Population growth will result in a significant anthropogenic environmental change worldwide through increases in developed land (DL) consumption. DL consumption is an important environmental and socioeconomic process affecting humans and ecosystems. Attention has been given to DL modeling inside highly populated cities. However, modeling DL consumption should expand to non-metropolitan areas where arguably the environmental consequences are more significant. Here, we study all counties within the conterminous U.S. and based on satellite-derived product (National Land Cover Dataset 2001) we calculate the associated DL for each county. By using county population data from the 2000 census we present a comparative study on DL consumption and we propose a model linking population with expected DL consumption. Results indicate distinct geographic patterns of comparatively low and high consuming counties moving from east to west. We also demonstrate that the relationship of DL consumption with population is mostly linear, altering the notion that expected population growth will have lower DL consumption if added in counties with larger population. Added DL consumption is independent of a county’s starting population and only dependent on whether the county belongs to a Metropolitan Statistical Area (MSA). In the overlapping MSA and non-MSA population range there is also a constant DL efficiency gain of approximately 20km² for a given population for MSA counties which suggests that transitioning from rural to urban counties has significantly higher benefits in lower populations. In addition, we analyze the socioeconomic composition of counties with extremely high or low DL consumption. High DL consumption counties have statistically lower Black/African American population, higher poverty rate and lower income per capita than average in both NMSA and MSA counties. Our analysis offers a baseline to investigate further land consumption strategies in anticipation of growing population pressures.     

Cytogenetic survey in couples with recurrent fetal wastage

Summary Cytogenetic studies have been performed in 1068 couples with antecedent fetal wastage, i.e., at least two spontaneous first trimester abortions or one spontaneous first trimester abortion and one late fetal death, particularly with multiple congenital malformations.Three major types: 33 reciprocal translocations (3.09%), 20 Robertsonian translocations (1.87%) and six other chromosomal abnormalities (0.56%) were found, bringing the total number of chromosomal abnormalities to 59 (5.5%) in 1068 couples under investigation.In contrast to couples with reciprocal translocations, a high excess of female over male carriers was found in the group of Robertsonian translocations.In the evaluation of chromosomal polymorphisms, only variants with particularly large paracentromeric constitutive heterochromatin blocks were taken into account, and their low frequency in the present study is therefore not comparable with that in a general population.The impact of further extensive familial investigation on genetic counseling and the follow-up of prenatal diagnosis are discussed.     

Sex ratio in Down syndrome. Studies in patients with confirmed trisomy 21

Male to female ratio (sex ratio, SR) for 1,329 liveborns with Down syndrome and for 178,160 newborns from the general population of St. Petersburg, Russia was determined as a function of a mother age. Male prevalence (an overall SR of 1.24) was found in children with all trisomy 21 variants except the cases with mosaicism (the ratio of 0.88). The most expressed male predominance was determined in children of mothers aged 20-24 years, where SR was 1.73 in the total group (p = 0.00003) and 1.61 in the cases with free trisomy (p = 0.0007). Some hypotheses concerning the male accumulation in this group are discussed including a suggestion that the SR deviations from the population value 1.06 might be due to different contribution of paternal chromosomal non-disjunction during spermatogenesis.     

Human chromosomal polymorphism

Summary Chromosomal Q polymorphism was studied in 157 adolescents of Yakut nationality (67 males and 90 females) living in Eastern Siberia, on the territory of the Yakut ASSR. Of the 157 subjects, 123 had chromosomal Q variants while 34 (21.7%) had no Q-heterochromatin bands with fluorescence levels 4 and 5. The mean number of Q variants per individual ranged from 0 to 5, with a mean of 1.64. No differences were observed in the frequency of Q variants between sexes. The observed homo- and heteromorph frequencies always agreed with those predicted by the law of Hardy-Weinberg. Of the 157 subjects, four (2.55%) had pericentric inversion of the Q-heterochromatin band in chromosome 3. The following topics are discussed: (1) possible selective value of chromosomal Q-heterochromatin material in the adaptation of human populations to extreme environmental factors, in particular to cold; (2) the taxonomic value of chromosomal Q polymorphism in ethnic anthropology.     

Strong male/male competition allows for nonchoosy females: high levels of polygynandry in a territorial frog with paternal care

Our knowledge about genetic mating systems and the underlying causes for and consequences of variation in reproductive success has substantially improved in recent years. When linked to longitudinal population studies, cross-generational pedigrees across wild populations can help answer a wide suite of questions in ecology and evolutionary biology. We used microsatellite markers and exhaustive sampling of two successive adult generations to obtain population-wide estimates of individual reproductive output of males and females in a natural population of the Neotropical frog Allobates femoralis (Aromobatidae), a pan-Amazonian species that features prolonged iteroparous breeding, male territoriality and male parental care. Parentage analysis revealed a polygynandrous mating system in which high proportions of males (35.5%) and females (56.0%) produced progeny that survived until adulthood. Despite contrasting reproductive strategies, successfully reproducing males and females had similar numbers of mating partners that sired the adult progeny (both sexes: median 2; range 1-6); the numbers of their offspring that reached adulthood were also similar (both sexes: median 2; range 1-8). Measures of reproductive skew indicate selection on males only for their opportunity to breed. Reproductive success was significantly higher in territorial than in nonterritorial males, but unrelated to territory size in males or to body size in both sexes. We hypothesize that female polyandry in this species has evolved because of enhanced offspring survival when paternal care is allocated to multiple partners.