Sex Differences In Growth Research Articles

Trace metal accumulation by the shrew Sorex araneus, : I. Total Body Burden, Growth, and Mortality

A laboratory feeding trial is described in which a known trace metal accumulator, the shrew Sorex araneus, was presented with an artificial diet containing high levels of copper and cadmium. Methodological difficulties relating to feeding trials on first generation offspring of insectivorous small mammals caught in the wild are described. There was no relationship between copper or cadmium intake and mortality during the trials. Sex differences in growth were apparently not influenced by metal intake. At the end of the trials there was a significant negative correlation between body weight and total cadmium burden. Whole body concentrations and burdens of cadmium increased with estimated intake. There was a significant negative correlation between percentage of cadmium retained as body burden and estimated cadmium intake. There was no discernible relationship between copper burden and intake.

The effect of increasing photoperiod and food restriction in sexed, broiler-type birds. II. Plasma thyroxine, triiodothyronine, insulin-like growth factor-I and insulin.

1. Sexed broiler-type chicks were raised either under a continuous (CON) 23 h light (L) and 1 h dark (D) schedule or an increasing photoperiod (INC). From 5 to 11 d of age birds were fed either: ad libitum (AL), energy intake (kJ ME) restricted to 9.414 x gBW0.67 (R1) or energy intake (kJ ME) restricted to 6.276 x gBW0.67 (R2). 2. Blood samples were taken at 4, 7, 11, 14 d of age and weekly thereafter to 49 d of age. Plasma thyroxine (T4), triiodothyronine (T3), insulin-like growth factor-I (IGF-I) and insulin were determined. 3. CON birds had elevated plasma T3 concentrations to 21 d of age, and greater plasma T4 concentrations at 11 and 21 d of age concurrent with greater food intake. Elevated plasma T3 concentrations in INC birds at 28 d of age coincided with lower plasma IGF-I concentrations at a time when growth and food intake were greater than CON birds. 4. Food restriction elevated plasma insulin and T4 but depressed plasma T3 and IGF-I. Plasma T3 was greater for food-restricted birds at 21 d of age, but subsequently, was generally lower than ad libitum-fed birds which may account for a lack of complete 'catch-up' in growth. 5. Plasma T3 was higher in females at 11 d of age when growth was equivalent for both sexes. From 28 to 42 d, when sex differences in growth became most apparent, plasma T3 was greater in males.

I. LIFE HISTORY FEATURES OF THREE SEXUAL MORPHS OF ATRIPLEX CANESCENS (CHENOPODIACEAE) CLONES GROWN IN A COMMON GARDEN

Reproductive and growth parameters of Atriplex canescens were examined in a common garden study. Cloned ramets of male, female, and hermaphrodite individuals from two natural populations were planted in irrigated and nonirrigated portions of the garden. Sexual differences in growth and flowering schedules suggest tradeoffs in resource allocation between growth and reproduction. Males flowered with the greatest frequency and intensity while producing the smallest growth parameters. Females had the largest measures of vegetative growth, but flowered with the least frequency and intensity. Hermaphrodites appear to have a biology distinct from males and females, being more like females in growth and more like males in reproduction.

I. Life History Features of Three Sexual Morphs of Atriplex canescens (Chenopodiaceae) Clones Grown in a Common Garden

Reproductive and growth parameters of Atriplex canescens were examined in a common garden study. Cloned ramets of male, female, and hermaphrodite individuals from two natural populations were planted in irrigated and nonirrigated portions of the garden. Sexual differences in growth and flowering schedules suggest tradeoffs in resource allocation between growth and reproduction. Males flowered with the greatest frequency and intensity while producing the smallest growth parameters. Females had the largest measures of vegetative growth, but flowered with the least frequency and intensity. Hermaphrodites appear to have a biology distinct from males and females, being more like females in growth and more like males in reproduction.

Methods for analysis of unbalanced, longitudinal, growth data.

We describe an approach to analysis of growth that does not depend on assumptions about the underlying functional growth pattern and that allows for multiple observations arising from individual-specific, irregularly spaced data. We produce estimated growth curves for predefined subject groups by using LOWESS, a nonparametric smoothing algorithm. We describe how statistical significance of curve features may be evaluated by using the "jackknife," a sample re-use method; this technique can be used to assess differences between subject groups. We then obtain residuals at each data point by reference to the estimated curve. Consistency of residuals is evaluated as a characteristic of individual subjects, and in the presence of individual consistency, relative size-for-age is then scored by the average residual for each individual. This allows study of relationships between relative size and other individual characteristics such as birth order, dominance rank, or age of maturation. Finally, we indicate flexibility of these methods and alternatives, propose uses related to other questions about growth, and suggest potential applications to variables other than body size. Appendices demonstrate application of the LOWESS and jackknife algorithms to the problem of testing sex differences in growth. © 1992 Wiley-Liss, Inc.

Long-term growth dynamics of young Pacific halibut: evidence of temperature-induced variation

The first five otolith growth zones of 744 Pacific halibut from 26 year-classes (1953–1978) were analyzed to identify patterns of annual growth and the sources of temporal variation. Sexual differences in growth appeared at an early age, and size selectivity of the gear types was shown to influence the perception of past growth. We adjusted the growth record for these two effects by removing variation in annual otolith growth that was linearly related to the size of the fish at capture. Correlation patterns of the otolith zones at the youngest ages suggested a general uncoupling of individual growth from one year to the next. Temporal variation was examined by developing a linear model to partition growth at different ages into both year and year-class effects. Randomization tests indicated that both effects are significant when all five ages are included, but when subsets of the data are examined, the year effect is strongest for youngest juveniles, whereas the year-class effect is significant for older juveniles. The year effect is probably attributable to interannual temperature changes, as indicated by a strong linear relationship between sea surface temperature (SST) and otolith growth from ages 0 to 2 years. However, analysis of residuals indicated a remaining year effect, suggesting that SST is an imperfect measure of the actual environment that regulates juvenile growth. The year-class effect observed in older juveniles was not present in the data adjusted for size selectivity, suggesting that this effect could be influenced by sampling bias, though intrinsic influences cannot be ruled out. Density-dependent growth did not appear to be a factor accounting for growth variation; instead, there appeared to be a slight positive correlation between otolith growth at ages 1 and 2 years and estimated year-class abundance (at age 8 years), suggesting that early growth is a factor in determining year-class strength.

Rearing cynomolgus monkeys (Macaca fascicularis) on surrogate mothers with bottle feeding.

Fifty-two cynomolgus monkeys were reared in peer groups on surrogate mothers and fed by bottle during the first months of life. A description of the technique of bottle feeding and the structure of surrogate mothers is presented. Results are shown in a growth curve. Inter-individual differences in body weight were very large. The mean weight was higher in males than in females, but no significant sex differences in growth occurred. The weight of mother-reared infants stayed within the standard deviation of the mean weight of the artificially-reared subjects.

The consequences of differences in litter size for the nursing cat and her kittens

Seventy‐one litters of kittens (mean litter size 4.4) were studied from birth to eight weeks of age in order to measure kitten growth and maternal body condition. Few sex differences in growth occur; male and female kittens place a similar burden on their lactating mother. A mother's weight (non‐pregnant, non‐lactating) interacts with litter size to determine the fate of her growing kittens. A large litter places a burden on both the mother and on the kittens, whose growth is affected; small mothers with large litters are particularly at risk. An acceleration in kitten growth occurs at about 32 days as the kittens take more solid food. This change in growth rate is more marked in large litters. Kittens of light mothers and kittens in large litters are weaned at a lower weight, and kittens of light mothers are weaned earlier. Our results indicate that, under poor environmental conditions, large litters would be less successful than small litters; kitten growth and survival would be affected and providing milk for a large litter would have a detrimental effect on the mother's health. The cost of lactation appears to have been a major evolutionary factor in determining mean litter size.

EXPERIMENTAL STUDIES ON THE DISTRIBUTION OF THE SEXES OF MERCURIALIS PERENNIS L.

SUMMARY(1) Populations of flowering male and female shoots of Mercurialis perennis were grown in three experiments under different light screens: (i) the sexes grown together in a replacement series under a screen transmitting 11 % incident light; (ii) the density of the plants varied under an 11 % light screen; and (iii) the sexes grown separately with Holcus mollis under light screens transmitting 31 % and 2% incident light.(2) In the replacement series with mixed sexes, the males grew more than the females at (male:female) 10:10 while the females grew more at 17:3 and 3:17. The sexes grew similarly in monoculture. The results for total yield of the plants suggest that competition between the sexes was less than that within them.(3) In the density experiment, the males grew more than the females as the density increased from 20 to 30 plants/box and both grew similarly at 42 plants/box.(4) It is suggested that observed uneven sex ratios in natural populations of shoots may be a result of the sexual differences in growth as the density of the plants increases.(5) In the replacement series with H. mollis under the 31 % light screens the males grew more than the females at (M. perennis: H. mollis) 3:17 while the females grew more at 17:3. These results suggest that males may persist longer in association with other species.(6) No consistent results were obtained from the H. mollis replacement series under the 2 % light screens.(7) The sexes grew similarly more under the 31 % compared to the 11 % light screens, suggesting that neither is physiologically intolerant to increased sunlight.

Sexual dimorphism in body composition changes during the pubertal period : As shown by French‐Canadian children

Size and velocity growth curves of stature to represent skeletal growth, lean arm circumference to represent muscle growth, and the sum of three skinfolds to represent fat tissue changes, are presented for a longitudinal study of Montreal school-age chidren. Both a chronological age scale, and one relative to the individual ages of peak growth velocity in stature, are used. Intercorrelations between the various components are tabulated for age groups based on the two scales. The three skinfolds are also analyzed separately. The results show that such simple anthropometric measures can be usefully taken to represent the growth of different body components. Longitudinal analysis reveals that, whereas the relationship of muscular to statural growth in boys is purely maturational, it is not so for girls, and that the different skinfolds show complex sexual differences in growth during the pubertal period.

Analysis of the adolescent growth spurt using smoothing spline functions.

Height growth velocity curves between 4.5 and 17.75 years were estimated, using smoothing spline functions, for 112 boys and 110 girls from the Zurich Longitudinal Study (1955--1976). Parameters characterizing the growth process, such as peak height velocity and age at peak height velocity, were calculated directly from the estimated curves. The variability of parameters describing the adolescent growth spurt is large, both between and within sexes. Peak height, defined as increase of height velocity during the growth spurt, and age at peak height velocity both characterize the sex difference in growth in a highly significant manner. Peak height of at least 4 cm/year is found in 70% of the boys, but in only 11% of the girls. The age at peak height velocity averages 12.2 years in girls and 13.9 years in boys and has a wide range of 5.7 years and 3.8 years respectively. The sex difference in adult height of 12.6 cm is composed of the following 4 factors: +1.6 cm caused by more prepubertal growth in boys, +6.4 cm by the boys' delay in spurt, +6.0 cm by the more extensive spurt in boys and -1.4 cm by more post-spurt growth in girls. Correlations between parameters indicate that the adult height depends neither on the duration of growth, nor on the duration and height of the peak. Minimal pre-spurt height velocity and peak height velocity, but not peak height, are age- and height-dependent. Partial correlations given adult height reveal two compensating mechanisms between growth in the prepubertal and in the pubertal period. Small prepubertal height and low height velocity with respect to adult height are followed by a late adolescent spurt and vice versa. Small height at the onset of the spurt with respect to adult height is followed by a longer lasting, but not higher spurt and vice versa.

The nature and basis of sexual dimorphism in the primate skeleton

This study sets out to document and analyse sexual dimorphism in the teeth and bones of five primate groups, including man. Specimens were only included in the analysis if their sexual attribution was reliable and was based on non‐osteological criteria. Ninety raw measurements, both cranial and post‐cranial, were used and 11 indices were computed from them.The parameters of each sample were computed in order to compare these results with previous estimates of dimorphism which have not always been based on reliably sexed samples. Correlation matrices were computed.The overall sex differences were subdivided into “shape” and “size” components using Penrose's size and shape distances and by computing the principal components of each data set. The visually apparent shape differences were confirmed metrically and then examined to see whether they could be explained by allometric effects or whether there was evidence for sexual differences in growth patterns.Using femur length as the independent variable, because of its correlation with overall size, allometric coefficients were computed for the logarithmically transformed data. The coefficients were in some cases very different between sexes but the majority did not achieve statistical significance. Of those that were significantly different only in Homo did such differences narrowly exceed the number that would be expected by chance alone.As the vast majority of allometric coefficients for the pooled male and female data differed from unity, the hypothesis that most of the considerable shape differences that exist between some male and female primates are due to underlying growth differences must be rejected. It is suggested that such differences are simply the result of disproportionate change in size.

Life History Pattens of the Littoral Gastropods Shaskyus Festivus (Hinds) and Ocenebra Poulsoni Carpenter (Prosobranchia: Muricidae)

Monthly recaptures of marked individuals in intertidal populations of the predatory gastropods Shaskyus festivus and Oceanebra poulsoni for 39 months near La Jolla, California, show annual variation in growth, reproduction, and recruitment rates consistent with the conclusion that the snails experienced only 1 successful year in 3. Eggs are deposited in capsules from March through July, and free—swimming veligers are released in 3 to 4 weeks. More than 99% of the mortality occurs in the plankton or during settlement. The major predator on the adults, the crab Cancer antennarius, annually destroys less than 1% of the adults Shaskyus and less than 2.5% of the adult Ocenebra. After settlement, Shaskyus can expect to live for more than 10 years, and Ocenebra for more than 9 years. The adult mortality rate was generally highest during the reproductive season but lowest in 1969, when the greatest reproductive effort was observed. Marked individuals of both species have been found in breeding aggregations in more than one season, suggesting iteroparity. Shell growth rates decreased and mortality rates increased as shell length increased in both species. The sex ratio of Shaskyus from 25.0 mm to 44.9 mm did not differ significantly from 1:1. The proporations of female Ocenebra longer than 14.9 mm increased as shell length increased. The determination of sex in smaller size classes was uncertain because many smaller males were probably immature and lacked penises. Sexual differences in growth and mortality rates were probably responsible for the paucity of males in the larger size classes. No evidence for sex reversal was found in repeated sex determinations of marked snails.

Sire × Sex Interactions and Sex Differences in Growth and Carcass Traits of Angus Bulls, Steers and Heifers

Sire × Sex Interactions and Sex Differences in Growth and Carcass Traits of Angus Bulls, Steers and Heifers

Direct action upon avian target organs by the antiandrogen cyproterone acetate.

AbstractAt ten days of age, intact male chicks had significantly larger combs than intact female chicks. Castration at four days of age eliminated the sex difference in growth of the comb. Growth of the comb, as a result of the secretion of endogenous androgens by the testes, was inhibited by inunction of the comb with small dosages of cyproterone acetate (Cyp A).Combs of other chicks were divided surgically into posterior and anterior portions of equal weight, thus providing two separate androgenic target organs in the same animal. The local action of Cyp A was investigated by inunction of this compound on the anterior or the posterior portion of the comb, along with simultaneous application of testosterone propionate to both portions. Small dosages of Cyp A antagonized the effect of androgen on the portion of the comb inuncted with Cyp A without affecting growth of the other target organ in the same animal. It was concluded that Cyp A exerted antiandrogenic actions directly upon target organs and was effective topically in doses too small to act systemically.The posterior portion of the comb, in comparison with the anterior, was more responsive both to the androgen and to the antiandrogen.

Effects of pre- and post-pubertal gonadectomy on sex differences in growth, adrenal and pituitary weights of hamsters.

SUMMARY Unlike rats, the adult female hamster is heavier and longer than the male. The small size of the males appears to be dependent on the continuous presence of androgens, since castration before or after puberty results in an immediate acceleration of ponderal and linear growth, which is maintained until the female size is reached. The growth of females is not affected by gonadectomy. Another sexual dimorphism which is reversed in hamsters in comparison with rats is adrenal weight; males have heavier adrenals than females. Castration reduces both absolute and relative adrenal weights of males to the levels of females. It is possible that the sex difference in growth is mediated through a differential secretion of adrenal hormones. On the other hand, the sexual dimorphism in pituitary weights of hamsters is similar to rats; females have heavier pituitaries than males. This may reflect a sex difference in the pattern of gonadotrophin secretion, which may be similar in both species.

GREATER TENDENCY TO ACNE IN WHITE AMERICAN THAN IN JAPANESE POPULATIONS.

In studies of white subjects living in the United States and of Japanese living in Tokyo and Yokohama, extensive acne was observed to be more common among the American than the Japanese populations. These observations, and the previously reported higher incidence of male pattern baldness in Caucasoids than in Mongoloids, are in accord with the hypothesis that tendencies to pronounced development of secondary sex characters may merge with tendencies to certain sex-selective pathologic conditions. Sex differences in acnegenesis were marked; especially in the Japanese; acne was more extensive and retained at a later age in males than in females. Ethnic and sex differences in the production of sebum and acne were similar in direction to ethnic and sex differences in growth of beard and axillary hair. This suggests that sebaceous and piliary structures can be a unit, not only morphologically in the form of pilosebaceous aparatuses, but also physiologically in that the component parts react similarly

Sex difference in growth in gonadectomised albino rats

Sex difference in growth in gonadectomised albino rats

Sexual Differences in Growth and Utilization of Feed in White Leghorn Chicks

THE purpose of the experiment reported herein was to determine if there were sexual differences in growth and in the utilization of feed in chicks. One of the great handicaps previously encountered in nutritional experiments with growing chicks has been the difficulty of adjustment of sexual differences in growth rate and feed efficiency where chicks of mixed sexes were used in the experiment. The weighing of the chicks individually has permitted the computation of sexual differences in growth, but it has been necessary to estimate the feed consumption and efficiency for males and females as the chicks were not segregated at the time of hatch.On April 11, 1934, a hundred day-old White Leghorn pullets and a hundred day-old White Leghorn cockerels were sexed and placed in separate compartments in electric battery brooders. Both the pullets and cockerels were fed the Washington chick starting mash: ground yellow corn 40, ground .

Review of Sex differences in growth of american school children.

Review of Sex differences in growth of american school children.