Beneficial Effects of Highly Palatable Food on the Behavioral and Neural Adversities induced by Early Life Stress Experience in Female Rats

This study examined the effects of highly palatable food during adolescence on the psycho-emotional and neural disturbances caused by early life stress experience in female rats. Female Sprague-Dawley pups were separated from dam for 3 h daily during the first two weeks of birth (MS) or left undisturbed (NH). Half of MS females received free access to chocolate cookies in addition to ad libitum chow from postnatal day 28. Pups were subjected to the behavioral tests during young adulthood. The plasma corticosterone response to acute stress, ΔFosB and brain-derived neurotrophic factor (BDNF) levels in the brain regions were analyzed. Total caloric intake and body weight gain during the whole experimental period did not differ among the experimental groups. Cookie access during adolescence and youth improved anxiety-/depression-like behaviors by MS experience. ΔFosB expression was decreased, but BDNF was increased in the nucleus accumbens of MS females, and ΔFosB expression was normalized and BDNF was further increased following cookie access. Corticosterone response to acute stress was blunted by MS experience and cookie access did not improve it. Results suggest that cookie access during adolescence improves the psycho-emotional disturbances of MS females, and ΔFosB and/or BDNF expression in the nucleus accumbens may play a role in its underlying neural mechanisms.     

Costs of Reproduction in Male Bicyclus anynana and Pieris napi Butterflies: Effects of Mating History and Food Limitation

Life history theory predicts trade‐offs arising from the costs of reproduction: individuals investing more into reproduction should have less energy available for their own somatic demands. Despite a wealth of research on such costs for females, very few studies have looked at the male side. We investigated the costs of reproduction in males of two butterfly species, Bicyclus anynana and Pieris napi. The males of these species differ tremendously in their allocation of nutrients to reproduction: virgin male spermatophores were 18.5 times larger in the latter compared with those in the former. Based on this striking difference, we expected to find a longevity cost of mating in P. napi, but not necessarily in B. anynana. In line with our predictions, we found no evidence for a survival cost of mating in B. anynana, while there was some evidence for such a cost in P. napi. Here, virgin males lived longer than once‐ or twice‐mated ones. However, this overall trend did not hold for all treatment groups, and there was no linear relationship between the number of copulations and longevity. Adult food limitation reduced longevity throughout, but had otherwise very little impact. Spermatophore dry mass decreased in later compared with first spermatophores, while water content increased, indicating that spermatophore production is indeed physiologically costly. Additionally, adult food limitation tended to reduce spermatophore fresh and dry mass, and tended to increase spermatophore water content. Based on our results we tentatively conclude that longevity and reproduction may not always be traded off against each other, as in our study organisms’ longevity seems to depend in first place on adult carbohydrate income, while male reproduction seems to be primarily (although not entirely) fuelled by larval storage reserves.     

The Effects of Food Limitation on Life History Tradeoffs in Pregnant Male Gulf Pipefish

Syngnathid fishes (pipefishes, seahorses and seadragons) are characterized by a unique mode of paternal care in which embryos develop on or in the male’s body, often within a structure known as a brood pouch. Evidence suggests that this pouch plays a role in mediating postcopulatory sexual selection and that males have some control over the events occurring within the pouch during the pregnancy. These observations lead to the prediction that males should invest differently in broods depending on the availability of food. Here, we use the Gulf pipefish to test this prediction by monitoring growth rate and offspring survivorship during the pregnancies of males under low- or high-food conditions. Our results show that pregnant males grow less rapidly on average than non-pregnant males, and pregnant males under low-food conditions grow less than pregnant males under high-food conditions. Offspring survivorship, on the other hand, does not differ between food treatments, suggesting that male Gulf pipefish sacrifice investment in somatic growth, and thus indirectly sacrifice future reproduction, in favor of current reproduction. However, a positive relationship between number of failed eggs and male growth rate in our low-food treatments suggests that undeveloped eggs reduce the pregnancy’s overall cost to the male compared to broods containing only viable offspring.     

Body Size at Birth Is Associated with Food and Nutrient Intake in Adulthood

Background

Small body size at birth is associated with an increased risk of cardiovascular disease and type 2 diabetes. Dietary habits are tightly linked with these disorders, but the association between body size at birth and adult diet has been little studied. We examined the association between body size at birth and intake of foods and macronutrients in adulthood.

Methodology/Principal Findings

We studied 1797 participants, aged 56 to 70, of the Helsinki Birth Cohort Study, whose birth weight and length were recorded. Preterm births were excluded. During a clinical study, diet was assessed with a validated food-frequency questionnaire. A linear regression model adjusted for potential confounders was used to assess the associations. Intake of fruits and berries was 13.26 g (95% confidence interval [CI]: 0.56, 25.96) higher per 1 kg/m³ increase in ponderal index (PI) at birth, and 83.16 g (95% CI: 17.76, 148.56) higher per 1 kg higher birth weight. One unit higher PI at birth was associated with 0.14% of energy (E%) lower intake of fat (95% CI: -0.26, -0.03) and 0.18 E% higher intake of carbohydrates (95% CI: 0.04, 0.32) as well as 0.08 E% higher sucrose (95% CI: 0.00, 0.15), 0.05 E% higher fructose (95% CI: 0.01, 0.09), and 0.18 g higher fiber (95% CI: 0.02, 0.34) intake in adulthood. Similar associations were observed between birth weight and macronutrient intake.

Conclusions

Prenatal growth may modify later life food and macronutrient intake. Altered dietary habits could potentially explain an increased risk of chronic disease in individuals born with small body size.     

The Impact of Psychological Stress on Men's Judgements of Female Body Size

Background

Previous work has suggested that the experience of psychological stress may influence physical attractiveness ideals, but most evidence in favour of this hypothesis remains archival. The objective of this study was to experimentally investigate the impact of stress on men''s judgements of female body size.

Methods

Men were randomly assigned to either an experimental group, in which they took part in a task that heightened stress (experimental group, n = 41) or in which they did not take part in such a task (control group, n = 40). Both groups rated the attractiveness of female bodies varying in size from emaciated to obese, completed a measure of appetite sensation, and had their body mass indices (BMIs) measured.

Results

Between-groups analyses showed that the experimental group was matched with the control group in terms of mean age, BMI, and appetite sensation. Further analyses showed that men in the experimental group rated a significantly heavier female body size as maximally attractive than the control group. Men in the experimental group also rated heavier female bodies as more attractive and idealised a wider range of female figures than did the control group.

Conclusion

This study found that the experience of stress was associated with a preference among men for heavier female body sizes. These results indicate that human attractiveness judgements are sensitive to variations in local ecologies and reflect adaptive strategies for dealing with changing environmental conditions.     

Female Preferences for Sailfin and Body Size in the Sailfin Molly, Poecilia latipinna

We tested the mating preference of female sailfin mollies (Poecilia latipinna) by presenting them with pairs of dummy males differing in: (I) sailfin and body size together (holding sailfin : body size ratio constant); (II) body size alone (holding sailfin size constant); (III) sailfin size alone (holding body size constant); and (IV) sailfin : body size ratio (holding total lateral projection area constant). Females spent more time near dummies of greater sailfin or greater body size. The preference functions based on the first three sets of stimuli showed a similar pattern: the preference between any two simultaneously presented dummies increased with the magnitude of the discrepancy in lateral projection area (LPA) between them. However, when LPA was held constant in expt (IV), neither body size, sailfin size, nor any particular dummy (i.e. any particular sailfin + body size combination) was preferred. These findings suggest that increased LPA is more stimulating to sexually receptive females and that females consequently prefer larger males. The sailfin may therefore have evolved as a way for males to exploit this sensory bias and appear larger to prospective mates.     

Female Choice, Female Reluctance to Mate and Sexual Selection on Body Size in the Dung Fly Sepsis cynipsea

We investigated the mechanisms of sexual selection in the common dung fly Sepsis cynipsea and how these affect selection on body size at the population level. Because of the presumed costs associated with mating, we predicted that there would be a decrease in the general reluctance of females to mate with any particular male at higher male densities at the mating site, a fresh cow pat, resulting in indirect female choice and a decrease in the strength of sexual selection. In contrast, classical direct female choice and male‐male competition should result in increased selection intensities because more opportunities for choice and competition exist at higher densities. Female reluctance to mate and female assessment of males are expressed in prominent female behaviour to repel mates in several insect species, including S. cynipsea. Laboratory pair‐wise choice experiments showed that large males were more likely to obtain copulations, which also ensued more promptly, suggesting female assessment of male quality (direct female choice). There was a basic influence of male activity but little further effect of male scramble competition on the outcome of mating. Another laboratory experiment showed a decrease in female shaking duration per male, associated with an asymptote in the shaking duration per female, as male density and harassment increased, but did not show the increase in mating frequency predicted by the female reluctance hypothesis. A study estimating sexual selection differentials in the field showed that directional selection for larger males was present overall and was negatively related to seasonally mediated variation in male density. Our study suggests that direct female choice in combination with indirect female choice (due to an interaction of female reluctance to mate and male persistence) is most consistent with the behavioural and selection patterns observed in S. cynipsea, but male effects cannot be definitively excluded.     

Early Rearing Conditions Affect the Development of Body Size and Song in Bengalese Finches

Birdsong is an acoustic ornament. According to indicator models, a trait must be costly to act as an honest signal, but the potential costs of elaborate songs are still poorly understood. The developmental stress hypothesis suggests that learned song characteristics could be an honest indicator of early developmental conditions because the brain structures associated with learning songs are susceptible to early developmental stress, which could thus affect song development. Unlike previous studies of developmental stress that examined the effect of a stress hormone or restricted nutrition, we observed Bengalese finches under semi‐natural breeding conditions in captivity to investigate the relationship between early rearing conditions (e.g., brood size and sex ratio) and the subsequent variation in body size and song among individuals. Our results suggest that the early rearing environment directly affects body size and song complexity, whereas song output is determined mainly by body size. These results support the developmental stress hypothesis. Moreover, our findings are the first to show that developmental condition affects not only the number of note types but also the syntactical complexity of the song.     

Ecdysone and Insulin Signaling Play Essential Roles in Readjusting the Altered Body Size Caused by the dGPAT4 Mutation in Drosophila

Body size is one of the features that distinguish one species from another in the biological world. Animals have developed mechanisms to control their body size during normal development. However, how animals cope with genetic alterations and/or environmental stresses to develop into normal-sized adults remain poorly understood. The ability of the animals to develop into a normal-sized adult after the challenges of genetic alterations and/or environmental stresses reveals a robustness of body size control. Here we show that the mutation of dGPAT4, a de novo synthase of lysophosphatidic acid, is a genetic alteration that triggers such a robust response of the animals to body size challenges in Drosophila. Loss of dGPAT4 leads to a severe delay of development, slow growth and resultant small-sized animals during the larval stages, but results in normal-sized adult flies. The robust body size adjustment of the dGPAT4 mutant is likely achieved by corresponding changes in ecdysone and insulin signaling, which is also manifested by compromised food intake. Thus, we propose that a strategy has been evolved by the animals to reach final body size when challenged by genetic alterations, which requires the coordinated ecdysone and insulin signaling.     

Effect of Population Density and Female Body Size on Number and Size of Offspring in a Species with Size‐Dependent Contests over Resources

When size‐dependent contests over resources influence reproductive success, the trade‐off between number and size of offspring depends on the frequency of contests. Under these circumstances, clutch size should decrease and offspring size should increase as contests become more frequent. We tested these predictions with the burying beetle Nicrophorus pustulatus through manipulation of rearing densities. Burying beetles reproduce on small vertebrate carcasses, a rare but high quality food source for the larvae. Large beetles are more likely to win contests over carcasses and gain exclusive access to a carcass. The winner of a contest kills eggs and larvae already present on a carcass. As a result of the rarity of carcasses, burying beetles are unlikely to breed more than once. As predicted, brood size of N. pustulatus decreased with increasing rearing density. Despite a negative correlation between brood size and larval mass, larval mass did not increase with increasing rearing density. This may be due to the special biology of N. pustulatus which can use snake eggs for reproduction. Potentially larger supply of resources and generally small population densities of N. pustulatus may weaken selection on body size and thus the correlation between brood size and larval mass. As size‐dependent constraints can limit reproductive phenotypes, we examined whether female size influenced reproductive phenotype. Small females produced larger broods with smaller, but more variable, offspring than large females. Mechanical constraints of egg size seem an unlikely explanation for the differences because burying beetles can compensate for small egg size through parental care. Energetic constraints may impact small females because body mass and brood size of small females decreased with increasing density. Yet, at all density levels small females produced larger, not smaller, broods than large females. The larger and more variable broods of small females seem to be in agreement with a bet‐hedging strategy.     

Early Life Predictors of Increased Body Mass Index among Indigenous Australian Children

Aboriginal and Torres Strait Islander Australians are more likely than non-Indigenous Australians to be obese and experience chronic disease in adulthood—conditions linked to being overweight in childhood. Birthweight and prenatal exposures are associated with increased Body Mass Index (BMI) in other populations, but the relationship is unclear for Indigenous children. The Longitudinal Study of Indigenous Children is an ongoing cohort study of up to 1,759 children across Australia. We used a multilevel model to examine the association between children’s birthweight and BMI z-score in 2011, at age 3-9 years, adjusted for sociodemographic and maternal factors. Complete data were available for 682 of the 1,264 children participating in the 2011 survey; we repeated the analyses in the full sample with BMI recorded (n=1,152) after multilevel multiple imputation. One in ten children were born large for gestational age, and 17% were born small for gestational age. Increasing birthweight predicted increasing BMI; a 1-unit increase in birthweight z-score was associated with a 0.22-unit (95% CI:0.13, 0.31) increase in childhood BMI z-score. Maternal smoking during pregnancy was associated with a significant increase (0.25; 95% CI:0.05, 0.45) in BMI z-score. The multiple imputation analysis indicated that our findings were not distorted by biases in the missing data. High birthweight may be a risk indicator for overweight and obesity among Indigenous children. National targets to reduce the incidence of low birthweight which measure progress by an increase in the population’s average birthweight may be ignoring a significant health risk; both ends of the spectrum must be considered. Interventions to improve maternal health during pregnancy are the first step to decreasing the prevalence of high BMI among the next generation of Indigenous children.     

Genetic and Environmental Influences on the Tracking of Body Size from Birth to Early Adulthood

Objective: This study identified genetic and environmental influences on the tracking of body size from birth to 16 to 18.5 years of age. Research Methods and Procedures: Longitudinal information was collected from a nationally representative sample of Finnish twin adolescents (birth cohorts 1975 to 1979) and their parents through questionnaires mailed when the twins were ages 16 and 18.5 years old. The sample included 702 monozygotic, 724 same‐sex dizygotic, and 762 opposite‐sex dizygotic sets of twins. The measures used were length, weight, ponderal index (kilograms per cubic meters), and gestational age at birth, and height, weight, and body mass index (kilograms per square meters) at 16 to 18.5 years of age. The changes in genetic and environmental influences on body size from birth to early adulthood were analyzed by quantitative genetic modeling. Results: The twins who had a higher weight or ponderal index at birth were taller and heavier in early adulthood, whereas those who were longer at birth were taller, but not heavier, later in life. Adult height was affected more by the birth size than body mass index. In the genetic modeling analyses, the genetic factors accounting for the variation of body size became more apparent with age, and both genetic and environmental influences on stature had a sizable carry‐over effect from birth to late adolescence, whereas for relative weight, the influences were more age‐specific. Discussion: The genetic and environmental architecture of body size changes from birth to adulthood. Even in monozygotic twins who share their genetic background, the initially larger twin tended to remain larger, demonstrating the long‐lasting effects of fetal environment on final body size.     

The Probabilistic Niche Model Reveals the Niche Structure and Role of Body Size in a Complex Food Web

The niche model has been widely used to model the structure of complex food webs, and yet the ecological meaning of the single niche dimension has not been explored. In the niche model, each species has three traits, niche position, diet position and feeding range. Here, a new probabilistic niche model, which allows the maximum likelihood set of trait values to be estimated for each species, is applied to the food web of the Benguela fishery. We also developed the allometric niche model, in which body size is used as the niche dimension. About 80% of the links in the empirical data are predicted by the probabilistic niche model, a significant improvement over recent models. As in the niche model, species are uniformly distributed on the niche axis. Feeding ranges are exponentially distributed, but diet positions are not uniformly distributed below the predator. Species traits are strongly correlated with body size, but the allometric niche model performs significantly worse than the probabilistic niche model. The best-fit parameter set provides a significantly better model of the structure of the Benguela food web than was previously available. The methodology allows the identification of a number of taxa that stand out as outliers either in the model''s poor performance at predicting their predators or prey or in their parameter values. While important, body size alone does not explain the structure of the one-dimensional niche.     

Diversity and Evolution of Body Size in Fishes

The diversity of body sizes observed among species of a clade is a combined result of microevolutionary processes (i.e. natural selection and genetic drift) that cause size changes within phylogenetic lineages, and macroevolutionary processes (i.e. speciation and extinction) that affect net rates of diversification among lineages. Here we assess trends of size diversity and evolution in fishes (non-tetrapod craniates), employing paleontological, macroecological, and phylogenetic information. Fishes are well suited to studies of size diversity and evolution, as they are highly diverse, representing more than 50% of all living vertebrate species, and many fish taxa are well represented in the fossil record from throughout the Phanerozoic. Further, the frequency distributions of sizes among fish lineages resemble those of most other animal taxa, in being right-skewed, even on a log scale. Using an approach that measures rates of size evolution (in darwins) within a formal phylogenetic framework, we interpret the shape of size distributions as a balance between the competing forces of diversification, pushing taxa away from ancestral values, and of conservation, drawing taxa closer to a central tendency. Within this context we show how non-directional mechanisms of evolution (i.e. passive diffusion processes) can produce an hitherto unperceived bias to larger size, when size is measured on the conventional log scale. These results demonstrate how the interpretation of macroecological datasets can be enriched from an historical perspective, and document the ways in which macroevolutionary and microevolutionary processes may be decoupled in the production of size diversity.     

Reduced Function of a Phenylacetate-Oxidizing Cytochrome P450 Caused Strong Genetic Improvement in Early Phylogeny of Penicillin-Producing Strains

The single-copy pahA gene from Penicillium chrysogenum encodes a phenylacetate 2-hydroxylase that catalyzes the first step of phenylacetate catabolism, an oxidative route that decreases the precursor availability for penicillin G biosynthesis. PahA protein is homologous to cytochrome P450 monooxygenases involved in the detoxification of xenobiotic compounds, with 84% identity to the Aspergillus nidulans homologue PhacA. Expression level of pahA displays an inverse correlation with the penicillin productivity of the strain and is subject to induction by phenylacetic acid. Gene expression studies have revealed a reduced oxidative activity of the protein encoded by pahA genes from penicillin-overproducing strains of P. chrysogenum compared to the activity conferred by phacA of A. nidulans. Sequencing and expression of wild-type pahA from P. chrysogenum NRRL 1951 revealed that an L181F mutation was responsible for the reduced function in present industrial strains. The mutation has been tracked down to Wisconsin 49-133, a mutant obtained at the Department of Botany of the University of Wisconsin in 1949, at the beginning of the development of the Wisconsin family of strains.     

Racial Differences in Selection of Ideal Body Size by Adolescent Females

Cultural differences may partially account for the fact that more black women than white women are overweight in the United States. This study measured perceptions of ideal body size among 93 black and 80 white females, 14–17 years old, who were randomly selected from three public high schools in a southeastern state. The subjects' height and weight were measured along with their estimates of their mother's body size, weight control attitudes, and demographic variables . Blacks preferred a significantly larger body sue than whites when asked to select ideal body size (p=0.045). Subjects who estimated their mother's size to be larger, also selected a larger ideal body size (p=.047). Those who perceived themselves as too fat were more likely to skip meals to help control their weight, compared with those who perceived themselves as normal or too thin (p=.003). Approximately 30% of the sample was overweight or obese. There were not significant racial differences in weight or BMI . These results suggest that overweight is more acceptable among black females than among white females and may help explain why more black females are obese .