Nutritional Reserves Research Articles

Nutrición durante el embarazo y la lactancia.

El embrión mamífero es completamente dependiente de la madre para su nutrición. Es absolutamente necesario mantener, en esta etapa de la vida, un correcto equilibrio entre los nutrientes circulantes de la sangre materna. Esta normalidad bioquímica depende de la dieta de la madre, sus reservas nutricionales y sus idiosincrasias metabólicas. En general, las repercusiones de una nutrición anormal dependen del nivel al cual el factor nutritivo actúa, la naturaleza del nutriente específico y la intensidad del desequilibrio. Los tipos de repercusiones son diferentes: muerte, alteraciones de tejidos, retraso de crecimiento, alteraciones en la diferenciación celular y malformaciones. Por lo tanto, la mejora en el pronóstico del embarazo dependerá en parte en el aumento del conocimiento acerca de los requerimientos nutricionales y de educar a la comunidad sobre los efectos indeseados de las deficiencias y excesos de nutrientes.

The State-Dependent Resource Allocation Hypothesis: Implications for the Foraging Ecology and Life History of Migratory Ungulates in the GYE

Understanding the behavioral and physiological responses of animals to environmental stressors is vital to our comprehension of their ecology and life history. The life-history strategy of ungulates is for females to prioritize survival over reproductive effort to maximize life-long fitness (Stearns 1992, Eberhardt 2002, Bårdsen et al. 2008). Consequently, an individual’s reproductive decisions are expected to be dependent on nutritional state (Bårdsen et al. 2008). Researchers have long assumed that individuals reduce their metabolism and energy expenditure to conserve nutritional reserves (i.e., fat and protein) during winter because winter has been demonstrated to be a period of energetic loss for temperate ungulates. Recent research, however, has shown that mule deer (Odocoileus hemionus) in a poor nutritional state are capable of increasing their nutritional reserves over winter (Monteith et al. 2013), and hormone analysis of moose (Alces alces; Jesmer et al. in review) indicates that animals with low nutritional reserves have high energy expenditure and energy intake. Therefore, regulation of nutritional state through plasticity in foraging behavior may allow animals to cope with resource shortages. We refer to this notion, wherein animals alter their energy intake and expenditure via foraging behavior as the State-Dependent Resource Allocation Hypothesis (Figure 1). In 2014 we proposed to apply state-of-the-art nutritional, isotopic, and hormone analyses to test the State-Dependent Resource Allocation Hypothesis (SRAH) in migratory mule deer within the Greater Yellowstone Ecosystem.

Condition of larvae of western rock lobster (Panulirus cygnus) in cyclonic and anticyclonic eddies of the Leeuwin Current off Western Australia

Changes in the offshore oceanographic processes are suspected to be the cause of a recent dramatic decline in the settlement of post-larvae of the Western Australian spiny lobster (Panulirus cygnus), which has greatly reduced the productivity from the world’s second-largest spiny lobster fishery. The present study assessed whether there are differences in the nutritional condition of the larvae of P. cygnus sampled from two pairs of cyclonic eddies (CEs) and anticyclonic eddies (AEs). Morphometric and biochemical analyses were undertaken on the mid–late-stage larvae (VI, VII, VIII) sampled offshore from two pairs of adjacent counter-rotating mesoscale eddies in the Leeuwin Current off Western Australia. The results showed that larvae captured from CEs had greater average total dry mass (P<0.001) than those from AEs. Stage VIII larvae from CEs contained more protein (P<0.008) (38.5% ±5.4s.e.) and lipid (P<0.005) (67.2% ±12.1) than did those from AEs. The possible causes for these differences are uncertain but may be related to differences in water temperatures in CEs v. AEs influencing the ability of phyllosomas to accumulate nutritional reserves.

In Memoriam

In Memoriam

Considerations on the late-preterm newborn with cardiac problems

Focus on the late preterm birth (LPB) and critical congenital heart defects (CCHD) Data on outcomes of CCHD specifically in late preterm infants are exceedingly scarce. The preterm newborn with associated complex CHD presents many intricate problems to clinicians who take care (neonatologist, cardiologist, cardiothoracic surgeon). Therapies used for the preterm neonate without heart disease frequently need to be altered in the presence of heart disease and those needed for management of heart disease may need to be altered because of prematurity. The population of newborn born preterm is at higher risk for postoperative death and short and long term complications than term newborn with the same CHD and the causes of this are multifactorial. Technical issue related to small cardiac structure, immaturity of other organ systems, decreased nutritional and cardiac reserve, increased risks of bleeding, abnormal chest wall mechanics after sternotomy can all together account for this epidemiologic data. In past years these findings were related in particular to low-birth weight infants and conventional management was oriented to await a threshold weight in order to reduce bypass-related morbidities. From 1990 rates of LPB have risen and now account for 75% of all preterm births. Whether late preterm infants with CHD, who may be only marginally more immature than their term counterparts, remain at risk for adverse outcome in unclear. Some recent papers do demonstrate the independent effect of LPB on mortality and morbidity if a CHD is present and this issue emerge as an important factor for a correct counseling. Natarajan have observed that the weight at surgical intervention was significantly lower and age higher in the late preterm infants compared to those delivered at term. Late preterm infants had significantly higher rates of NEC and seizures, with a greater risk of supplemental oxygen and tube feeding at discharge. Costello have examined mortality and morbidity stratified by gestational age, reporting for LPB group with CHD an hospital mortality rate of 16.4% compared to 2.6-8% in the term group. The exact mechanism of this vulnerability remains unclear although functional immaturity of the lung and the brain are plausible aetiologies. Altered intrinsic cardiac mechanism could play a role in adverse outcome of late preterm with CHD. Gestational age at delivery can be a risk factor over which clinicians might have some control. Before birth the challenge is planning the time and the place for the delivery of a foetus with CHD. After birth the challenge is not waiting for obtain an arbitrary correct weight for surgery but working in a complex team to discuss each case in order to maximize outcome. Domande inerenti la relazione del Dott. Stefano Fiocchi

Seeds of prevention: The impact on health behaviors of young adolescent girls in Uttar Pradesh, India, a cluster randomized control trial

Of the world's 1.2 billion adolescents (10–19 years), India is home to the largest number globally, about 243 million. However not much is known about the health of young adolescent girls (11–14 years) in India who enter puberty with substantial nutritional and health deficits. Identifying early adolescence as a “gateway” moment, the Saloni pilot study is arandomized control trial (RCT) to improve nutrition, hygiene and reproductive health behaviors in 30 schools in rural Uttar Pradesh (UP), India. A prevention model that includes Sadharanikaran, an ancient Indian theory of communication, guided the development of the intervention.The Saloni strategy includes a 10 session in-school intervention based on compassion, self efficacy, emotional well being, peer and parental support, packaged in the form of short, easy-to-use instructional modules. A diary designed to engage adolescent girls is provided to each girl.The cluster RCT was conducted from January 2010 to October 2011 with adolescent girls (11–14 years of age) in Hardoi district. The trial is a two-level, nested RCT with the unit of randomization being the block with 15 schools in the intervention arm and 15 schools in the control arm. A sample of 1200 girls was randomly selected.The intervention had a significant impact on more than 13 preventive health behaviors. About 65 percent girls in the intervention group had adopted 13 or more health behaviors at end line compared 4.5 percent in the control group at end line and 5 percent at baseline. Behavioral impact was demonstrated in all three areas of nutrition, hygiene and reproductive health. The study provides evidence that early adolescence is indeed a “gateway moment” to build nutritional and health reserves.

Lipid and Moisture Content Modeling of Amphidromous Dolly Varden Using Bioelectrical Impedance Analysis

AbstractThe physiological well‐being or condition of fish is most commonly estimated from aspects of individual morphology. However, these metrics may be only weakly correlated with nutritional reserves stored as lipid, the primary form of accumulated energy in fish. We constructed and evaluated bioelectrical impedance analysis (BIA) models as an alternative method of assessing condition in amphidromous Dolly Varden Salvelinus malma collected from nearshore estuarine and lotic habitats of the Alaskan Arctic. Data on electrical resistance and reactance were collected from the lateral and ventral surfaces of 192 fish, and whole‐body percent lipid and moisture content were determined using standard laboratory methods. Significant inverse relationships between temperature and resistance and reactance prompted the standardization of these data to a constant temperature using corrective equations developed herein. No significant differences in resistance or reactance were detected among spawning and nonspawning females after accounting for covariates, suggesting that electrical pathways do not intersect the gonads. Best‐fit BIA models incorporating electrical variables calculated from the lateral and ventral surfaces produced the strongest associations between observed and model‐predicted estimates of proximate content. These models explained between 6% and 20% more of the variability in laboratory‐derived estimates of proximate content than models developed from single‐surface BIA data and 32% more than models containing only length and weight data. While additional research is required to address the potential effects of methodological variation, bioelectrical impedance analysis shows promise as a way to provide high‐quality, minimally invasive estimates of Dolly Varden lipid or moisture content in the field with only small increases in handling time.Received June 17, 2013; accepted December 3, 2013

Regulation of vitellogenin genes in insects

AbstractVitellogenins (Vg) genes code for the major egg yolk protein precursor in insects and many other oviparous species. In insects, the Vg gene is expressed extra‐ovarially in the fat body in sex‐, tissue‐ and stage‐specific manners. During the reproductive phase, the Vg mRNA is expressed in large quantities, which is then translated, secreted into hemolymph and ultimately taken up by the developing oocytes through receptor‐mediated endocytosis. Once sequestered, the Vgs are stored as vitellin (Vn), the main nutritional reserve for the developing embryo. The regulation of Vg genes is directly under the control of hormones at the transcriptional level. Hormones involved in Vg gene transcription are juvenile hormone (JH), ecdysteroids and some neuropeptides. The overall understanding that has emerged is that the insects can be classified, based on the system of hormonal regulation of Vg gene transcription, into three groups: (i) insects (like most of hemipterans) that use only JH for Vg gene transcription; (ii) insects (like dipterans) that need both JH and ecdysteroids for Vg regulation; and (iii) insects like lepidopterans that require JH, ecdysteroids and additional hormones to regulate their reproductive biology. However, why insect species diverge in using different hormones to govern their reproductive physiology remains unclear. The present contribution focuses on the current status of knowledge regarding the regulation of Vg genes in insects. Besides a brief information on biochemical and molecular features, the role of Vg genes as a target of endocrine disruptors will be addressed. Also, the molecular mechanism of Vg gene regulation will be discussed.

Host response, malnutrition and oral diseases. Part 2.

Acute phase proteins enhance antioxidant defenses; they are involved in the activation of complement components, opsonization and increase in platelet aggregation as well as inhibition of the respiratory burst in the course of inflammation. Malnutrition plays an important role in the course of response of acute phase proteins. The role of nutrients as antioxidants or as key components of antioxidant enzymes is commonly known. In the course of various inflammatory states, including oral diseases, disorders are observed in caloric requirements of the organism and the requirements for specific amino acids. Numerous experimental studies in animals have also confirmed the relationship between protein- calorie malnutrition and hypofunction of the salivary glands. Studies in children with malnutrition syndrome showed a significantly lower volume of saliva compared to properly nourished children. Depleted nutritional reserves due to long-term chronic malnutrition cause a significant reduction in resistance, progressive damage to the oral mucosa, and reduce resistance to colonization and invasion of pathogenic microorganisms.

Novel perennial ryegrass-Neotyphodium endophyte associations: relationships between seed weight, seedling vigour and endophyte presence

Two forage cultivars of perennial ryegrass (Lolium perenne) colonised by the mutualistic fungal endophyte Neotyphodium lolii, strain AR37, were used to investigate relationships between seed weight, seed vigour and endophyte presence. Seed was separated into six fractions according to weight, with each fraction divided into two further groups with the first being subject to accelerated ageing. Seed germination rates and proportions of viable and total endophyte frequencies were assessed for each fraction. Heavier fractions of seed produced a higher number of endophyte infected seedlings sooner than the lighter fractions for both cultivars. The highest proportion of viable endophyte was found in the fastest germinating perennial ryegrass seed for all weight fractions, from both cultivars, indicating a strong relationship between endophyte presence and seed germination rate. For one of the cultivars, after accelerated ageing, as seed weight increased the proportion of viable endophyte increased and the discrepancy between the proportion of endophyte in fresh and accelerated aged seed was reduced. This implies that for this cultivar heavier ryegrass seed provides a more favourable habitat to the dormant endophyte than lighter seed during storage and/or allowed for a greater biomass of endophyte hyphae to proliferate in the seed tissues prior to seed dormancy, thus allowing the fungus to develop more propagules and greater nutritional reserves.

Extreme Costs of Mating for Male Two-Spot Ladybird Beetles

Male costs of mating are now thought to be widespread. The two-spot ladybird beetle (Adalia bipunctata) has been the focus of many studies of mating and sexual selection, yet the costs of mating for males are unknown. The mating system of A. bipunctata involves a spermatophore nuptial gift ingested by females after copulation. In this study, we investigate the cost to males of mating and of transferring spermatophores in terms of lifespan, ejaculate production and depletion of nutritional reserves. We found that males faced a strong trade-off between mating and survival, with males that were randomly assigned to mate a single time experiencing a 53% reduction in post-mating lifespan compared to non-mating males. This is among the most severe survival costs of a single mating yet reported. However, spermatophore transfer did not impact male survival. Instead, the costs associated with spermatophores appeared as a reduced ability to transfer spermatophores in successive matings. Furthermore, males ingested more food following spermatophore transfer than after matings without spermatophores, suggesting that spermatophore transfer depletes male nutritional reserves. This is to our knowledge the first report of an effect of variation in copulatory behaviour on male foraging behaviour. Overall, our study highlights the advantages of assessing mating costs using multiple currencies, and suggests that male A. bipunctata should exhibit mate choice.

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Introduction: To estimate the relation between BMI (Body Mass Index) with length of stay in the ICU and hospital. Methods: Patients admitted between Jan, 2012 and July, 2013 were included and data was assessed for retrospective analysis. A total of 878 patients were included and the variables collected included age, gender, APS (acute physiology score), predicted ICU length of stay (PIS) and predicted hospital length of stay (PHS), predicted mortality, actual ICU stay(AIS) and actual hospital stay (AHS), and actual mortality in context of BMI. World Health Organization classification of BMI for obesity was used for the study. Data was extracted through the APACHE- IV scoring system. We used analysis of variance and logistic regression analysis with SPSS version 22 (SPSS, Chicago, IL). Results: Increase in APS was found with increase in BMI but surprisingly the correlation was not found to be statistically significant. Mean ICU stay was 4.85, 5.21, 5.34, 6.20, 6.96 days for normal BMI, overweight, obesity class I, II, and III respectively. Both PIS and AIS correlated with increase in BMI in linear fashion (P < 0.01). Similarly, both PHS and AHS correlated with increase in BMI in linear fashion (P < 0.01). Surprisingly, no significant correlation was found between BMI and predicted ICU mortality or actual ICU mortality. Likewise, no significant correlation was found between age and gender of patients with ICU and hospital length of stay. Conclusions: BMI is related linearly with the ICU and hospital length of stay which could be explained by various comorbid conditions associated with obesity. However, absence of statistically significant correlation between increasing BMI with APS and ICU mortality was surprising, but supports the findings of previously published studies. Various theories have been proposed for this obesity paradox; for instance high level of anti-inflammatory cytokines, better nutritional reserve, and effective adrenal steroid synthesis in the critically ill obese population. It would seem, however, that obesity is an independent predictor of the ICU duration, and that should be factored into current reimbursement equations in our evolving health care environment.

Larval nutrition differentially affects adult fitness and Plasmodium development in the malaria vectors Anopheles gambiae and Anopheles stephensi

BackgroundMosquito fitness is determined largely by body size and nutritional reserves. Plasmodium infections in the mosquito and resultant transmission of malaria parasites might be compromised by the vector’s nutritional status. We studied the effects of nutritional stress and malaria parasite infections on transmission fitness of Anopheles mosquitoes.MethodsLarvae of Anopheles gambiae sensu stricto and An. stephensi were reared at constant density but with nutritionally low and high diets. Fitness of adult mosquitoes resulting from each dietary class was assessed by measuring body size and lipid, protein and glycogen content. The size of the first blood meal was estimated by protein analysis. Mosquitoes of each dietary class were fed upon a Plasmodium yoelii nigeriensis-infected mouse, and parasite infections were determined 5 d after the infectious blood meal by dissection of the midguts and by counting oocysts. The impact of Plasmodium infections on gonotrophic development was established by dissection.ResultsMosquitoes raised under low and high diets emerged as adults of different size classes comparable between An. gambiae and An. stephensi. In both species low-diet females contained less protein, lipid and glycogen upon emergence than high-diet mosquitoes. The quantity of larval diet impacted strongly upon adult blood feeding and reproductive success. The prevalence and intensity of P. yoelii nigeriensis infections were reduced in low-diet mosquitoes of both species, but P. yoelii nigeriensis impacted negatively only on low-diet, small-sized An. gambiae considering survival and egg maturation. There was no measurable fitness effect of P. yoelii nigeriensis on An. stephensi.ConclusionsUnder the experimental conditions, small-sized An. gambiae expressed high mortality, possibly caused by Plasmodium infections, the species showing distinct physiological concessions when nutrionally challenged in contrast to well-fed, larger siblings. Conversely, An. stephensi was a robust, successful vector regardless of its nutrional status upon emergence. The data suggest that small-sized An. gambiae, therefore, would contribute little to malaria transmission, whereas this size effect would not affect An. stephensi.

Role of nutritional reserves and body size in Anopheles gambiae males mating success

A better knowledge of the different parameters that account for male mating success in the wild is critical to the development of genetic control strategies. In this study, we measured energy budgets (total sugar and glycogen) as the daily energetic investment in swarming males of An. gambiae s.s. M and S molecular forms from two different field locations, VK7 and Soumousso. We also looked at the difference between energetic reserves in mated males compared to unmated ones, and assessed wing length in both molecular forms to explore whether this phenotypic trait was involved in swarming behavior or mating success. The current study showed that the energetic cost of 25min of swarming was around 50% of the male's sugar (M form: 48.5%, S form: 56.2%) and glycogen (M form: 53.1%, S form: 59%) reserves. However, no difference in carbohydrate content was observed between mated and unmated males. Mated males were found to be bigger than unmated ones, while intermediate size of males is advantageous in mating system, both in M and S molecular forms and when collected in two different locations. Regardless of the collection location, no difference in wing size was observed in swarming males collected early or late during a particular swarm. The results are discussed in the context sexual selection in different ecological locations.

The shape of the placental surface at birth and colorectal cancer in later life

Many chronic diseases, including certain cancers, may originate through variations in the supply of nutrients to the fetus. These variations change gene expression and permanently set the structure and function of the body, a process known as programming. Fetal nutrition depends on the mother's metabolism and nutritional reserves, and on the placenta's ability to transfer nutrients from mother to baby. In this study, we examine how colorectal cancer is related to maternal and placental characteristics. We ascertained 275 cases of colorectal cancer among the 20,431 people in the Helsinki Birth Cohort, who were born during 1924-1944 and whose body size at birth was recorded, together with the shape and size of the placenta. Hazard ratios for colorectal cancer increased as the placental surface became longer and more oval. The hazard ratio was 2.3 (95% CI 1.2-4.7) among people in whom the difference between the length and breadth of the surface exceeded 6 cm, compared with those in whom there was no difference. Colorectal cancer was unrelated to other placental measurements or to body size at birth. An oval placental surface at birth is associated with later colorectal cancer. The shape of the placental surface is determined by events at around 8-12 weeks gestation. We speculate that, if the spiral arteries open prematurely, the surface becomes more oval and the fetus is at risk of oxidative damage at a time when the colon is differentiating.

Exopolymer Diversity and the Role of Levan in Bacillus subtilis Biofilms

Exopolymeric substances (EPS) are important for biofilm formation and their chemical composition may influence biofilm properties. To explore these relationships the chemical composition of EPS from Bacillus subtilis NCIB 3610 biofilms grown in sucrose-rich (SYM) and sucrose-poor (MSgg and Czapek) media was studied. We observed marked differences in composition of EPS polymers isolated from all three biofilms or from spent media below the biofilms. The polysaccharide levan dominated the EPS of SYM grown biofilms, while EPS from biofilms grown in sucrose-poor media contained significant amounts of proteins and DNA in addition to polysaccharides. The EPS polymers differed also in size with very large polymers (Mw>2000 kDa) found only in biofilms, while small polymers (Mw<200 kD) dominated in the EPS isolated from spent media. Biofilms of the eps knockout were significantly thinner than those of the tasA knockout in all media. The biofilm defective phenotypes of tasA and eps mutants were, however, partially compensated in the sucrose-rich SYM medium. Sucrose supplementation of Czapek and MSgg media increased the thickness and stability of biofilms compared to non-supplemented controls. Since sucrose is essential for synthesis of levan and the presence of levan was confirmed in all biofilms grown in media containing sucrose, this study for the first time shows that levan, although not essential for biofilm formation, can be a structural and possibly stabilizing component of B. subtilis floating biofilms. In addition, we propose that this polysaccharide, when incorporated into the biofilm EPS, may also serve as a nutritional reserve.

Gene expression profiles during embryo development in Brassica napus

AbstractThe seed in angiosperms is produced through coordinated development of the embryo, endosperm and seed coat. In dicots, most of the seed mass is taken up by the embryo with nutritional reserves stored in the cotyledons. During embryogenesis, well‐coordinated developmental and genetic programmes establish the embryonic body plan, and the associated complex metabolic pathways result in the production of diverse nutrients and deposition of important seed storage reserves. To gain insights into the genetic programmes that operate during embryo development in Brassica napus L. (canola), an important oilseed crop, we performed gene and protein expression analyses. We used the key stages from single‐cell zygote to mature embryo to generate comprehensive EST and proteome data sets. Analysis of these data sets identified 20 183 genes and 2607 proteins that are differentially expressed across different stages of embryo development. B. napus genes share high degree of homology with Arabidopsis and display stage‐specific and shared expression patterns associated with developmental and metabolic pathways. Together, this study has generated useful new molecular and genomic resources for embryo development in B. napus.

Plant systemic induced responses mediate interactions between root parasitic nematodes and aboveground herbivorous insects.

Insects and nematodes are the most diverse and abundant groups of multicellular animals feeding on plants on either side of the soil–air interface. Several herbivore-induced responses are systemic, and hence can influence the preference and performance of organisms in other plant organs. Recent studies show that plants mediate interactions between belowground plant parasitic nematodes (PPNs) and aboveground herbivorous insects. Based on the knowledge of plant responses to pathogens, we review the emerging insights on plant systemic responses against root-feeding nematodes and shoot-feeding insects. We discuss the potential mechanisms of plant-mediated indirect interactions between both groups of organisms and point to gaps in our knowledge. Root-feeding nematodes can positively or negatively affect shoot herbivorous insects, and vice versa. The outcomes of the interactions between these spatially separated herbivore communities appear to be influenced by the feeding strategy of the nematodes and the insects, as well as by host plant susceptibility to both herbivores. The potential mechanisms for these interactions include systemic induced plant defense, interference with the translocation and dynamics of locally induced secondary metabolites, and reallocation of plant nutritional reserves. During evolution, PPNs as well as herbivorous insects have acquired effectors that modify plant defense responses and resource allocation patterns to their advantage. However, it is also known that plants under herbivore attack change the allocation of their resources, e.g., for compensatory growth responses, which may affect the performance of other organisms feeding on the plant. Studying the chemical and molecular basis of these interactions will reveal the molecular mechanisms that are involved. Moreover, it will lead to a better understanding of the ecological relevance of aboveground–belowground interactions, as well as support the development of sustainable pest management technologies.

Coordenação temporal da degradação das reservas dos cotilédones de jatobá (Himenaea courbaril L.)

The plant germination is a delicate phase of the development. The correct use of the nutritional reserves could define seedling or death. In this work we highlight the main particularities of jatoba germination, presenting the already known metabolic control points and discussing the future perspectives in the field, focusing the temporal coordination involved in this process

Variation in energy reserves and role of body size in the mating system ofAnopheles gambiae

Anopheles gambiae mates in flight. Males gather at stationary places at sunset and compete for incoming females. Factors that account for male mating success are not known but are critical for the future of any genetic control strategy. The current study explored variations in nutritional reserves (sugars, glycogen, lipids, and proteins) in wild-caught swarming and resting males and evaluated the effect of body size and wing symmetry on male mating success. Our results showed that glycogen and sugar reserves are mobilized for flight. Males consume proportionally 5.9-fold as much energy derived from sugars in swarming activities than when they are at rest. Mated males were on average bigger than unmated ones (P<0.0001). A strong correlation between the left and right wings in both mated and unmated males was found and additional analysis on fluctuating asymmetry did not show any indication of mated males being more symmetrical than unmated ones. The distribution of wing size of mated males was focused around a central value, suggesting that intermediate size of males is advantageous in the An. gambiae mating system. The results are discussed in the context of sexual selection.