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Indicator models of sexual selection posit that females choose males on the basis of traits that reveal male genetic quality and thereby enjoy increased offspring production. Here, we report that females of the butterfly Eurema hecabe receive indirect benefits from choosing males based on their ultraviolet (UV) wing coloration, a heritable and condition-dependent trait in this species. We first used a large laboratory-bred pedigree to demonstrate a per-family association between inbreeding and male UV trait value. Females exerted choice for UV-bright males within this protocol, and the average male UV trait value increased over six consecutive generations, presumably due to such selection and despite an increasing rate of pedigree-wide inbreeding. We then experimentally imposed a standard strength of inbreeding upon lines of divergent male UV trait values. Inbreeding depressed the siring performance of low UV treatment males more severely and resulted in a marginal reduction of their UV brightness, which rebounded sharply following subsequent outcrossing. These findings are consistent with the ornament-based signaling of genetic quality as a function of underlying individual-level mutational load. [ABSTRACT FROM AUTHOR]

Viability indicator traits are expected to be integrated extensively across the genome yet sex-limited to ensure that any benefits are sexually concordant. Understanding how such expectations are accommodated requires elucidating the quantitative genetic architecture of candidate traits in and across the sexes. Here we applied an animal modelling approach to partition the autosomal, allosomal, and direct maternal bases of variation in sexual versus non-sexual dorsal wing colouration in the butterfly Eurema hecabe. The sexual colour trait—coherently scattered ultraviolet that is under strong directional selection due to female choice—is brighter and more expansive in males, and overlays non-sexual pigmentary yellow markings that otherwise dominate both wing surfaces in each sex. Our modelling estimated high and sexually equivalent autosomal variances for ultraviolet reflectance (furnishing h 2 ~ 0.58 overall and ~0.75 in males), accompanied by smaller but generally significant Z-linked and maternal components. By contrast, variation in non-sexual yellow was largely attributed to Z-linked sources. Intersexual genetic correlations based upon the major source of variation in each trait were high and not different from 1.0, implying regulation by a pool of genes common to each sex. An expansive autosomal basis for ultraviolet is consistent with its hypothesized role as a genome-wide viability indicator and ensures that both sons and daughters will inherit their father's attractiveness. [ABSTRACT FROM AUTHOR]

The vacuolar H+-ATPase is an enzymatic complex that functions in an ATP-dependent manner to pump protons across membranes and acidify organelles, thereby creating the proton/pH gradient required for membrane trafficking by several different types of transporters. We describe heterozygous point variants in ATP6V0C , encoding the c-subunit in the membrane bound integral domain of the vacuolar H+-ATPase, in 27 patients with neurodevelopmental abnormalities with or without epilepsy. Corpus callosum hypoplasia and cardiac abnormalities were also present in some patients. In silico modelling suggested that the patient variants interfere with the interactions between the ATP6V0C and ATP6V0A subunits during ATP hydrolysis. Consistent with decreased vacuolar H+-ATPase activity, functional analyses conducted in Saccharomyces cerevisiae revealed reduced LysoSensor fluorescence and reduced growth in media containing varying concentrations of CaCl2. Knockdown of ATP6V0C in Drosophila resulted in increased duration of seizure-like behaviour, and the expression of selected patient variants in Caenorhabditis elegans led to reduced growth, motor dysfunction and reduced lifespan. In summary, this study establishes ATP6V0C as an important disease gene, describes the clinical features of the associated neurodevelopmental disorder and provides insight into disease mechanisms. [ABSTRACT FROM AUTHOR]

The article revisits innovations in English language teaching (ELT) approaches and practices. It outlines principles to guide ELT curriculum innovation planning in further studies and identifies state education system-level barriers to curriculum implementation including insufficient professional support for English teachers. Also noted is a strand of ELT curriculum innovation research which explores lived experiences of the curriculum implementation process in classrooms.

In 2018, the A.S. Hornby Educational Trust launched its 'Decentring ELT' initiative, with the aim of identifying, publicizing, and supporting ways in which English language educators in low- and middle-income countries work locally and collaboratively to develop activities that respond to their particular circumstances. This article aims to explore the notion of 'decentring' in ELT by means of a provisional characterization and by presenting examples of activities carried out by ELT teacher associations in Africa, Latin America, and South Asia which involve: localization/devolution; encouragement of success-sharing; support for teacher research; investigation of members' needs and/or capabilities; and/or attempts to bring about wider change. On the basis of feedback received so far on our provisional characterization of decentring, we end by highlighting some ways in which this notion, and outside support for it, may need to be not only extended but also problematized and critiqued. [ABSTRACT FROM AUTHOR]

Sexual selection is thought to be responsible for the rapid divergent evolution of male genitalia with several studies detecting multivariate sexual selection on genital form. However, in most cases, selection is only estimated during a single episode of selection, which provides an incomplete view of net selection on genital traits. Here, we estimate the strength and form of multivariate selection on the genitalia arch of Drosophila simulans when mating occurs in the absence of a competitor and during sperm competition, in both sperm defence and offense roles (i.e., when mating first and last). We found that the strength of sexual selection on the genital arch was strongest during noncompetitive mating and weakest during sperm offense. However, the direction of selection was similar across selection episodes with no evidence for antagonistic selection. Overall, selection was not particularly strong despite genitals clearly evolving rapidly in this species. [ABSTRACT FROM AUTHOR]

Context Interleukin 6 (IL-6) contributes to bone remodeling in preclinical studies. Clinical trials investigating the role of IL-6 in bone remodeling are limited. Objective To investigate if IL-6 regulates bone remodeling in humans. Design Plasma concentrations of the bone resorption marker carboxy-terminal type I collagen crosslinks (CTX) and of the bone formation marker procollagen type 1 N-terminal propeptide (P1NP) were measured during a mixed-meal tolerance test (MMTT) in 3 placebo-controlled human studies. Participants Five healthy individuals participated in study 1; 52 obese individuals, in study 2; and 10 healthy individuals, in study 3. Interventions Study 1 was a single-blinded crossover study consisting of a 1-h infusion of saline (placebo) or the IL-6 receptor antibody tocilizumab followed by an exercise bout. Study 2 was a randomized, double-blinded 12-week exercise training intervention study. Participants received infusions of saline or tocilizumab. Study 3 was a randomized, double-blinded, crossover study consisting of 30 min infusion of saline or IL-6. Main outcomes measures Effect of IL-6 on CTX levels. Results CTX was significantly (P < 0.01) decreased during MMTTs in all 3 studies. Treatment with tocilizumab did not affect exercise or meal induced changes in plasma CTX or P1NP concentrations acutely (study 1) or after a 12-week treatment period (study 2). Exogenous IL-6 had no effect on CTX or P1NP plasma concentrations (study 3). Conclusions IL-6 may not regulate bone remodeling in humans. [ABSTRACT FROM AUTHOR]

Reference price effects on consumer price perceptions are often explained by Helson's adaptation-level theory, in which the cognitive representation of reference price is the prototype of the relevant category. However, recent conceptualizations and empirical evidence suggest the possibility of an exemplar model, which may be specified using Volkmann's range theory or Parducci's range-frequency theory. In two experiments, these three contextual models of reference price effects are pitted against one another. Based on the MANOVA and model fitting, range-frequency theory accounted for reference price effects that the other theories could not, suggesting that consumers compare the target price against specific members of the category rather than the category prototype. A third experiment demonstrated that range and frequency effects are moderated by the stimulus presentation condition, suggesting that consumers place greater weight on extreme prices anchoring the range for internal reference prices than for external reference prices. [ABSTRACT FROM AUTHOR]

Infertility is common in nature despite its obvious cost to individual fitness. Rising global temperatures are predicted to decrease fertility, and male sterility is frequently used in attempts to regulate pest or disease vector populations. When males are infertile, females may mate with multiple males to ensure fertilization, and changes in female mating behavior in turn could intensify selection on male fertility. Fertility assurance is a potentially wide-spread explanation for polyandry, but whether and how it actually contributes to the evolution of polyandry is not clear. Moreover, whether a drop in male fertility would lead to a genetic increase in polyandry depends on whether females respond genetically or through behavioral plasticity to male infertility. Here, we experimentally manipulate male fertility through heat-exposure in Drosophila pseudoobscura , and test female discrimination against infertile males before and after mating. Using isogenic lines, we compare the roles of behaviorally plastic versus genetically fixed polyandry. We find that heat-exposed males are less active and attractive, and that females are more likely to remate after mating with these males. Remating rate increases with reduced reproductive output, indicating that females use current sperm storage threshold to make dynamic remating decisions. After remating with fertile males, females restore normal fecundity levels. Our results suggest that male infertility could explain the evolution of adaptively flexible polyandry, but is less likely to cause an increase in genetic polyandry. [ABSTRACT FROM AUTHOR]

What drives mating system variation is a major question in evolutionary biology. Female multiple mating (polyandry) has diverse evolutionary consequences, and there are many potential benefits and costs of polyandry. However, our understanding of its evolution is biased towards studies enforcing monandry in polyandrous species. What drives and maintains variation in polyandry between individuals, genotypes, populations and species remains poorly understood. Genetic variation in polyandry may be actively maintained by selection, or arise by chance if polyandry is selectively neutral. In Drosophila pseudoobscura, there is genetic variation in polyandry between and within populations. We used isofemale lines to found replicate populations with high or low initial levels of polyandry and tracked polyandry under experimental evolution over seven generations. Polyandry remained relatively stable, reflecting the starting frequencies of the experimental populations. There were no clear fitness differences between high versus low polyandry genotypes, and there was no signature of balancing selection. We confirmed these patterns in direct comparisons between evolved and ancestral females and found no consequences of polyandry for female fecundity. The absence of differential selection even when initiating populations with major differences in polyandry casts some doubt on the importance of polyandry for female fitness. [ABSTRACT FROM AUTHOR]

The rapid evolutionary divergence of male genital structures under sexual selection is well documented. However, variation in female genital traits and the potential for sexual conflict to drive the coevolution between male and female traits has only recently received attention. In many lepidopterans, females possess genital teeth (collectively, signa). Comparative studies suggest these teeth, involved in the deflation of spermatophores, may have coevolved with male spermatophore thickness via sexually antagonistic coevolution in a contest over the rate of deflation of spermatophores within the reproductive tract. We tested the hypothesis that sexual conflict should generate coevolution between genital teeth and spermatophore morphology by examining these traits under experimental manipulation of sexual conflict intensity. Using micro‐CT scanning, we examined spermatophore and teeth morphology in populations of the Indian moth, Plodia interpunctella, which had been evolving for 110 generations under different adult sex‐ratio biases. We found divergence in female signa morphology in response to sexual conflict: females from female‐biased populations (reduced sexual conflict) developed wider signa. However, we found no evidence of coevolution between signa traits and spermatophore thickness as reported from comparative studies. [ABSTRACT FROM AUTHOR]

Multiple mating by females (polyandry) is a widespread behavior occurring in diverse taxa, species, and populations. Polyandry can also vary widely within species, and individual populations, so that both monandrous and polyandrous females occur together. Genetic differences can explain some of this intraspecific variation in polyandry, but environmental factors are also likely to play a role. One environmental factor that influences many fundamental biological processes is temperature. Higher temperatures have been shown to directly increase remating in laboratory studies of insects. In the longer term, high temperature could also help to drive the evolution of larger-scale patterns of behavior by changing the context-dependent balance of costs and benefits of polyandry across environments. We examined the relative influence of rearing and mating temperatures on female remating in populations of Drosophila pseudoobscura that show a latitudinal cline in polyandry in nature, using a range of ecologically relevant temperatures. We found that females of all genotypes remated more at cooler temperatures, which fits with the observation of higher average frequencies of polyandry at higher latitudes in this species. However, the impact of temperature was outweighed by the strong genetic control of remating in females in this species. It is likely that genetic factors provide the primary explanation for the latitudinal cline in polyandry in this species. [ABSTRACT FROM AUTHOR]

Sperm commonly compete within females to fertilize ova, but research has focused on short-term sperm storage: sperm that are maintained in a female for only a few days or weeks before use. In nature, females of many species store sperm for months or years, often during periods of environmental stress, such as cold winters. Here we examine the outcome of sperm competition in the fruit fly Drosophila pseudoobscura, simulating the conditions in which females survive winter. We mated females to two males and then stored the female for up to 120 days at 4°C. We found that the outcome of sperm competition was consistent when sperm from two males was stored for 0, 1 or 30 days, with the last male to mate fathering most of the offspring. However, when females were stored in the cold for 120 days, the last male to mate fathered less than 5% of the offspring. Moreover, when sperm were stored long term the first male fathered almost all offspring even when he carried a meiotic driving sex chromosome that drastically reduces sperm competitive success under short-term storage conditions. This suggests that long-term sperm storage can radically alter the outcome of sperm competition. [ABSTRACT FROM AUTHOR]

Segregation distorters located on sex chromosomes are predicted to sweep to fixation and cause extinction via a shortage of one sex, but in nature they are often found at low, stable frequencies. One potential resolution to this longstanding puzzle involves female multiple mating (polyandry). Because many meiotic drivers severely reduce the sperm competitive ability of their male carriers, females are predicted to evolve more frequent polyandry and thereby promote sperm competition when a meiotic driver invades. Consequently, the driving chromosome's relative fitness should decline, halting or reversing its spread. We used formal modeling to show that this initially appealing hypothesis cannot resolve the puzzle alone: other selective pressures (e.g., low fitness of drive homozygotes) are required to establish a stable meiotic drive polymorphism. However, polyandry and meiotic drive can strongly affect one another's frequency, and polyandrous populations may be resistant to the invasion of rare drive mutants. [ABSTRACT FROM AUTHOR]

STUDY QUESTION Can high-resolution array comparative genomic hybridization (CGH) analysis of DNA samples from women with primary ovarian insufficiency (POI) improve the diagnosis of the condition and identify novel candidate genes for POI? SUMMARY ANSWER A mutation affecting the regulatory region of growth differentiation factor 9 (GDF9) was identified for the first time together with several novel candidate genes for POI. WHAT IS KNOWN ALREADY Most patients with POI do not receive a molecular diagnosis despite a significant genetic component in the pathogenesis. STUDY DESIGN, SIZE, DURATION We performed a case–control study. Twenty-six patients were analyzed by array CGH for identification of copy number variants. Novel changes were investigated in 95 controls and in a separate population of 28 additional patients with POI. The experimental procedures were performed during a 1-year period. PARTICIPANTS/MATERIALS, SETTING, METHODS DNA samples from 26 patients with POI were analyzed by a customized 1M array-CGH platform with whole genome coverage and probe enrichment targeting 78 genes in sex development. By PCR amplification and sequencing, the breakpoint of an identified partial GDF9 gene duplication was characterized. A multiplex ligation-dependent probe amplification (MLPA) probe set for specific identification of deletions/duplications affecting GDF9 was developed. An MLPA probe set for the identification of additional cases or controls carrying novel candidate regions identified by array-CGH was developed. Sequencing of three candidate genes was performed. MAIN RESULTS AND THE ROLE OF CHANCE Eleven unique copy number changes were identified in a total of 11 patients, including a tandem duplication of 475 bp, containing part of the GDF9 gene promoter region. The duplicated region contains three NOBOX-binding elements and an E-box, important for GDF9 gene regulation. This aberration is likely causative of POI. Fifty-four patients were investigated for copy number changes within GDF9, but no additional cases were found. Ten aberrations constituting novel candidate regions were detected, including a second DNAH6 deletion in a patient with POI. Other identified candidate genes were TSPYL6, SMARCC1, CSPG5 and ZFR2. LIMITATIONS, REASONS FOR CAUTION This is a descriptive study and no functional experiments were performed. WIDER IMPLICATIONS OF THE FINDINGS The study illustrates the importance of analyzing small copy number changes in addition to sequence alterations in the genetic investigation of patients with POI. Also, promoter regions should be included in the investigation. STUDY FUNDING/COMPETING INTEREST(S) The study was supported by grants from the Swedish Research council (project no 12198 to A.W. and project no 20324 to A.L.H.), Stockholm County Council (E.I., A.W. and K.R.W.), Foundation Frimurare Barnhuset (A.N., A.W. and M.B.), Karolinska Institutet (A.N., A.L.H., E.I., A.W. and M.B.), Novo Nordic Foundation (A.W.) and Svenska Läkaresällskapet (M.B.). The funding sources had no involvement in the design or analysis of the study. The authors have no competing interests to declare. TRIAL REGISTRATION NUMBER Not applicable. [ABSTRACT FROM PUBLISHER]

Most insects harbour a variety of maternally inherited endosymbionts, the most widespread being Wolbachia pipientis that commonly induce cytoplasmic incompatibility ( CI) and reduced hatching success in crosses between infected males and uninfected females. High temperature and increasing male age are known to reduce the level of CI in a variety of insects. In Drosophila simulans, infected males have been shown to mate at a higher rate than uninfected males. By examining the impact of mating rate independent of age, this study investigates whether a high mating rate confers an advantage to infected males through restoring their compatibility with uninfected females over and above the effect of age. The impact of Wolbachia infection, male mating rate and age on the number of sperm transferred to females during copulation and how it relates to CI expression was also assessed. As predicted, we found that reproductive compatibility was restored faster in males that mate at higher rate than that of low mating and virgin males, and that the effect of mating history was over and above the effect of male age. Nonvirgin infected males transferred fewer sperm than uninfected males during copulation, and mating at a high rate resulted in the transfer of fewer sperm per mating irrespective of infection status. These results indicate that the advantage to infected males of mating at a high rate is through restoration of reproductive compatibility with uninfected females, whereas uninfected males appear to trade off the number of sperm transferred per mating with female encounter rate and success in sperm competition. This study highlights the importance Wolbachia may play in sexual selection by affecting male reproductive strategies. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to determine bone mineral density (BMD), markers of bone metabolism, fractures, and steroids reflecting hormonal control in adult males with congenital adrenal hyperplasia (CAH). Subjects, methods, and design:We compared CAH males with 21-hydroxylase deficiency (n=30), 19-67 years old, with age- and sex-matched controls (n=32). Subgroups of CYP21A2 genotypes, age, glucocorticoid preparation, poor control vs overtreatment, and early vs late (>36 months) diagnosis were studied. BMD measured by dual energy X-ray absorptiometry and markers of bone metabolism and androgens/17-hydroxyprogesterone levels were investigated. Results: All, including older (>30 years), CAH patients had lower BMD in all measured sites compared with control subjects. The null group demonstrated lower BMD in more locations than the other groups. Osteoporosis/osteopenia was present in 81% of CAH patients compared with 32% in controls (⩾30 years). Fracture frequency was similar, osteocalcin was lower, and fewer patients than controls had vitamin D insufficiency. IGF1 was elevated in the milder genotypes. In patients, total body BMD was positively correlated to weight, BMI, total lean body mass, and triglycerides, and negatively to prolactin. Patients on prednisolone had lower BMD and osteocalcin levels than those on hydrocortisone/cortisone acetate. Patients with poor control had higher femoral neck BMD. There were no differences in BMD between patients with an early vs late diagnosis. Conclusions: CAH males have low BMD and bone formation markers. BMD should be monitored, adequate prophylaxis and treatment established, and glucocorticoid doses optimized to minimize the risk of future fractures. [ABSTRACT FROM AUTHOR]

Males and females experience differences in gene dose for loci in the nonrecombining region of heteromorphic sex chromosomes. If not compensated, this leads to expression imbalances, with the homogametic sex on average exhibiting greater expression due to the doubled gene dose. Many organisms with heteromorphic sex chromosomes display global dosage compensation mechanisms, which equalize gene expression levels between the sexes. However, birds and Schistosoma have been previously shown to lack chromosome-wide dosage compensation mechanisms, and the status in other female heterogametic taxa including Lepidoptera remains unresolved. To further our understanding of dosage compensation in female heterogametic taxa and to resolve its status in the lepidopterans, we assessed the Indian meal moth, Plodia interpunctella. As P. interpunctella lacks a complete reference genome, we conducted de novo transcriptome assembly combined with orthologous genomic location prediction from the related silkworm genome, Bombyx mori, to compare Z-linked and autosomal gene expression levels for each sex. We demonstrate that P. interpunctella lacks complete Z chromosome dosage compensation, female Z-linked genes having just over half the expression level of males and autosomal genes. This finding suggests that the Lepidoptera and possibly all female heterogametic taxa lack global dosage compensation, although more species will need to be sampled to confirm this assertion. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Fertility in males with congenital adrenal hyperplasia (CAH) is reported from normal to severely impaired. Therefore, we investigated fertility/fecundity, social/sexual situation, and pituitary–gonadal function in CAH males. SUBJECTS AND METHODS: The patient cohort comprised 30 males, aged 19–67 years, with 21-hydroxylase deficiency. Their fertility was compared with age-matched national population data. For the evaluation of social/sexual factors and hormone status, age-matched controls were recruited (n=32). Subgroups of different ages (<30 years and older) and CYP21A2 genotypes (null (severe salt-wasting (SW)), I2splice (milder SW), and I172N (simple virilizing)) were also studied. Patients underwent testicular ultrasound examination (n=21) and semen analysis (n=14). RESULTS: Fertility was impaired in CAH males compared with national data (0.9±1.3 vs 1.8±0.5 children/father, P<0.001). There were no major differences in social and sexual factors between patients and controls apart from more fecundity problems, particularly in the I172N group. The patients had lower testosterone/estradiol (E2) ratio and inhibin B, and higher FSH. The semen samples were pathological in 43% (6/14) of patients and sperm concentration correlated with inhibin B and FSH. Testicular adrenal rest tumors (TARTs) were found in 86% (18/21). Functional testicular volume correlated positively with the testosterone/E2ratio, sperm concentration, and inhibin B. Patients with pathological semen had increased fat mass and indications of increased cardiometabolic risk. CONCLUSIONS: Fertility/fecundity was impaired in CAH males. The frequent occurrence of TARTs resulting in testicular insufficiency appears to be the major cause, but other factors such as elevated fat mass may contribute to a low semen quality. [ABSTRACT FROM AUTHOR]

Objective: Most patients with NR5A1 (SF-1) mutations and poor virilization at birth are sex-assigned female and receive early gonadectomy. Although studies in pituitary-specific Sf-1 knockout mice suggest hypogonadotropic hypogonadism, little is known about endocrine function at puberty and on germ cell tumor risk in patients with SF-1 mutations. This study reports on the natural course during puberty and on gonadal histology in two adolescents with SF-1 mutations and predominantly female phenotype at birth. Design and methods: Clinical and hormonal data and histopathological studies are reported in one male and one female adolescent with, respectively, a nonsense mutation (c.9T>A, p.Tyr3X) and a deletion of the first two coding exons (NCBI36/hg18 Chr9:g.(126306276-126307705)-(126303229- 126302828)del) of NR5A1, both predicted to fully disrupt gene function. Results: LH and testosterone concentrations were in the normal male range, virilization was disproportionate to the neonatal phenotype. In the girl, gonadectomy at 13 years revealed incomplete spermatogenesis and bilateral precursor lesions of testicular carcinoma in situ. In the boy, at the age of 12, numerous germ cells without signs of malignancy were present in bilateral testicular biopsy specimen. Conclusions: In SF-1 mutations, the neonatal phenotype poorly predicts virilization at puberty. Even in poorly virilized cases at birth, male gender assignment may allow spontaneous puberty without signs of hypogonadotropic hypogonadism, and possibly fertility. Patients with SF-1 mutations are at increased risk for malignant germ cell tumors. In case of preserved gonads, early orchidopexy and germ cell tumor screening is warranted. The finding of premalignant and/or malignant changes should prompt gonadectomy or possibly irradiation. [ABSTRACT FROM AUTHOR]

Sex chromosome dosage compensation was once thought to be required to balance gene expression levels between sex-linked and autosomal genes in the heterogametic sex. Recent evidence from a range of animals has indicated that although sex chromosome dosage compensation exists in some clades, it is far from a necessary companion to sex chromosome evolution, and is in fact rather rare in animals. This raises questions about why complex dosage compensation mechanisms arise in some clades when they are not strictly needed, and suggests that the role of sex-specific selection in sex chromosome gene regulation should be reassessed. We show there exists a tremendous diversity in the mechanisms that regulate gene dosage and argue that sexual conflict may be an overlooked agent responsible for some of the variation seen in sex chromosome gene dose regulation. [ABSTRACT FROM AUTHOR]

Males and females share a genome and express many shared phenotypic traits, which are often selected in opposite directions. This generates intralocus sexual conflict that may constrain trait evolution by preventing the sexes from reaching their optimal phenotype. Furthermore, if present across multiple loci, intralocus sexual conflict can result in a gender load that may diminish the benefits of sexual selection and help maintain genetic variation for fitness. Despite the importance of intralocus sexual conflict, surprisingly few empirical studies conclusively demonstrate its operation. We show that the pattern of multivariate selection acting on three sexually dimorphic life-history traits (development time, body size, and longevity) in the Indian meal moth, Plodia interpunctella, is opposing for the sexes. Moreover, we combined our estimates of selection with the additive genetic variance-covariance matrix (G) to predict the evolutionary response of the life-history traits in the sexes and showed that the angle between the vector of responses and the vector of sexually antagonistic selection was almost orthogonal at 84.70°:. Thus, G biases the predicted response of life-history traits in the sexes away from the direction of sexually antagonistic selection, confirming the presence of strong intralocus sexual conflict in this species. Despite this, sexual dimorphism has evolved in all of the life-history traits examined suggesting that mechanism(s) have evolved to resolve this conflict and allow the sexes to reach their life-history optima. We argue that intralocus sexual conflict is likely to play an important role in the evolution of divergent life-history strategies between the sexes in this species. [ABSTRACT FROM AUTHOR]

In Drosophila melanogaster, the DDT resistance allele (DDT-R) is beneficial in the presence of DDT. Interestingly, DDT-R also elevates female fitness in the absence of DDT and existed in populations before DDT use. However, DDT-R did not spread regardless of DDT-independent selective advantages in females. We ask whether sexual antagonism could explain why DDT-R did not spread before pesticide use. We tested pre- and post-copulatory male fitness correlates in two genetic backgrounds into which we backcrossed the DDT-R allele. We found costs to DDT-R that depended on the genetic background in which DDT-R was found and documented strong epistasis between genetic background and DDT-R that influenced male size. Although it remains unclear whether DDT-R is generally sexually antagonistic, or whether the fitness costs noted would be sufficient to retard the spread of DDT-R in the absence of DDT, general fitness advantages to DDT-R in the absence of DDT may be unlikely. [ABSTRACT FROM AUTHOR]

Sexual selection is responsible for many of the most spectacular displays in nature, and female preference for certain males is central to much of this. However, female preference is relatively poorly understood, particularly the relative importance of a female's genes, the environment and their interaction on her preference. We investigated preference in a no-choice design using Drosophila melanogaster iso-female lines and find that there are genotype-by-environment interactions for female preference. Whereas the choosiness of some female genotypes differed little across environments, that of others differed greatly, so that the choosiness rank of females in one environment did not necessarily predict their rank in another. Furthermore, the genetic variance underlying preference also varied across environments. These findings have important consequences for the evolution of female preference and the male sexual traits preference targets. [ABSTRACT FROM AUTHOR]

Selfish genetic elements occur in all living organisms and often cause reduced fertility and sperm competitive ability in males. In the fruit fly Drosophila pseudoobscura, the presence of a sex-ratio distorting X-chromosome meiotic driver Sex Ratio (SR) has been shown to promote the evolution of increased female remating rates in laboratory populations. This is favored because it promotes sperm competition, which decreases the risk to females of producing highly female-biased broods and to their offspring of inheriting the selfish gene. Here, we show that non-SR males in these SR populations evolved an increased ability to suppress female remating in response to the higher female remating rates, indicating male–female coevolution. This occurred even though SR was rare in the populations. This was further supported by a correlation between females’ remating propensity and males’ ability to suppress female remating across populations. Thus SR can generate sexual conflict over female remating rate between females and the noncarrier males that make up the majority of the males, promoting evolution of increased ability of males to suppress female remating. [ABSTRACT FROM AUTHOR]

Male genitalia evolve through sexual selection and, in insects, tend to show negative static allometry, low phenotypic variation, and are usually relatively small. Much less is known about the genetic variation and heritability of male genitalia. Additionally, in instances where the intromittent organ is greatly elongated, it is unclear whether typical patterns of genital scaling and variation also apply. In the present study, we investigated the allometry, variation, and heritability of male genital length in the seedbug, Lygaeus equestris, a species with a greatly elongated intromittent organ (i.e. almost as long as male body size). We found that genital length was negatively allometric, in spite of its great length, and was no more variable than nongenital traits. Additionally, genital length was significantly heritable and had considerable evolvability. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98, 400–405. [ABSTRACT FROM AUTHOR]

Selfish genetic elements (SGEs) are ubiquitous in animals and often associated with low male fertility due to reduced sperm number in male carriers. In the fruit fly Drosophila pseudoobscura, the meiotic driving X chromosome “sex ratio” kills Y-bearing sperm in carrier males (SR males), resulting in female only broods. We competed SR males against the ejaculates of noncarrying standard males (ST males), and quantified the number of sperm transferred by SR and ST males to females. We show that SR males are very poor sperm competitors, which is partly related to transfer of fewer sperm during mating. However, sperm numbers alone cannot explain the observed paternity reduction, indicating SR males’ sperm may be of reduced quality, possibly due to damage during the killing of the noncarrying Y-sperm. The reduction in sperm competitive ability due to SR is large enough to potentially stabilize the spread of sex ratio drive through populations. The poor sperm competitive ability of SR males coupled with their low fitness as mates could favor increased remating by females to reduce paternity by SR males. Given the generally poor performance of SGE-carrying males in sperm competition, this may generate strong selective pressure favoring polyandry in many species. [ABSTRACT FROM AUTHOR]

Maternally inherited parasites are known to impose a wide variety of reproductive manipulations upon their host. These often produce strong selection on the host to suppress the parasite, resulting in a reduction in the frequency of the parasite. However, in the butterfly Hypolimnas bolina, infected with a Wolbachia bacterium, field data demonstrate that suppression of the male-killing phenotype does not depress parasite frequency. Here we test and verify one hypothesis to explain this apparent paradox— Wolbachia induces a second phenotype, Cytoplasmic Incompatibility (CI), in populations where host suppression has evolved. We further demonstrate that the capacity to induce CI has not evolved de novo, but instead is instantaneously expressed upon the survival of infected males. The significance of these results is threefold: (1) multiple phenotypes can provide Wolbachia with the means to maintain itself in a host following suppression of a single manipulative phenotype; (2) the ability to induce CI can remain hidden in systems in which male-killing is observed, just as the ability to induce male-killing may be obscured in strains exhibiting CI; (3) the evolutionary maintenance of CI in a system in which it is not expressed suggests a functional link with male-killing or other traits under selection. [ABSTRACT FROM AUTHOR]

The genetic incompatibility avoidance hypothesis as an explanation for the polyandrous mating strategies (mating with more than one male) of females of many species has received significant attention in recent years. It has received support from both empirical studies and a meta-analysis, which concludes that polyandrous females enjoy increased reproductive success through improved offspring viability relative to monandrous females. In this study we investigate whether polyandrous female Drosophila simulans improve their fitness relative to monandrous females in the face of severe Wolbachia-associated reproductive incompatibilities. We use the results of this study to develop models that test the predictions that Wolbachia should promote polyandry, and that polyandry itself may constrain the spread of Wolbachia. Uniquely, our models allow biologically relevant rates of incompatibility to coevolve with a polyandry modifier allele, which allows us to evaluate the fate of the modifier and that of Wolbachia. Our empirical results reveal that polyandrous females significantly reduce the reproductive costs of Wolbachia, owing to infected males being poor sperm competitors. The models show that this disadvantage in sperm competition can inhibit or prevent the invasion of Wolbachia. However, despite the increased reproductive success obtained by polyandrous females, the spread of a polyandry modifier allele is constrained by any costs that might be associated with polyandry and the low frequency of incompatible matings when Wolbachia has reached a stable equilibrium. Therefore, although incompatibility avoidance may be a benefit of polyandry, our findings do not support the hypothesis that genetic incompatibilities caused by Wolbachia promote the evolution of polyandry. [ABSTRACT FROM AUTHOR]

The maternally inherited bacterium Wolbachia pipientis infects 25–75% of arthropods and manipulates host reproduction to improve its transmission. One way Wolbachia achieves this is by inducing cytoplasmic incompatibility (CI), where crosses between infected males and uninfected females are inviable. Infected males suffer reduced fertility through CI and reduced sperm production. However, Wolbachia induce lower levels of CI in nonvirgin males. We examined the impact of Wolbachia on mating behaviour in male Drosophila melanogaster and D. simulans, which display varying levels of CI, and show that infected males mate at a higher rate than uninfected males in both species. This may serve to increase the spread of Wolbachia, or alternatively, may be a behavioural adaptation employed by males to reduce the level of CI. Mating at high rate restores reproductive compatibility with uninfected females resulting in higher male reproductive success thus promoting male promiscuity. Increased male mating rates also have implications for the transmission of Wolbachia. [ABSTRACT FROM AUTHOR]

Male nutrient provisioning is widespread in insects. Females of some species use male-derived nutrients for increased longevity and reproductive output. Despite much research into the consequences of paternal nutrient investment for male and female fitness, the heritability, and therefore the potential of this trait to respond to selection, has rarely been examined. Males of several butterfly species provide the female with nutrients in the spermatophore at mating. Females of the green-veined white butterfly Pieris napi (Lepidoptera: Pieridae) use male donations both for developing eggs (resulting in higher lifetime fecundity of multiply mated females), but also for their somatic maintenance (increasing longevity). Using half-sib, father-son regression and full-sib analyses, 1 showed that paternal nutrient investment is heritable, both in terms of the absolute but also the relative size of the spermatophore (controlling for body size). Male size and spermatophore size were also genetically correlated. Furthermore, a separate study showed male genotype had a significant effect on female longevity and lifetime fecundity. In contrast, male genotype had no influence on the immediate egg-laying rate of females following mating, suggesting limited scope for male manipulation of immediate female oviposition. These results indicate that females may derive both direct (increased lifetime fecundity and longevity) and indirect (sons with greater reproductive success) fitness benefits from paternal nutrient donations in this species. [ABSTRACT FROM AUTHOR]

The maternally inherited bacterium, Wolbachia pipientis, manipulates host reproduction by rendering uninfected females reproductively incompatible with infected males (cytoplasmic incompatibility, CI). Hosts may evolve mechanisms, such as mate preferences, to avoid fitness costs of Wolbachia infection. Despite the potential importance of mate choice for Wolbachia population dynamics, this possibility remains largely unexplored. Here we model the spread of an allele encoding female mate preference for uninfected males alongside the spread of CI inducing Wolbachia. Mate preferences can evolve but the spread of the preference allele depends on factors associated with both Wolbachia infection and the preference allele itself. Incomplete maternal transmission of Wolbachia, fitness costs and low CI, improve the spread of the preference allele and impact on the population dynamics of Wolbachia. In addition, mate preferences are found in infected individuals. These results have important consequences for the fate of Wolbachia and studies addressing mate preferences in infected populations. [ABSTRACT FROM AUTHOR]

Presents a study which concluded that the maternal effects on offspring depend on female mating pattern and offspring environment in yellow dung flies. Materials and methods; Results; Discussion.

Abstract Butterflies in the family Lycaenidae that have obligate associations with ants frequently exhibit ant-dependent egg laying behaviour. In a series of field and laboratory choice tests, we assessed oviposition preference of the Australian lycaenid Jalmenus evagoras in response to different species and populations of ants. Females discriminated between attendant and nonattendant ant species, between attendant ant species, and to some extent, between populations of a single ant species. When preferences were found, ovipositing butterflies preferred their locally predominant attendant ant species and geographically proximate attendant ant populations. A reciprocal choice test using adults from a generation of butterflies reared in the absence of ants indicated a genetic component to oviposition preference. Individual females were flexible with respect to oviposition site choice, often ovipositing on more than one treatment during a trial. Preferences arose from a hierarchical ranking of ant treatments. These results are discussed in terms of local adaptation and its possible significance in the diversification of ant-associated lycaenids. [ABSTRACT FROM AUTHOR]

Butterflies show considerable variability in female mating frequency, ranging from monandrous species to females mating several times in their lifetime. Degree of polyandry also varies within species, with some females only mating once and others mating multiply. Previous studies have shown that one reason for female multiple mating is to obtain nutritious male donations that both increase the longevity of females and result in higher lifetime fecundity. Despite the presence of male nutrient donations, some females of the green-veined white butterfly (Pieridae: Pieris napi) never mate more than once. In this study, we examined this apparent paradox. We assessed to what degree polyandry is under genetic control by a full-sib analysis, and we also estimated the broad sense heritability of female lifetime fecundity in singly mated females. Both polyandry and lifetime fecundity have a genetic component. However, degree of polyandry appears to be traded off against reduced longevity when denied the opportunity to mate more than once. It is possible that female P. napi display different reproductive strategies, with some females relying on male donations to realize their potential fecundity and others relying on their own resources for egg production. In nature, polyandrous females may be prevented from mating multiply due to unfavorable weather. We discuss the possibility that the trade-off between degree of polyandry and life span when singly mated may affect the maintenance of genetic variability in female mating frequency in this species. Possible reasons for these different reproductive strategies are discussed. [ABSTRACT FROM AUTHOR]

Female mating rate is fundamental to evolutionary biology as it determines the pattern of sexual selection and sexual conflict. Despite its importance, the genetic basis for female remating rate is largely unknown and has only been demonstrated in one species. In paternally investing species there is often a conflict between the sexes over female mating rate, as females remate to obtain male nutrient donations and males try to prevent female remating to ensure high fertilization success. Butterflies produce two types of sperm: fertilizing, eupyrene sperm, and large numbers of nonfertile, apyrene sperm. The function of apyrene sperm in the polyandrous, paternally investing green-veined white butterfly, Pieris napi, is to fill the female’s sperm storage organ thereby reducing her receptivity. However, there is large variation in number of apyrene sperm stored. Here, I examine the genetic basis to this variation, and if variation in number of apyrene sperm stored is related to females’ remating rate. The number of apyrene sperm stored at the time of remating has a genetic component and is correlated with female remating tendency, whereas no such relationship is found for fertilizing sperm. The duration of the nonreceptivity period in P. napi also has a genetic component and is inversely related to the degree of polyandry. Sexual conflict over female remating rate appears to be present in this species, with males using their apyrene sperm to exploit a female system designed to monitor sperm in storage. Ejaculates with a high proportion of nonfertile sperm may have evolved to induce females to store more of these sperm, thereby reducing remating. As a counter-adaptation, females have evolved a better detection system to regain control over their remating rate. Sexually antagonistic co-evolution of apyrene sperm number and female sperm storage may be responsible for ejaculates with predominantly nonfertile sperm in this butterfly. [ABSTRACT FROM AUTHOR]

Presents a study of the mating success and phenotype of male field crickets Gryllus bimaculatus and their offspring. Materials and methods of the study; Results and discussions.

Presents information on a study which determined the significance of multiple mates in the cricket Gryllus bimaculatus. Materials and methods used on the study; Results and discussion.

Studies the relationship of the spermatophore size of male bushcrickets with the refractory period of females and fertilization success. Role of nuptial gifts during courtship and copulation activities of insects; Variation in spermatophore size as a function of mating effort rather than paternal investment.