Sexual size dimorphism (SSD) varies in animals from male biased to female biased. The evolution of SSD is potentially influenced by a number of factors, such as territoriality, fecundity, and ...temporal breeding patterns (explosive vs. prolonged). In general, frogs show female-biased SSD with broad variance among species. Using comparative methods, we examine how different selective forces affect male and female sizes, and we test hypotheses about size-dependent mechanisms shaping SSD in frogs. Male size was weakly associated with SSD in all size classes, and we found no significant association among SSD, male size, temporal breeding pattern, and male territoriality. In contrast, female size best explained SSD variation across all size classes but especially for small-bodied species. We found a stronger evolutionary association between female body size and fecundity, and this fecundity advantage was highest in explosively breeding species. Our data indicate that the fecundity advantage associated with female body size may not be linear, such that intermediate and large females benefit less with body size increases. Therefore, size-dependent selection in females associated with fecundity and breeding patterns is an important mechanism driving SSD evolution in frogs. Our study underscores the fact that lineage-specific ecology and behavior should be incorporated in comparative analyses of animal SSD.
Diagnosis and Management of Infertility: A Review Carson, Sandra Ann; Kallen, Amanda N
JAMA : the journal of the American Medical Association,
2021-Jul-06, 2021-07-06, 20210706, Letnik:
326, Številka:
1
Journal Article
Recenzirano
Odprti dostop
In the US, approximately 12.7% of reproductive age women seek treatment for infertility each year. This review summarizes current evidence regarding diagnosis and treatment of infertility.
...Infertility is defined as the failure to achieve pregnancy after 12 months of regular unprotected sexual intercourse. Approximately 85% of infertile couples have an identifiable cause. The most common causes of infertility are ovulatory dysfunction, male factor infertility, and tubal disease. The remaining 15% of infertile couples have "unexplained infertility." Lifestyle and environmental factors, such as smoking and obesity, can adversely affect fertility. Ovulatory disorders account for approximately 25% of infertility diagnoses; 70% of women with anovulation have polycystic ovary syndrome. Infertility can also be a marker of an underlying chronic disease associated with infertility. Clomiphene citrate, aromatase inhibitors such as letrozole, and gonadotropins are used to induce ovulation or for ovarian stimulation during in vitro fertilization (IVF) cycles. Adverse effects of gonadotropins include multiple pregnancy (up to 36% of cycles, depending on specific therapy) and ovarian hyperstimulation syndrome (1%-5% of cycles), consisting of ascites, electrolyte imbalance, and hypercoagulability. For individuals presenting with anovulation, ovulation induction with timed intercourse is often the appropriate initial treatment choice. For couples with unexplained infertility, endometriosis, or mild male factor infertility, an initial 3 to 4 cycles of ovarian stimulation may be pursued; IVF should be considered if these approaches do not result in pregnancy. Because female fecundity declines with age, this factor should guide decision-making. Immediate IVF may be considered as a first-line treatment strategy in women older than 38 to 40 years. IVF is also indicated in cases of severe male factor infertility or untreated bilateral tubal factor.
Approximately 1 in 8 women aged 15 to 49 years receive infertility services. Although success rates vary by age and diagnosis, accurate diagnosis and effective therapy along with shared decision-making can facilitate achievement of fertility goals in many couples treated for infertility.
The psyllid Cacopsylla chinensis (Yang & Li) (Hemiptera: Psyllidae) is a serious pest of pears in China. To determine and contrast the fitness of the psyllid on two endemic cultivars of Pyrus ...bretschneideri (i.e., BHXS and BSL) and two introduced cultivars of Pyrus communis (i.e., CB and CRB), we analyzed data on the development, survival, and fecundity from C. chinensis individuals reared on the four cultivars. The age-stage, two-sex life table theory was used in order to enable the inclusion of males in the analysis as well as a means of identifying the variation in developmental durations among individuals. Results indicated that C. chinensis can successfully develop and reproduce on all four pear cultivars. However, based on the lower preadult survival rate, longer preadult duration, longer total preoviposition period (TPOP), and lower fecundity that occurred on both cultivars of P. communis, these two cultivars are less favorable hosts for C. chinensis than the P. bretschneideri cultivars. The lower intrinsic rate of increase (r), finite rate of increase (λ), and net reproduction rate (R0) on CB and CRB pears showed these two introduced cultivars are more resistant to C. chinensis than the endemic BHXS and BSL pears. These resistant cultivars would be appropriate candidates for managing C. chinensis. We used the bootstrap technique to estimate the uncertainty of the population parameters (r, λ, R0, etc.), while also demonstrating that it can be used for estimating the 0.025 and 0.975 percentile confidence intervals of the age of survival rate. Graphical Abstract Age-stage, two-sex life table can reveal the survial and stage differentiation for assessment of differences between treatments
Over 40 years ago, Kempton (Biometrics, 35, 1979, 307) reported significant modification to plant community structure following a long‐term fertilization experiment. Many researchers have ...investigated this phenomenon in the years since. Collectively, these studies have shown consistent shifts in rank abundance relationships among species in communities following fertilization. The previous studies indicated that fertilization affects community structure through several critical processes, including trait‐based functional response, reordering of species in rank abundance diagram (RAD), and niche dimensionality, although some questions have remained. How does the species reordering driven by the plant responses cause characteristic trends in temporal changes of RAD? Why are those trends ubiquitous in various systems? To answer those questions, we theoretically investigated the effects of fertilization on community structure based on a colonization model (or Levins model) with competition–fecundity trade‐offs, which can result in the coexistence of multiple species under competition. The model represents characteristic RAD, which can be an adequate tool to study community composition. Our theoretical model comprehensively represents observed trends in rank abundance relationships following long‐term fertilization and suggests that competitive interactions among species are a critical factor in structuring species diversity in plant communities.
Colonization model explained trends in structural change of plant community that results from long‐term fertilization. Our analyses provide new insight into the formation of community structure and species diversity.
Effects of temperature on the survival of the pea crab Afropinnotheres monodi, and on its realized fecundity (number of eggs) and actual fecundity (number of zoeas) were experimentally estimated on ...individuals from the Gulf of Cadiz (Huelva and Cadiz) at Southwestern Spain. The adult crabs of different demographic categories (soft females, hard females, and males) were cultured in seawater (salinity of 36) at six different temperatures: 5, 10, 15, 20, 25, 30 °C. After 42 days of culture, the three demographic categories survive at a wide range of temperatures (10 to 30 °C), although survival was high (88.5% to 98.8%, on average) for adults cultured at temperatures between 15 and 30 °C and moderate (69.4%, on average) for those cultured at 10 °C. When ovigerous females collected in winter (field temperature: 15 °C) were cultured at the four temperatures at which survival rates were high (15, 20, 25 and 30 °C), the actual fecundity average of the first brood decreased from 95.9% for females maintained at 15 °C to 3.2% for those maintained at 30 °C; whereas when females were collected in summer (field temperature: 23 °C) this actual fecundity average only displayed a moderate decrease from of 98.3% at 30 °C to 88.3% at 15 °C. Irrespective of the temperature, the number of eggs of the second brood of each female was on average smaller than that of the first brood. The duration of embryonic development was temperature dependent, becoming shorter as the temperatures increased between 15 °C and 30 °C. The embryonic plus larval development times in the Bay of Cadiz, estimated with a temperature dependent model, lasts from 105 days in winter to 43 days in summer. Besides, the effect of temperature on fecundity in the natural environment was estimated on ovigerous females seasonally collected from Cadiz and Huelva. The realized fecundity of A. monodi is higher than in most brachyurans and increases potentially with the size of the female; within females of the same size, there were no significant differences between seasons or locations, except in Huelva in autumn, when a decrease in fecundity was observed. Adult survivals and development time, expected for this species at the current seawater temperatures in the north of the Iberian Peninsula, suggest that northward expansion of A. monodi constitutes a potential risk to the mussel cultures and bivalve shellfishery catch in that area.
•All the demographic categories of A. monodi can survive from 10 to 30 °C.•Embryonic plus larval development time decreases with increased temperatures.•A. monodi reproduces throughout the year in the Gulf of Cadiz.•A future Northward expansion of A. monodi could infest mussel cultures of Galicia.
The evolution of sexual size dimorphism (SSD) is a long-standing topic in evolutionary biology, but there is little agreement on the extent to which SSD is driven by the different selective forces. ...While sexual selection and fecundity selection have traditionally been proposed as the two leading hypotheses, SSD may also result from natural selection through mechanisms such as sexual niche divergence, which might have reduced resource competition between sexes. Here, we revisited the niche divergence hypothesis by testing the relationship between the sexual overlap in diet and SSD of 56 bird species using phylogenetic comparative analyses. We then assessed how SSD variation relates to the three main hypotheses: sexual selection, fecundity selection, and sexual niche divergence using phylogenetic generalized least squares (PGLS). Then, we compared sexual selection, fecundity selection and niche divergence selection as SSD drivers through phylogenetic confirmatory path analyses to disentangle the possible causal evolutionary relationships between SSD and the three hypotheses. Phylogenetic generalized least squares showed that SSD was negatively correlated with diet overlap, that is, the greater the difference in body size between males and females, the less diet overlap. As predicted by sexual selection theory, the difference in body size between sexes was higher in polygynous species. Confirmatory phylogenetic path analyses suggested that the most likely evolutionary path might include the mating system as a main driver in SSD and niche divergence as a result of SSD. We found no evidence of a role of fecundity selection in the evolution of female-biased SSD. Our study provides evidence that sexual selection has likely been the main cause of SSD and that dietary divergence is likely an indirect effect of SSD.
BACKGROUND:An increasing number of studies have linked air pollution to decreased fertility. Whether this is due to an effect on ovarian reserve is unknown.
METHOD:Our study included 632 women ...attending the Massachusetts General Hospital Fertility Center (2004–2015) who had a measured antral follicle count. Validated spatiotemporal models estimated daily particulate matter <2.5 µg/m (PM2.5) (based on residential address) for the 3 months before the antral follicle count. We analyzed associations with Poisson regression.
RESULTS:Every 2 µg/m increase in estimated PM2.5 exposure was associated with a −7.2% (95% confidence interval = −10.4%, −3.8%) lower antral follicle count adjusting for age, body mass index, smoking status, and year and season of the count. The association of PM2.5 with antral follicle count was stronger among women with female factor infertility (−16.3% per 2 µg/m).
CONCLUSIONS:Among women from an infertility clinic, higher PM2.5 exposure was associated with lower ovarian reserve, raising concern that air pollution may accelerate reproductive aging.
The homeostatic properties of reproduction in aging female Drosophila melanogaster are investigated. Classic studies based on cohort analysis suggest that homeostatic capacity declines gradually as ...daily oviposition rates decline in aging flies. Analysis at the level of individuals gives a very different picture: reproductive homeostasis remains relatively constant for most of adult life until a critical point when oviposition either ceases entirely or continues in dysregulated fashion. The collapse of homeostatic capacity is abrupt. Enhanced homeostasis is associated with increased lifetime fecundity and improved prospects for survival. The fractal concept of lacunarity can be used to parameterize the "roughness" of individual fecundity trajectories and is inversely related to homeostatic capacity.
ABSTRACT
Body size is central to ecology at levels ranging from organismal fecundity to the functioning of communities and ecosystems. Understanding temperature‐induced variations in body size is ...therefore of fundamental and applied interest, yet thermal responses of body size remain poorly understood. Temperature–size (T–S) responses tend to be negative (e.g. smaller body size at maturity when reared under warmer conditions), which has been termed the temperature–size rule (TSR). Explanations emphasize either physiological mechanisms (e.g. limitation of oxygen or other resources and temperature‐dependent resource allocation) or the adaptive value of either a large body size (e.g. to increase fecundity) or a short development time (e.g. in response to increased mortality in warm conditions). Oxygen limitation could act as a proximate factor, but we suggest it more likely constitutes a selective pressure to reduce body size in the warm: risks of oxygen limitation will be reduced as a consequence of evolution eliminating genotypes more prone to oxygen limitation. Thus, T–S responses can be explained by the ‘Ghost of Oxygen‐limitation Past’, whereby the resulting (evolved) T–S responses safeguard sufficient oxygen provisioning under warmer conditions, reflecting the balance between oxygen supply and demands experienced by ancestors. T–S responses vary considerably across species, but some of this variation is predictable. Body‐size reductions with warming are stronger in aquatic taxa than in terrestrial taxa. We discuss whether larger aquatic taxa may especially face greater risks of oxygen limitation as they grow, which may be manifested at the cellular level, the level of the gills and the whole‐organism level. In contrast to aquatic species, terrestrial ectotherms may be less prone to oxygen limitation and prioritize early maturity over large size, likely because overwintering is more challenging, with concomitant stronger end‐of season time constraints. Mechanisms related to time constraints and oxygen limitation are not mutually exclusive explanations for the TSR. Rather, these and other mechanisms may operate in tandem. But their relative importance may vary depending on the ecology and physiology of the species in question, explaining not only the general tendency of negative T–S responses but also variation in T–S responses among animals differing in mode of respiration (e.g. water breathers versus air breathers), genome size, voltinism and thermally associated behaviour (e.g. heliotherms).
In a previous study, immunoproteomics was used to identify a serine protease inhibitor (TsSPI) of
T. spiralis
excretory/secretory (ES) proteins that exhibited an inhibitory effect on trypsin ...enzymatic activity, but the precise role of TsSPI on worm infection and development in its host is not well understood. The objective of the present study was to use RNA interference to ascertain the function of TsSPI in larval invasion and growth. TsSPI-specific small interference RNAs (siRNAs) were delivered to muscle larvae (ML) to silence TsSPI expression by electroporation. Four days after electroporation, the ML transfected with 2 μM siRNA-653 exhibited a 75.75% decrease in TsSPI transcription and a 69.23% decrease in TsSPI expression compared with control ML. Although the silencing of TsSPI expression did not decrease worm viability, it significantly suppressed the larval invasion of intestinal epithelium cells (IEC) (
P
< 0.01), and the suppression was siRNA dose-dependent (
r
= 0.981). The infection of mice with siRNA-653-treated ML produced a 63.71% reduction of adult worms and a 72.38% reduction of muscle larvae. In addition, the length of the adults, newborn larvae, and ML and the fecundity of female
T. spiralis
from mice infected with siRNA-treated ML were obviously reduced relative to those in the control siRNA or PBS groups. These results indicated that the silencing of TsSPI by RNAi suppressed larval invasion and development and decreased female fecundity, further confirming that TsSPI plays a crucial role during the
T. spiralis
lifecycle and is a promising molecular target for anti-
Trichinella
vaccines.
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