Ecological drivers of body size evolution and sexual size dimorphism in short-horned grasshoppers (Orthoptera: Acrididae).

Sexual size dimorphism (SSD) is widespread and variable in nature. Although female-biased SSD predominates among insects, the proximate ecological and evolutionary factors promoting this phenomenon remain largely unstudied. Here, we employ modern phylogenetic comparative methods on eight subfamilies of Iberian grasshoppers (85 species) to examine the validity of different models of evolution of body size and SSD and explore how they are shaped by a suite of ecological variables (habitat specialization, substrate use, altitude) and/or constrained by different evolutionary pressures (female fecundity, strength of sexual selection, length of the breeding season). Body size disparity primarily accumulated late in the history of the group and did not follow a Brownian motion pattern, indicating the existence of directional evolution for this trait. We found support for the converse of Rensch's rule (i.e. females are proportionally bigger than males in large species) across all taxa but not within the two most speciose subfamilies (Gomphocerinae and Oedipodinae), which showed an isometric pattern. Our results do not provide support for the fecundity or sexual selection hypotheses, and we did not find evidence for significant effects of habitat use. Contrary to that expected, we found that species with narrower reproductive window are less dimorphic in size than those that exhibit a longer breeding cycle, suggesting that male protandry cannot solely account for the evolution of female-biased SSD in Orthoptera. Our study highlights the need to consider alternatives to the classical evolutionary hypotheses when trying to explain why in certain insect groups males remain small.

The role of environment and core-margin effects on range-wide phenotypic variation in a montane grasshopper.

The integration of genetic information with ecological and phenotypic data constitutes an effective approach to gain insight into the mechanisms determining interpopulation variability and the evolutionary processes underlying local adaptation and incipient speciation. Here, we use the Pyrenean Morales grasshopper (Chorthippus saulcyi moralesi) as study system to (i) analyse the relative role of genetic drift and selection in range-wide patterns of phenotypic differentiation and (ii) identify the potential selective agents (environment, elevation) responsible for variation. We also test the hypothesis that (iii) the development of dispersal-related traits is associated with different parameters related to population persistence/turnover, including habitat suitability stability over the last 120 000 years, distance to the species distribution core and population genetic variability. Our results indicate that selection shaped phenotypic differentiation across all the studied morphological traits (body size, forewing length and shape). Subsequent analyses revealed that among-population differentiation in forewing length was significantly explained by a temperature gradient, suggesting an adaptive response to thermoregulation or flight performance under contrasting temperature regimes. We found support for our hypothesis predicting a positive association between the distance to the species distribution core and the development of dispersal-related morphology, which suggests an increased dispersal capability in populations located at range edges that, in turn, exhibit lower levels of genetic variability. Overall, our results indicate that range-wide patterns of phenotypic variation are partially explained by adaptation in response to local environmental conditions and differences in habitat persistence between core and peripheral populations.

Evidence of subtle departures from Mendelian segregation in a wild lesser kestrel (Falco naumanni) population.

Some alleles are inherited more frequently than expected from Mendel's rule. This phenomenon, known as transmission ratio distortion (TRD), is found in a broad variety of taxa, but it is thought to be unusual and occurs at a low frequency in any particular population. Here, we used seven microsatellite markers to search for possible TRD in a wild lesser kestrel (Falco naumanni) population. Among the nine alleles analysed with at least 200 known meioses for each sex, we found that two of them (156-AG5 in males and 362-FN1.11 in females) presented subtle (k=0.6) but significant departures from Mendelian segregation. Moreover, in a sample of 53 alleles with at least 15 known meioses, we found a positive correlation between their transmission rates and their frequencies in the population. To estimate the transmission scores for the loci and individuals, we developed a method that allowed us to discover that another locus, FP-46, showed significant TRD, despite the lack of a significant deviation from parity for the alleles considered individually. Finally, we found a consistent transmission bias both within loci and within individuals across loci. Inter-individual differences in TRD support the idea that distorters act over several loci that are evenly distributed across the whole genome, particularly in individuals bearing the distorter alleles. Overall, these findings suggest that TRD might be a more widespread phenomenon than previously revealed by analyses at the allele level.

Temporal variation of heterozygosity-based assortative mating and related benefits in a lesser kestrel population.

Heterozygosity as a target of mate choice has received much attention in recent years and there is growing evidence supporting its role in the evolution of mate preferences. In this study we analyse mating patterns in relation to heterozygosity in a lesser kestrel (Falco naumanni) population intensively monitored over six study years (2002-2007). The magnitude of heterozygosity-based assortative mating varied over time, being particularly patent in the last study years (2006, 2007). We have found evidence that this mating pattern entails both direct and indirect-genetic benefits. Clutch size increased with female heterozygosity and more heterozygous males raised a higher number of fledglings particularly in those years when the strength of the heterozygosity-based assortative mating was markedly higher. In the last study year, parent-offspring correlation of heterozygosity was stronger and higher than the expected if individuals would have randomly mated with respect to heterozygosity. Overall, our results offer empirical support to the heterozygous mate hypothesis of sexual selection but suggest that genetic diversity may act as a temporally variable target for mate choice.

What should we weigh to estimate heterozygosity, alleles or loci?

The interest to study the effects of inbreeding in natural populations has increased in the last years. Several microsatellite-derived metrics have recently been developed to infer inbreeding from multilocus heterozygosity data without requiring detailed pedigrees that are difficult to obtain in open populations. Internal relatedness (IR) is currently the most widespread used index and its main attribute is that allele frequency is incorporated into the measure. However, IR underestimates heterozygosity of individuals carrying rare alleles. For example, descendants of immigrants paired with natives (normally more outbred) bearing novel or rare alleles would be considered more homozygous than descendants of native parents. Thus, the analogy between homozygosity and inbreeding that generally is carried out would have no logic in those cases. We propose an alternative index, homozygosity by loci (HL) that avoids such problems by weighing the contribution of each locus to the homozygosity index depending on their allelic variability. Under a wide range of simulated scenarios, we found that our index (HL) correlated better than both IR and uncorrected homozygosity (H(O)), measured as proportion of homozygous loci) with genome-wide homozygosity and inbreeding coefficients in open populations. In these populations, which are likely to prevail in nature, the use of HL instead of IR reduced considerably the sample sizes required to achieve a given statistical power. This is likely to have important consequences on the ability to detect heterozygosity fitness correlations assuming the relationship between genome-wide heterozygosity and fitness traits.

The effects of the minimum threshold condition for breeding on offspring sex-ratio adjustment in the lesser kestrel.

We propose a model for sex-ratio adjustment complementary to that of Trivers and Willard. In addition to the three basic assumptions of the Trivers-Willard model, our model assumes that the sex with more variable reproductive success (normally male) is also the sex less constrained for reproduction. This assumption seems realistic, because several studies have demonstrated that poor-condition males may adopt alternative mating strategies and sire some offspring, whereas females have physiological constraints for gestation or egg production that cannot be avoided. Thus, under these circumstances, sons of both poor and good condition would be more valuable for parents than daughters, whereas daughters would be relatively more valuable than sons at intermediate condition. This model predicts, therefore, a U-shaped relationship between parental condition and offspring sex ratio. We present a case study for the monogamous lesser kestrel (Falco naumanni) that fulfills the assumptions and predictions of the model. The minimum body condition for breeding, measured as pectoral thickness, was lower for sons than for daughters. Below this minimum, males had a higher chance of breeding than females. Above this minimum, however, the lifetime reproductive success was condition dependent in males but not in females. Thus, males in better body condition attain, on average, higher reproductive success than females. Offspring sex ratio varied with the size of the father's ornaments and mother condition according to the U-shaped pattern predicted by the model.

Static lung volumes: reference values from a Latin population of Spanish descent.

BACKGROUND AND OBJECTIVES: The aim of this study was to develop a set of prediction equations and 90% confidence intervals for static lung volumes using the multibreath helium equilibration method from a sample of asymptomatic Caucasian subjects of Spanish descent. Moreover, these equations were compared with those of previous studies. METHODS: Measurements of static lung volumes using techniques recommended by the American Thoracic Society and the European Community for Steel and Coal were carried out on a selected sample of 591 healthy nonsmoking volunteers (305 men and 286 women) aged 18-88 years, living in the metropolitan area of Valencia, on the east coast of Spain. Multiple regression analysis using height, age and weight as independent variables were used to provide predicted values for both sexes. These reference values were compared with other sets of prediction equations reported in the literature using an independent sample of 69 subjects (32 men and 37 women). RESULTS: Simple linear regression equations using age, height and body weight predicted all the subdivisions of lung volumes (vital capacity, expiratory reserve volume (ERV), inspiratory capacity, functional residual capacity (FRC), residual volume (RV), total lung capacity (TLC), FRC/TLC and RV/TLC) as well as more complex equational models. The distribution of residuals fulfilled the assumptions of multiple regression analysis (independence, homoscedasticity and Gaussian distribution of residuals), except for ERV, using simple linear models. The derived equations did not differ significantly from most of the previously reported equations and were usually superior in their ability to predict the lung volumes. CONCLUSIONS: The use of the present prediction equations is recommended in the Latin population of Spanish descent and in populations with similar Caucasian characteristics.

[Prognostic features of residual pleural thickening in metapneumonic pleural effusion]. / Factores predictivos del engrosamiento pleural residual en el derrame pleural metaneumónico.

Residual pleural thickening (RPT) develops in some patients after metapneumonic pleural effusion (MPE). Our aim was to identify factors that predict the development of RPT by retrospectively analyzing patients with MPE secondary to bacterial pneumonia in our practice from 1992 through April 1997. Patients were assigned to groups based on the presence or not of RPT (> 10 mm) three months or more after diagnosis of MPE. One hundred twenty-eight patients were included in the analysis. Seventy-nine patients (62%) developed RPT and 49 (38%) did not. Patients with RPT had significantly lower glucose levels and pH and higher LDH levels in pleural fluid. A higher percentage of patients with RPT had loculate pleural effusions and empyema, and they more often required insertion of drains. Logistic regression analysis showed that only glucose < 40 mg/dl (OR: 3.4; CI 95%: 2.3 to 4.5; p < 0.05) and the presence of pus collected from the initial thoracocentesis (OR: 3.6; CI 95%: 2.6 to 4.5; p < 0.01) were significantly associated with increased risk of developing residual pachypleuritis in subjects with MPE.

Pulmonary infection with Nocardia species: a report of 10 cases and review.

Pulmonary nocardiosis (PN) is an infrequent and severe infection due to Nocardia spp., microorganisms that may behave both as opportunists and as primary pathogens. The aim of this study and review was to evaluate the clinical features, evolution and prognostic factors of PN. The study group comprised 10 consecutive patients with pulmonary nocardiosis acquired in a community setting, diagnosed and followed in a tertiary teaching hospital. Chronic obstructive pulmonary disease (COPD), neoplastic disease and human immunodeficiency virus (HIV) infection were the most frequent predisposing factors. Four patients were receiving corticosteroid treatment. Clinical course was chronic and diagnosis was delayed 3 weeks or more in seven of the patients. Lobar or multilobar condensation was the most frequent radiographic pattern. Antimicrobial susceptibility testing showed: 100% sensitivity for amikacin; 83% for imipenem; 71% for cefotaxime; and 71% for trimethoprim-sulphamethoxazole. The disease remained localized in the lung in five cases, with a trend toward chronicity in one with bronchiectasis. In the other five, the disease disseminated, affecting subcutaneous tissue, the central nervous system and the kidney. Three patients died, one with disseminated disease and two who were receiving corticosteroid therapy. The following conclusions were reached: 1) pulmonary nocardiosis is difficult to diagnose, diagnosis is frequently delayed and a high level of suspicion is, thus, required in patients with underlying diseases or chronic corticosteroid therapy; 2) there is frequent dissemination and high mortality; and 3) antimicrobial combinations with proven synergy, such as imipenem and amikacin, are recommended for initial therapy.

[Maximum static respiratory pressures in adults. The reference values for a Mediterranean Caucasian population]. / Presiones respiratorias estáticas máximas en adultos. Valores de referencia de una población caucasiana mediterránea.

The aim of this study was to establish reference values for PImax and PEmax for the Mediterranean adult population. Male and female individuals between 18 and 83 years old meeting the criteria for consideration as references and residing in the metropolitan area of Valencia were assigned by decades to six subgroups, each containing at least 20 men and 20 women. PEmax was obtained from the point of maximum expiration (residual volume) and PImax was the point of maximum inspiration (total lung capacity). The cohort, which finally included 264 subjects (129 men and 135 women), was separated a priori by sex for data analysis. The following types of variables were studied: sociological (employment, educational level and exercise), biometric (age, height and weight) and spirometric results. A linear correlation analysis was performed for each pair of variables and a Kolmogorov-Smirnov test of normality was performed. In order to check the accuracy of PImax and PEmax readings, intra-individual variability was determined by performing three consecutive procedures over 3 days in 39 randomly selected individuals (18 men and 21 women). Significant inter-day and inter-test effects for respiratory pressures were thus ruled out. Predictive equations were worked out using a simple linear model including all predictive variables and eliminating weaker variables in a stepwise manner. Mathematical goodness of fit was assessed by a coefficient for multiple determinations (R2); also determined were the estimated standard error and statistical significance. We also compared observed and estimated values and the behavior of residual values in terms of their independence, normality and homoscedasticity. Reference limits were established by defining percentiles. The equations finally arrived at for men were as follows: PImax (-cmH2O) - 1.03 x Age + 0.59 x Weight + 133.07, PEmax (cmH2O) - 1.31 x Age + 263.12. The equations for women were PImax (-cmH2O) - 0.64 x Age + 125.18, PEmax (cmH2O) - 0.57 x Age + 0.65 x Weight + 116.26. Agreement with the usual references (the Black and Hyatt equations) was analyzed.

[Long-term effects of nasal continuous positive airway pressure on ventilatory patterns of patients with obstructive sleep apnea syndrome]. / Efectos a largo plazo de la CPAP nasal sobre el patrón ventilatorio de los pacientes con síndrome de apnea obstructiva del sueño (SAOS).

We studied 20 patients with obstructive sleep apnea syndrome (OSAS) prospectively, before and after administering continuous positive airway pressure through a nasal mask (CPAPn) at night for 10 months, with the aim of determining the effects of ventilatory pattern of long-term treatment with CPAPn in OSAS patients. The following data were collected for all patients: anthropometric variables, lung function test results, arterial gasometric readings at rest, oxygen alveolar-arterial differential [Dif(A-a)O2)], central respiratory function variables at rest and during hypercapnic stimulus. Mean duration (range) of treatment with CPAPn was 12.5 (10-18) months. We observed a significant increase in PaO2 (p = 0.01) and a decrease in PaCO2 (p = 0.02) with slight variations in body weight and no changes in lung mechanics or in Dif(A-a)O2. The ventilatory pattern at rest showed an increased in VE and in respiratory frequency (p = 0.0003 and p = 0.033, respectively) with non significant changes in VT. The VT/Ti ratio increased (p = 0.015) and P0.1 decreased slightly (p = 0.025). We found no significant changes in the CO2 response slopes of VE or P0.1. In conclusion, CPAPn improves hypoxemia and hypercapnia in OSAS patients, above all by increasing baseline basal ventilation. The exact mechanisms implicated are poorly understood, but our data suggest a certain direct or indirect effect on respiratory muscles, reducing muscle fatigue, thus favoring greater availability during sleep.

[Primary pulmonary hypertension: treatment with prostacyclin before lung transplantation]. / Hipertensión pulmonar primaria: tratamiento con prostaciclina como puente al trasplante pulmonar.

We report our experience with two patients diagnosed of primary pulmonary hypertension who later received lung transplants, with treatment with short-acting pulmonary vasodilators (epoprostenol) provided as a bridge to transplantation. Continuous intravenous perfusion at a dose of 6 ng/kg/min was provided to the first patient, a 19-year-old man, for 26 days. An initial dose of 4 ng/kg/min followed by 6 ng/kg/min was given to the second patient, a 49-year-old woman, for 6 months. Symptoms were drastically reduced in both patients, significantly improving their quality of life.

[Bronchiolitis obliterans organizing pneumonia. Clinical and evolutive features]. / Bronquiolitis obliterante con neumonía organizada. Características clínicas y evolutivas.

A series is here reported of eleven patients with the histological diagnosis of bronchiolitis obliterans with organized pneumonia (BOOP) and the clinical course after one year of corticosteroid therapy. Four patients had idiopathic BOOP, one patient BOOP secondary to bone marrow transplantation and the other six patients had BOOP secondary to inhalation of toxic substances (Ardystil syndrome). The most common radiological feature at the onset of the disease was the presence of bilateral patchy infiltrates; the most common functional finding was a decreased diffusion capacity for carbon monoxide. After one year of follow-up, seven out of the ten patients still alive had a normal radiology and all showed a significant improvement in ventilatory and gasometric parameters.

Epidemic outbreak of interstitial lung disease in aerographics textile workers--the "Ardystil syndrome": a first year follow up.

BACKGROUND: The longer term respiratory effects of massive inhalational exposure of textile printing sprayers to Acramin (the "Ardystil syndrome") are not well established. METHODS: A 12 month follow up of 27 heavily exposed textile sprayers was performed. RESULTS: Twenty one patients experienced cough, 18 dyspnoea, and 17 nose bleeding at initial exposure, with histological evidence of organising pneumonia in 13 cases, radiological abnormalities detected by computed tomographic scanning in 20 cases, and diminution of diffusion capacity to below 80% of predicted in seven cases. At one year after exposure symptoms persisted in 15 cases, radiological alterations in six, and diffusion capacity was reduced in nine. CONCLUSIONS: Whilst most of our patients showed improvement at one year, evidence of persistent lung involvement was present in an appreciable minority of exposed cases.