Sexual size dimorphism and assortative mating for morphological traits in Passer domesticus

In this study, assortative mating for different morphological traits was studied in a captive population of house sparrows (Passer domesticus). Males were larger than females. Assortative mating was found for tail length, wing length and general body size. Males with larger badge size mated with females with longer tails. The strongest assortative mating occurred for tail length (r=0.77), and this assortative mating remained significant after controlling for wing length, mass and tarsus length, suggesting that it was not an artefact of assortative mating for body size. The possibility of sexual selection for tail length in the house sparrow is discussed.     

Assortative mating for anthropometric traits in parents of Punjabi twins

The marital correlations between 97 pairs of parents of Punjabi twins reveal positive phenotypic assortative mating for body traits while almost random mating with respect to cranio-facial traits. There is no evidence of any significant negative assortative mating for any of the 50 traits. The results have been compared with those from other world populations. The data contradict the earlier reported hypothesis that assortative mating is associated with lowered fertility.     

Study of transferrin (TF), group specific component (GC) and alpha-1-antitrypsin (PI) subtypes in the populations of Basque country (Spain)

Genetic polymorphisms of three serum proteins Transferrin (TF), Group Specific Component (GC), and Alpha-l-Antitrypsin were investigated by isoelectric focusing (IEF) in the Basque and non Basque populations from Vizcaya and Guipuzcoa, Spain. Two of the three genetic systems (TF and PI) showed conclusive genetic heterogeneity between the Basque populations of these two provinces. In addition to the past genetic drift, the present day genetic differentiation in the Basque country seems to be contributed by the unique structure of its populations.     

The role of marker traits in the assortative mating within red crossbills, Loxia curvirostra complex

We conducted mate choice experiments to determine whether differences in calls or bill morphology might influence assortative mating between call types of red crossbills (Loxia curvirostra complex) that have diverged in bill structure to specialize on different species of conifers. Females preferred males that gave calls that matched their own type, but did not prefer males that more closely approximated the average or optimal bill size of the female's call type. These results were consistent with our breeding simulations, which showed that females gained an indirect fitness benefit by choosing a male of her own call type because this reduced the production of offspring with morphologies that fell between adaptive peaks. However, choice based on bill morphology within a call type provided no further benefit. Calls, which crossbills learn from their parents, likely act as a marker trait indicative of the morphological adaptations of the group, allow for easy assessment of potential mates and facilitate rapid divergence under ecological selection.     

Pollinator-mediated assortative mating in mixed ploidy populations of Chamerion angustifolium (Onagraceae)

Establishment of polyploid individuals within diploid populations is theoretically unlikely unless polyploids are reproductively isolated, pre-zygotically, through assortative pollination. Here, we quantify the contribution of pollinator diversity and foraging behaviour to assortative pollen deposition in three mixed-ploidy populations of Chamerion angustifolium (Onagraceae). Diploids and tetraploids were not differentiated with respect to composition of insect visitors. However, foraging patterns of the three most common insect visitors (all bees) reinforced assortative pollination. Bees visited tetraploids disproportionately often and exhibited higher constancy on tetraploids in all three populations. In total, 73% of all bee flights were between flowers of the same ploidy (2x–2x, 4x–4x); 58% of all flights to diploids and 83% to tetraploids originated from diploid and tetraploid plants, respectively. Patterns of pollen deposition on stigmas mirrored pollinator foraging behaviour; 73% of all pollen on stigmas (70 and 75% of pollen on diploid and tetraploid stigmas, respectively) came from within-ploidy pollinations. These results indicate that pollinators contribute to high rates of pre-zygotic reproductive isolation. If patterns of fertilization track pollen deposition, pollinator–plant interactions may help explain the persistence and spread of tetraploids in mixed-ploidy populations.     

Description and evaluation of a sampling strategy for macroinvertebrate communities in Basque rivers (Spain)

This paper describes the results of a pilot study on the macroinvertebrate communities occurring in a fast-flowing river in Northern Spain. The objective was to devise a sampling strategy for use on a series of Basque rivers included in a site classification study. Two contrasted sites were chosen for the pilot-study on the River Lea (Bizkaia), at the headwaters and near the mouth. Taxon richness and distribution across the river was examined using two sampling techniques at each site. It was concluded that, ideally, timed sampling units should be collected at intervals across a river transect in order to acquire a representative list of taxa. In addition, adequate sampling in marginal areas was stressed because a number of taxa appeared to be exclusive to marginal areas. Sampling location and total sampling effort were also shown to be a major consideration when taxon lists were acquired for the application of routine biological surveillance techniques.     

Demographic and health patterns in a rural community from the Basque area in Spain (1800-1990)

In this work, the evolution of demographic and health patterns in a Basque rural population from Spain is analysed, as they relate to progress in demographic and epidemiological transition. For this purpose, parochial record data on 13,298 births and 9,215 deaths, registered during the 19th and 20th centuries (1800-1990), were examined. The study area is a rural community called Lanciego, which is located at the southern end of the Rioja Alavesa area (Alava Province, Basque Country). In Lanciego, demographic transition began in the final decade of the 19th century, when a definite, irreversible trend began towards a reduction in mortality. The decrease in the birth rate came later than that in the death rate, and did not start until the 1930s. The post-transitional stage seemed to be reached in the 1970s, when the birth and death rates showed values below 20 per 1,000. Other characteristics observed for the post-transitional stage in Lanciego are: (i) very low rates of infant mortality achieved at the expense of effective control of exogenous mortality; (ii) the mortality curve by ages changes from a U-shape (typical of populations with a high infant mortality rate and low life expectancy at birth) to a J-shape more characteristic of modern societies where longevity and life expectancy are considerably higher; (iii) a certain level of over-mortality among women in the senior age group (>65); and (iv) a significant proportion of mortality in recent times (1970-90) resulting from cardiovascular diseases and malignant neoplasms (post-transition causes). This last point is in contrast with observations from the first four decades of the 20th century, when infectious diseases and respiratory ailments were determining factors in mortality among this population. The data provided by the study of the variation over time in demographic and health patterns indicate that reducing the risk of mortality is one of the most important preconditions for fertility decline.     

Floral traits and mating system of Hibiscus trionum (Malvaceae)

Variations in floral traits and floral structures influence plant mating systems. Hibiscus trionum produces large, showy flowers typical of an outcrossing species, yet flowers are autonomously self-pollinated. In this study, we measured floral morphology, breeding system and outcrossing rate estimated by ISSR markers. Results indicate that two types of flowers were observed in H. trionum, and the type I with bigger petals appears to be much more visible to pollinators, demonstrated by than type II flowers with smaller petals. The flowers with hand pollination were closed 1 h earlier than intact flowers, whether they were type I or II. The relationship between the amount of pollen deposited on the stigma and the number of seeds per capsule was highly significant, and 80 or more pollens per flower can make the mean number of seeds (mean = 37) in H. trionum. Delayed selfing in H. trionum did not provide a large contribution to seed production, since reproductive assurance were only 0.025. However, successful reproduction of 72.5% flowers in the absence of pollinators suggested that selfing provides reproductive assurance during seasons, in which pollinators were limiting. The multilocus outcrossing rates in different populations varied from 0.982 to 1.200, with a mean of 1.116. Our data provide an empirical demonstration of a predominantly outcrossing species with potential delayed selfing when pollinators are absent or scarce.     

Clinal variation in morphology and assortative mating in the soldier beetle, Chauliognathus pennsylvanicus (Goleoptera: Cantharidae)

In north Georgia populations of the soldier beetle, Chauliognathus pennsylvanicus , the length of the elytral spot varies clinally. At the southern end of a 200 km cline the distribution of spot length is unimodal with longer spot lengths predominating while at the northern end of the cline the distribution is bimodal but with shorter spot lengths being more frequent. North of the cline only short elytral spot lengths are observed, while the converse is true south of the cline. The strength of assortative mating on the basis of elytral spot length increases from south to north along the cline, resulting in complete pre-mating isolation between short and long spot length morphs at the north end of the cline. Laboratory mate choice tests indicate that assortative mating in the field is not the result of differential timing of activity or microhabitat choice but rather that it represents a real behavioural preference. Individuals from monomorphic populations on either side of the cline do not mate assortatively in the laboratory, indicating that reproductive isolation has evolved on the cline.     

The antimicrobial effects of propolis collected in different regions in the Basque Country (Northern Spain)

The antimicrobial activity of 19 propolis extracts prepared in different solvents (ethanol and propylene glycol) (EEP/PEP), was evaluated against some bacterial and fungal isolates using the agar-well diffusion method. It was verified that all the samples tested showed antimicrobial activity, although results varied considerably between samples. Results revealed that both types of propolis extracts showed highly sensitive antimicrobial action against Gram-positive bacteria and fungi at a concentration of 20% (Staphylococcus aureus, Streptococcus mutans, Candida albicans and Saccharomyces cerevisae) with a minimal inhibitory concentration (MIC) ranging from 0.5 to 1.5 mg/ml, with a moderate effect against Streptococcus pyogenes (MIC from 17 to 26 mg/ml). To our knowledge, this is the first study showing elevated antimicrobial activity against Gram-negative bacteria [Salmonella enterica (MIC from 0.6 to 1.4 mg/ml)] and lesser activity against Helicobacter pylori (MIC from 6 to 14 mg/ml), while Escherichia coli was resistant. This concluded that the Basque propolis had a strong and dose-dependent activity against most of the microbial strains tested, while database comparison revealed that phenolic substances were responsible for this inhibition, regardless of their geographical origin and the solvent employed for extraction. Statistical analysis showed no significant differences (P ≤ 0.05) between EEP and PEP extracts.     

Recent data about age at menarche in the biscay province (Basque Country, Spain)

Data on menarcheal age were collected by thestatus quo method on a sample of 808 schoolgirls (8–19 years of age), from the Margen Izquierda area of the Biscay province (Basque Country). Probit analysis provided a mean age at menarche of 12.5±0.05 years with a standard deviation of 1.0 years. The result was compared with data from other previous Basque studies and related to age at PHV of the same sample.     

Time trends and determinants of completed family size in a rural community from the Basque area of Spain (1800-1969)

The focus of this work is the analysis of changes in completed family size and possible determinants of that size over time, in an attempt to characterize the evolution of reproductive patterns during the demographic transition. With this purpose in mind, time trends are studied in relation to the mean number of live births per family (as an indirect measure of fertility), using family reconstitution techniques to trace the reproductive history of each married woman. The population surveyed is a Spanish rural community called Lanciego, located at the southern end of the province of Alava (Basque Country). A total of 24,510 parish records of baptisms, marriages and burials made between 1800 and 1969 were examined to obtain the demographic data set. For each reconstituted family, the variables included in the study were the number of live births per family or family size (FAMS), year of marriage (YEAR), age at marriage of both partners (AMAN, AWOM), wife's age at the end of marriage (WEND), duration of marriage (MARD), age at first maternity (A1CH), length of reproductive span (REPS) and number of children dying before their first anniversary (MINF). Through a principal component analysis, three factors were found that explained more than 75% of the total variance. Association of variables in factors I and III was particularly useful in characterizing the variability of mean family size in pre-transitional, transitional and post-transitional cohorts. During demographic transition, a decreasing trend is observed in the variables FAMS, REPS and MINF, while variables AWOM, AMAN, WEND and A1CH show a tendency to increase over the 20th century. Results obtained by multiple regression analysis confirm that the best predictors of family size (dependent variable) were REPS and MINF, which between them explained over 85% of the total variation in FAMS (R2 = 0.853). In Lanciego, birth control seems to be present on the evidence of an increase in age at first maternity and a decrease in age at last parturition, indicating that the beginning of the reproductive span is delayed and its end is brought forward. Interaction between family size and infant mortality is discussed in the light of various hypotheses, including replacement of descendants, the so-called biological effect and the theory of r and k selection.     

Inbreeding effects on mating system traits for two species of Lupinus (Leguminosae)

The consequences of inbreeding for reproductive traits were investigated for two closely related annual lupines that differ in their mating system. Lupinus bicolor (Leguminosae) is a primarily selling species while Lupinus nanus outcrosses at intermediate rates. A controlled crossing program was used for each species to produce selfed and outcrossed progeny. These progeny were then grown in a greenhouse and scored for the date of first flower, flower morphology, and autofertility. Selfed progeny of L. bicolor produced significantly smaller flowers but did not differ from outcrossed progeny for the remaining traits. Selfed progeny of L. nanus produced flowers that significantly differed in shape and had fewer ovules than the flowers of outcrossed progeny. Selfed progeny of L. nanus also had significantly lower rates of autofertility in comparison to outcrossed progeny. The significant effects of inbreeding on these mating system traits may indicate the presence of directional dominance at the loci underlying these characters. The consequences of these direct effects of inbreeding on reproductive traits for plants growing in natural populations may include nonadaptive changes in the outcrossing rate between generations.