Ecological and evolutionary consequences of alternative sex-change pathways in fish.

Sequentially hermaphroditic fish change sex from male to female (protandry) or vice versa (protogyny), increasing their fitness by becoming highly fecund females or large dominant males, respectively. These life-history strategies present different social organizations and reproductive modes, from near-random mating in protandry, to aggregate- and harem-spawning in protogyny. Using a combination of theoretical and molecular approaches, we compared variance in reproductive success (V k*) and effective population sizes (N e) in several species of sex-changing fish. We observed that, regardless of the direction of sex change, individuals conform to the same overall strategy, producing more offspring and exhibiting greater V k* in the second sex. However, protogynous species show greater V k*, especially pronounced in haremic species, resulting in an overall reduction of N e compared to protandrous species. Collectively and independently, our results demonstrate that the direction of sex change is a pivotal variable in predicting demographic changes and resilience in sex-changing fish, many of which sustain highly valued and vulnerable fisheries worldwide.

The ART of mating: alternative reproductive tactics and mating success in a nest-guarding fish.

Behavioural observations in the field of male Mediterranean damselfish Chromis chromis were combined with molecular analyses, using bi-parentally and maternally inherited markers, to investigate reproductive success patterns of alternative reproductive tactics (ARTs) in terms of number of eggs sired and number of females contributing to each nest. Cuckoldry was observed in every nest sampled, with at least two and up to seven sneaker males per nest. The nesting male, however, always significantly fertilized the greater number of eggs (on average 49%) in each clutch, whereas each sneaker fertilized around 7% of the clutch. The average number of females whose eggs were fertilized by nesting males was 6·76 (range 2-13), while each sneaker on average fertilized the eggs of 1·74 (range 1-8) females. Using this sibship reconstruction, some of the factors involved in the regulation of the dynamic equilibrium of reproductive success were investigated between the two ARTs shown by C. chromis males. Results show that the sneakers' reproductive success was positively linked to egg clutch size; the density of individuals in the nesting area negatively affected the size of egg clutches; the rate of defence behaviours performed by nesting males negatively influenced the number of females contributing to each nest.

A field test of a model for the stability of androdioecy in the freshwater shrimp, Eulimnadia texana.

The evolution of hermaphroditism from dioecy is a poorly studied transition. Androdioecy (the coexistence of males and hermaphrodites) has been suggested as an intermediate step in this evolutionary transition or could be a stable reproductive mode. Freshwater crustaceans in the genus Eulimnadia have reproduced via androdioecy for 24+ million years and thus are excellent organisms to test models of the stability of androdioecy. Two related models that allow for the stable maintenance of males and hermaphrodites rely on the counterbalancing of three life history parameters. We tested these models in the field over three field seasons and compared the results to previous laboratory estimates of these three parameters. Male and hermaphroditic ratios within years were not well predicted using either the simpler original model or a version of this model updated to account for differences between hermaphroditic types ('monogenic' and 'amphigenic' hermaphrodites). Using parameter estimates of the previous year to predict the next year's sex ratios revealed a much better fit to the original relative to the updated version of the model. Therefore, counter to expectations, accounting for differences between the two hermaphroditic types did not improve the fit of these models. At the moment, we lack strong evidence that the long-term maintenance of androdioecy in these crustaceans is the result of a balancing of life history parameters; other factors, such as metapopulation dynamics or evolutionary constraints, may better explain the 24+ million year maintenance of androdioecy in clam shrimp.

Sex chromosome evolution in the clam shrimp, Eulimnadia texana.

Chromosomes that determine sex are predicted to evolve differently than autosomes: a lack of recombination on one of the two sex chromosomes is predicted to allow an accumulation of deleterious alleles that eventually leads to reduced functionality and potential physical degradation of the nonrecombining chromosome. Because these changes should occur at an elevated evolutionary rate, it is difficult to find appropriate species in which to test these evolutionary predictions. The unique genetic sex-determining mechanism of the crustacean Eulimnadia texana prevents major chromosome degeneration because of expression of both 'proto-sex' (i.e. early stage of development) chromosomes in homozygous form (ZZ and WW). Herein, we exploit this unique genetic system to examine the predicted accumulation of deleterious alleles by comparing both homogametic sexual types to their heterogametic counterpart. We report differences in crossing over in a sex-linked region in the ZW hermaphrodites (approximately 3%) relative to the ZZ males (approximately 21%), indicative of cross-over suppression in the ZW hermaphrodites. Additionally, we report that both ZZ and WW genotypes have reduced fitness relative to ZW hermaphrodites, which is consistent with the prediction of harboured recessive mutations embedded on both the Z and the W chromosomes. These results suggest that the proto-sex chromosomes in E. texana accumulate recessive deleterious alleles. We hypothesize that recessive deleterious alleles of large effect cannot accumulate because of expression in both ZZ and WW individuals, keeping both chromosomes from losing significant function.

Calidad de vida en mujeres con síndrome de ovario poliquístico / Quality of life in women with polycystic ovary syndrome

El síndrome de ovario poliquístico (SOP) afecta entre un 5-10 por ciento de las mujeres en edad reproductiva y constituye la endocrinopatía más frecuente de la población adolescente de nuestro país. Su diversa sintomatología puede provocar un impacto en la calidad de vida de las mujeres, lo que amenaza la identidad femenina en ellas. Esta revisión bibliográfica tiene como objetivo conocer de qué manera el SOP afecta la calidad de vida de las mujeres. La literatura señala que al comparar la calidad de vida entre mujeres sanas y con SOP, éstas últimas presentan un deterioro en diversos dominios estudiados con instrumentos generales. Al ser evaluada la calidad de vida de mujeres con SOP, por medio de un instrumento específico para dicha patología, los dominios más afectados fueron: el área de problemas menstruales, emociones y vello corporal. Investigaciones que evalúan el efecto de la sintomatología del SOP por separado en la calidad de vida de las mujeres señalan igualmente un impacto negativo. Se concluye en base a esta revisión que el SOP afecta la calidad de vida en sus diferentes dimensiones, por lo que se postula la importancia de evaluar este parámetro en las mujeres afectadas y la necesidad de que los profesionales de la salud lo consideren al momento de evaluar la intervención realizada.

Concreteness, context availability, and imageability ratings and word associations for abstract, concrete, and emotion words.

Normative values on various word characteristics were obtained for abstract, concrete, and emotion words in order to facilitate research on concreteness effects and on the similarities and differences among the three word types. A sample of 78 participants rated abstract, concrete, and emotion words on concreteness, context availability, and imagery scales. Word associations were also gathered for abstract, concrete, and emotion words. The data were used to investigate similarities and differences among these three word types on word attributes, association strengths, and number of associations. These normative data can be used to further research on concreteness effects, word type effects, and word recognition for abstract, concrete, and emotion words.