Límite de la responsabilidad del heredero

Fil: Bidau, José F. Universidad de Buenos Aires. Facultad de Derecho. Cátedra Derecho Civil. Buenos Aires, Argentin

Contrasting patterns of sexual size dimorphism in the grasshoppers Dichroplus vittatus and D. pratensis (Acrididae, Melanoplinae)

Sexual size dimorphism (SSD) can be the result of sexual selection (SS) or natural selection (NS). Due to male-male competition for access to females, SS could favor an increase in male body size. On the other hand, larger size in females could be favored by NS, since egg production is directly correlated with body size. Rensch`s rule states that SSD increases with increasing body size in animals, where males are the larger sex, and decreases when females are larger than males. Thus, Rensch’s rule predicts that in those insects where females are larger than males, SSD should decrease with increasing body size, when comparing populations and species. We analyzed SSD in 19 Argentine populations of the grasshoppers Dichroplus vittatus and 25 of D. pratensis. Both species show latitudinal and altitudinal variation in body size, following the converse to Bergmann’s rule: body size decreases with increasing latitude and decreasing ambient temperature. SSD occurs in both species across their geographical distribution ranges, also involving differences in allometry and shorter developmental times in males. In D. vittatus, the degree of SSD increased significantly with general body size, whereas in D. pratensis SSD decreased as body size increased. A plausible explanation of SSD is that SS favors a differential increase in female body size related to a preference by males for more fecund females. Given the close phylogenetic relationship between both species, the differences in SSD between them may be the result of differential natural and sexual selective pressures. In D. vittatus both sexes could be reacting differently to environmental conditions regarding body size, while in D. pratensis protandry could be the main factor behind SSD.Fil: Bidau, Claudio Juan. Instituto Oswaldo Cruz; BrasilFil: Marti, Dardo Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas; Argentin

The central-marginal hypothesis in acridid Orthoptera: a critique of Colombo's (2012) article

We discuss and criticise the contention of Colombo (2012) that the central-marginal model does not apply to three species of chromosomally polymorphic acridid grasshoppers, and that chromosomal clines in these species are a consequence of temperature gradients. We also discuss Colombo's interpretation of our own results on the South American melanopline grasshopper, Dichroplus pratensis Bruner.Fil: Bidau, Claudio Juan. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Misiones. Facultad de Ciencias Exactas, Químicas y Naturales; ArgentinaFil: Marti, Dardo Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Universidad Nacional de Misiones. Instituto de Biología Subtropical; Argentina. Universidad Nacional de Misiones. Facultad de Ciencias Exactas, Químicas y Naturales; Argentin

B chromosomes and Robertsonian fusions of Dichroplus pratensis (Acrididae): intraspecific support for the centromeric drive theory

We tested the centromeric drive theory of karyotypic evolution in the grasshopper Dichroplus pratensis, which is simultaneously polymorphic for eight Robertsonian fusions and two classes of B chromosomes. A logistic regression analysis performed on 53 natural populations from Argentina revealed that B chromosomes are more probably found in populations with a higher proportion of acrocentric chromosomes, as the theory predicts. Furthermore, frequencies of B-carrying individuals are significantly negatively correlated with the mean frequency of different Robertsonian fusions per individual. No significant correlations between presence/absence or frequency of Bs, and latitude or altitude of the sampled populations, were found. We thus provide the first intraspecific evidence supporting the centromeric drive theory in relation to the establishment of B chromosomes in natural populations.Fil: Bidau, Claudio Juan. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Misiones. Facultad de Humanidades y Ciencias Sociales. Departamento de Genética. Laboratorio de Genética Evolutiva y Molecular; ArgentinaFil: Marti, Dardo Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Universidad Nacional de Misiones. Instituto de Biología Subtropical; Argentin

Chromosome fusion polymorphisms in the grasshopper, Dichroplus fuscus (Orthoptera: Acrididae: Melanoplinae): Insights on meiotic effects

Robertsonian changes account for many of the changes in the evolution of the orthopteran karyotype; in their origin, a centric fusion is involved between two acro-telocentric chromosomes, forming a single bi-armed chromosome. It is usual for these rearrangements to be associated with profound changes in meiosis, such as modification in frequency and distribution of chiasmata. Dichroplus fuscus is a South American grasshopper with a wide distribution. In this work we analyzed nine populations from Misiones Province, north-eastern Argentina. This species presents a standard karyotype of 2n = 23/24 (♂/♀) with all chromosomes acro-telocentric and an X0/XX chromosomal sex determining mechanism. This standard karyotype has been modified by the occurrence of two Robertsonian fusions involving chromosomes 1/3 and 2/4; values of fusions per individual (fpi) show a significant increase in the presence of karyotypic polymorphisms towards southern populations. In individuals showing chromosomal rearrangements, we observed a clear redistribution of chiasmata towards distal positions; significant differences were noted between Robertsonian homozygotes (Ho) and heterozygotes (Ht) for chromosomes arms L1 and M3, although this was not the case between Ho and Ht for chromosomes L2 and M4. With regard to the orientation of trivalents, values obtained for non-convergent orientation were low.Fil: Taffarel, Alberto. Provincia de Misiones. Comité de Desarrollo e Innovación Tecnológica. Centro de Desarrollo e Innovación Tecnológica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas; ArgentinaFil: Bidau, Claudio Juan. Universidad Nacional de Misiones; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Marti, Dardo Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas; Argentin

A phylogenetic approach to the study of sexual size dimorphism in Felidae and an assessment of Rensch´s rule

El dimorfismo sexual de tamaño (SSD) es un fenómeno poco comprendido respecto a sus causas ontogenéticas y evolutivas, y generalizaciones como la regla de Rensch, que interpreta la relación del SSD con el tamaño corporal, no han sido satisfactoriamente fundamentadas. Escogimos la familia Felidae para realizar un estudio comparativo del SSD debido a su homogeneidad morfológica, sus características reproductivas y su rango de tamaños. Planteamos tres hipótesis: 1. la poliginia que ocurre en todas las especies de félidos predice un alto grado de SSD sesgado hacia los machos; 2. como existe una amplia varianza de tamaño corporal, se predice que, si la regla de Rensch se verifica, la sensibilidad de los métodos utilizados podrá detectarla en una muestra abarcando todo el rango de tamaños; 3. como el tamaño en los carnívoros se correlaciona con muchas variables ecológicas y de historia vital, si el SSD escala con el tamaño según la regla de Rensch, debería esperarse que el SSD se correlacionase también con algunas de estas variables. Construimos una base de datos de masa y longitud corporales de machos y hembras a partir del 90 % de las especies de Felidae. Estudiamos el SSD y su relación con el tamaño corporal, y realizamos comparaciones con características de historia vital, variables climáticas y geográficas de las especies usando contrastes filogenéticamente independientes (PICs). Los félidos mostraron niveles altos de SSD para la masa corporal, pudiendo esto ser resultado del comportamiento poligínico y el bajo/nulo cuidado parental masculino generalizados en la familia. El SSD no mostró relación con el tamaño del cuerpo, no corroborando por tanto la regla de Rensch: el SSD y la masa corporal poseen patrones de distribución filogenética absolutamente no coincidentes. Así también, el SSD no mostró relación con ninguna de los predictores analizados. Son necesarios un mayor número de estudios a nivel intraespecífico en las especies de amplia distribución para evaluar la variación geográfica de tamaño y su impacto sobre el SSD, así como para poder comprender los mecanismos que modulan el SSD en la familia.Sexual size dimorphism (SSD) is a poorly understood phenomenon with respect to its ontogenetic and evolutionary causes, and generalizations such as Rensch's rule that interprets the relationship between SSD and body size, have not been satisfactorily supported. We chose the Felidae to perform a comparative study of SSD because of its morphological homogeneity, reproductive characteristics, and range of body sizes. We posed three hypotheses: 1. polyginy that occurs in all felid species a predicts a high degree of male-biased SSD; 2. since a great variance in body size occurs, we predicted that, if Rensch's rule is verified, the sensibility of the employed methods will detect it in a sample comprising the whole size range; 3. since in Carnivora size is correlated with many ecological and life-history variables, if SSD scales with size according to Rensch's rule, it would be expected that SSD would be also correlated with some of these variables. We constructed a database of body masses and lengths of males and females of 90 % of the species of Felidae. We studied SSD and its relation to body size and performed comparisons with life-history, climatic, and geographic variables of all species using phylogenetically independent contrasts (PICs). Felids showed high levels of SSD for body mass which could be the result of the polygynic behaviour and low/null male parental care generalized in the family. SSD did not show a relationship with body size thus not supporting Rensch's rule: SSD and body mass have completely non-coincident phylogenetic distribution patterns. Also, SSD did not show any correlation with the analyzed predictors. A larger number of studies at the intraspecific level of species with large distributions is needed to evaluate geographic size variation and its impact on SSD and to understand the mechanisms that modulate SSD within the family

Impugnación del reconocimiento de hijo matrimonial en el derecho argentino

Fil: Bidau, José F. Universidad de Buenos Aires. Facultad de Derecho. Buenos Aires, Argentin

Funcionamiento de la separación de patrimonios en el derecho positivo argentino

Fil: Bidau, José F. Universidad de Buenos Aires. Facultad de Derecho. Cátedra Derecho Civil V. Buenos Aires, Argentin

Rensch's rule is not verifiedin melanopline grasshoppers (Acrididae)

Sexual size dimorphism (SSD) is almost universal in animals. Rensch?s rule proposes that SSD increases with increasing average body size in taxa where males are larger than females (male- biased SSD; MBSSD) and decreases when females are larger (femalebiased SSD; FBSSD). Although it was proposed thatboth patterns are part of the same evolutionary trend, there is more evidence for Rensch?s rule in the first case. We analyzed SSD in the acridid subfamily Melanoplinae ina sample of 718 species and subspecies covering all tribes and representative genera. As in all Orthopera, SSD is female-biased. Body length was used as a proxy for body size. Mean body size within the subfamily varied between 9 and 34.5 mm in males (N= 812) and 12.75 and 44.0 mm in females (N= 735). Except for five species (0.7%) all taxa (from subfamily to subspecies) showed moderate to strong FBSSD (mean= 1.27). The lowest SSD was observed in Melanoplus chumash(SSD= 1.01), and the highest in Phaedrotettix aptera coquinae(SSD= 1.83). To test Rensch?s rule we performed reduced major axis (RMA) regressions between log10 (male body length) and log10 (female body length). In no case RMA slopes were significantly higher than 1.0 which would signal Rensch?s rule. Thus, Melanoplinae representsa new case of FBSSD where Rensch?s rule is not verified. The proximatecauses of FBSSD and the non-occurrence of Rensch?s rule in the Orthoptera are discussed as well as the relationship between SSD patterns at the intra- and supraspecific levels.Fil: Bidau, Claudio Juan. Universidad Nacional de Rio Negro; ArgentinaFil: Marti, Dardo Andrea. Universidad Nacional de Misiones. Facultad de Humanidades y Cs.sociales. Departamento de Genetica. Laboratorio de Genetica Evolutiva y Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Castillo, Elio Rodrigo Daniel. Universidad Nacional de Misiones. Facultad de Humanidades y Cs.sociales. Departamento de Genetica. Laboratorio de Genetica Evolutiva y Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin