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Uno de los retos más importantes sobre los estudios en humanos es el de explicar los mecanismos fisiológicos que subyacen en el despliegue del comportamiento. La psicología evolutiva trata de establecer una relación de causa-efecto entre la forma en que se comporta el humano y los cambios fisiológicos que ocurren en él. A fin de darle una interpretación evolutiva a la conducta humana, en el presente trabajo se sometió a prueba la hipótesis que propone que los hombres perciben a la mujer más atractiva durante la ovulación en función de ciertos cambios fenotípicos causados por las concentraciones de estrógenos, lo que les indica señales de su condición de fertilidad. Además, proponemos que otras mujeres también son capaces de discriminar la ovulación como un mecanismo de competencia femenina, dado que en ese periodo podrían ser más atractivas para sus parejas. Para poner a prueba la hipótesis se realizó un seguimiento de progesterona y estradiol a lo largo del ciclo menstrual a 50 mujeres, tomándoles fotos en cada una de las fases del ciclo (folicular temprana, folicular tardía, periovulatoria y fase lútea) y se les preguntó a hombres y mujeres en qué foto se veían más atractivas. Tanto los hombres como las mujeres respondieron que perciben a las mujeres como más atractivas en el periodo periovulatorio (folicular tardía y periovulatoria).

Orexins A and B are two neuropeptides synthesized in the lateral hypothalamus, perifornical area and dorsomedial hypothalamus. Bothare derived from the proteolytic cleavage of a protein called pre-pro-orexin; they together exert their biological effects through two G protein-coupled receptors named OX1R and OX2R. The axons of theorexinergic neurons are distributed almost throughout the central nervous system and they can be found in some organs including the reproductive tract of both sexes. The wide distribution of orexins and their receptors includes the entire hypothalamic-pituitary-gonadal axis and brain nuclei related to reward processing such as the ventral tegmental area and the nucleus accumbens. Although the reproductive process has been extensively investigated, recent evidence suggests that in addition to the hypothalamic-pituitary-gonadal neuroendocrine axis, there are other systems such as orexinergic system that are heavily involved in the regulation of reproductive process and sexual behavior in vertebrates, mainly in mammals. [ABSTRACT FROM AUTHOR]

In this study native turkey backyard production units (UP) in the five physiographic regions of Michoacan state were characterized. Backyard meleagriculture is present in all physiographic regions of the State, UP averages ranging from 7.20 to 14.80 birds. The female/male ratio found ranged from 1.69 to 3.69. According to plumage's color, the following varieties were observed: Bronze, Narrangansett, Royal Palm, Spanish Black, Slate or silver and Buffy (brown or red) and other colors that could not be allocated to the these varieties. Live weight of adult birds of more than 12 mo of age ranged between 6.70 and 8.90 kg in males and between 2.90 and 4.35 kg in females. The heavier birds were located in the temperate areas. Females nest 2 to 3 times per year 12 to 15 eggs in each nesting event, hatching rate was 10-12 poults/nesting. Practically all (94.3 %) UP are non technified, using only some improved management practices: balanced diets in chicks up to two months old, little or null vaccination plan, non use of improved varieties, which indicate that the genetic type of turkey is native and constitutes a real genetic fund. [ABSTRACT FROM AUTHOR]

En este trabajo se caracterizaron unidades de producción (UP) de traspatio de guajolote doméstico en las cinco regiones fisiográficas del estado de Michoacán. La meleagricultura de traspatio se lleva a cabo en todas las regiones fisiográficas del estado, con UP promedio de 7.20 a 14.80 aves. La relación hembra/macho es de 1.69 a 3.69 hembras por macho. De acuerdo a la coloración del plumaje, se encontraron las variedades Bronceado, Narrangansett, Palma Real, Negro español, Slate o plateado y Buffy (café o rojo) y otros colores que no se pudieron asignar a las variedades descritas. El peso en adultos mayores de 12 meses fue de 6.70 a 8.90 kg machos y 2.90 a 4.35 kg hembras. Las aves más pesadas se localizaron en las regiones de clima templado. Las hembras anidan 2 a 3 veces por año, produciendo de 12 a 15 huevos por evento con nacimientos de 10 a 12 pavipollos por evento. El 94.3 % de las unidades son no tecnificadas, con incorporación de algunas prácticas de manejo mejorado, como utilización de alimento balanceado en pavipollos hasta los dos meses de edad, poco o nulo esquema de vacunación y sin utilización de variedades "mejoradas", lo que indica que el tipo genético de guajolote es autóctono y es un fondo genético propio. [ABSTRACT FROM AUTHOR]

White-tailed deer is a species with a large behavioral plasticity and adaptation to different habitats, including their food habits. This study was conducted with the aim to determine the food habits of this species in the cloud (BMM) and pine-oak (BPE) forests. Deer scats and plant samples were obtained following standard methods, from Sierra Nanchititla Park in the State of Mexico, from June 1990 to May 1992. A total of 104 deer pellet-groups were collected, and histological analysis for herbivores was used and compared with stock samples of plant tissues collected from the study area. We applied the Spearman correlation and Morisita index to determine alimentary preference. The results showed that the deer consumes 79.44% of plant species from BMM and 20.56% of the BPE. There is a selectivity tendency for 12 of the 14 plant species located in the BMM, while for BPE no tendency was observed. Key species that are part of the elemental diet of the deer in these areas were: Acalypha setosa, Smilax pringlei, Psidium sartorianum and Dendropanax arborea. The consumption of plants did not differ significantly between the dry and rainy seasons in terms of biological form, however, during the dry season there is a tendency to consume trees, and by the end of the rainy season to consume herbs. The data indicate that the deer can be selective with BMM plants, while for the BPE tends to be opportunistic.