Desarrollo postembrionario y evolución de los órganos mecanorreceptores de Latrodectus diaguita carcavallo, y estudio de la Tricobotriotaxia de Latrodectus quartus abalos [Araneae, theridiidae]

Fil: González, Alda. Centros de Estudios Parasitológicos y de vectores [CEPAVE]. Paseo del Bosque s/n, 1900 La Plata, Argentin

Desarrollo postembrionario de latrodectus mirabilis, latrodectus corallinus y latrodectus antheratus (Araneae, theridiidae)

Fil: González, Alda. Centro de Estudios en Parasitología y Vectores (CEPAVE). Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; Argentin

Araneofauna asociada a cultivos de trigo y hábitats adyacentes en Buenos Aires, Argentina

A census of spiders was undertaken in winter wheat fields of Buenos Aires province, Argentina, as well as from their margins and from wheat stubble. Spiders were collected weekly over 3 consecutive years using entomological sweeping and pitfall traps. Field margins were the richest and densest habitats (H’= 3.27, J’= 0.82) and registered 52 species from 14 families, while 31 species from 13 families were found in wheat. Thomisidae and Araneidae were the most abundant families in the herbaceous layer of both the margins and the crop, and Lycosidae in the soil litter. In contrast, 17 species from 8 families were recorded from wheat stubble, making it the least diverse habitat surveyed (H’= 1.67, J’= 0.72). These results could be related to repeated disturbance of wheat fields by harvest, tillage and other field work. Furthermore, the similarity observed in the families of both margin and crop communities indicates that colonization of wheat fields is from the adjacent areas.Se realizó un censo de arañas en cultivos de trigo de invierno de la provincia de Buenos Aires, Argentina, así como en sus márgenes y en el rastrojo. Las arañas fueron recolectadas semanalmente con redes entomológicas y trampas de caída durante 3 años consecutivos. El margen del cultivo fue el hábitat más rico y más denso (H’= 3.27, J’= 0,82) y registró un total de 52 especies pertenecientes a 14 familias, mientras que en el cultivo de trigo se encontraron 31 especies pertenecientes a 13 familias. Thomisidae y Araneidae fueron las familias más abundantes en el estrato herbáceo (tanto en los márgenes como en el cultivo) y Lycosidae en el suelo; mientras que en el rastrojo del trigo se registraron 17 especies representantes de 8 familias y fue el hábitat menos diverso (H’= 1.67, J’= 0,72). Estos resultados podrían estar relacionados con el disturbio repetido, debidos a la cosecha, la labranza y otros trabajos de campo. Por otra parte, la similitud observada entre las familias de ambas comunidades del margen y del cultivo indicaría que el proceso de colonización se iniciaría en las áreas adyacentes.Centro de Estudios Parasitológicos y de Vectore

La primera Symphytognathidae (Arachnida: Araneae) para Argentina, con la descripción de una nueva especie de Anapistula para la selva de montaña Yungas

The spider family Symphytognathidae is reported from Argentina for the first time. Anapistula yungas, a new species of this family is described and illustrated. The specimen was collected during an ecological study of biodiversity in different sites from northwestern Argentina. Dichotomous key to Neotropical female species of genus Anapistula is provided.La familia de arañas Symphytognathidae es registrada por primera vez en Argentina. Anapistula yungas, una nueva especie de esta familia, es descripta e ilustrada. Los especímenes fueron colectados durante un estudio ecológico de biodiversidad en diferentes sitios del noroeste de Argentina. Se proporciona una clave dicotòmica para hembras de las especies neotropicales del género Anapistula.Centro de Estudios Parasitológicos y de Vectores (CONICET- Universidad Nacional de La Plata

Spiders of soybean crops in Santa Fe Province, Argentina: Influence of surrounding spontaneous vegetation on lot colonization

Trials during two consecutive soybean cycles were performed in central Santa Fe in order to determine the main spider families present in the crop and to determine the influence of spontaneous margin flora on colonization towards the lot. Samplings were done by sweeping net and pitfall traps. It was concluded that: 1. Oxyopidae was the most frequent family in the herbaceous layer of both the margins and the soybean crop, and Lycosidae in the lower layer; 2. Margin strips in a soybean lot contribute to the colonization of the crop by spiders of aerial habits and also promote re-colonization following pesticide applications, since they act as shelters. The influence on spiders of terrestrial habits was somewhat lower; 3. The distribution of the populations of spiders of terrestrial habits was homogeneous in a soybean crop seeded directly and these predators had a greater capacity to control pests at all points of the lot.Centro de Estudios Parasitológicos y de Vectore

Primera descripción del macho de Oonops nigromaculatus Mello-Leitão, 1944 (Araneae: Oonopidae) con la redescripción de la hembra y nuevos registros

The male of Oonops nigromaculatus Mello-Leitão 1944 is described for the first time and the female is redescribed from recently collected specimens. New records from Argentina and Uruguay are provided.Se describe por primera vez el macho de Oonops nigromaculatus Mello-Leitáo 1944, y la hembra se redescribe sobre la base de nuevos especímenes colectados recientemente. Se proveen nuevos registros de la Argentina y Uruguay.Centro de Estudios Parasitológicos y de Vectore

Conceptos claves en biología

El conocimiento de la organización de la materia es indispensable para comprender la estructura y función de los seres vivos. Justamente las interrelaciones entre los átomos y las moléculas, son las que permiten el desarrollo de todas las funciones vitales de los organismos animales. Estos están constituidos por miles de moléculas orgánicas diferentes, que se agrupan en cuatro categorías principales: carbohidratos, lípidos, proteínas o ácidos nucleicos. La información genética que controla la vida de cada célula está contenida en sus cromosomas, más específicamente en su ADN, codificándose y transfiriéndose de generación en generación. A lo largo de miles de millones de años surgieron las especies a partir de otras preexistentes por un proceso llamado de "descendencia con modificación" o "evolución". Una de las características de la naturaleza es la gran diversidad de organismos que la componen. La taxonomía, es la ciencia que se encarga de la búsqueda del orden natural, mediante la que se obtienen las distintas clasificaciones animales.Facultad de Ciencias Naturales y Muse

Evaluation of the design effects of different agropastoral systems on the diversity and density of spiders

Sustainable agro-ecological design is challenging when the goal is self-regulation of the system. The objective of this study was to evaluate if the agropastoral design system affects the spider community, as spiders are the main predators in these production systems, and to determine those designs which maximize the diversity and density of spiders. The study was conducted during 2009/2010, at the Experimental Research Station of Agriculture (EEA-INTA) Reconquista (Santa Fe, Argentina) where we considered four different designs: C1 (five agricultural fields), C2 (three agricultural fields and fourlivestock fields), C3 (six agricultural fields and one livestock field) and C4 (five agricultural fields and one forest area). In each design, the spiders were collected by pitfall traps and suction samples with a G-Vac (garden-vacuum). The designs proposed were considered on the basis of environmental heterogeneity. The C4 treatment had the greatest number of species, followed by C2, C3 and C1 (183, 178, 144 and 14 species, respectively), and C2 presented the greatest abundance of spiders followed by C4, C3 and C1 (n=5708, 4785, 4271 and 3448, respectively). Eight guilds were present in C3 and C4. This study is the first to evaluate the diversity of spiders in agropastoral systems in Argentina. Our results show that designs that include more fields with livestock orequal to those for agriculture, as well as forest areas, increase environmental heterogeneity. Therefore, the presence of a biological controller and dominant predatory group will be possible with sustainable designs that have environmental heterogeneity, contributing to improved pest control in agricultural systems.Centro de Estudios Parasitológicos y de Vectore

Historical biogeography of the genus Cyriocosmus (Araneae: Theraphosidae) in the Neotropics According to an Event-Based Method and Spatial Analysis of Vicariance

The distributional history of the South American endemic genus Cyriocosmus (Araneae, Theraphosidae) was reconstructed, and a spatial analysis of vicariance was conducted. Results obtained with the software RASP (Reconstruct Ancestral State in Phylogenies), suggest that Cyriocosmus originated within an area currently represented by the biogeographical subregions of the Amazonian and Paramo Punan. We found 3 vicariant nodes: the 1st into the Amazonian-Caribbean, the 2nd into the Caribbean, and the 3rd into the Amazonian-Parana, Amazonian-Chacoan, and Amazonian-Parana and Chacoan. Using the Vicariance Inference Program we found that 1 vicariant node different from that obtained with RASP, and the hypothetical barriers for the clade were represented by the Voronoi lines in South America. In order to interpret biogeographical events that affected the genus Cyriocosmus, these results are contrasted with major geological events that occurred in South America, and also with previous biogeographical hypotheses.Centro de Estudios Parasitológicos y de Vectore