We summarize the geotectonic history of the southern (mostly Patagonian) Andean Cordillera, and its possible influence on the regional expression of global climates, biogeography, and important aspects of mammalian evolution in South America. The northern Patagonian segment of the Andes contrasts with neighbouring sections in that, during Palaeogene times, there was a transform margin stage; this influenced the Andean climate in addition to global climate changes. This segment underwent alternating subduction and transform episodes that suggest the existence of a proto‐Andes and an Oligocene Andean gap for the San Carlos de Bariloche area. Coeval with this gap (and at the backarc region of this segment), the 1200–1500 m uplift of the Northern Patagonian Massif took place, resulting in an altiplano (high plateau), or Northern Patagonian High Plateau (NPHP), of 100 000 km2, which dominated northern Patagonia during the Oligocene. It is estimated that, by these times, climate in the NPHP was humid and seasonally cool, in contrast to the seasonally more uniform, humid climates of the lower lands peripheral to it. The NPHP may have acted as a biogeographical barrier between central and southern Patagonia, on one side (as part of the Austral Biogeographical Kingdom), and the rest of South America (Holotropical Kingdom) on the other. The most important Paleogene mammalian turnover transpired at the Early Oligocene, concomitantly with the full opening of the Drake Passage and associated global cooling. The latitudinal climate gradient that began at the Eocene–Oligocene transition affected sharply the entire Patagonian region, an effect that was enhanced by the uplift of the NPHP. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 103, 305–315. Se resume la historia geotectónica del sector sur (principalmente Patagonia) de la Cordillera Andina y su posible influencia en la expresión regional de los climas globales, biogeografía e importantes aspectos de la evolución de los mamíferos en Sud América. El sector norte de los Andes Patagónicos contrasta con los sectores vecinos en que durante el Paleógeno existió un estadio de margen transformante; esto influenció el clima en los Andes en forma adicional a los cambios climáticos globales. Este segmento fue sometido a la alternancia de episodios de subducción y margen transformante, que sugieren la existencia de un proto‐Andes y la existencia de un gap Oligoceno de los Andes para el área de San Carlos de Bariloche. Contemporáneo a este gap (y en la región del retroarco de este segmento) tiene lugar el levantamiento del Macizo Norpatagónico a una altura de 1200–1500 m, dando como resultado la formación de un altiplano (plateau elevado), o Plateau Elevado del Macizo Norpatagónico (NPHP), con una superficie de 100.000 km2 la cual dominaba el norte de Patagonia durante el Oligoceno. Se estima que para esos tiempos, el clima en el NPHP fue húmedo con estaciones frías, en contraste con el clima estacionalmente más uniforme y húmedo de las tierras b...
A trade-off is a relationship between two life history characteristics principally reproduction and adult longevity that are fundamental in predicting the optimal life history in any given environment. Mating is indispensable for sexual reproduction, but also can impose risks to females. Nevertheless, in the majority of insects, females allow multiple mating. Dichelops furcatus (Hemiptera: Pentatomidae) is a pest of wheat and corn in Argentina and southern Brazil, but little is known about its reproduction (i.e., the characteristics of the process that results in offspring). We analyzed reproductive attributes of D. furcatus, and the effect of single mating vs. multiple matings, evaluating the trade-off between fecundity and adult female longevity. We found that mating is not required for D. furcatus to oviposit, and multiple copulations were costly in terms of reduced longevity. Although multicopulated females lived a shorter period, only the pre- and post-reproductive periods were shortened. Fecundity was not affected but fertility was incremented in multicopulated females. Females copulated only once oviposited most of the eggs in the first half of the reproductive period, while eggs oviposited in the second half were all inviable (did not hatch). Studying demographic attributes of phytophagous insects provides relevant information to better understand the population dynamics of pests.
The performance of Tetranychus urticae and its predator Neoseiulus californicus on ten strawberry cultivars was determined in the laboratory. Development time and survival of T. urticae from egg to adult were recorded on Albión, Aromas, Camarosa, Diamante, Festival, Kp, Sabrosa, Selva, Sweet Charlie, and Whitney. Fecundity of newly molted and mated females was recorded during the first 10 days of oviposition. Predation rate and fecundity of N. californicus were tested on Albión, Aromas, Festival, Kp, Sabrosa, and Whitney. Predator females reared on each cultivar were placed individually in experimental units, and the number of eggs per day was counted during 3 days. Cultivars with high hairiness (Albión, Aromas, and Festival) and cultivars with low hairiness (Sabrosa, Whitney and Kp) were identified, to assess the effect on the performance of both species. Development time, survival from egg to adult, and fecundity of T. urticae differed among cultivars. Festival was classified as moderately resistant, Aromas and Kp were moderately susceptible, and the others were intermediate. The number of prey consumed per day per female of N. californicus differed between cultivars and time. Fecundity of N. californicus did not differ among cultivars; however, it did over time. The development time and fecundity of T. urticae did not differ among high and low hairiness cultivars. The glandular hairiness affected neither consumption nor fecundity of N. californicus. According to detrimental and propitious effect on T. urticae and N. californicus performance, respectively, we concluded that Festival and Albión could be used along with this predator in T. urticae management programs.
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