Caracterização dos danos de Spodoptera eridania (Cramer) e Spodoptera cosmioides (Walker) (Lepidoptera: Noctuidae) a estruturas de algodoeiro / Characterization of the damage of Spodoptera eridania (Cramer) and Spodoptera cosmioides (Walker) (Lepidoptera: Noctuidae) to structures of cotton plants

The cotton plant, Gossypium hirsutum, hosts various pests that damage different structures. Among these pests, Spodoptera cosmioides (Walker) and Spodoptera eridania (Cramer) (Lepidoptera: Noctuidae) are considered important. The objectives of this study were to characterize and to quantify the potential damage of S. eridania and S. cosmioides feeding on different structures of cotton plants. For this purpose, newly-hatched larvae were reared on the following plant parts: leaf and flower bud; leaf and boll; flower bud or boll; and leaf, flower bud and boll. The survival of S. cosmioides and S. eridania was greater than 80 percent and 70 percent for larvae fed on cotton plant parts offered separately or together, respectively. One larva of S. eridania damaged 1.7 flower buds, but did not damage bolls, while one larva of S. cosmioides damaged 5.2 flower buds and 3.0 cotton bolls. Spodoptera eridania and S. cosmioides can be considered species with potential to cause economic damage to cotton plants because they can occur throughout cotton developmental stages causing defoliation and losses of reproductive structures. Therefore, the results validate field observations that these two species of Spodoptera are potential pests for cotton.

Distribuição espacial e variação temporal da composição de espécies de borrachudos (Diptera: Simuliidae) em uma microbacia situada no norte do Paraná / Spatial distribution and temporal variation in composition of black fly species (Diptera: Simuliidae) in a small watershed located in the Northern of Paraná State, Brazil

In this work, the survey of simuliid species and the study of their spatial distribution in four streams of a small watershed situated in Londrina, Paraná State, were carried out from January to October 2007. Changes in the species composition of the breeding sites were also checked along the sampling months. Seventeen black fly species were found, being Simulium botulibranchium Lutz, Simulium travassosi d'Andretta & d'Andretta, Simulium anamariae Vulcano, Simulium brachycladum Lutz & Pinto and Simulium metallicum s. l. Bellardi new records for Paraná State. The Canonical Correspondence Analysis showed that the environmental variables most correlated to the species distribution among sample sites were water conductivity and those linked to physical dimensions of the breeding sites, like width, depth and water velocity. The matrix of faunistic similarity among collecting dates was negatively correlated to the time interval of sampling matrix for three of the water bodies studied, showing the existence of temporal changes in the species composition. According to Multiple Regression Analysis, temporal abundance variation of Simulium perflavum Roubaud, Simulium inaequale Paterson & Shannon and Simulium lutzianum s. l. Pinto was not linked to air temperature, photoperiod and rainfall, suggesting the influence of other factors, probably those directly associated to specific breeding site conditions. The results indicate that differences in physical and chemical characteristics among water bodies may affect the taxonomic composition of simuliids in this watershed.