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Para Ceroglossus chilensis se realizo un análisis de Asimetría Fluctuante (AF) en poblaciones presentes en plantaciones de Pinus radiata de diferentes edades y tipos de manejo, ubicadas en la cordillera de la costa y precordillera andina de la Región del Bío-Bío, Chile. El objetivo fue comparar en diferentes poblaciones de C. chilensis niveles de AF, a través de medidas del tercer segmento antenal. Para ello los insectos se recolectaron mediante trampas de intercepción entre diciembre 2004 y enero 2005, en plantaciones de 6-7, 10, 13 y 22-24 años. Nuestros resultados mostraron para el total de individuos (n = 128), diferencias significativas en los valores de AF en plantaciones de 6-7 (post primer raleo) y 10 años (previo raleo comercial) para ambas situaciones geográficas. Al analizar los sexos por separado, se encontró machos y hembras asimétricas en plantaciones de 13 años de la precordillera andina y Cordillera de la Costa, respectivamente. No se encontró correlación entre las abundancias, porcentaje de cobertura del sotobosque y asimetría fluctuante para ambas situaciones geográficas. Se discute si la asimetría en antenas puede afectar negativamente la adecuación biológica de los individuos expresada en menor éxito en la captura de presas y encuentro de pareja, reflejo probable del efecto que el tipo de manejo al que ha sido sometida la plantación tendría sobre la ontogenia de los individuos.

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A high degree of specialization between host and parasite is a well-known outcome of a long history of coevolution, and it is strikingly illustrated in a coordination of their life cycles. In some cases, the arms race ensued at the establishment of a symbiotic relationship results in the adoption of manipulative strategies by the parasite. We have already learned that Steinina ctenocephali, a gregarine living in the alimentary canal of cat flea, Ctenocephalides felis follows its phenology and metamorphosis. Despite these findings the outcome of their symbiotic partnership (mutualist, parasitic or commensal) remains unclear. To address this important question, we measured life history parameters of the flea in the presence of varying infection intensities of gregarine oocysts in laboratory conditions. We found that neither the emergence nor survival rate of fleas was affected by harbouring the gregarines. More surprisingly, our results show that flea larvae infected with gregarines developed faster and emerged earlier than the control group. This gregarine therefore joins the selected group of protists that can modify physiological host traits and provides not only new model taxa to be explored in an evolutionary scenario, but also potential development of control strategies of cat flea.

The alteration of habitat generates different degrees of stress in insects. It has been suggested that the degrees of phenotypic disturbances reflect the ability of an individual to overcome the effects of stress. The Baker River Basin in the Aysén Region, Chilean Patagonia has a very fragmented landscape, due to the destruction of the native forest and the use of land for agriculture and animal husbandry. This alteration should generate different degrees of disturbances in the insect communities, whose effects may be quantified by geometric morphometric tools. We analyzed morphological differences in 244 males and 133 females of the the Chilean magnificent beetle, Ceroglossus chilensis (Eschscholtz) (Coleoptera: Carabidae) collected in January, 2007, in mixed forests of Nothofagus dombeyi Mirbel (Ørsted) (Fagales: Nothofagaceae) and N. nitida Hofmus and in Second-growth forest of N. pumilio (Poepp. & Endl.) Krasser. Males were generally wider in the pronotum, while females had wider abdominal sternites. Although there were significant differences in shape and size between mature forests and second-growth forest, these were less significant among the sites within each type of vegetal formation. Individuals had more shape variations in the mature forest. We suggest that differences in shape are due at least in part to the isolation of the habitat. The differences found between sexes raises the question of how morphological variations and sexual dimorphism may be affected spatially by natural selection.