ABSTRACT
The following work consists of the description of four new species of the genus Pseudephedrus Starý (Aphidiinae), endemic to South America, associated with endemic callaphidid aphid hosts. The descriptions of the new species are based on new samples from Chile and Argentina. The new species described here are as follows: Pseudephedrus staryi sp.n., which is morphologically very close to the already described P. chilensis Starý, with clear apomorphies; P. pubescens sp.n., which presents a setose scutellum, P. flava sp.n. and P. patagonicus sp.n. which have distinct, very elongated, and crenulated petioles representing synapomorphies and probably form separate phylogenetic lineages within Pseudephedrus. All hosts are aphids from the genus Neuquenaphis Blanchard, with varying degrees of diet specialization. From our field and laboratory observations, we hypothesize that, since attempts to sample parasitoids using sweep nets were much more successful than sampling from collected aphids, and since we found mummified aphids only on the ground among the fallen leaves under the trees, Neuquenaphis aphids fall to the ground showing a dropping behaviour as a defence against natural enemies after being stung by parasitoids. This makes rearing from live aphids very unsuccessful and could help explain why it has been difficult to collect and describe species. We supplement the distribution of Pseudephedrus from South America and present a key for the identification of all species based on their morphology.
ABSTRACT
BACKGROUND: Parasitoids are frequently used in biological control due to the fact that they are considered host specific and highly efficient at attacking their hosts. As they spend a significant part of their life cycle within their hosts, feeding habits and life history of their host can promote specialization via host-race formation (sequential radiation). The specialized host races from different hosts can vary morphologically, behaviorally and genetically. However, these variations are sometimes inconspicuous and require more powerful tools in order to detect variation such as geometric morphometrics analysis. METHODS: We examined Aphidius ervi, an important introduced biological control agent in Chile associated with a great number of aphid species, which are exploiting different plant hosts and habitats. Several combinations (biotypes) of parasitoids with various aphid/host plant combinations were analyzed in order to obtain measures of forewing shape and size. To show the differences among defined biotypes, we chose 13 specific landmarks on each individual parasitoid wing. The analysis of allometric variation calculated in wing shape and size over centroid size (CS), revealed the allometric changes among biotypes collected from different hosts. To show all differences in shape of forewings, we made seven biotype pairs using an outline-based geometric morphometrics comparison. RESULTS: The biotype A. pis_pea (Acyrthosiphon pisum on pea) was the extreme wing size in this study compared to the other analyzed biotypes. Aphid hosts have a significant influence in the morphological differentiation of the parasitoid forewing, splitting biotypes in two groups. The first group consisted of biotypes connected with Acyrthosiphon pisum on legumes, while the second group is composed of biotypes connected with aphids attacking cereals, with the exception of the R. pad_wheat (Rhopalosiphum padi on wheat) biotype. There was no significant effect of plant species on parasitoid wing size and shape. DISCUSSION: Although previous studies have suggested that the genotype of parasitoids is of greater significance for the morphological variations of size and shape of wings, this study indicates that the aphid host on which A. ervi develops is the main factor to alter the structure of parasitoid forewings. Bigger aphid hosts implied longer and broader forewings of A. ervi.
ABSTRACT
Justificación: Al ser la salud un derecho en sí misma y tener relación recíproca con el crecimiento económico de un país, adquiere relevancia el análisis de las repercusiones del Tratado de Libre Comercio con EEUU (TLC) en el sector salud costarricense. El objetivo de este trabajo es determinar el conocimiento de médicos trabajadores de la CCSS acerca de los posibles efectos del TLC sobre el sector salud. Metodología: Se elaboró un cuestionario compuesto por preguntas abiertas y cerradas, el cual se aplicó a 60 médicos, entre abril y mayo de 2006, en tres hospitales nacionales de la CCSS, esoecíficamente: Hospital San Juan de Dios, Hospital "Dr. Rafael A. Calderón Guardia" y Hospital de las Mujeres "Dr. Adolfo Carit Eva". Resultados: De los sesenta médicos entrevistados, un 37 por ciento fueron mujeres y un 63 por ciento hombres. El 83 por ciento mencionó conocer el TLC, un 75 por ciento por los medios de comunicación y un 53 por ciento había sido informado acerca del contenido sobre propiedad intelectual. Los efectos sobre la salud más frecuentemente mencionados fueron: el acceso a los medicamentos genéricos (60 por ciento), la accesibilidad a los servicios de salud (50 por ciento) y las oportunidades laborales (40 por ciento), solo un 15 por ciento no reconoció ningún efecto. Conclusión: Los médicos, como profesionales, como trabajadores de la CCSS y como consumidores deben conocer sobre los contenidos del TLC que pueden afectar su desempeño laboral. Este estudio demuestra que muchos de los entrevistados no tienen un adecuado conocimiento del TLC ni de sus implicaciones o efectos en el sistema de salud costarricense.
