Ampliación de la distribución de dos especies de mosquitos (Diptera: Culicidae) en Argentina y notas sobre su bionomía

En esta nota, se informa el hallazgo de los mosquitos Toxorhynchites haemorrhoidalis (Lynch Arribálzaga) y de Ochlerotatus milleri Dyar en la provincia de Corrientes y Buenos Aires respectivamente; con lo cual se amplía la distribución geográfica de ambas especies en Argentina.This paper reports the discovery of the mosquitoes Toxorhynchites haemorrhoidalis (Lynch Arribálzaga) and Ochlerotatus milleri Dyar in Corrientes and Buenos Aires provinces respectively, thereby extending the geographical distribution of both species in Argentina.Instituto de Limnología "Dr. Raúl A. Ringuelet

The aquatic communities inhabiting internodes of two sympatric bamboos in Argentinean subtropical forest

In order to determine if phytotelmata in sympatric bamboos of the genus Guadua might be colonized by different types of arthropods and contain communities of different complexities, the following objectives were formulated: (1) to analyze the structure and species richness of the aquatic macroinvertebrate communities, (2) to comparatively analyze co-occurrences; and (3) to identify the main predators. Field studies were conducted in a subtropical forest in Argentina, where 80 water-filled bamboo internodes of Guadua chacoensis (Rojas Acosta) Londoño and Peterson (Poales: Poaceae) and G. trinii (Nees) Nees and Rupr. were sampled. Morphological measurements indicated that G. chacoensis held more fluid than G. trinii. The communities differed between Guadua species, but many macroinvertebrate species used both bamboo species. The phytotelmata were mainly colonized by Diptera of the families Culicidae and Ceratopogonidae.Instituto de Limnología "Dr. Raul A. Ringuelet

The aquatic communities inhabiting internodes of two sympatric bamboos in Argentinean subtropical forest

In order to determine if phytotelmata in sympatric bamboos of the genus Guadua might be colonized by different types of arthropods and contain communities of different complexities, the following objectives were formulated: (1) to analyze the structure and species richness of the aquatic macroinvertebrate communities, (2) to comparatively analyze co-occurrences; and (3) to identify the main predators. Field studies were conducted in a subtropical forest in Argentina, where 80 water-filled bamboo internodes of Guadua chacoensis (Rojas Acosta) Londoño and Peterson (Poales: Poaceae) and G. trinii (Nees) Nees and Rupr. were sampled. Morphological measurements indicated that G. chacoensis held more fluid than G. trinii. The communities differed between Guadua species, but many macroinvertebrate species used both bamboo species. The phytotelmata were mainly colonized by Diptera of the families Culicidae and Ceratopogonidae.Instituto de Limnología "Dr. Raul A. Ringuelet

The aquatic communities inhabiting internodes of two sympatric bamboos in Argentinean subtropical forest

In order to determine if phytotelmata in sympatric bamboos of the genus Guadua might be colonized by different types of arthropods and contain communities of different complexities, the following objectives were formulated: (1) to analyze the structure and species richness of the aquatic macroinvertebrate communities, (2) to comparatively analyze co-occurrences; and (3) to identify the main predators. Field studies were conducted in a subtropical forest in Argentina, where 80 water-filled bamboo internodes of Guadua chacoensis (Rojas Acosta) Londoño and Peterson (Poales: Poaceae) and G. trinii (Nees) Nees and Rupr. were sampled. Morphological measurements indicated that G. chacoensis held more fluid than G. trinii. The communities differed between Guadua species, but many macroinvertebrate species used both bamboo species. The phytotelmata were mainly colonized by Diptera of the families Culicidae and Ceratopogonidae.Instituto de Limnología "Dr. Raul A. Ringuelet

Phytotelmata colonization in bamboo (Guadua sp.) culms in northeast Argentina

This study aimed to determine the susceptibility of stumps and internodes of bamboos to colonization by different types of macroinvertebrates and the formation of communities of different complexity. Semi-controlled field studies were carried out in a subtropical area of Argentina to analyse community structure, species richness of the aquatic macroinvertebrate communities and co-occurrences of predators and prey to delineate the food webs. Water-filled bamboos were sampled every season during a year by removing, without replacing, all water and macroinvertebrates. This study shows that the variation in the morphology of the container provides different resources, leading to segregation of species per container type, and allowing each of them to establish aquatic communities with differences in diversity. The Diptera was best represented in the communities of bamboos, where Culicidae showed the highest species richness and Ceratopogonidae were the most abundant numerically. Eleven taxa were present in both phytotelmata, 12 were unique in internodes and 13 in stumps. The community in internodes was composed of 21 taxa where mosquitoes were represented by Sabethini and Toxorhynchitini. By contrast, stumps were colonized by 24 taxa and Ceratopogonidae were numerically dominant. Regarding food webs established in stumps and internodes, no differences in length were found, except for the species that played equivalent roles in each of the studied phytotelmata.Instituto de Limnología "Dr. Raúl A. Ringuelet

Aquatic Diptera (Insecta) assemblages in four sympatric Eryngium (Apiaceae) phytotelmata in flowering and senescent times

This study addresses how Diptera assemblages differ in four sympatric phytotelmata. The Eryngium species retain water in their axils forming a phytotelm and this situation leads to the speculation that dipteran assemblages may differ, mainly when the plants begin to grow and retain more water in their axils, and when becoming senescent. Diptera from Eryngium horridum, Eryngium stenophyllum, Eryngium aff. serra and Eryngium elegans were sampled. This study revealed that the Eryngium spp. are used by Diptera differentially and their populations show seasonal changes, with peaks in the autumn. Diptera were represented by immature stages belonging to six aquatic and seven semi-aquatic families. The most important were Chironomidae, Culicidae, Periscelididae and Ceratopogonidae. Two species of Chironomids were the most abundant. Culicidae, Periscelididae and Ceratopogonidae were more selective than Chironomidae. Saprophages were the most abundant where the fine detritus feeders were the dominant group. Periscelididae was the main free-swimming predator.Instituto de Limnología "Dr. Raúl A. Ringuelet

Predadores de mosquitos

Fil: Fischer, Sylvia. Grupo de Estudio de Mosquitos. Instituto de Ecología, Genética y Evolución de Buenos Aires. Departamento de Ecología, Genética y Evolución. Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. CABA; ArgentinaFil: Byttebier, Barbara. Grupo de Estudio de Mosquitos. Instituto de Ecología, Genética y Evolución de Buenos Aires. Departamento de Ecología, Genética y Evolución. Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. CABA; ArgentinaFil: Campos, Raúl Ernesto. Instituto de Limnología Dr. Raúl A. Ringuelet (ILPLA). Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; Argentin

Efecto de la sequía continua y la inmersión sobre la respuesta de eclosión de los huevos de Ochlerotatus albifasciatus (Diptera: Culicidae) almacenados a baja temperatura

Se estudió el rol de los factores ambientales sobre la eclosión de los huevos de O. albifasciatus (Macquart), simulando condiciones de invierno. La hipótesis planteada fue que la respuesta de eclosión de los huevos depende de: (1) tiempo de permanencia a baja temperatura, (2) condiciones de almacenamiento, y (3) tiempo de aclimatación. Los huevos fueron almacenados a 5º C en condiciones de sequía y sumergidos durante 7, 21, 35, 90 y 146 días; luego fueron aclimatados a 22º C durante 24, 72, y 168 horas y posteriormente inundados para inducir la eclosión. El porcentaje de huevos eclosionados se analizó con un Modelo Lineal Generalizado con distribución binomial. Los resultados mostraron que: (1) largos períodos de almacenamiento en frío y largos tiempos de aclimatación mejoran la respuesta de eclosión, (2) la condición de almacenamiento tiene un efecto moderado en la eclosión, siendo más marcada en los huevos almacenados en seco; (3) tiempos prolongados de aclimatación mejoran aún más las eclosiones de los huevos sumergidos, que los almacenados en seco; (4) largo tiempo en frío mejora la eclosión de los huevos almacenados en seco, que los sumergidos; (5) los huevos que permanecieron más tiempo en frío respondieron mejor cuando el tiempo de aclimatación fue prolongado.The role of environmental factors on the hatching response of O. albifasciatus (Macquart) eggs is studied by simulating winter conditions in the laboratory. The hypothesis tested was that hatching response is affected by: (1) time that eggs remain at low temperature, (2) storage conditions, and (3) acclimatization time. Eggs were stored at 5ºC in drought and immersion conditions during 7, 21, 35, 90 and 146 days, immediately after, they were acclimatized at 22ºC during 24, 72, and 168 hours, and then eggs were flooded to induce hatching. Percent of hatched eggs was analyzed with a Generalized Lineal Model with a binomial distribution. Results show that: (1) a long storage period at cold temperature and long acclimatization periods improve the hatching response; (2) storage conditions have a moderate effect on hatching, being more evident in eggs stored dry; (3) a long time of acclimatization favors the hatching response in submerged eggs more than in eggs stored dry; (4) long time at cold favors the hatching response in eggs stored dry more than in submerged eggs; (5) the hatching response of eggs that remain for a long time at low temperature is higher when the time of acclimatization is long.Instituto de Limnología "Dr. Raúl A. Ringuelet"Facultad de Ciencias Naturales y Muse

Recent investigations on Toxorhynchites rutilus (Diptera: Culicidae) with reference to the biological control of mosquitos inhabiting containers

Esta revisión provee actualización de las investigaciones sobre Toxorhynchites rutilus, un depredador utilizado para el control de mosquitos. Una investigación a largo plazo en Florida (EUA) demostró reducción de mosquitos en huecos de árboles que fue atribuida a depredación por esta especie. Extinciones locales del vector potencial Aedes triseriatus no estuvieron asociadas con la presencia de T. rutilus en huecos. La disminución en el consumo durante la diapause debe explicar parcialmente la reducción del impacto de T. rutilus en el invierno. La sobrevivencia de T. rutilus en huecos y llantas, indican que la mortalidad es mayor en el primer estadio y que la proporción relativa de muertes es alta en el cuarto, debido al canibalismo. La diversidad de presas observadas en disecciones de T. rutilus coleccionados del campo fue amplia, y los mosquitos no fueron las presas más frecuentes. Artrópodos terrestres aparentemente capturados desde la superficie del agua, fueron comunes en la dieta, especialmente en depredadores del tercero y cuarto estadio. Juliano y Gravel (en prensa) demostraron que A. triseriatus expuestos a T. rutilus, son sujetos a una rápida selección de comportamiento(s) anti-depredador. En la naturaleza, esta presión de selección es débil, resultando en una distribución heterogénea de comportamientos anti-depredador en distintas poblaciones geográficas. En experimentos en internodos de bambú, la especie invasiva Aedes albopictus evitó la depredacion de T. rutilus mejor que la especie nativa A. triseriatus. En este trabajo, discutimos el significado de estos resultados para el control biológico de mosquitos por T. rutilus.This review describes research on Toxorhynchites rutilus, a predator used for mosquito control. A long-term investigation in Florida (USA) demonstrated a reduction in treehole mosquitoes attributable to predation by this species. Local extinctions of the potential vector Aedes triseriatus were not associated with the presence of T. rutilus in treeholes. A decline in prey consumption during diapause may partially explain the reduced winter impact of T. rutilus in the long-term data. Survivorship of T. rutilus in treeholes and discarded tires indicates that the mortality rate is highest in the first instar and that the relative proportion of deaths is also high in the fourth stage, owing to cannibalism. In dissected T. rutilus collected from the field, a broad diversity of prey types was observed, and mosquitoes were not the most common prey. Terrestrial arthropods, apparently captured from the water surface, were common in the diet, especially of third and fourth instars. Juliano and Gravel (in press) demonstrated that A. triseriatus exposed to T. rutilus experience rapid selection for anti-predator behavior(s). This selective pressure is weak in nature, resulting in a heterogeneous distribution of anti-predator behaviors in distinct geographic populations. In experiments conducted in bamboo sections, the invasive species Aedes albopictus escaped predation by T. rutilus better than A. triseriatus. We discuss the significance of these results for the biological control of mosquitoes by T. rutilusInstituto de Limnología "Dr. Raúl A. Ringuelet

Stenomicra (Diptera: Opomyzoidea) en Argentina, con información sobre la biología del género

This is the first literature record of the genus Stenomicra Coquillett (Diptera: Periscelididae) from South America (Neotropical Region). New information on the biological cycle of Stenomicra species in the wild is provided, and four species of the genus Eryngium L. (Apiaceae) are recorded as host plants for immature stages of this taxon. The specimens of Stenomicra sp. were collected in Sierra de la Ventana, Buenos Aires province, Argentina.En este estudio, se publica por primera vez para Sudamérica (Región Neotropical) el género Stenomicra Coquillett (Diptera: Periscelididae). Se aporta información sobre su ciclo biológico en condiciones naturales y se mencionan cuatro especies del género Eryngium L. (Apiaceae), como plantas hospedadoras de los estados inmaduros. Los ejemplares de Stenomicra sp. fueron colectados en Sierra de la Ventana, Provincia de Buenos Aires, Argentina.Instituto de Limnología "Dr. Raúl A. Ringuelet