Sylvia Fischer

Universidad de Buenos Aires | UBA

The “oviposition preference-offspring performance” hypothesis proposes that females lay their eggs in habitats that maximize the fitness of their offspring. The aim of this study was to assess the oviposition site selection by Aedes aegypti females and the success of their larvae in habitats with different detritus accumulation times, under conditi...

Mayaro virus (MAYV; Alphavirus : Togaviridae ) is an emerging pathogen in Latin America, causing fever and polyarthritis. Sporadic outbreaks of MAYV have occurred in the region, with reported human cases being imported to Europe and North America. Although primarily a risk for those residing in the Amazon basin's tropical forests, recent reports hi...

In many insects, short photoperiods induce females to lay diapausing eggs, which are associated with a reduction in female fecundity, and/or with an increase in their growth rate, allowing for a larger size at adulthood. The effects of short photoperiods may also differ among populations, depending on the different selection pressures imposed by th...

Freely available from: https://papers.ssrn.com/sol3/papers.cfm?abstract_id=4016945 Aedes aegypti (L.) (Diptera: Culicidae) survives in the egg stage under unfavorable environmental conditions. In this study, we assessed the survival of Ae. aegypti eggs under natural winter conditions as an overwintering mechanism. To address this, field collected...

Aedine mosquitoes go through unfavorable periods as dormant eggs. However, extended dormancy times lead to a depletion of egg reserves, which might be partially compensated by changes in larval-feeding behavior. Changes in larval behavior may also be induced by parasitism by mermithids probably as a strategy to reduce the impact of the parasite on...

Aedes aegypti larvae that develop in containers largely depend on plant detritus as a source of nutritional resources. However, few studies have evaluated the performance of immature individuals under natural amounts and quality of this food source. Here, we aimed to assess the effect of the variation in the accumulation time and amount of detritus...

Many insects use photoperiod as a signal to anticipate upcoming unfavorable conditions. Photoperiod sensitivity may be a relevant factor in Aedes (Stegomyia) aegypti (L.) populations at the cool margins of the species’ range, where winter conditions have a strong effect on population dynamics. In this study, we evaluated the effect of parental phot...

The distribution of Aedes aegypti (L.) (Diptera: Culicidae) is expanding towards colder regions, which could be aided by an adaptation of the immature stages to the local thermal conditions. This study aimed to assess the developmental success at different temperatures in three populations of Ae. aegypti located across a climate gradient in Argenti...

Aedes aegypti and Aedes albopictus are mosquito vectors of numerous arboviruses of sanitary importance. Presently in Argentina, neither Ae. aegypti nor Ae. albopictus, have displaced the other species in the places where they coexist, since the introduction of the latter in 1998. In this study, we evaluated whether these species coexist at differen...

Many insects overwinter in diapause, a pre-programmed anticipated response to unfavorable environmental conditions, often induced by a short-day photoperiod. Diapause involves morphological changes and increased energy stores required for metabolic demands during winter. In diapausing mosquito eggs, the accumulation of lipids plays an important rol...

In Argentina, the mosquito Aedes aegypti (L.) (Diptera: Culicidae) is distributed from subtropical to temperate climates. Here, we hypothesized that the expansion of Ae. aegypti into colder regions is favoured by high-phenotypic plasticity and an adaptive inhibition of egg hatching at low temperatures. Thus, we investigated the hatching response of...

The expansion of the invasive mosquito Aedes aegypti L. (Diptera: Culicidae) towards temperate regions in the Americas is causing concern because of its public health implications. As for other insects, the distribution limits of Ae. aegypti have been suggested to be related to minimum temperatures and to be controlled mainly by cold tolerance. The...

This study aimed to evaluate the effects of egg dormancy times on susceptibility of larvae of the floodwater mosquito Aedes albifasciatus (Diptera: Culicidae) to parasitism by their natural enemy Strelkovimermis spiculatus (Nematoda: Mermithidae) and on their life history traits. Aedes albifasciatus eggs stored for 2, 4, 6, 8 and 10 months were hat...

Most studies of the effects of low temperature on the development of immature stages of Aedes aegypti (L.) have been performed at constant temperatures in the laboratory, which may not accurately reflect the variable environmental conditions in the field. Thus, the aim of this study was to assess the effect of constant temperatures (CT) and fluctua...

Dormancy is a developmental arrest in arthropods, in response to unfavorable conditions in temporally varying environments. In Aedes aegypti, the supposed inability of eggs to inhibit hatching has been used to explain the restriction of this species to tropical and subtropical regions. However, the geographic range of Ae. aegypti is constantly expa...

In temperate regions, the populations of Aedes aegypti (L.) remain in the egg stage during the cold season. The ability of these eggs to survive until the next favorable season is affected by several mortality factors, including the action of predators. In the present study, we analyzed the temporal dynamics of the loss of eggs and identified preda...

The aim of the present study was to investigate the variables associated with the composition of mosquito species in rain pools of ‘Bosque de Ezeiza’, a large peri-urban forested park of Buenos Aires city, Argentina. A total of 12 rain pools were sampled biweekly over a 1-yr period in search of mosquito immature stages. Mosquito immature stages wer...

Few studies have assessed the effects of food scarcity or excess on the life history traits of Aedes aegypti (L.) (Diptera: Culicidae) independently from larval density. We assessed immature survival, development time, and adult size in relation to food availability. We reared cohorts of 30 Ae. aegypti larvae from newly hatched to adult emergence w...

Aedes aegypti is the main vector of dengue in the Americas. Despite its tropical or¬igin, this species has successfully established in temperate regions during the last decades. In Buenos Aires province (Argentina), at the boundary of this species in South America, more than twenty new cities have been colonized by Ae. aegypti in recent years, expa...

En este capítulo se hace una revisión de lo que se conoce hasta el momento de los distintos predadores sobre cada una de las etapas del ciclo de vida de los mosquitos, y se discuten las perspectivas de cada uno como herramienta de control biológico.

Las especies de mosquitos que se desarrollan en charcos temporarios tienen adaptaciones específicas a la disponibilidad y fluctuaciones del nivel de agua. Las especies que utilizan estos ambientes tienen huevos de resistencia para sobrevivir a los períodos sin agua (géneros Aedes y Psorophora) o son generalistas en el uso del hábitat y aprovechan l...

Buenos Aires city is located near the southern limit of the distribution of Aedes aegypti (Diptera: Culicidae). This study aimed to assess long-term variations in the abundance of Ae. aegypti in Buenos Aires in relation to changes in climatic conditions. Ae. aegypti weekly oviposition activity was analyzed and compared through nine warm seasons fro...

Aedes (Ochlerotatus) albifasciatus (Macquart) es un mosquito neotropical distribuido ampliamente en Argentina. Entre los enemigos naturales, el nematodo Strelkovimermis spiculatus Poinar y Camino, es el factor biológico de mortalidad más importante de los estados inmaduros. La interacción entre el mosquito y el nematodo se produce en charcos efímer...

Aedes (Ochlerotatus) albifasciatus (Macquart), es un mosquito considerado plaga, que ataca al hombre y a los animales domésticos, y presenta importancia sanitaria ya que fue confirmado como vector del virus de la Encefalitis Equina del Oeste. Los estados inmaduros de esta especie se desarrollan en charcos efímeros formados por agua de lluvia y la e...

Los grandes espacios verdes pueden ser productores de una alta diversidad de mosquitos, afectando la salud y el bienestar de las personas que los frecuentan o habitan en zonas cercanas. El conocimiento de la composición y dinámica de estos insectos es esencial para la implementación de posibles estrategias de manejo. Este trabajo tiene como objetiv...

Distintos estudios sugieren que las poblaciones de mosquitos que se desarrollan en recipientes están reguladas por la disponibilidad de recursos alimenticios. Algunas de las consecuencias de esta limitación nutricional incluyen una menor supervivencia durante el desarrollo, una menor tasa de desarrollo, y una menor tasa de crecimiento corporal si s...

In temperate regions, the seasonal dynamics of Aedes aegypti (L.) (Diptera: Culicidae) is mainly influenced by temperature. It is assumed that, during the winter season, the population remains as eggs and that the development and population growth of surviving eggs begin during the following spring. The aim of the current study was to assess egg ha...

We described the carryover of Strelkovimermis spiculatus (Poinar and Camino) (Nematoda: Mermithidae) from mosquito larvae, the primary site of maturation, to adults. We analyzed the survival time of male and female Aedes albifasciatus (Macquart) (Diptera: Culicidae) parasitized by S. spiculatus, the time of emergence of nematodes from adult mosquit...

Aedes aegypti is the main vector of dengue in the Americas, and its continuously expanding distribution may be a critical factor involved in the constant increase in the incidence and geographic range of dengue disease. The aim of this study was to update the southern distribution of Ae. aegypti in Buenos Aires province, Argentina. We sampled tire...

Larvae of Culex (Melanoconion) pilosus were collected during February–April 2014 in temporary pools in ''Bosques de Ezeiza,'' a large forested park, near Buenos Aires city, Argentina. This is the first record in Buenos Aires Province, extending the distribution of this species 380 km to the south. Regarding habitat use, Cx. (Mel.) pilosus is a gene...

In temperate and subtropical regions, populations of Aedes (Stegomyia) aegypti (L.) survive unfavorable winter conditions in the egg stage. Knowing their survival rates can be of great interest for the health authorities in charge of control activities. In this study, we analyzed the mortality of Ae. aegypti eggs exposed to the cold season as well...

Ochlerotatus albifasciatus (Macquart) (Diptera: Culicidae) larvae develop synchronously after rainfall events in ephemeral or temporary pools, where they occasionally attain very high abundance. The aims of the current study were to analyze the response of life history parameters such as daily larval mortality, time to pupation, and adult size of O...

In temperate regions, Aedes aegypti (L.) (Diptera: Culicidae) populations remain in the egg stage during the cold season. To ensure the start of a new breeding season, eggs should hatch at the beginning of a favorable period. The aim of the current study was to investigate the hatching response of two Ae. aegypti egg batches collected and stored fo...

Notonectids are well-known predators in aquatic habitats, where mosquito larvae, chironomids, and cladocerans constitute their main diet. Our purpose was to assess the effect of structural complexity on the predatory ability of Buenoa fuscipennis, a common predator in aquatic habitats of Buenos Aires city (Argentina). Buenoa fuscipennis showed type...

In temperate regions, the seasonal dynamics ofAedes aegypti(L.) (Diptera: Culicidae) is mainly inßuenced by temperature, whereas the probability of local extinction depends on the egg mortality during the cold season. The aim of the current study was to assess the importance of temperature and egg mortality in determining the differences in the ovi...

The aim of the present study was to compare 2 urban habitat types: pools artificially filled with water from damaged or leaking water pipes (AF) and pools naturally filled by rainwater (NF), with regard to their favorability as breeding sites for mosquitoes. Two study areas were analyzed, 1 for 5 months and the other for 9 months, covering the whol...

Here, we present and discuss a compartmental stochastic model for Aedes aegypti conceived as a math- ematical structure able to interpolate and extrapolate (predict) biological phenomena, and direct the attention to biological matters that need experimental elucidation. The model incorporates weather information in the form of daily temperatures an...

The dynamics of Enochrus variegatus (Steinheil) and Enochrus vulgaris (Steinheil) in temporary pools and permanent ponds were studied in an urban park of Buenos Aires, Argentina. Samples were collected from both types of habitats weekly throughout one year, and variables like water surface and vegetation cover were recorded. In permanent ponds, adu...

Predators may have multiple effects on prey, including the mortality caused by consumption, but also non-consumptive effects when prey alter their life history traits in the presence of predators. This study aimed to describe the consumption ability and the non-consumptive effects of Notonecta sellata (Heteroptera: Notonectidae) on immature stages...

In temperate regions, populations of Aedes aegypti survive the cold season in the egg stage. In the present work, we studied the cold-season mortality of Ae. aegypti eggs and their subsequent hatching pattern in Buenos Aires city. Eggs were exposed during the winter season (three months) in three neighborhoods located along a gradient of distance t...

Several studies showed that Aedes aegypti has a heterogeneous distribution in the city of Buenos Aires. Favorable areas in the periphery and less favorable areas near the city center and the Rio de la Plata River were identified. The aim of this work was to study the effect of temperature and mortality of eggs as possible causal factors for the men...

We present the results of the first survey on the aquatic and semiaquatic water beetles from the Ernesto Tornquist Provincial Park. The material was obtained from several quantitative samplings of aquatic insects covering all seasons from 2005 to 2007. The surveyed habitats were the Ventana, El Loro and Sauce Grande streams and two rain pools. A to...

The seasonal variation in the density of swimming pools and the occurrence of immature mosquitoes in these habitats were studied in the temperate city of Buenos Aires, Argentina. The density of swimming pools was highest in the summer (6.0 pools/ha) when temporal pools predominated; it was lowest in the winter (0.9 pools/ha) when only permanent poo...

We examined the responses of a Spartina densiflora (Poaceae) marsh to an accidental summer fire taking place in the Otamendi Natural Reserve (Argentina). Green, standing dead, reproductive and litter fractions of S. densiflora, as well as forbs biomass were determined before and after burning using randomly selected quadrates. Fire reduced most of...

Distribution among pools of six mosquito species and 23 predatory insect taxa were studied in temporary rain pools during the summer and fall season in Buenos Aires city. Both mosquito immatures and predators were disproportionally more abundant in pools with high flooded surface, depth, and duration. Mosquito immatures differed in their habitat us...

Because of its capacity to infect human beings and domestic animals with a number of different viruses, the study of the mosquito Ochlerotatus albifasciatus (Macquart, 1938, (Diptera: Culicidae)) assumes great importance from the point of view of sanitation. It is a well-known fact that the abundance of this species peaks after drought periods in t...

We studied the effects of fire on the structural attributes of a Spartina densiflora salt marsh. The study was carried out from November 1995, spring (N95S) to December 1996, late spring (D96LS). In November 1995, we installed 37 permanent plots. In January 1996, 32 of the plots were accidentally burned (B) and the remaining were not burned (NB). V...

The study was conducted in a park of Buenos Aires City, where a total of 89 rain pools were sampled weekly for mosquito immature stages over a one-year period. The aim of the present paper was to investigate the seasonal dynamics of three Culex species breeding in temporary rain pools and to analyze the relationships of the presence of these specie...

The immature stages of Ochlerotatus albifasciatus develop in temporary pools. The present study aims at evaluating the seasonal dynamics of the aquatic stages of this mosquito, also analyzing the relationship among their presence and breeding success to some relevant climatic and environmental variables in the ephemeral rain pools of an urban park....

Tiller dynamics and net aerial primary productivity (NAPP) were studied in permanent sample plots of Spartina densiflora at Otamendi Natural Reserve (Buenos Aires Province, Argentina) from June 1996 to December 1997. Emergence, growth, senescence, survival, biomass dynamics, and tiller productivity were analyzed. These population attributes varied...

Aedes albifasciatus is a floodwater mosquito that breeds in temporary waters. This semi-domestic species, widely distributed in Argentina, is a competent vector of the western equine encephalitis. The present study was carried out in two rain pools of the city of Buenos Aires, from April 1998 through March 1999. Samples were taken twice a week duri...

We describe the seasonal variations of the insect community of the rain pools in a park of Buenos Aires during a 1-year period, based on a weekly sampling programme. We also analyse the relationships between the observed biotic patterns and some physical and meteorological variables. Four periods, fairly coincident with the seasons of the year, wer...