Preliminary observations on the patterns of co-occurrence of Black fly (Diptera: Simuliidae) larvae and some of their potential macroinvertebrate predators

ABSTRACT Biotic factors such as predation, although important drivers of the black fly community, are rarely investigated in the literature. This study aimed to test the hypothesis that the patterns of co-occurrence of black fly larvae and its potential predators is not random and that there is a correlation between its frequencies and Simuliidae larvae abundances. Larvae were sampled from two localities in the Pedra Branca State Park, Rio de Janeiro, Brazil, during the dry season in june 2018. We collected Simulium pertinax Kollar, 1832, Simulium subpallidum Lutz, 1910, Simulium (Inaequalium) sp., Simulium (Psaroniocompsa) sp. and Simulium (Trichodagmia) sp. The predators families present were Perlidae, Hydropsychidae, Leptoceridae, Libellulidae and Chironomidae. The null models showed that species co-occurred significantly more than expected by chance. The canonical correlation analyses for the Vargem Grande and Pau da Fome areas area showed a significant relationship between black fly abundances and predator abundances. In Vargem Grande the abundance of Chironomidae showed a highly significant positive correlation to S. (Psaroniocompsa) sp., while Hydropsychidae was significantly correlated to Simulium sp. On the other hand, in Pau da Fome Libellulidae was significantly correlated to S. (Psaroniocompsa) sp. and Simulium sp. and Chironomidae correlated significantly to Simulium sp. The result is consistent with what would be expected of organisms that exercise mutual population regulation, although other factors than biotic interactions may be causing these patterns. However the lack of mechanistic evidences on the effect of biotic interactions on black fly populations pose a challenge on the understanding of these patterns.

Water pollution and distribution of the black fly (Diptera: Simuliidae) in the Atlantic Forest, Brazil / Contaminación del agua y distribución de la mosca negra (Díptera: Simuliidae) en el bosque Atlán&tico, Brasil

Abstract:Black flies have medical importance because some species are vectors of the Onchocerciasis and Mansonelosis, nevertheless, their ecology and potential use as bioindicators is still poorly studied in the Neotropical Region. In Brazil, bioindicators use is strongly focused in a multimetrical ecological index approach; this way, we investigated the black fly spatial distribution, in relation to abiotic factors correlated to water quality, to provide baseline information for their utilization as standalone indicators of lotic systems integrity. We have tested the hypothesis that environmental changes related to urbanization, lead to decreased abundance and loss in the number of species of the black fly fauna. The sampling was conducted in 10 urban and 10 preserved streams during the dry season (August-September) of 2012, in the mountainous region of Teresópolis, State of Rio de Janeiro, Brazil. The streams were characterized for their environmental integrity conditions and physico-chemical properties of water. In each stream, five different rapid points were sampled in a section of 50 meters, 10 meters apart from each other. The black flies were sampled with a kick-net sampler on rocky substrates. The material was separated and the larvae were sorted in morphotypes, and later, the final instar specimens were dissected and identified with the help of taxonomical literature at species level. A total abundance of 488 larvae from nine species were collected, 5 (1.02 %) in extremely impacted streams, 470 (96.31 %) in intermediate streams and 13 (2.66 %) in preserved streams. The visual evaluation (HII) differed in rela&tion to the water physico-chemical evaluation, in which more variation in the characterization of the sampling sites was observed. In Canonical Correspondence Analysis Simulium subpallidum, S. inscrustatumand S. pertinaxwere significantly associated with intermediate values of most of the variables, and then to intermediate impacted sites. On the other hand, Lutzsimulium hirticosta, S. subnigrumand Simuliumsp. A were associated to low values of chemical variables, and then to more preserved sites. Most studies on the bioindicator potential of Simuliidae have suggested an approach to agricultural impacts, while our results, on the other hand, showed that Simuliidae species were present in streams with intermediate urban pollution impacts, but absent in heavily impacted sites. Thus, our data suggested that some species are associated to more pristine breeding sites, such as L. hirticostaand Simuliumsp. A, while others may be good bioindicators of moderately impacted streams, such as S. pertinax, S. subnigrumand S. subpallidum.

Resumen:Aunque las moscas negras tienen importancia médica debido a que algunas de sus especies son vectores de la Oncocercosis y Mansonelosis, su ecología y su potencial como bioindicadores es aún poco estudiado en la Región Neotropical. En Brasil el uso de bioindicadores se centra principalmente en un índice ecológico multimétrico, en este estudio investigamos la distribución espacial de las moscas negras y su relación con los factores abióticos, para su utilización como indicadores de la integridad de los sis&temas lóticos. En este sentido, hemos probado la hipótesis de que los cambios ambientales relacionados con la urba&nización conducen a la disminución de la abundancia y la pérdida de especies de la mosca negra. El muestreo se llevó a cabo en la región montañosa del Estado de Río de Janei&ro, Brasil, en 10 zonas urbanas y 10 arroyos conservados durante la estación seca (agosto-septiembre) de 2012. Los arroyos se caracterizaron por sus condiciones de integridad del ambiente y las propiedades físico-químicas de agua. Las moscas negras se muestrearon en sustratos rocosos con un kick-net sampler.El material se separó y las larvas se ordenaron por morfotipos y más tarde los especímenes en último estadio se disectaron e identificaron con la ayuda de la literatura taxonómica a nivel de especie. Una abundancia total de 488 larvas de nueve especies fueron recolectadas, 5 (1.02 %) en arroyos muy afectados, 470 (96.31 %) en intermedios y 13 (2.66 %) en conservados. La evaluación visual (HII) difiere de la físico-química del agua, en la que se observó una mayor variación. En el Análisis Correspon&dencia Canónica, Simulium subpallidum, S. inscrustatumy S. pertinaxestaban asociadas significativamente con sitios de impacto intermedio, para la mayoría de las variables. Por otro lado, Lutzsimulium hirticosta, S. subnigrumy Simuliumsp. A se asocian con valores bajos de las varia&bles químicas, relacionado a sitios más conservados. La mayoría de los estudios sobre el potencial bioindicador de Simuliidae tienden a enfocarse en los impactos agrícolas, mientras que nuestros resultados, por otro lado, sugieren que las especies de Simuliidae están presentes en arroyos con impactos intermedios de contaminación urbana, pero ausentes en los sitios fuertemente afectados. Por lo tanto, nuestros datos sugieren que algunas especies tales como L. hirticostay Simuliumsp. A están asociadas a lugares de reproducción más prístinos, mientras que otras pueden ser bioindicadores de arroyos moderadamente afectados, como S. pertinax, S. subnigrumy S. subpallidum.

Evidence of phenotypic plasticity of larvae of Simulium subpallidum Lutz in different streams from the Brazilian Cerrado

In this paper, the overall morphological differences between populations of Simulium subpallidum Lutz, 1909 are studied. Several studies found in the literature point to a relationship between the labral fans and body size and the habitat where blackfly larvae occur. However, other characteristics potentially related to the microhabitat, such as abdominal hook circlet morphology, which is used for larvae to fix themselves in the substratum, and thoracic prolegs morphology, which help larvae move in the substratum, were analyzed in three different populations of S. subpallidum, one of which occupied a faster flow. The results suggest phenotypic plasticity in S. subpallidum and a tendency toward larger structures in faster flows.

Boletim da Pesquisa "Monitoramento da saúde, acesso à EPIs de técnicos de enfermagem, agentes de combate às endemias, enfermeiros, médicos e psicólogos, no município do Rio de Janeiro em tempos de Covid-19"

O objetivo geral desta pesquisa é produzir e ampliar as informações acerca do impacto da pandemia por Covid-19 na saúde de trabalhadores que estão na linha de frente do combate ao novo coronavírus, especialmente os técnicos de enfermagem, enfermeiros, médicos, psicólogos e agentes de combate às endemias, que atuam em serviços públicos de saúde na atenção primária, especificamente na Estratégia Saúde da Família (ESF); na atenção psicossocial, especificamente nos Centros de Atenção Psicossocial (CAPS); e nas Unidades de Pronto Atendimento (UPA) municipais do Rio de Janeiro.