RESUMO

The use of imidacloprid is a common pest control practice in the Neotropical region. However, the imidacloprid unintended sublethal effects on Neotropical aquatic non-target arthropods and undesirable consequences for aquatic environments remain unclear. Here, we assessed the susceptibility of Chironomus columbiensis (Diptera: Chironomidae) larvae to the neonicotinoid imidacloprid and evaluated whether sublethal exposure types would trigger sex-dependent adaptive responses (e.g., emergence, body mass, reproduction, wing morphology). We conducted a concentration-mortality curve (96 h of exposure) and established chronic and acute sublethal exposure bioassays. While chronic sublethal exposures consisted of exposing individuals during their entire larval and pupal stages, the acute sublethal exposures represented a single short duration (24 h) exposure episode during either the first or fourth larval instar. Our results revealed that chronic sublethal exposure reduced the body mass of males, while acute sublethal exposures during the first instar resulted in heavier males than those that were not exposed to imidacloprid. Chronic exposure also reduced the reproduction of males and females, while the acute sublethal exposure only affected the reproduction of individuals that were imidacloprid-exposed on their later larval instar. Chronic and acute sublethal exposures did differentially affect the wing properties of C. columbiensis males (e.g., increased size when chronically exposed and highly asymmetric wings when acutely exposed in early larval phase) and females (e.g., highly asymmetric wings when chronically and acutely exposed). Collectively, our findings demonstrated that imidacloprid can cause unintended sublethal effects on C. columbiensis, and those effects are dependent on sex, exposure type, and developmental stage.

Assuntos

RESUMO

Sublethal exposure to insecticides can trigger unintended responses in non-target insects that may disrupt reproductive and developmental performances of these organisms. Here, we assessed whether sublethal exposure to the pyrethroid insecticide deltamethrin in early life had sublethal and transgenerational effects on the reproduction (i.e., fecundity and fertility) and wing morphology of Chironomus columbiensis, an aquatic insect used as a water quality indicator. We first conducted concentration-response bioassays to evaluate the susceptibility of C. columbiensis larvae to deltamethrin. Our results revealed that deltamethrin toxicity was approximately 7-fold higher when C. columbiensis larvae where exposed to 96 h (LC50 = 0.17 [0.15-0.20] µg/L) than to 24 h (LC50 = 1.17 [0.97-1.43] µg/L). Furthermore, the sublethal exposures (at LC1 = 0.02 µg/L or LC10 = 0.05 µg/L) of immature C. columbiensis resulted in lower fecundity (e.g., reduced eggs production) and morphometric variation wing shapes. Further reduction in fertility rates (quantity of viable eggs) occurred at deltamethrin LC10 (0.05 µg/L). Almost 80% of the fecundity was recovered with only a single recovery generation; however, two subsequent recovery generations were not sufficient to fully recover fecundity in C. columbiensis. Specimens recovered from 98.5% of wing morphometric variation after two consecutive generations without deltamethrin exposure. Collectively, our findings demonstrates that sublethal exposure to synthetic pyrethroids such as deltamethrin detrimentally affect the reproduction and wing shape of C. columbiensis, but also indicate that proper management of these compounds (e.g., concentration and frequency of application) would suffice for these insects' population recovery.

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Con el objetivo de contribuir al conocimiento taxonómico y de distribución de los géneros del orden Ephemeroptera en Caldas, se estudiaron especímenes colectados entre mayo de 2008 y mayo de 2012 en 12 municipios del departamento de Caldas - Colombia, abarcando un rango altitudinal de 159 a 3433 m y un total de 55 fuentes hídricas. Se encontraron seis familias y 26 géneros de Ephemeroptera, de los cuáles Cabecar constituye un nuevo registro para Colombia, y también se realiza el primer registro de las ninfas de Tikuna y Ulmeritoides para el país. Americabaetis, Apobaetis, Callibaetis, Cloeodes, Guajirolus, Paracloeodes, Cabecar, Traveryphes, Tricorythodes, Terpides, Tikuna, Ulmeritoides, Caenis y Campsurus son nuevos registros para Caldas. Se encontraron diferencias en la composición de la fauna de Ephemeroptera en las diversas zonas altitudinales, siendo las zonas de altitud inferior a 1000 m las de mayor riqueza de géneros.(AU)

With the aim of contribute to the knowledge of taxonomy and distribution of the genera of the order Ephemeroptera in Caldas, samples were taken between May of 2008 and May of 2012 in 12 municipalities of the department of Caldas - Colombia, covering an altitudinal range from 159 to 3433 m and a total of 55 water sources. Six families and 26 genera of Ephemeroptera were found, of which Cabecar is a new record for Colombia, also recording for the first time the nymphs of Tikuna and Ulmeritoides for the country. Americabaetis, Apobaetis, Callibaetis, Cloeodes, Guajirolus, Paracloeodes, Cabecar, Traveryphes, Tricorythodes, Terpides, Tikuna, Ulmeritoides, Caenis and Campsurus are new records for Caldas. Differences in the composition of the fauna in the diverse altitudinal zones were found, being the areas below 1000 m with highest genera richness.(AU)

Assuntos

RESUMO

Con el objetivo de contribuir al conocimiento taxonómico y de distribución de los géneros del orden Ephemeroptera en Caldas, se estudiaron especímenes colectados entre mayo de 2008 y mayo de 2012 en 12 municipios del departamento de Caldas - Colombia, abarcando un rango altitudinal de 159 a 3433 m y un total de 55 fuentes hídricas. Se encontraron seis familias y 26 géneros de Ephemeroptera, de los cuáles Cabecar constituye un nuevo registro para Colombia, y también se realiza el primer registro de las ninfas de Tikuna y Ulmeritoides para el país. Americabaetis, Apobaetis, Callibaetis, Cloeodes, Guajirolus, Paracloeodes, Cabecar, Traveryphes, Tricorythodes, Terpides, Tikuna, Ulmeritoides, Caenis y Campsurus son nuevos registros para Caldas. Se encontraron diferencias en la composición de la fauna de Ephemeroptera en las diversas zonas altitudinales, siendo las zonas de altitud inferior a 1000 m las de mayor riqueza de géneros.

With the aim of contribute to the knowledge of taxonomy and distribution of the genera of the order Ephemeroptera in Caldas, samples were taken between May of 2008 and May of 2012 in 12 municipalities of the department of Caldas - Colombia, covering an altitudinal range from 159 to 3433 m and a total of 55 water sources. Six families and 26 genera of Ephemeroptera were found, of which Cabecar is a new record for Colombia, also recording for the first time the nymphs of Tikuna and Ulmeritoides for the country. Americabaetis, Apobaetis, Callibaetis, Cloeodes, Guajirolus, Paracloeodes, Cabecar, Traveryphes, Tricorythodes, Terpides, Tikuna, Ulmeritoides, Caenis and Campsurus are new records for Caldas. Differences in the composition of the fauna in the diverse altitudinal zones were found, being the areas below 1000 m with highest genera richness.

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RESUMO

Tricorythodes molinerii sp. n. é descrita e ilustrada baseada em ninfas do sudeste do Brasil. A espécie nova pode ser distinguida das demais espécies de Tricorythodes Ulmer pela seguinte combinação de caracteres: 1) projeção genal presente; 2) palpo maxilar bi-segmentado, com seta apical curta; 3) pronoto com projeções anterolaterais bem desenvolvidas; 4) região dorsal do fêmur anterior com uma fileira transversal de setas; 5) garra tarsal sem dentículos marginais e com um dentículo submarginal de cada lado; 6) brânquia opercular triangular, sombreada com negro e com uma marca esbranquiçada subbasal; e 7) comprimento do corpo grande.

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RESUMO

Tricorythodes molinerii sp. n. is described and illustrated based on nymphs from southeastern Brazil. The new species can be distinguished from other species of Tricorythodes Ulmer by the following characters: 1) genal projection present; 2) maxillary palp bi-segmented, with short apical seta; 3) pronotum with well developed anterolateral projection; 4) dorsum of fore femora with a transverse row of setae; 5) tarsal claws without marginal denticles and with one submarginal denticle on each side; 6) operculate gills triangular, shaded with black, and with whitish mark in subbasal zone; and 7) very large size.

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RESUMO

A key to the Brazilian genera of Ephemerelloidea, nymphs and adults, belonging to the families Coryphoridae, Leptohyphidae and Melanemerellidae is presented. Currently, seven genera of this superfamily are known in Brazil. The Leptohyphidae is the most representative family, with five genera registered from the country, Leptohyphes Eaton, 1882, Leptohyphodes Ulmer, 1920, Traverhyphes Molineri, 2001, Tricorythodes Ulmer, 1920 and Tricorythopsis Traver, 1958. The families Coryphoridae and Melanemerellidae are monotypic, represented by Coryphorus Peters, 1981and Melanemerella Ulmer, 1920.

Neste trabalho é apresentada uma chave para identificação dos gêneros brasileiros de Ephemerelloidea, ninfas e adultos, pertencentes às famílias Coryphoridae, Leptohyphidae e Melanemerellidae. Atualmente, sete gêneros desta superfamília são conhecidos no Brasil. Leptohyphidae é a família mais representativa, com cinco gêneros registrados para o país, Leptohyphes Eaton, 1882, Leptohyphodes Ulmer, 1920, Traverhyphes Molineri, 2001, Tricorythodes Ulmer, 1920 and Tricorythopsis Traver, 1958. Coryphoridae e Melanemerellidae são monotípicas, representadas por Coryphorus Peters, 1981e Melanemerella Ulmer, 1920.