DISTRIBUCIÓN ESPACIO - TEMPORAL DE INSECTOS ACUÁTICOS EN QUEBRADAS DE LA LLANURA AMAZÓNICA, LORETO, PERÚ.

This study aimed to determine the spatial and temporal distribution of aquatic insects in 10 streams of the Amazon lowlands located within the area of ​​influence of the Iquitos-Nauta highway (Loreto, Peru). Samplings were made in two zones with different access roads, anthropic influence and stream sizes, which were named: ZM 1 and ZM 2; and, during three distinct hydrological periods: draining season, dry season and rising season. Richness, abundance, diversity, and dominance of aquatic insects; as well as water pH, temperature (ºC), dissolved oxygen (mg/l) and electrical conductivity (μS/cm) levels of each stream were recorded. Results report a total richness of 63 families and 4771 individuals; of which the families Leptophlebiidae, Caenidae, Libellulidae, Hidrophilidae, Elmidae, Hydropsychidae, Polycentropodidae, Tipulidae, Ceratopogonidae and Chironomidae, are widely distributed in the evaluated streams. Significant differences were recorded between the two sampling areas (p=0.01) and among the three collection periods evaluated (p=0.035); reporting higher records of richness, abundance and diversity; as well as higher values ​​of pH, temperature, dissolved oxygen and electrical conductivity in the streams of the ZM 2 and during the dry season. The highest level of dominance occurred in the streams of ZM 1, during the draining and rising water seasons, being Chironomidae, the dominant family. Our results provide baseline information for the optimization of methods for evaluating the environmental quality of streams in the Peruvian Amazon lowlands.  El objetivo del estudio fue conocer la distribución espacial y temporal de insectos acuáticos en 10 quebradas de llanura amazónica, ubicadas dentro del área de influencia del eje carretero Iquitos-Nauta (Loreto, Perú). Las colectas fueron realizadas en dos zonas de muestreo con diferentes vías de acceso, grado de influencia antrópica y dimensión de las quebradas, que fueron denominadas: ZM 1 y ZM 2; y, durante tres distintos periodos hidrológicos del año: vaciante, seca y creciente. Se evaluó la riqueza, abundancia, diversidad y dominancia de estos organismos; así como los niveles de pH, temperatura (ºC), oxígeno disuelto (mg/l) y conductividad eléctrica (μS/cm) de la columna de agua de cada quebrada. Los resultados reportan una riqueza total de 63 familias y 4771 individuos; de las cuales las familias Leptophlebiidae, Caenidae, Libellulidae, Hidrophilidae, Elmidae, Hydropsychidae, Polycentropodidae, Tipulidae, Ceratopogonidae y Chironomidae, están ampliamente distribuidas en las quebradas evaluadas. Se registraron diferencias significativas entre las dos zonas de muestreo (p=0,01) y entre los tres periodos de colecta, evaluados (p=0,035); reportándose mayores registros de riqueza, abundancia y diversidad; así como mayores valores de pH, temperatura, oxígeno disuelto y conductividad eléctrica en las quebradas de la ZM 2 y en el periodo de seca. El mayor nivel de dominancia fue reportada en las quebradas de la ZM 1 durante los periodos de vaciante y creciente; siendo Chironomidae la familia dominante. Nuestros resultados aportan información de referencia para la optimización de métodos de evaluación de la calidad ambiental de quebradas de llanura amazónica peruana. &nbsp

ANALISIS DE LAS ESTADÍSTICAS DE PRODUCCIÓN DE CARNE Y SEMILLA DE PAICHE Arapaima gigas EN LORETO Y UCAYALI (PERÚ)

El presente trabajo, tiene como objetivo analizar la evolución reciente de las estadísticas de producción de semilla y carne de paiche (Arapaima gigas) en la región Loreto y Ucayali; tomando como base, la información estadística de las Direcciones Regionales de la Producción (DIREPRO) de ambas regiones. Adicionalmente, se presentan datos de comercialización y exportación de productos derivados del paiche del Ministerio de la Producción

Desarrollo del cladócero nativo Ceriodaphnia sp con clorofitas (Scenedesmus sp y Chlorella sp) en condiciones de laboratorio

The effect of the chlorophytes Scenedesmus sp and Chlorella sp used as feed on the growth of the native cladoceran Ceriodaphnia sp were studied. Three treatments with three repetitions for each chlorophyte were used: T1 = 5 ml.L-1 (25 x 106 cells), T2 = 10 ml.L-1 (50 x 106 cells) and T3 = 15 ml.L-1 (75 x 106 cel). The physical and chemical characteristics of the water in the containers varied between 28.4 and 28.6 °C, pH between 6.57 and 7.36 and the dissolved oxygen between 6.34 and 6.66 mg/l between treatments. The results showed that Ceriodaphnia sp prefers the Chlorella sp microalgae, where diets with a concentration of 10 ml.l-1 (50 x 106 cells) were better than the other diets.Se presentan los resultados del efecto de las clorofitas Scenedesmus sp y Chlorella sp utilizadas como alimento sobre el desarrollo del cladócero nativo Ceriodaphnia sp. Se emplearon tres tratamientos con tres repeticiones para cada clorifita, T1= 5 ml.L-1 (25 x 106 cel), T2= 10 ml.L-1 (50 x 106 cel) y T3=15 ml.L-1 (75 x 106 cel). Las características físicas y químicas del agua de los recipientes variaron entre 28.4 y 28.6 °C, pH entre 6.57 y 7.36 y el oxígeno disuelto entre 6.34 y 6.66 mg/l entre tratamientos. Los resultados mostraron que Ceriodaphnia sp tiene preferencia por la microalga Chlorella sp, donde las dietas con la concentración de 10 ml.l-1 (50 x 106 cel) fueron superiores a las otras dietas

REPRODUCCIÓN INDUCIDA DE GAMITANA Colossoma macropomum USANDO EXTRACTOS DE PITUITARIA DE CARPA COMÚN Y DE PAICHE

Hypophysation was the first known induced reproduction technique in fish farming and, it continues being applied to this day. The study aimed to evaluate the reproductive response of adult males and females of black-finned pacu Colossoma macropomum, induced with injections of paiche pituitary extract (EPP) and carp pituitary extract (CPE). We used ten females and ten males with an average body weight of 6,81 ± 1,86 kg and 6,59 ± 2,34 kg, respectively. Four females were treated with carp pituitary extract (CPE) at 6,0 mg/kg body weight, while another six received paiche pituitary extract (PPE) at 3,5 mg/kg body weight. In both cases, the dose was administered in two injections (10% at the beginning and 90% twelve hours later). Four males were induced with EPC and six with EPP at 1 mg/kg body weight administered in two 50% doses simultaneously as the females. The females induced with the EPP spawned in their entirety, while with the EPC only 75% of them. The means of total weight of spawned oocytes, number of oocytes per gram, absolute fecundity, hatching rate and the total number of larvae produced from the two hormonal treatments used in the present study did not present significant differences (P>0.05). The present work demonstrated that it is possible to carry out the induced reproduction of Colossoma macropomum using paiche pituitary extract.La hipofización fue la primera técnica de reproducción inducida conocida en piscicultura y sigue siendo una técnica aplicada hasta la actualidad. El objetivo del estudio fue evaluar la respuesta reproductiva de machos y hembras adultas de gamitana Colossoma macropomum, inducidas con inyecciones de extracto de pituitaria de paiche (EPP) y extracto de pituitaria de carpa (EPC). Utilizamos diez hembras y diez machos con un peso corporal promedio de 6,81 ± 1,86 kg y 6,59 ± 2,34 kg, respectivamente. Cuatro hembras fueron tratadas con el extracto de hipófisis de carpa (EPC) a 6,0 mg/kg de peso corporal, mientras que otras seis recibieron el extracto de pituitaria de paiche (EPP) a razón de 3,5 mg/kg de peso corporal. En ambos casos la dosis fue administrada en dos inyecciones (10% al inicio y 90% doce horas después). Cuatro machos fueron inducidos con EPC y seis con EPP a razón de 1 mg/kg de peso corporal administrados en dos dosis de 50%, al mismo tiempo que las hembras. Las hembras inducidas con el EPP desovaron en su totalidad, mientras que con el EPC solo el 75% de ellas. La tasa de desove, así como las medias de peso total de ovocitos desovados, número de ovocitos por gramo, fecundidad absoluta, tasa de eclosión y el número total de larvas producidas de los dos tratamientos hormonales utilizados en el presente estudio no presentaron diferencias significativas (P>0.05). El presente trabajo demostró que es posible realizar la reproducción inducida de Colossoma macropomum utilizando el extracto de pituitaria de paiche

Cytotaxonomy of Simulium cauchense Floch & Abonnenc and Simulium quadrifidum Lutz (Diptera: Simuliidae) in Brazilian Amazonia

Simulium cauchense Floch & Abonnenc and Simulium quadrifidum Lutz are widely distributed in the Amazon region and are morphologically similar at the larval and pupal stages. Chromosomally, these species are readily distinguished by the position of the nucleolar organizer, which is in the short arm of chromosome I in S. cauchense and in the long arm of chromosomes III in S. quadrifidum. They also differ by three fixed inversions. Sex chromosomes are undifferentiated in both species. Chromosomal resolution of the two species allowed us to evaluate four structural features previously used as diagnostic aids at the larval stage. Characters that distinguish larvae of the two species are the number of branches and branching patterns of the dorsal abdominal setae and the dark band on each primary fan. Branching patterns of the gill histoblasts were often diagnostic, with S. quadrifidum exhibiting more proximal branching and S. cauchense more distal branching. Sites where both species occurred sometimes had larvae with one petiole branching proximally and the other distally; in these cases examination of the chromosomes permitted assignment of the specimen to species. Pigmentation patterns of larvae, on the other hand, are highly variable. Color typically is sex linked in both species

Estudos citotaxonômicos e moleculares de Simulium quadrifidum Lutz, 1917 e Simulium cauchense Floch & Abonnenc, 1946 (Diptera: Simuliidae) na Amazônia, Brasil /

A classificação da família Simuliidae na região neotropical é controversa no momento. Certos autores incluem espécies dos subgêneros Coscaroniellum e Cerqueirellum no subgênero Psaroniocompsa, colocando-os em sinonímia. Outros consideram esses dois subgêneros válidos e ainda outros consideram esses dois subgêneros como gêneros. Este trabalho teve como objetivo caracterizar Simulium quadrifidum e Simulium cauchense, duas espécies envolvidas no problema subgenérico acima citado, mediante a análise do padrão de restrição de quatro enzimas (PCR-RFLP) e da seqüência nucleotídica da região ITS, incluindo a região 5.8S (ITS1 + 5.8S + ITS2) do DNA ribossomal. Foram analisados espécimes procedentes dos Estados do Amapá, Amazonas, Rondônia e Roraima. Caracteres morfológicos utilizados na identificação destas espécies se apresentaram variáveis, com sobreposição de alguns deles em algumas populações (principalmente simpátricas). As populações das duas espécies analisadas apresentaram-se monomórficas. A análise dos cromossomos politênicos indica que essas duas espécies são estreitamente relacionadas e se diferenciam pela presença de três inversões fixas, um marcador sexual ligado ao cromossomo X e pela posição do organizador nucleolar (NO) em cromossomos diferentes. A análise do PCR-RFLP utilizando quatro enzimas (Taq I, Xba I, Alu I, Rsa I) indicou que só os padrões de restrição produzidas pelas enzimas Taq ! e Xba I, foram diagnósticas para ambas espécies. Enquanto as seqüências nucleotídicas, 469 pb correspondentes a seqüência parcial da região ITS incluindo a região 5.8S, revelaram uma distância genética de 7,1% entre as espécies, apesar da similaridade na composição nucleotídica dessa região em ambas espéices. Eventos de inserção/deleção (indels) e substituições nucleotídicas, principalmente tranversões, marcaram diferenças entre elas. Simulium cauchense apresentou menor variabilidade do que S. quadrifidum. Estes resultados servem de base para futuras comparações destas espécies com outros simulídeos membors dos subgêneros Psaroniocompsa e/ou Cerqueirellum e Coscaroniellum, e demonstram a importância de estudos integrados no auxílio da taxonomia dos simulídeos

Larval biometry of Simulium rubrithorax (Diptera: Simuliidae) and size comparison between populations in the states of Minas Gerais and Roraima, Brazil

The number of larval instars of Simulium (Hemicnetha) rubrithorax Lutz (Diptera: Nematocera) was determined using the lateral length of the head capsule. In this study 1,035 larvae, of different sizes, were measured (639 from the state of Roraima and 396 from the state of Minas Gerais). A frequency distribution analysis was carried out on the measurements of the lateral length of the head capsule to determine the number of larval instars. The limits of each instar were defined by the lower frequency of the measurements falling in a range of values, by the presence of the "egg burster" that characterizes the first larval instar, and by the developmental stage of the gill histoblast. The determination of the instar number was tested using a Student's t-test (p < 0.05), the Dyar rule and the Crosby growth rule. The results indicate the existence of 7 larval instars for this species, although this result was not in accordance to the Crosby rule. Last-instar larvae from two widely separated geographical populations (Roraima and Minas Gerais), collected in habitats with different water temperature were compared and no differences (p > 0.05) were observed between them