Quantitative biological response of two predators (Heteroptera: Notonectidae) in the larval control of Aedes aegypti (Diptera: Culicidae).

Predation is a biotic factor that influences the structure and functioning of ecosystems, its effect can be quantified through functional (FR) and numerical response in a successful-invasion context. We use FR to understand the coevolutionary relationships, and measured the biological response of the predators Notonecta peruviana and Buenoa fasciata in the control of fourth-stage larvae of Aedes aegypti (F1) at different densities (5, 10, 20, 35, 55 and 80 larvae / liter). Fasting predators (48 hours) were introduced to the test containers (one individual per species) and the FR, the number of preys consumed (Ne), the attack coefficient (a) and handling time (Th). N. peruviana and B. fasciata developed a type II FR in the consumption of larvae of Ae. aegypti (p ≤ 0.01), and occupied close handling times (Th) (t = –1.93; df = 12; p = 0.078). N. peruviana preyed (Ne) twice as many larvae of Ae. aegypti (p ≤ 0.05) and showed a higher attack coefficient (a) in relation to B. fasciata (t = 14.92; df = 12; p = 0.000). The predators N. peruviana and B. fasciata rapidly destabilized and consumed the preys. N. peruviana preyed twice as many larvae, attributable to the recent predator-prey effect compared to the possible coevolutionary adjustment between B. fasciata and Ae. aegypti. It would be important to consider the predator species in the vector control programs for aedine mosquitoes

First record of Pilularia americana A. Braun (Polypodiidae, Salviniales, Marsileaceae) from Peru

The aquatic fern Pilularia americana A. Braun is known from several countries in South and North America. Here we provide a first report of this species for Peru, from 2 localities in the Ancash and Ayacucho regions (central Peru), which confirm its presence in the national flora

First record of Pilularia americana A. Braun (Polypodiidae, Salviniales, Marsileaceae) from Peru

The aquatic fern Pilularia americana A. Braun is known from several countries in South and North America. Here we provide a first report of this species for Peru, from 2 localities in the Ancash and Ayacucho regions (central Peru), which confirm its presence in the national flora

Macroinvertebrados acuáticos en los sistemas lóticos de dos bofedales altoandinos, Ayacucho Perú.

Los bofedales altoandinos son ecosistemas únicos, donde se distinguen dos sistemas acuáticos, lénticos (pequeñas áreas con aguas estancadas temporales y permanentes) y lóticos (aguas corrientes que actúan como drenajes), en ello existen una diversidad (poco estudiada) de macroinvertebrados acuáticos. La investigación se realizó en los sistemas lóticos de los bofedales Guitarrachayocc y Pichccahuasi con extensiones de 43 has y 27 has respectivamente, ubicados a 4500 msnm, ubicado en el distrito de Paras, provincia de Cangallo, departamento de Ayacucho, entre los meses de octubre de 2016 a abril del 2017. Se empleó una red Surber, colectando muestras de tres sistemas lóticos dentro del bofedal Guitarrachayocc y un sistema en el bofedal Pichccahuasi, donde se ubicaron siete y cuatro zonas de muestreo, respectivamente. Se halló 26 géneros pertenecientes a 20 familias, 11 órdenes y 5 clases (Insecta, Clitella, Gastropoda, Malacostraca y Oligochaeta); siendo la Insecta la más diversa con 21 géneros. Los géneros más abundantes fueron Dicrotendipes (26,9%), Macrelmis (19,85%) y Claudioperla (9,5%). El análisis cluster (Paired group, Sorensen) con un 60% de similitud, en la comunidad se distingue tres grupos que identifican las zonas de muestreo en los dos bofedales y un grupo constituido solo por una zona ubicada en el bofedal Guitarrachayocc (presenta aguas con promedios de conductividad eléctrica de 1117 µS/cm y pH de 3,2).Resumen extens

Distribución altitudinal de macroinvertebrados acuáticos y su relación con las variables ambientales en un sistema fluvial amazónico (Perú)

In the Peruvian Amazon, there are few ecological studies on the diversity patterns of aquatic macroinvertebrates, essential for the management of these fluvial ecosystems. In such context, our objective was to determine the taxonomic composition and its relationship with environmental variables along an altitude gradient of the Alto Madre de Dios River, a basin with the potential to register new species. We established 22 stations in an altitudinal range from 398 to 2411 masl and evaluated the water physicochemical characteristics and the fluvial habitat: pH, water temperature (T, ° C), electrical conductivity (CE, μS.cm-1), river width (A, m), depth (P, cm), shadow, current flow speed (m · s-1), and depth. We took macroinvertebrate samples with a 200-μm-mesh-size kick net and identified 56 taxa distributed in the orders Acari, Ephemeroptera, Coleoptera, Diptera, Hemiptera, Megaloptera, Odonata, Plecoptera, Trichoptera, and Decapoda. In the multivariate classification and grouping analysis, four groups of statistically differentiated stations (p <0,05) were classified, mainly by speed and the type of dominant substrate, which explains the abundance and wide distribution of Chironomidae, Baetodes, Traulodes, and Anacroneuria. Macroinvertebrate taxa changed notably along the gradient reporting a greater diversity in areas with middle altitudes and a relationship with environmental variables