In the Anthropocene, man has imposed his activities above the natural processes of ecosystems. Rivers have undergone major changes associated with urban centers, so monitoring them is important to determine their status and suitability to provide environmental services. Studies applying the community ecology approach, such as energy flow in aquatic macroinvertebrate assemblages, may be appropriate to determine their status and functioning. This study characterized an Andean river that runs across the city of Ayacucho (Peru). Water physicochemical parameters and biotic quality indices were used and compared with the abundance of trophic guild components and functional feeding groups to demonstrate that the latter are at least equally suitable to estimate water quality. The river section studied ranged from 2640 to 2900 m a.s.l. and was monitored in the wet and dry seasons. Six monitoring stations were established according to the extent of the influence of the urban center. Water physicochemical variables and macroinvertebrate abundances were determined. A Surber net was used for multihabitat sampling; macroinvertebrates were identified to genus level (in most cases) and counted to estimate relative abundances. Trophic guilds (detritivore, predator, herbivore) were formed using the genus data from identification according to the information available in Argentina, Colombia, Ecuador, Bolivia, and Peru. Functional feeding groups were set based on the classification of families. The sensitivity of trophic metrics was assessed by relating them to environmental variables and the Andean Biotic Index (ABI), the Biological Monitoring Working Party adapted for Colombia (BMWP/Col.), and the Ephemeroptera, Plecoptera, Trichoptera (EPT) indices. Environmental variables and biotic indices increased significantly in the most impacted stations, where the abundance of most taxa decreased. The components of trophic guilds and functional groups varied, and those feeding on fine particles increased in sites with a higher urban impact. The metrics based on trophic characteristics were highly correlated with the BMWP/Col and ABI indices. Therefore, these indices can be used to estimate river water quality and provide information on its functioning.

Peru is one of the megadiverse countries worldwide, displaying a great diversity of ecosystems due to its tropical location, marine currents, and complex relief, which jointly define environments differentiated by altitude and climatic conditions. The arid and semi-arid ecosystems comprising xeric and Andean shrublands, coastal deserts, and coastal hills, illustrate this diversity of ecosystems; these stretch over 177 358 km2, representing 13.8% of the Peruvian territory. Several studies on aquatic macroinvertebrates are being conducted in these ecosystems; although not so numerous yet, have shown a rise in recent years. The objective of this work was to determine the composition and distribution of aquatic macroinvertebrates in the arid and semi-arid ecosystems of Peru. To this end, we conducted a literature survey; the articles and theses found were reviewed and analyzed. The following keywords were used: macroinvertebrates, macrozoobenthos, bioindicators, diversity of aquatic organisms, and water quality; we used the Google Academic search engine, Scopus, Web of Science, ResearchGate and the thesis repositories of Peruvian universities, additionally a thesis from the University of Barcelona. Of a total of 53 sources of information, 38 are theses and 15 are scientific articles conducted from 1992 to 2020, referring to studies conducted at elevations ranging from 0 to 3,831 m asl. Most studies were conducted at the Lima and La Libertad departments, resulting in 20 and 10 publications, respectively. The topics addressed most frequently were bioindication, biodiversity, taxonomy, and distribution. Most theses were carried in the Universidad Nacional de Trujillo and the Universidad Nacional Mayor de San Marcos, with 12 and 10 theses, respectively. The period 2011–2020 records the largest number of publications (40). According to the type of aquatic ecosystem, rivers (38) were the systems most intensively studied, followed by coastal wetlands (14) and lagoons (2); to note, one thesis studied two types of ecosystems. Specimens were collected mainly with the Surber and D nets; as a result, seven phyla, 10 classes, 39 orders, and 118 families were reported. The highest richness of families corresponds to rivers (110), followed by coastal wetlands (57), and lagoons (12). The western hydrographic slope recorded the highest richness at phylum, class, order, and family levels, likely because most investigations were conducted in this slope. On the other hand, the phyla Cnidaria, Nematoda, and Nematomorpha were not recorded in the eastern slope, which showed fewer orders (19) relative to the western slope (39). A similar trend is observed at the family level: of the 118 families recorded, 59 were reported for the eastern slope. The most common families at both sides were Chironomidae, Baetidae, Simuliidae, Elmidae, Hydrophilidae, Libellulidae, Physidae, Dytiscidae, Ceratopogonidae, Coenagrionidae, Hydroptilidae, Hydropsychidae, and Tipulidae. Separately, the most common families in all types of aquatic ecosystems were Chironomidae, Baetidae, and Dytiscidae. It is recommended to further promote studies on macroinvertebrates living in the eastern slope, addressing taxonomic, and ecological topics, as well as broadening the approach to an integral ecosystem view. Finally, the biotic indices should be calibrated and validated for the main hydrographic basins. This work is an initial effort to review, systematize, analyze, and gather the results of studies on aquatic macroinvertebrates in Peru, particularly in arid and semi-arid ecosystems.

Introducción. Los ecosistemas tropicales andinos y amazónicos determinan la gran biodiversidad presente en Perú. Sin embargo, los estudios sobre mosquitos (Diptera: Culicidae) en el país son escasos, lo que resulta en un vacío de información en cuanto a su diversidad, ecología, distribución y abundancia. Objetivo. Buscar evidencia documentada sobre la diversidad y distribución de mosquitos en el Perú, y establecer —con relación a las especies de importancia médica— su potencial vínculo con el ciclo epidemiológico de algunas enfermedades metaxénicas. Materiales y métodos. Se realizó una revisión de la literatura en Google Académico, ScienceDirect, PubMed y Scielo, y así como en siete bases de datos especializadas en taxonomía de insectos, usando términos específicos y diferentes combinaciones con operadores booleanos (“AND” y “OR”). Estrategia de búsqueda: tipos de estudios: artículos originales de investigación, artículos de revisión, libros y capítulos de libros. Periodo de publicación: sin límite inicial a junio del 2020. Idiomas: inglés, español y portugués. Resultados. La búsqueda inicial arrojó 99 estudios, 84 en las 4 bases de datos electrónicas y 15 en las bases de especializadas, de los cuales 41 cumplieron los criterios de inclusión. También se incluyó un registro adicional debido a su relevancia con el objetivo de la revisión. Los estudios incluídos fueron artículos originales (n=28), artículos de revisión (n=6), Libros (n=5), capítulos de libro (n=2), y Tesis de pregrado (n=1). Respecto al idioma de publicación, 25 (59.52%) estaban en inglés y 17 (40.48%) en español. Conclusiones. En Perú, la mayor diversidad de géneros de mosquitos se encuentra presente en los departamentos de Loreto, Huánuco y Madre de Dios. El conocimiento sobre la diversidad de mosquitos en Perú que tiene el potencial de generar problemas de salud es relativamente escaso, y se centra en  Aedes aegypti y algunas especies de los géneros Anopheles, y Culex, dejando de lado una rica diversidad distribuida en los bosques amazónicos, selva alta y valles interandinos.

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.

La depredación es un factor biótico que influye en la estructura y funcionamiento de los ecosistemas, su efecto se puede cuantificar a través de la respuesta funcional (RF) y numérica en un contexto de éxito-invasión. Utilizamos la RF para entender las relaciones coevolutivas y medir la respuesta biológica de los depredadores Notonecta peruviana y Buenoa fasciata en el control de larvas de cuarto estadio de Aedes aegypti (F1) a diferentes densidades (5, 10, 20, 35, 55 y 80 larvas/litro). Los depredadores en ayuno (48 horas) se introdujeron a los envases de ensayo (un individuo por especie) y se evaluó a las 24 horas la RF, número de presas consumidas (Ne), coeficiente de ataque (a) y tiempo de manipuleo (Th). N. peruviana y B. fasciata desarrollaron una RF tipo II en el consumo de larvas de Ae. aegypti (p ≤ 0,01) y ocuparon cercanos tiempos de manipuleo (Th) (t = –1,93; gl = 12; p = 0,078). N. peruvianadepredó (Ne) el doble de larvas de Ae. aegypti (p ≤ 0,05) y mostró un mayor coeficiente de ataque (a) en relación con B. fasciata (t = 14,92; gl = 12; p = 0,000). Los depredadores N. peruviana y B. fasciata desestabilizaron y consumieron en forma rápida las presas. N. peruviana devoró el doble de larvas atribuible al efecto depredador-presa de origen reciente en comparación al posible ajuste coevolutivo entre B. fasciata y Ae. aegypti. Sería importante considerar a las especies de depredadores en los programas de control larval de mosquitos aedinos.