Review of the inquilinous fauna associated with insect galls in Brazilian restingas / Revisão da fauna inquilina associada a galhas de insetos em restingas brasileiras

Several records of associated fauna, including parasitoids, inquilines, predators, and successors, have been reported by insect gall inventories in Brazilian restingas. Although most guilds are well established, inquilines have frequently been misinterpreted. In this paper, the inquilinous fauna of insect galls is revised based on five criteria: food habit; coexistence with the inducer; modification of gall tissues or production of new tissues; phylogenetic relationship with the inducer; and mobility. Gall inventories dated from 1988 to 2019 were examined, totaling 16 publications, eight of them with inquiline records. This guild was reported in 53 gall morphotypes in 44 plant species and four morphospecies distributed among 36 genera of 24 host families for a total of 65 records. Most inquilines were repositioned into the cecidophage guild and others into the kleptoparasite guild, resulting in a large reduction in the frequency of inquilines (from 65 to five records), and in first reports of cecidophages and kleptoparasites, with 46 and 13 records, respectively. Cecidophage was the most diverse guild with insects of five orders (Diptera, Coleoptera, Lepidoptera, Hemiptera, and Thysanoptera) while kleptoparasites were represented only by two orders (Diptera and Hymenoptera) and inquiline solely by Hymenoptera. Other results indicate that Leptothorax sp. (Formicidae) could be a successor and not an inquiline.

Vários registros de fauna associada, incluindo parasitoides, inquilinos, predadores e sucessores são encontrados em inventários de galhas de insetos em restingas brasileiras. Embora a maioria das guildas esteja bem estabelecida, os inquilinos são frequentemente interpretados de forma equivocada. Nesse trabalho, a fauna inquilina de galhas de insetos é revisada com base em cinco critérios: hábito alimentar, coexistência com o indutor, modificação dos tecidos da galha ou produção de novos tecidos, relação filogenética com o indutor e mobilidade. Inventários de galhas publicados entre 1988 e 2019 foram examinados, totalizando 16 artigos, oito deles com registro de inquilinos. Essa guilda foi assinalada em 53 morfotipos de galhas em 44 espécies de plantas e quatro morfoespécies distribuídas em 36 gêneros de 24 famílias vegetais, totalizando 65 registros. A maioria dos inquilinos foi reposicionada na guilda dos cecidófagos e outros na guilda dos cleptoparasitas, resultando em uma grande redução da frequência dos inquilinos (de 65 para cinco registros), e na primeira ocorrência de cecidófagos e cleptoparasitas, com 46 e 13 registros, respectivamente. A guilda dos cecidófagos foi a mais diversa, com insetos de cinco ordens (Diptera, Coleoptera, Lepidoptera, Hemiptera e Thysanoptera), enquanto que os cleptoparasitas foram representados por apenas duas ordens (Diptera e Hymenoptera) e os inquilinos somente por Hymenoptera. Outros resultados indicam que Leptothorax sp. (Formicidae) pode ser um sucessor e não um inquilino.

Three new species of Euplocania Enderlein (Psocodea, 'Psocoptera', Ptiloneuridae), for the state of Roraima, Brazil

The three new species of Brazilian Euplocania are described and illustrated, two species belong in the amabilis species group (Euplocania maraca sp. nov. and Euplocania ufrr sp. nov.) and one species belong in the marginata species group (Euplocania macuxi sp. nov.). Information on species groups, species subgroups and distribution by Brazilian states is included for known species of Euplocania.(AU)

Morphological characterization of insect galls and new records of associated invertebrates in a Cerrado area in Bahia State, Brazil / Caracterização morfológica de galhas de insetos e novos registros de invertebrados associados em uma área de Cerrado do Estado da Bahia, Barreiras, Brasil

Abstract In this study, we report the first records and morphological characterization of galls in a Cerrado area in western Bahia, Brazil. The data were collected monthly over two hours between March and September 2015. Fifteen gall morphotypes were found in twelve plant species distributed among seven families. The plant family with the greatest richness of galls was Fabaceae (n = 8). The following gall morphologies were found: globoid, lenticular, marginal leaf roll, conical, cylindrical, fusiform, spherical and pocket shaped. Cecidomyiidae induced globoid, lenticular, conical, fusiform, spherical and cylindrical morphotypes. In addition, species of microhymenoptera belonging to the Eulophidae, Eurytomidae and Encyrtidae families were found. Marginal leaf roll and pocket-shaped galls induced by Thysanoptera were also verified. Springtails were also identified as a successor. Undescribed species of Schizomyia and Lopesia were recorded in B. cupulata and Andira humilis, respectively.

Resumo Nesse trabalho são apresentadas informações sobre a ocorrência e a caracterização morfológica de galhas induzidas por insetos em uma área de Cerrado do Oeste da Bahia, Brasil. Os materiais foram coletados mensalmente durante duas horas entre Março e Setembro de 2015. Foram encontrados quinze morfotipos de galhas em doze espécies vegetais, distribuídas em sete famílias. A família de planta com maior riqueza de galhas foi Fabaceae (n = 8). Com relação à morfologia externa, foram encontradas galhas com forma globoide, lenticular, enrolamento marginal, cônica, cilíndrica, fusiforme, esférica e bolso. Quanto à fauna associada às galhas, os morfotipos globoide, cônico, lenticular, fusiforme, esférico e cilíndrico foram induzidos por Cecidomyiidae. Além disso, espécies de microhimenópteros pertencentes às famílias Eulophidae, Eurytomidae e Encyrtidae foram encontrados. A indução de galhas por Thysanoptera, nos morfotipos enrolamento marginal e formato de bolso, também foi detectada. Espécies de colembôlos foram identificadas como sucessoras. Espécies não descritas de Schizomyia e Lopesia foram registradas em Bauhinia cupulata e Andira humilis, respectivamente.

Two new species and updated checklist of Oxyethira Eaton, 1873 (Trichoptera, Hydroptilidae) from Brazil

ABSTRACT Two new species of Oxyethira Eaton, 1873 are described: Oxyethira cascadanta sp. n. and Oxyethira quadrilobata sp. n. Description and illustrations of the new species are provided based on specimens collected in Parque Nacional da Serra da Canastra, Minas Gerais State, Southeast Brazil. Both species are assigned to the subgenus Loxotrichia but differ from other species mainly in morphology of the subgenital plate, subgenital processes and inferior appendages. Additionally, we provide an updated checklist of the Oxyethira species from Brazil.

Insect Galls of the Parque Nacional do Itatiaia (Southeast Region, Brazil)

ABSTRACT The Parque Nacional do Itatiaia (PNI) (Brazilian Southeast Region) was surveyed monthly for insect galls from February/2014 to December/ 2015. A total of 432 gall morphotypes were found. This number places the PNI as the richest Atlantic forest area in number of gall morphotypes. The galls were found on 47 plant families. Among them, Asteraceae were pointed out as the superhost. The gall richness in the lower part of the PNI is higher than that of the plateau. The insect galls were found in 154 native, 56 endemic and only one exotic plant species. Concerning the conservational status, the host plants include two vulnerable species with three morphotypes together. Several new botanical records were reported. Leaves were the most galled plant organ, followed by stems. Globoid, green, glabrous and one-chambered galls were the most frequent. Cecidomyiidae were the most common gallers. Parasitoids, successors and inquilines composed the associated fauna.

Insect galls of Restinga de Marambaia (Barra de Guaratiba, Rio de Janeiro, RJ) / Galhas de insetos da Restinga de Marambaia (Barra de Guaratiba, Rio de Janeiro, RJ)

Abstract Thirty-one morphotypes of insect galls and two flower damages were found on 16 families, 22 genera and 24 plant species in Restinga de Marambaia (Barra de Guaratiba, Rio de Janeiro, RJ). Fabaceae and Myrtaceae were the plant families with the greatest richness of insect galls (4 and 6 morphotypes, respectively), and the greatest number of galled plants (four and three species, respectively). Galls were mostly found on leaves and stems (77% and 10%, respectively). The galling insects are represented by Diptera, Lepidoptera, and Hemiptera. The majority of the galls (81%) were induced by gall midges (Cecidomyiidae: Diptera).

Resumo Foram encontrados 31 morfotipos de galhas de insetos e dois danos em flores em 16 famílias, 22 gêneros e 24 espécies de plantas, na Restinga de Marambaia (Barra de Guaratiba, Rio de Janeiro, RJ). Fabaceae e Myrtaceae foram as famílias de plantas com maior riqueza de galhas (4 e 6 morfotipos, respectivamente) e maior número de espécies com galhas (quatro e três espécies, respectivamente). As galhas predominaram nas folhas e caules (77% e 10%, respectivamente). Os insetos galhadores estão representados por Diptera, Lepidoptera e Hemiptera. A maioria das galhas (81%) foi induzida por Cecidomyiidae (Diptera).

Effects of habitat management on different feeding guilds of herbivorous insects in cacao agroforestry systems / Efecto del manejo de hábitat en diferentes gremios alimentarios de insectos herbívoros en sistemas agroforestales de cacao

AbstractHuman pressure on natural habitats increases the importance of agroforests for biodiversity conservation. The objective of this study was to evaluate the role of cacao traditional cultivation system (CTCS) on the conservation of the herbivorous insect community when compared with a monodominant rubber agroforest, a type of agricultural system for cacao cultivation. The insects were sampled in three habitats in Southeastern Bahia, Brazil: native forests, CTCS and rubber agroforests. In each habitat, 18 plots of 10 m2 were established, and the structural measures were collected and herbivorous insects were sampled with a Malaise/window trap. The diversity of folivorous decreased with the simplification of vegetation structure, but species composition was similar among habitats. In addition to a decrease in the availability of resources in monodominant rubber agroforests, the latex present in these systems have limited the occurrence of species that cannot circumvent latex toxicity. The diversity of sap-sucking insects was similar among habitats, but species composition was similar only in the CTCS and native forest, and it was different in the rubber agroforest. We observed turnover and a higher frequency of individuals of the family Psyllidae in the rubber agroforest. The biology and behavior of Psyllids and absence of natural enemies enable their diversity to increase when they are adapted to a new host. We observed a shift in the composition of xylophagous insects in the rubber agroforest compared to that in other habitats. Moreover, this agroforest has low species richness, but high individual abundance. Latex extraction is likely an important additional source of volatile compounds discharged into the environment, and it increases the attraction and recruitment of coleoborers to these sites. We concluded that CTCS has an herbivorous insect community with a structure similar to the community found in native forests of the region, and they present a more interesting conservation strategy when compared to rubber agroforests. We also emphasized the potential risk of local pest outbreaks in rubber agroforests for both the rubber and associated cacao trees. Rev. Biol. Trop. 64 (2): 763-777. Epub 2016 June 01.

ResumenLa presión humana sobre los hábitats naturales aumenta la importancia de los sistemas agroforestales para la conservación de la biodiversidad. El objetivo de este estudio fue evaluar el papel del sistema tradicional de cultivo de cacao en la conservación de la comunidad de insectos herbívoros en comparación con el agrobosque monodominante de caucho, un tipo de sistema agrícola para el cultivo de cacao. Los insectos fueron muestreados en tres hábitats en el sureste de Bahia, Brasil: bosque nativo, sistema tradicional de cultivo de cacao y agrobosque de caucho. En cada hábitat, se establecieron 18 parcelas de 10 m2, se tomaron medidas estructurales y se muestrearon los insectos herbívoros con una trampa tipo Malaise. La diversidad de folívoros disminuyó con la simplificación de la estructura de la vegetación, pero la composición de especies fue similar entre hábitats. Además se presentó una disminución de la disponibilidad de recursos en agrobosques de caucho, el látex presente en estos sistemas han limitado la aparición de especies que no pueden evadir la toxicidad de látex. La diversidad de insectos chupadores de savia fue similar entre los hábitats, pero la composición de especies fue similar sólo en el sistema tradicional de cultivo de cacao y el bosque nativo, y diferente en el agrobosque de caucho. Hemos observado que hay una mayor frecuencia de individuos de la familia Psyllidae en el agrobosque de caucho. La biología y el comportamiento de los psílidos y ausencia de enemigos naturales permiten que su diversidad aumente cuando se adaptan a un nuevo huésped. Hemos observado un cambio en la composición de los insectos xilófagos en el agrobosque de caucho en comparación con la de otros hábitats. Por otra parte, este agrobosque tiene una baja riqueza de especies, pero gran abundancia individual. La extracción de látex probablemente es una fuente adicional importante de compuestos volátiles que son vertidos en el ambiente, y aumenta la atracción y el reclutamiento de curculiónidos en estos sitios. Hemos llegado a la conclusión de que el sistema tradicional de cultivo de cacao tiene una comunidad de insectos herbívoros con una estructura similar a la comunidad que se encuentra en los bosques nativos de la región, y presenta una estrategia de conservación más interesante si se compara con los sistemas agroforestales de caucho. También hicimos hincapié en el riesgo potencial de aparición de plagas locales en sistemas agroforestales de caucho, tanto para el caucho como para los árboles de cacao asociados.

Resource allocation in Copaifera langsdorffii (Fabaceae): how supra-annual fruiting affects plant traits and herbivory?

AbstractPlants have limited resources to invest in reproduction, vegetative growth and defense against herbivorous. Trade-off in resources allocation promotes changes in plant traits that may affect higher trophic levels. In this study, we evaluated the trade-off effect between years of high and low fruiting on the investment of resources for growth and defense, and their indirect effects on herbivory in Copaifera langsdorffii. Our questions were: (i) does the resource investment on reproduction causes a depletion in vegetative growth as predicted by the Carbon/Nutrient Balance hypothesis (CNBH), resulting in more availability of resources to be allocated for defense?, (ii) does the variation in resource allocation for growth and defense between years of high and low fruiting leads to indirect changes in herbivory? Thirty-five trees located in a Cerrado area were monitored during 2008 (year of high fruiting) and 2009 (year of no fruiting) to evaluate the differential investment in vegetative traits (biomass, growth and number of ramifications), plant defense (tannin concentration and plant hypersensitivity) and herbivory (galling attack and folivory). According to our first question, we observed that in the fruiting year, woody biomass negatively affected tannin concentration, indicating that fruit production restricted the resources that could be invested both in growth as in defense. In the same way, we observed an inter-annual variation in herbivorous attack, and found that plants with higher leaf biomass and tannin concentration, experienced higher galling attack and hypersensitive reaction, regardless years. These findings suggested that plants’ resistance to herbivory is a good proxy of plant defense and an effective defense strategy for C. langsdorffii, besides the evidence of indirect responses of the third trophic level, as postulated by the second question. In summary, the supra-annual fruiting pattern promoted several changes on plant development, demonstrating the importance of evaluating different plant traits when characterizing the vegetative investment. As expected by theory, the trade-off in resource allocation favored changes in defense compounds production and patterns of herbivory. The understanding of this important element of insect-plant interactions will be fundamental to decipher coevolutionary life histories and interactions between plant species reproduction and herbivory. Besides that, only through long-term studies we will be able to build models and develop more accurate forecasts about the factors that trigger the bottom-up effect on herbivory performance, as well the top-down effect of herbivores on plant trait evolution. Rev. Biol. Trop. 64 (2): 507-520. Epub 2016 June 01.

ResumenLas plantas tienen recursos limitados para invertir en reproducción, crecimiento vegetativo y defensa contra herbívoros. El cambio en la distribución de recursos promueve variaciones en rasgos vegetales, que pueden afectar los niveles tróficos superiores. Durante dos años consecutivos de alta y baja inversión reproductiva se evaluó el cambio de recursos entre crecimiento vegetativo y defensa, y su efecto indirecto sobre la herbivoría en Copaifera langsdorffii. Nos preguntamos: i) ¿La inversión de recursos para la reproducción causa reducción del crecimiento vegetativo, como predice la hipótesis de equilibrio carbono/nutrientes, haciendo posible gastar más recursos en defensa? ii) ¿La variación en distribución de recursos para crecimiento y defensa entre años de alta y baja fructificación modifica indirectamente la herbivoría? Se monitorearon treinta y cinco árboles durante 2008 (gran fructificación) y 2009 (sin fructificación) en un área de vegetación de cerrado (Brasil), para evaluar la inversión diferencial en rasgos vegetativos (biomasa, crecimiento y No. de ramificaciones), defensa (concentración de taninos e hipersensibilidad vegetal) y herbivoría. De acuerdo a nuestra primera pregunta, se observó que en el año de fructificación la biomasa leñosa afectó negativamente la concentración de taninos, indicando que la producción de frutos redujo los recursos que podían invertirse en crecimiento y defensa. Además, la resistencia de las plantas y el ataque de agallas fueron influidos positivamente por la concentración de taninos y la biomasa foliar, lo que sugiere que la resistencia de los árboles a la herbivoría es un buen indicador de defensa vegetal y una estrategia efectiva de defensa de C. langsdorffii, además hay evidencia de respuesta trófica indirecta, como se postula en la segunda pregunta. En resumen, el patrón de fructificación supra-anual provoca varios efectos en el desarrollo de las plantas, mostrando la importancia de evaluar diversos rasgos vegetales al caracterizar la inversión de recursos de una especie. Como se esperaba, el cambio en la distribución de recursos modifica la producción de compuestos de defensa y los patrones de herbivoría. El entendimiento de este elemento importante de las interacciones insecto-planta será fundamental para descifrar la historia natural coevolutiva y las interacciones entre reproducción vegetal y ataque herbívoro. Además de eso, solo a través de estudios a largo plazo vamos a ser capaces de construir modelos y desarrollar pronósticos más precisos acerca de los factores que desencadenan el efecto de abajo hacia arriba en el rendimiento de la herbivoría, así el efecto de arriba hacia abajo de los herbívoros sobre la evolución de las plantas.

Seed predation food web, nutrient availability, and impact on the seed germination of Senegalia tenuifolia (Fabaceae) / Red alimentaria de depredación de semillas, disponibilidad de nutrientes e impacto sobre la germinación de las semillas de Senegalia tenuifolia (Fabaceae)

Abstract:Food web studies, which include qualitative and quantitative information about species interactions for all trophic levels in a specific community, are important tools to characterize the community structure, and to understand the role of species interaction in natural communities. With this aim, we collected fruits of Senegalia tenuifolia from a total of nine sites from three different areas in Minas Gerais, from June to August 2011. Fruits were collected and taken to the laboratory in special containers, to allow insect development and description. And then, we characterized the food web of insects associated with these seeds, and described interactions between these organisms and the host plant, and assessed the impact of insect attacks on seed germination with an experiment under controlled conditions. Additionally, we estimated the available NPK content and the Carbon:Nitrogen ratio in both fruits and seeds. In S. tenuifolia seeds, we have found 937 associated insects of 15 species structured in four trophic levels. We found two Bruchinae seed-feeders species: Merobruchus terani and Stator maculatopygus. We also have observed the seed-feeding hymenopteran species Allorhogas sp. 1 and Prodecatoma sp. 1, and hymenopteran parasitoids species such as Eupelmus sp.1, Lyrcus sp.1, Eurytoma sp.1, Horismenu s sp.1, Chelonus sp.1, Aprostocetus sp.1, Eiphosoma sp.1 and an unidentified Pteromalinae. Considering quantitative food web metrics, our data have suggested low values of generality and high values of trophic vulnerability, besides others, which demonstrated how species interactions are specialized. The impact of seed-feeding insects on seeds was found severe and prevented their germination. Lastly, seeds contained higher NPK content than fruits. In conclusion, the seed predation food web supported by S. tenuifolia has depicted two different features: specialized species interactions, considering parasitoids and seed-feeding species, and, generalized species interactions, considering host-plant and seed-feeding species. Indeed, seeds are resources with high nutrient concentration supporting a rich and complex food web. Finally, S. tenuifolia seeds are directly impacted by seed-feeding insects, preventing them from germination, which could result in a negative effect on host-plant population.

Resumen:Estudios de redes alimentarias, que incluyen información cualitativa y cuantitativa sobre las interacciones entre especies para todos los niveles tróficos en una comunidad específica, son herramientas importantes para caracterizar la estructura de la comunidad, y para comprender el papel de la interacción de las especies en las comunidades naturales. Con este objetivo, se recolectaron frutos de Senegalia tenuifolia de un total de nueve sitios de tres áreas diferentes, en Minas Gerais, entre junio y agosto 2011. Los frutos fueron recolectados y llevados al laboratorio en contenedores especiales, para permitir el desarrollo y descripción del insecto. Luego, se caracterizó la red alimentaria de los insectos asociados a estas semillas, se describieron las interacciones entre estos organismos y la planta hospedera, y se evaluó el impacto del ataque de insectos en la germinación de semillas mediante un experimento en condiciones controladas. Además, se estimó el contenido de NPK y la relación carbono:nitrógeno en frutos y en semillas. En semillas de S. tenuifolia, se encontraron 937 insectos de 15 especies estructuradas en cuatro niveles tróficos. Se encontraron dos especies de Bruchinae que se alimentan de semillas: Merobruchus terani y Stator maculatopygus. También se observaron especies de himenópteros que se alimentan de semillas: Allorhogas sp. 1 y Prodecatoma sp. 1, y especies de himenópteros parasitoides como: Eupelmus sp.1, Lyrcus sp.1, Eurytoma sp.1, Horismenus sp.1, Chelonus sp.1, Aprostocetus sp.1, Eiphosoma sp.1 y un Pteromalinae no identificado. Nuestros datos sugieren valores bajos de generalidad trófica y valores altos de vulnerabilidad trófica, además de otros, lo que demuestra cómo las interacciones entre especies son especializadas. El impacto en las semillas de los insectos que se alimentan de estas es severo e impidió su germinación. Por último, las semillas tenían un mayor contenido de NPK que los frutos. En conclusión, la red alimentaria de depredación de semillas con S. tenuifolia tiene dos características: interacciones de especies especializadas, considerando parasitoides y especies comedoras de semillas, e interacciones generalizadas entre especies, teniendo en cuenta la planta hospedera y las especies comedoras de semillas. De hecho, las semillas son recursos con alta concentración de nutrientes que proveen una rica y compleja red trófica. Por último, las semillas de S. tenuifolia se ven directamente afectadas por los insectos que se alimentan de semillas, que les impide la germinación, lo que podría resultar en un efecto negativo en la población planta-hospedero.

Distribución espacial y temporal de larvas de Trichoptera (Insecta) en el río Manzanares, Sierra Nevada de Santa Marta (Colombia) / Spatial and temporal distribution of Trichoptera (Insecta) larvae in the Manzanares river Sierra Nevada of Santa Marta (Colombia)

The aquatic insects are important bioindicators of water quality in rivers and streams. The order Trichoptera is part of this group, plays an important role in aquatic systems and because of the multiple functions they fulfill, it is essential to know about their biodiversity. This study aimed to know the Trichoptera composition, and its spatial and temporal distribution, in close relationship with the available microhabitats, and some physical and chemical variables, in the middle and lower sections of the Manzanares river basin (Sierra Nevada of Santa Marta, Colombia). A total of eight microhabitats were sampled in three sites from August 2002 to February 2003, and during the rainy and dry seasons. A total sample of 3 316 Trichoptera larvae were collected, belonging to 10 family and 14 genera; six of these genera and one family are new records for the Magdalena department. The caddisflies presented the greatest abundance and richness on leaves in pool, leave in riffles and stones in riffle, where Nectopsyche (28%), Leptonema (17%) and Smicridea (15%) were the more predominant genus. Structure and composition of Trichoptera genus in each site changed in function to the rainfall pattern, and physical and chemical variables presented in the basin, showing the lowest abundance and richness during high rainfall period (October and November), and the greatest abundance and richness in low rainfall period (December, January and February). Likewise, stations with higher values of dissolved oxygen and lower in temperature and conductivity reported the greatest abundance of Trichoptera. The Trichoptera showed affinity to the specific microhabitats, variations in their composition in relationship whit climatic periods and pollution levels of the river. To know others aspects about the Trichoptera distribution, we recommended continuing these studies including annual cycles and increasing the altitudinal gradients.

Los insectos acuáticos son importantes como indicadores de calidad de aguas en ríos y arroyos. Uno de los grupos más abundantes son los Thichoptera, ellos juegan un papel importante por su papel funcional en los sistemas acuáticos. Por eso conocer su diversidad es prioritario. El objetivo de este estudio es conocer la estructura de la comunidad del orden Trichoptera y su dinámica espacio-temporal en relación con los microhábitats y algunas variables físicas y químicas, en la parte media y baja de la cuenca del río Manzanares (Sierra Nevada de Santa Marta, Colombia). Se muestrearon mensualmente ocho microhábitats entre agosto 2002 y febrero 2003, durante los periodos de lluvias y sequía. Se recolectaron 3 316 larvas, repartidas en tres subórdenes pertenecientes a 10 familias y 14 géneros; seis de estos géneros y una familia son los primeros registros para el departamento del Magdalena (Colombia). Los tricópteros presentaron la mayor abundancia y riqueza genérica en los microhábitats Hojarasca Corriente Lenta, Hojarasca Corriente Rápida y Piedra Corriente Rápida, donde Nectopsyche (28%), Leptonema (17%) y Smicridea (15%) fueron los géneros más predominantes. La estructura, y composición de los géneros del orden Trichoptera variaron en cada estación en función del régimen pluviométrico y las variables físicas y químicas presentadas en la localidad de estudio, evidenciando las menores abundancias y riqueza en los periodos de altas precipitaciones (octubre y noviembre) y las mayores en épocas de precipitaciones bajas (diciembre, enero y febrero). De igual forma las estaciones con mayores valores de oxígeno disuelto y menores valores en temperatura y conductividad reportaron las mayores abundancias de tricópteros. Los tricópteros evidenciaron preferencias por microhábitats específicos, variación en su composición de acuerdo con los periodos climáticos y respuesta a los niveles de polución del río. Se recomienda complementar estos estudios con ciclos anuales y aumentar el gradiente altitudinal para conocer aspectos de su distribución.

Ecología de la polinización de tres especies de Oenocarpus (Arecaceae) simpátricas en la Amazonia Colombiana / Pollination ecology of three sympatric species of Oenocarpus (Arecaceae) in the Colombian Amazon

The understanding of pollination mechanisms is vital for developing management and conservation actions of economically important species. In order to understand the pollination mechanisms of the promising palms in the genus Oenocarpus (Arecaceae), we studied floral morphology and biology, of three sympatric species in the Colombian Amazon: O. bataua, O. balickii and O. minor. During the period 2010-2012 we made direct and continuous observations of inflorescences (visitors, pollinators, and reproductive success) of the three species in every development phase. We determined the association of the palms with their floral visitors through a complex or interaction network, whereas specificity or preference of the insects for each individual palm was assessed through paired similarity analysis, similarity analysis (ANOSIM), and ordering analysis based on non-metric multidimensional scaling (NMSD). The three species flowered throughout the year; their inflorescences have long rachillae that hang close to each other from a short rachis, and they bear flowers in dyads or triads. Inflorescences are protandrous, thermogenic; anthesis takes place during daytime but pollination is nocturnal. We recorded 79 species of insects, mainly beetles, 33 of which visited O. balickii, 63 visited O. bataua, and 33 visited O. minor. Although they shared some visitors, their abundance during the pistillate phase, as well as their pollen loads showed that only a few species of Curculionidae and Nitidulidae are the principal pollinators of the three studied species. Differences in network structure between staminate and pistillate phases, as well as difference in abundance found with the ANOSIM and NMSD similarity tests, suggest a high specificity of pollinators, leading to reproductive isolation among the three species. Because all pollinating beetles were found to develop their life cycles within the inflorescences, we hypothesize the occurrence of a specialized system of mutual dependence between each of this three Oenocarpus species and their pollinators. This specialization assures a year-round availability of the pollinators. Rev. Biol. Trop. 63 (1): 35-55. Epub 2015 March 01.

La comprensión de los mecanismos de polinización son de gran importancia para el desarrollo de planes de manejo y acciones de conservación de las especies de importancia económica. Con el objeto de conocer los mecanismos de polinización de palmas promisorias del género Oenocarpus (Arecaceae), se estudió la morfología, la biología floral, los visitantes, los polinizadores y éxito reproductivo de tres especies simpátricas en la Amazonía colombiana: O. bataua, O. balickii y O. minor. Durante el período 2010-2012 realizamos observaciones directas durante las fases de desarrollo de las inflorescencias en las tres especies. Se determinó la asociación de las palmas con sus visitantes florales a través de una red compleja, mientras que la especificidad o la preferencia de los insectos por cada palma individual se evaluó mediante el análisis similitud pareada, análisis de similitud (ANOSIM), un análisis de ordenación a partir del escalamiento multidimensional no métrico (NMSD). Las tres palmas florescen todo el año; sus inflorescencias contienen raquilas que cuelgan de un raquis corto, y presentan flores agrupadas en díadas o tríadas. Las inflorescencias son protandras, termogénicas; la antesis tiene lugar durante el día, pero la polinización es nocturna. Se registraron 79 especies de insectos, principalmente coleópteros, 33 de los cuales visitaron O. balickii, 63 a O. bataua y 33 a O. minor. Aunque compartían algunos visitantes, su abundancia en la fase pistilada, así como la carga de polen mostró que sólo unas pocas especies de Curculionidae y Nitidulidae son los polinizadores de las tres especies. Las diferencias en la estructura de la red entre las fases estaminadas y pistiladas, así como la diferencia en la abundancia encontrada con las pruebas de similitud ANOSIM y NMSD, sugieren una alta especificidad de polinizadores, lo que lleva a un aislamiento reproductivo entre las tres especies. Debido a que se encontró que todas las especies de coleópteros polinizadores desarrollan su ciclo de vida dentro de las inflorescencias de cada palma, se sugiere la presencia de un sistema especializado y de mutua dependencia entre los polinizadores y las especies de Oenocarpus. Esta especialización garantiza la disponibilidad de polinizadores durante todo el año.

The rainy season increases the abundance and richness of the aquatic insect community in a Neotropical reservoir / Período chuvoso aumenta a abundância e riqueza da comunidade de insetos aquáticos em um reservatório neotropical

Alterations in aquatic systems and changes in water levels, whether due to rains or dam-mediated control can cause changes in community structure, forcing the community to readjust to the new environment. This study tested the hypothesis that there is an increase in the richness and abundance of aquatic insects during the rainy season in the Serra da Mesa Reservoir, with the premise that increasing the reservoir level provides greater external material input and habitat diversity, and, therefore, conditions that promote colonization by more species. We used the paired t test to test the differences in richness, beta diversity, and abundance, and a Non-metric Multidimensional Scaling (NMDS) was performed to identify patterns in the community under study. Additionally, Pearson correlations were analyzed between the richness, abundance, and beta diversity and the level of the reservoir. We collected 35,028 aquatic insect larvae (9,513 in dry period and 25,515 in the rainy season), predominantly of the Chironomidae family, followed by orders Ephemeroptera, Trichoptera, and Odonata. Among the 33 families collected, only 12 occurred in the dry season, while all occurred in the rainy season. These families are common in lentic environments, and the dominance of Chironomidae was associated with its fast colonization, their behavior of living at high densities and the great tolerance to low levels of oxygen in the environment. The hypothesis was confirmed, as the richness, beta diversity, and abundance were positively affected by the increase in water levels due to the rainy season, which most likely led to greater external material input, greater heterogeneity of habitat, and better conditions for colonization by several families.

Alterações nos sistemas aquáticos, bem como variações nos níveis da água, sejam devido a chuvas ou pelo controle exercido pela barragem podem provocar mudanças na estruturação das comunidades fazendo com que as mesmas sejam obrigadas a se readequar às novas características do ambiente. Este estudo testou a hipótese de que ocorre aumento na riqueza e abundância de insetos aquáticos na estação chuvosa no reservatório de Serra da Mesa com a premissa que o aumento do nível do reservatório proporciona maior entrada de material alóctone, maior diversidade de habitats e, consequentemente, condições para a colonização de mais espécies. Para testar as diferenças na riqueza, diversidade beta e abundância foi utilizado o test t pareado e, além disso, foi feita uma NMDS para identificar padrões na comunidade em estudo. Foram coletados 35.028 larvas de insetos aquáticos (9513 no período seco e 25.515 no período de cheia) com predominância da família Chironomidae seguida das famílias Ephemeroptera, Trichoptera e Odonata. Dentre as 33 famílias coletadas, apenas 12 ocorreram no período de seca, enquanto todas ocorreram no período chuvoso. Essas famílias são bastante encontradas em ambientes lênticos e a dominância de Chironomidae está associada ao seu rápido processo de colonização, ao seu comportamento de viver em altas densidades e sua grande tolerância a baixos teores de oxigênio no ambiente. A hipótese testada foi corroborada visto que a riqueza, a diversidade beta e a abundância de insetos aquáticos foram influenciadas positivamente pelo aumento do nível da água, decorrente do período chuvoso, que, provavelmente, propiciou uma maior entrada de material alóctone, maior heterogeneidade de habitat e melhores condições para a colonização das diversas famílias.

Biologia floral e sistema reprodutivo da erva-baleeira (Varronia curassavica Jacq. ) / Flowering phenology and reproductive system of the Cordia (Varronia curassavica Jacq. )

RESUMOO conhecimento do sistema reprodutivo é fundamental para a conservação e manejo de uma espécie. O objetivo deste trabalho foi descrever a fenologia da floração, a antese, registrar os insetos visitantes no período de floração, determinar as características morfométricas das flores e o sistema reprodutivo da erva-baleeira, em um ambiente de Cerrado do Norte de Minas Gerais. Entre maio a dezembro de 2012 foi caracterizado o comportamento fenológico da floração. Na análise da fenologia floral foi determinado: o crescimento da inflorescência, o número de flores e frutos por inflorescências. Utilizou-se seis acessos que tiveram dez inflorescências marcadas em cada acesso, totalizando 60 inflorescências. A antese foi determinada utilizando quatro inflorescências em duas plantas. Os visitantes florais foram observados in loco e capturados em três dias consecutivos de coleta. As características morfométricas foram determinadas com paquímetro utilizando 20 flores, sendo cinco flores de quatro acessos. Para determinar o sistema reprodutivo utilizou-se a razão pólen:óvulo (P:O), utilizando 50 flores, sendo 10 flores de cinco acessos em pré-antese. Nas condições de Montes Claros, o crescimento das inflorescências de erva-baleeira ocorreu entre meados de agosto e início de outubro, totalizando 45 dias. O florescimento foi observado entre meados de setembro e final de outubro, enquanto a frutificação ocorreu de meados de outubro a início de dezembro, sendo que ambos ocorreram de forma irregular. A antese floral de erva-baleeira, neste estudo, ocorre entre 7:00 e 11:00 horas. Os insetos visitantes pertencem as ordens Coleoptera, Hemiptera, Diptera e Hymenoptera. As flores apresentaram o diâmetro de 2,13 ± 0,05 (mm), o comprimento de 3,29 ± 0,08 (mm), diâmetro do ovário de 0,70 ± 0,02 (mm), o comprimento do ovário de 2,48 ± 0,12 (mm), o diâmetro da antera de 0,67 ± 0,01(mm) e o comprimento da antera de 0,93 ±0,02 (mm), quatro óvulos e cinco anteras por flor. A razão P:O foi de 576,542, indicando que a espécie é alógama facultativa.

ABSTRACTThe knowledge of the reproductive system is essential for the conservation and management of the species. This study aimed on several procedures, as follows: to describe the phenology of flowering, the anthesis; to record the visiting insects during flowering and to determine the morphometric characteristics of the flowers and the reproductive system of the "erva-baleeira", in an environment of Northern Cerrado in the State of Minas Gerais. From May to December 2012, the flowering phenology of six access was characterized. In the analyzes of floral phenology it were determined the growth of the inflorescence and the number of flowers and fruits per inflorescence by using six access which had ten inflorescences marked in each access l, totalizing sixty inflorescences. The anthensis was assessed using four inflorescences in two plants. The flower`s visitors were observed live and captured in three consecutive days of sampling. The morphometric characteristics were determined with a caliper using 20 flowers, with five flowers from four access. In order to determine the reproductive system it was employed a ratiopollen: ovule (P: O) with 50 flowers and 10 of them belonging to five accesses in the pre-anthesis. Under the conditions of Montes Claros, the growth of inflorescences from Cordia occurred between mid-August and early October, totalizing 45 days. The flowering was observed between mid-September and late October, and the fruiting occurred from mid-October to early December. Both phases happened irregularly. The anthesis of the Cordia, in this study, occurred between 7:00 and 11:00 o`clock.. The visiting insects identified were from the orders of Coleoptera, Hemiptera, Diptera and Hymenoptera. The flowers exhibited a diameter of 2.13 ± 0.05 (mm), length of 3.29 ± 0.08 (mm), diameter of 0.70 ± 0.02 Ovarian (mm), the length of the ovary was 2.48 ± 0.12 (mm), the diameter of the anther 0.67 ± 0.01 (mm) and the length anther was 0.93 ± 0.02 (mm), with five anthers and four ovules per flower. The reason P: O was 576.542, indicating that the species is facultative allogamous.

Comparative study of the floral biology and of the response of productivity to insect visitation in two rapeseed cultivars (Brassica napus L.) in Rio Grande do Sul / Estudo comparativo da biologia floral e da resposta da produtividade à visita por insetos em duas cultivares de canola (Brassica napus L.) no Rio Grande do Sul

Planning the artificial pollination of agricultural crops requires knowledge of the floral biology and reproductive system of the crop in question. Many studies have shown that rapeseed (Brassica napus Linnaeus) is self-compatible and self-pollinated, but its productivity may be increased by insect visitation. In the present study, the floral biology and the response of productivity to insect visitation of two rapeseed cultivars (Hyola 420 and Hyola 61) were analyzed and compared in three regions of Rio Grande do Sul, Brazil. The rapeseed flowers presented three stages during anthesis, with the time periods varying between the cultivars. Both cultivars are self-compatible, but free visitation of insects increased productivity by 17% in the Hyola 420 cultivar and by approximately 30% in the Hyola 61 cultivar. Therefore, it is concluded that the cultivar Hyola 61 is more dependent on insect pollination than Hyola 420.

O planejamento de polinização dirigida nas culturas agrícolas requer o conhecimento da biologia floral e do sistema reprodutivo da cultura em questão. Muitos estudos mostram que a canola (Brassica napus Linnaeus) é auto compatível e auto polinizada, no entanto, sua produtividade pode ser aumentada pela visita por insetos. Nesse estudo, a biologia floral e a resposta da produtividade à visita por insetos de duas cultivares de canola (Hyola 420 e Hyola 61) foram analisadas e comparadas em três regiões do Rio Grande do Sul, Brasil. As flores de canola apresentaram três fases durante a antese, havendo variação no período de tempo de acordo com a cultivar. Ambas as cultivares são auto compatíveis, mas a livre visita por insetos aumentou a produtividade em 17% na cultivar Hyola 420 e cerca de 30% na cultivar Hyola 61. Dessa maneira, concluímos que a cultivar Hyola 61 é mais dependente da polinização entomófila que a Hyola 420.

Trophic analysis of three species of Marilia (Trichoptera: Odontoceridae) from the neotropics / Análisis trófico de tres especies de Marilia (Tri-choptera: Odontoceridae) del neotrópico

The trophic ecology of the aquatic insect fauna has been widely studied for the Northern temperate zone. However, the taxa originally classified within a given particular trophic group in temperate ecosystems, do not necessarily exhibit the same dietary profile beyond its geographic limits. Since, the trophic ecology of caddisfly larvae is largely incomplete in the Neotropical Region, the present work aims to describe feeding habits inferred from quantitative analysis of data taxonomically resolved at the species level. For this, the feeding habits of three Trichoptera species Marilia cinerea, M. elongata and M. flexuosa were recorded in the Yungas forests of Argentina and Bolivia. A total of 15 larvae of each species were sampled from 13 different streams were selected for gut content analysis. The ingested material was extracted from the foregut and midgut by using ventral dissection of thorax. For each species, mandibles were dissected, mounted in glycerin and illustrated in order to highlight morphological differences between these mouth pieces purportedly associated to the dietary behavior of individuals, and their habitats. The niche overlap was estimated through Schoener’s method. The diet analysis revealed that M. cinerea, M. elongata and M. flexuosa feed on the same food items, but through different patterns of preferences. Larvae of M. cinerea were collected on both emerging surfaces of rocks on which a thin layer of running water flows and streams sliding areas with stony bottoms attached to the rock surfaces. They displayed a gut content consisting predominantly of invertebrate vestiges and have strong mouthparts provided of large molar areas; this allowed us to allocate the species within the functional group of predators. M. elongata feeds mainly on fine particulate material, its mouthparts are scoop-shaped and occurs in areas of low flow; this set of features is linked to a collector-gatherer strategy. Finally, larvae of M. flexuosa have been primarily assigned to the functional group of shredders and secondarily to the collector-gatherer class. They inhabit sandy bottoms of mountain streams, have strong scoop-shaped mouthparts and show a diet dominated by leaf litter and fine particulate material. We concluded that the functional group assignment to the genus level for Marilia is not recommended, and further studies at species level are necessary. Rev. Biol. Trop.62 (2): 543-550. Epub 2014 June 01.

La ecología trófica de insectos acuáticos ha sido desarrollada en zonas templadas. Sin embargo, la asignación de un taxón a un grupo trófico no representa necesariamente el mismo en otras regiones. En la Región Neotropical, el conocimiento sobre la ecología trófica de larvas de tricópteros es incompleta y la literatura sobre este tema rara vez se ocupa del análisis de los hábitos alimentarios de larvas con datos cuantitativos a nivel de especie. Este trabajo aporta al conocimiento de las características tróficas de la trichopterofauna del Neotrópico. Se describen los hábitos alimentarios de tres especies de Trichoptera registrados en arroyos de Yungas de Argentina y Bolivia: Marilia cinerea, M. elongata y M. flexuosa. Se seleccionaron 15 larvas de cada especie en 13 arroyos de Yungas surandinas para analizar las piezas bucales y el contenido estomacal. El solapamiento de nicho trófico se estimó mediante el índice de Schoener. El análisis de la dieta reveló que las especies difieren en la preferencia de los ítems registrados, hábitat y forma de sus mandíbulas. Las larvas de M. cinerea habitan en superficies de rocas emergentes. Poseen mandíbulas fuertes con grandes zonas molares y consumen principalmente invertebrados. Esta evidencia permite asignarle el grupo funcional depredador. M. elongata consume material fino, sus mandíbulas tienen forma de cuchara y su ubicación en zonas de bajo flujo permite asignarle una estrategia colectora-recolectora. Las larvas de M. flexuosa habitan en fondos arenosos de arroyos de montaña, tienen fuertes piezas bucales en forma de cuchara y una dieta dominada por hojarasca y material fino. Pertenecen al grupo funcional triturador, secundariamente colector-recolector. Sugerimos que la asignación de grupo funcional a nivel de género no es recomendable para Marilia. Se recomiendan mayores estudios a nivel de especie.

The insect gall collection of the Museu Nacional/Universidade Federal do Rio de Janeiro: biome cerrado, rupestrian fields / A coleção de galhas de insetos do Museu Nacional/Universidade Federal do Rio de Janeiro: bioma cerrado, campos rupestres

An inventory of the insect gall from Brazilian savanna (Cerrado) was elaborated based on samples of the collection of the Museu Nacional, Universidade Federal do Rio de Janeiro. Data on localities and host plants were obtained from the labels and information about the gall morphology (plant organ of occurrence, shape, and presence of trichomes) by observing the samples. The galling species was determined based on the literature. The collection includes 131 morphotypes of galls from Cerrado, obtained from 71 host plant species distributed in 50 genera and 30 botanical families (Table 1). All galls were collected in rupestrian fields (a rare vegetation physiognomy of the Brazilian Cerrado) in the state of Minas Gerais. As the collection comprises a great diversity of insect galls, it can be considered representative of this physiognomy.

Um levantamento de galhas de insetos do Cerrado brasileiro foi elaborado baseado em amostras da coleção do Museu Nacional/Universidade Federal do Rio de Janeiro. Dados de localidades e plantas hospedeiras foram obtidos das etiquetas e informações sobre a morfologia da galha (órgão vegetal de ocorrência, forma, e presença de tricomas) pela observação da amostra. As espécies galhadoras foram determinadas baseadas em literatura. A coleção inclui 131 morfotipos de galhas de Cerrado, obtidos de 71 espécies de plantas hospedeiras, distribuídas em 50 gêneros e 30 famílias botânicas (Tabela 1). Todas as galhas foram coletadas em campos rupestres (uma fisionomia vegetal rara do cerrado brasileiro) do Estado de Minas Gerais. Como a coleção compreende grande diversidade de galhas de insetos, pode ser considerada representativa para essa fisionomia.

Insect herbivores associated with an evergreen tree Goniorrhachis marginata Taub. (Leguminosae: Caesalpinioideae) in a tropical dry forest / Insetos herbívoros associados a uma árvore sempre verde Goniorrhachis marginata Taub. (Leguminosae: Caesalpinioideae) em uma floresta tropical seca

Goniorrhachis marginata Taub. (Leguminosae: Caesalpinioideae) is a tree species found in Brazilian tropical dry forests that retain their leaves during the dry season. That being, we addressed the following question: i) How do insect diversity (sap-sucking and chewing), leaf herbivory and defensive traits (tannin and leaf sclerophylly) vary on the evergreen tree species G. marginata between seasons? The abundance of sap-sucking insects was higher in the dry season than in the rainy season. However, we did not verify any difference in the species richness and abundance of chewing insects between seasons. Leaf herbivory was higher in the rainy season, whereas leaf sclerophylly was higher in the dry season. However, herbivory was not related to sclerophylly. Insect herbivores likely decrease their folivory activity during the dry season due to life history patterns or changes in behaviour, possibly entering diapause or inactivity during this period. Therefore, G. marginata acts as a likely keystone species, serving as a moist refuge for the insect fauna during the dry season in tropical dry forest, and the presence of this evergreen species is crucial to conservation strategies of this threatened ecosystem.

Goniorrhachis marginata Taub. (Leguminosae: Caesalpinioideae) é uma árvore encontrada em florestas tropicais secas do Brasil que mantém as suas folhas durante a estação seca. Baseado neste fato, nós levantamos a seguinte questão: i) como a diversidade de insetos herbívoros (sugadores e mastigadores), herbivoria foliar e características defensivas (taninos e esclerofilia foliar) variam em G. marginata entre as estações seca e chuvosa. A abundância de insetos sugadores foi maior na estação seca, entretanto, a riqueza e abundância de insetos mastigadores não diferiram entre as estações. A herbivoria foliar foi maior na estação chuvosa, enquanto a esclerofilia foliar foi maior na estação seca. Não foi observado efeito significativo da esclerofilia sobre os níveis de herbivoria foliar. Insetos herbívoros reduzem a sua atividade de consumo foliar durante a estação seca, fato este devido à sua história natural e/ou mudança comportamental, provavelmente, entrando em diapausa durante este período. Nossos resultados demonstram que G. marginata atua como refúgio para fauna de insetos durante a estação seca, e que a presença desta espécie merece relevante destaque em estratégias de conservação deste ameaçado ecossistema.

Factores ambientales asociados con la preferencia de hábitat de larvas de tricópteros en cuencas con bosque seco tropical (Tolima, Colombia)

Environmental factors associated with habitat preferences by caddisfly larvae in tropical dry forest watersheds (Tolima, Colombia). River ecosystems, mainly those draining tropical dry forests, are among the most endangered tropical ecosystems and a major conservation priority in South America, as elsewhere. In this study, we assessed the influence of environmental factors (e.g., precipitation) and riparian vegetation on Trichoptera larval assemblages colonizing four substrates (rock, gravel, sand, and litter) in the Venadillo and Opia watersheds (Tolima, Colombia). In each river, five 20m reaches nested into two 100m segments (one at ~550 and another at ~250masl), were surveyed for benthic invertebrates in the above mentioned substrates. In addition, water samples were collected for physicochemical analyses and the QBR index (“qualitat del bosc de ribera” or riparian forest quality) was applied in both rivers. A total of 6 282 larvae were collected, belonging to 11 families and 22 genera, representing 73.30% and 43.13% of the Trichoptera fauna reported to Colombia, respectively. The most abundant families were Hydropsychidae (49.86%) and Philopotamidae (25.44%) and the least abundant Odontoceridae (0.16%) and Hydrobiosidae (0.06%). The genera Smicridea, Chimarra, Protoptila, Neotrichia, and Leptonema, were common during dry and rainy seasons. The main factors related to changes in composition, richness, and abundance of larval Trichoptera were seasonality and riparian vegetation, which can influence organic matter supply, availability and stability of substrates, and colonization and population dynamics. Trichoptera assemblages showed no significant differences among substrates. However sampling points located at high elevation and in non-urbanized areas offered the largest variety of substrates and richness. Our results indicate that Trichoptera larvae are an important biotic element in freshwater ecosystems and that they are sensitive to environmental changes. Hence, our study suggests that caddisflies may be used as potential organisms for the biomonitoring of tropical dry forest rivers. The implementation of these studies is urgent, considering that degradation of freshwater ecosystems tends to be severe and persistent in dry forest. Rev. Biol. Trop. 62 (Suppl. 2): 21-40. Epub 2014 April 01.

Los ríos de bosques secos tropicales están amenazados en todo el mundo, y en Suramérica son una de las prioridades en términos de conservación. En este estudio se determinó la influencia de variables ambientales (por ejemplo precipitación) y la vegetación ribereña sobre las comunidades del orden Trichoptera en cuatro sustratos (roca, grava, arena y hojarasca) en las cuencas Opia y Venadillo (Tolima, Colombia). En cada río, en dos segmentos de 100m (uno a ~550 y otro a ~250msnm), fueron evaluados los sustratos mencionados anteriormente. Se realizaron análisis físico-químicos, y se aplicó el índice QBR (calidad del bosque de ribera) en ambos ríos. Se recolectaron 6 282 larvas, pertenecientes a 11 familias y 22 géneros, que representan el 73.30% y 43.13% de la fauna Trichoptera registrada en Colombia, respectivamente. Las familias más abundantes fueron Hydropsychidae (49.86%) y Philopotamidae (25.44%). Los géneros Smicridea, Chimarra, Protoptila, Neotrichia y Leptonema fueron comunes en periodos de baja y alta precipitación. Las asociaciones de tricópteros no mostraron diferencias significativas a nivel de sustrato. Los principales factores que determinaron la composición, riqueza y abundancia de tricópteros fueron la estacionalidad y la vegetación de ribera. Sin embargo, las localidades situadas a mayor altitud y no urbanizadas, ofrecen mayor variedad de sustratos y mayor riqueza de géneros. Nuestros resultados indican que a futuro las larvas de Trichoptera constituyen un elemento biótico relevante en los ecosistemas dulceacuícolas, debido a que son sensibles a disturbios ambientales. Por ende, sugerimos el uso de los tricópteros para biomonitoreo en ríos tropicales. La implementación de estos estudios es urgente, teniendo en cuenta que la degradación de los ecosistemas dulceacuícolas tiende a ser intensa y persistente.

Do omnivorous shrimp influence mayfly nymph life history traits in a tropical island stream?

Interspecific interactions can play an important role in determining habitat selection and resource use between competing species. We examined interactions between an omnivorous shrimp and a grazing mayfly, two co-dominant taxa found in Puerto Rican headwater streams, to assess how predator presence may influence mayfly resource use and instantaneous growth in a tropical rainforest ecosystem. We conducted a series of behavioral and growth experiments to determine the effects of the freshwater shrimp, Xiphocaris elongata, on the growth rate and resource selection of mayfly nymphs in the family Leptophlebiidae. For resource choice assessments, we conducted a series of five day laboratory experiments where mayflies were given access to two resource substrate choices (cobble vs. leaves) in the presence or absence of shrimp. To assess for the effects of shrimp on mayfly fitness, we measured mayfly growth in laboratory aquaria after five days using four treatments (cobble, leaves, cobble + leaves, no resource) in the presence or absence of shrimp. In resource choice experiments, mayflies showed preference for cobble over leaf substrata (p<0.05) regardless of the presence of shrimps, however, the preference for cobble was significantly greater when shrimp were present in the leaf habitat. In growth experiments, there were no statistical differences in mayfly growth in the presence or absence of shrimp (p=0.07). However, we measured increased mayfly nymph growth in the absence of predators and when both cobble and leaves were available. Our results suggest that interspecific interactions between these taxa could potentially influence organic matter resource dynamics (e.g., leaf litter processing and export) in Puerto Rican streams. Rev. Biol. Trop. 62 (Suppl. 2): 41-51. Epub 2014 April 01.

Las relaciones interespecíficas pueden jugar un papel importante en la determinación del uso de recursos y selección de hábitat entre especies que compiten. Hemos examinado las interacciones entre un camarón omnívoro y un efemeróptero que se alimenta de vegetación , dos taxones codominantes en las partes altas de arroyos de Puerto Rico, para evaluar el efecto de los depredadores en el uso de recursos del efemeróptero y el crecimiento instantáneo en un ecosistema de selva tropical. Examinamos experimentalmente el efecto del camarón Xiphocaris elongata sobre la tasa de crecimiento y selección de recursos en ninfas efemerópteras (Leptophlebiidae). Hicimos experimentos de laboratorio de 5 días, dando a los efemerópteros acceso a dos opciones de sustrato (piedrecillas u hojas) en presencia o ausencia del camarón. Para evaluar los efectos sobre el crecimiento probamos cuatro tratamientos (piedrecillas, hojas , piedrecillas + hojas, sin ambas), en presencia o ausencia del camarón. Los efemerópteros prefirieron las piedrecillas a las hojas ( p < 0,05 ) independientemente de la presencia de los camarones. Esta preferencia fue mayor cuando junto a las hojas había camarones. Los camarones no afectaron el crecimiento de los efemerópteros (p = 0,07). Las ninfas efemerópteras crecieron mejor sin camarones y en acuarios con piedrecillas y hojas. Nuestros resultados sugieren que las interacciones interespecíficas entre estos animales podrían influir en la dinámica de la materia orgánica (por ejemplo, procesamiento de la hojarasca y su exportación) en los arroyos puertoriqueños.

Efecto de los factores ambientales sobre la diversidad de insectos hemimetábolos y coleópteros acuáticos en la cuenca del Río Xichú, Guanajuato, México / Effects of environmental factors over aquatic hemimetabola and Coleoptera diversity in the Xichu’s basin, Guanajuato, México

Lotic systems, in particular temporal streams, represent an important proportion of continental waters, but are poorly studied. This is particularly clear in central Mexico, where temporal streams are abundant and remain poor studied despite their great potential for high diversity and the important energy within these ecosystems. The aim of this study was to analyze the environmental variables and scales at which these variables have effects on aquatic insect assemblages in a semiarid fluvial system in Central Mexico. A total of 89 genera were registered, the order Coleoptera showing the highest richness. Peak values for alpha diversity were found on permanent sites in the dry season (¹D=10.63), the more stable environment in permanent streams during the dry season might accounted for this pattern. Assemblages at our study sites showed low similarity (Ij < 0.45) indicating high genera replacement among sites, possibly related to differences in hydroperiod. Partition analysis indicates that variation in genera composition among rivers contributed a large proportion of the diversity (37%). Results from the canonical correspondence analysis point to mesohabitat, velocity, ecological quality, and hydrological order, as the most important variables explaining diversity patterns. In addition, hydrological condition and intermittency were important factors related to diversity (~21-22%). The results suggest that permanent sites function has species sources for intermittent sites, highlighting the need for conservation planning at the landscape level in the Xichu’s basin. Rev. Biol. Trop. 62 (Suppl. 2): 69-80. Epub 2014 April 01.

Los sistemas lóticos integrados por cauces temporales representan una alta proporción de las aguas continentales del planeta, no obstante se encuentran entre los sistemas menos estudiados a nivel mundial. En cuanto a diversidad entomológica, el centro de México -donde se ubican estos sistemas- permanece poco estudiado a pesar del alto potencial que presenta la zona de albergar una alta diversidad y de los vínculos importantes que este grupo desempeña en los flujos de energía de los ecosistemas acuáticos. El objetivo del presente trabajo fue analizar las variables ambientales que determinan los cambios en la diversidad y las escalas en que tienen efecto, en las comunidades de insectos acuáticos de un sistema fluvial semiárido del centro de México. Se registraron un total de 89 géneros, con el orden Coleoptera presentando la mayor riqueza. Los valores más altos de diversidad alfa se encontraron sobre sitios permanentes en la temporada de sequía (¹D:10.63), lo que se atribuye a la mayor estabilidad que presentan los sistemas fluviales en esta temporada. Las comunidades establecidas sobre cauces permanentes e intermitentes presentaron baja similitud (Ij <0.45), indicando un alto recambio entre comunidades establecidas sobre cauces con diferente hidroperiodo. Los análisis de distribución (“partición”) de la diversidad indican que el mayor aporte a la diversidad regional se da por cambios en la composición de géneros a nivel de ríos (37%), entre temporadas (22%) y por el tipo de sistema (21%). De acuerdo con el Análisis de Correlación Canónica las variables de mesohábitat, velocidad de corriente, calidad ecológica y orden del cauce son las que mejor explican la variación en la presencia de los taxones. Los resultados sugieren que los sitios permanentes se encuentran actuando como fuente de especies de los sitios intermitentes y que los esfuerzos de conservación en la región deben implementarse a escala de paisaje.