New records of Harpacticoids (Crustacea, Copepoda) from a coastal system of northern Colombia

Three species of harpacticoids are herein recorded from the zooplankton of Rodadero beach, Santa Marta, Magdalena, Colombia. Samples were collected from the littoral zone, mainly at inshore areas covered by mangrove vegetation and in an adjacent oyster bank. One of them, Laophonte cornuta Philippi, 1840 is new to the Colombian harpacticoid fauna, the other two species: Distioculus minor (Scott T., 1894) and Microsetella norvegica (Boeck, 1865) are new reports to the Magdalena department. This is the first illustrated record confirming their presence in Colombia and Magdalena, northern Colombia. Comparative morphological comments and illustrations of these species are also provided to document this report.

Se registran tres especies de harpacticoides en el zooplancton de playa Rodadero, Santa Marta, Magdalena, norte de Colombia. Se recolectaron muestras en la zona litoral, principalmente en áreas costeras de manglar y en un banco de ostras. Una de ellas, Laophonte cornuta Philippi, 1840 es nueva para la fauna de harpacticoides de Colombia; las otras dos especies: Distioculus minor (Scott T., 1894) y Microsetella norvegica (Boeck 1865) son nuevos reportes para el departamento del Magdalena. Este es el primer registro ilustrado que confirma su presencia en Colombia y Magdalena. Se proporcionan comentarios morfológicos comparativos e ilustraciones de estas especies.

Copépodos epipelágicos en Bahía Cupica, Pacífico colombiano: composición de especies, distribución y variación temporal / Epipelagic copepods in Bahía Cupica, Colombian Pacific: species composition, distribution and temporal variation

Resumen: Los cambios en la composición y abundancia de las especies de copépodos a escala espacial y temporal, ayudan a comprender el funcionamiento de los ecosistemas y de cómo la dinámica oceanográfica afecta su variación. Debido a los pocos estudios de este grupo en zonas costeras del Pacífico colombiano, se estudiaron los cambios en la distribución espacial y temporal de la comunidad de copépodos de Bahía Cupica, durante diciembre 2012 y febrero 2013. Se realizaron arrastres oblicuos en 22 estaciones a lo largo de seis transectos perpendiculares a línea de costa, durante dos periodos oceanográficos contrastantes, usando una red bongo (30 cm de diámetro, 2.1 m de largo, con mallas de 250 µm y 500 µm) equipada con un flujómetro. Los resultados mostraron cambios significativos en las condiciones oceanográficas y en el patrón de circulación superficial. Se identificaron en total 52 especies de copépodos de las cuales 35 son nuevos registros para el Pacífico colombiano. La mayor abundancia se presentó durante febrero 2013 (28 604 ind. 100 m-3), con una prevalencia de especies de pequeña talla en los dos periodos. Durante diciembre 2012 se registró una mayor abundancia de especies del orden Poecilostomatoida (58.2 %), y durante febrero 2013 por especies del orden Calanoida (69.5 %). Se identificaron cinco agrupaciones significativas con diferente estructura y composición de especies, tres en diciembre 2012, y dos durante febrero 2013, dividiendo la bahía en diferentes zonas. La estructura del ensamblaje de copépodos presentó una correlación positiva con la temperatura en ambos periodos, siendo mayor durante diciembre 2012. Los resultados sugieren que la zona nerítica del norte del Pacífico colombiano se ve modulada por procesos de surgencia, el patrón de circulación superficial local y la descarga de agua continental de la región, lo que determina la estructura y composición del ensamblaje de copépodos, además de cambios significativos en la abundancia de las especies. Los resultados son útiles para entender la estructura de la comunidad de copépodos, y los estudios futuros deberían intentar examinar otras variables (e.g. el efecto de la disponibilidad de alimento y la concentración de oxígeno disuelto) para mejorar el entendimiento de la estructura de copépodos en la región costera del Pacífico colombiano.

Abstract: The study of changes in abundance and composition of copepod species, at different temporal and spatial scales, help to understand the ecosystems function and how the oceanographic dynamics affects their variability and other resources abundances. Since very few studies have been developed on this group in Colombian Pacific coastal areas, the purpose of this study was to assess the spatial and temporal changes in the copepods community distribution at Cupica Bay, between December 2012 and February 2013. For this, oblique plankton hauls were performed along six transects perpendicular to the coast, in 22 stations, using a Bongo Net (30 cm diameter, 2.1 m large, with mesh size 250 µm and 500 µm) equipped with a flowmeter, during two contrasting oceanographic periods. The results showed significant changes in oceanographic conditions and superficial circulation patterns. Fifty two (52) copepods species were identified, from which thirty five (35) were new records for the Colombian Pacific. The biggest copepod abundance was recorded in February 2013 (28 604 ind. 100 m-3), and small copepods species were the most dominant. During December 2012, species of the order Poecilostomatida were the most abundant (58.2), but during February were the species of the order Calanoida (69.5 %). The community structure and species composition was characterized by five significant groups, three groups during December 2012 and two during February 2013, dividing the bay in different zones. A positive correlation between temperature and copepods assemblages was evident during both periods, but stronger during December 2012. The results suggested that community structure and species composition of resident copepods in North Colombian Pacific neritic zones, are modelled by the intensity of upwelling, superficial local pattern circulation, and continental freshwater discharges in the region. The results are helpful to understand the copepods community structure, and the future studies should attempt to examine other variables (e.g. effect of food available and oxygen concentration dissolved) to improve understanding of copepods structure in the Pacific coast region of Colombia. Rev. Biol. Trop. 65 (3): 1046-1061. Epub 2017 September 01.

COMPLEMENTARY DESCRIPTION AND RECORD OF Neocyclops ferrarii (Cyclopidae: Halicyclopinae) FROM NORTHERN COLOMBIA / Descripción complementaria y registro de Neocyclops ferrarii (Cyclopidae: Halicyclopinae) en el norte de Colombia

ABSTRACT The interstitial cyclopoid copepod Neocyclops ferrarii Rocha, 1995 was found in samples obtained from littoral areas of Rodadero Bay, northern Colombia. The specimens from Colombia share the diagnostic features of N. ferrarii presented in the original description. However, the Colombian specimens show some degree of variation with respect to the type material in: 1) the number of teeth in the labrum; 2) the length of outer exopodal spine on female leg 5; 3) the relative length of the mandibular palp setae; 4) length/width ratio of caudal rami; 5) the length ratio of caudal setae VI/III; 6) the length ratio of caudal setae VII/VI; 7) the male body size; 8) the male caudal rami length/width ratio; 9) This is the second record of this species after its original description from Belizean waters. In the Caribbean region N. ferrarii most closely resembles N. vicinus Herbst, both of them bear an antennary exopod, a 12-segmented female antennule, P3ENP3 armature formula 3,III, but can be separated from the latter by difference in the length/width ratio of the female caudal ramus, the length ratio of caudal setae VI/III, the length ratio of caudal setae VII/VI, the male body size, the number of segment of P4ENP, the armature details of mandibular palp and the number of segments of male P5. This is the second species of Neocyclops recorded from Colombia and represents a distributional range expansion of N. ferrarii in the Caribbean Basin.

RESUMEN El copépodo ciclopoide intersticial Neocyclops ferrarii Rocha, 1995 fue encontrado en muestras litorales obtenidas de la bahía Rodadero, al norte de Colombia. Los especímenes de Colombia comparten las características diagnósticas de N. ferrarii de la descripción original. Sin embargo, los especímenes colombianos muestran cierta variación con respecto al material tipo en: 1) el número de dientes en el labro; 2) la longitud de la espina exopodal externa de la pata 5 de la hembra; 3) la longitud relativa de las setas del palpo mandibular; 4) la relación largo/ancho de la rama caudal; 5) la longitud proporcional de las setas caudales VI / III; 6) la longitud proporcional de las setas caudales VII / VI; 7) la talla del macho; 8) la relación largo/ancho de la rama caudal del macho. Este es el segundo registro de esta especie después de su descripción original en aguas de Belice. En la región Caribe N. ferrarii se asemeja más estrechamente a N. vicinus Herbst, ambos poseen exópodo antenal, anténulas con 12 segmentos en la hembra, la fórmula P3ENP3 de 3, III, pero difieren en la proporción de la rama caudal en la hembra, la longitud de las setas caudales VI / III y VII / VI, el tamaño del macho, el número de segmento de P4ENP, en detalles del armamento del palpo mandibular y en el número de segmentos de la P5 del macho. Esta es la segunda especie de Neocyclops registrada en Colombia y representa una expansión de la distribución conocida de N. ferrarii en la Cuenca del Caribe.

Biology of Boeckella poopoensis Marsh, 1906 (Copepoda, Calanoida) in natural conditions in temporary saline lakes of the central Argentina / Biología de Boeckella poopoensis Marsh, 1906 (Copepoda, Calanoida) en condiciones naturales en lagos salinos temporarios del centro de Argentina

Boeckella poopoensis Marsh, 1906 is the dominant copepod in saline lakes from northern Patagonia to southern Peru. It is a tolerant species, which has been registered at salinities between 20 and 90 g.L-1, and is important because it integrates the diet of flamingos and fishes of commercial and sport interest. The aims of this study were to analyze the characteristics of populations of B. poopoensis in the central region of Argentina and to establish their relationships with environmental parameters. Monthly samples during 2007 were taken in four temporary lakes of La Pampa province. Environmental parameters and density, size, biomass, number and size of eggs were determined. The salinity ranged between 13.38 and 32.90 g.L-1. In three lakes that had previously continuously contained water, B. poopoensis was registered throughout the whole study. In the fourth lake, which was filled in January, it was present only when salinity exceeded 15 g.L-1. The population of the lake that was filled differed from that of the other lakes in terms of the density and biomass of adults and copepodites. The number of ovigerous females represented a higher percentage of the population during the colonization of the lake that had been dried and these produced the highest number of eggs. In the three lakes in which B. poopoensis was always recorded, its characteristics were more influenced by the availability of food than by temperature or salinity. It was found that the strategies of the species vary throughout the hydroperiod; at the beginning, thrives when the salinity rises and impedes the presence of less tolerant species. At this point, the production of relatively small eggs is high, allowing rapid colonization. When the lakes become relatively stable, B. poopoensis allocates more energy to reach larger sizes and although egg production is not so high, they are larger, allowing it to maintain stable populations.

Boeckella poopoensis Marsh, 1906 es el copépodo dominante en lagos salinos desde el norte de Patagonia hasta el sur del Perú. Es una especie halotolerante registrada con salinidades entre 20 y 90 g.L-1 y es importante dado que integra la dieta de flamencos y de peces de interés comercial o deportivo. El objetivo del estudio fue analizar características de poblaciones de B. poopoensis en la región central de Argentina y establecer sus relaciones con los parámetros ambientales. Durante 2007 se tomaron muestras mensuales en cuatro lagos temporarios de la provincia de La Pampa. Se determinaron parámetros ambientales y la densidad, espectro de tallas, biomasa, número y tamaão de los huevos. La salinidad varió entre 13,38 and 32,90 g.L-1. En tres lagos que habían contenido agua en forma continua, B. poopoensis se registró durante todo el estudio. En el cuarto, que se llenó en enero, sólo estuvo presente cuando la salinidad superó 15 g.L-1. La densidad y biomasa de los adultos y copepoditos de la población del lago que se llenó difirieron de las de los otros. El número de hembras ovígeras representó un mayor porcentaje del total de la población durante la colonización del lago que había estado seco y fueron las que produjeron el mayor número de huevos. En los tres lagos en los que B. poopoensis se registró siempre, sus características fueron influidas más por la disponibilidad de alimento que por la temperatura o salinidad. Este estudio mostró que las estrategias de la especie varían a lo largo del hidroperíodo; al principio, prospera cuando la salinidad aumenta e impide la presencia de especies menos tolerantes. En este momento, la producción de abundantes huevos relativamente pequeãos permite una rápida colonización. Cuando los lagos alcanzan una relativa estabilidad, B. poopoensis destina más energía a alcanzar tamaãos mayores y, aunque la producción de huevos no es tan elevada son más grandes, permitiéndole mantener poblaciones estables.

Community effectiveness of copepods for dengue vector control: systematic review.

OBJECTIVE: Vector control remains the only available method for primary prevention of dengue. Several interventions exist for dengue vector control, with limited evidence of their efficacy and community effectiveness. This systematic review compiles and analyses the existing global evidence for community effectiveness of copepods for dengue vector control. METHODS: The systematic review follows the PRISMA statement, searching six relevant databases. Applying all inclusion and exclusion criteria, 11 articles were included. RESULTS: There is evidence that cyclopoid copepods (Mesocyclops spp.) could potentially be an effective vector control option, as shown in five community effectiveness studies in Vietnam. This includes long-term effectiveness for larval and adult control of Ae. aegypti, as well as dengue incidence. However, this success has so far not been replicated elsewhere (six studies, three community effectiveness studies--Costa Rica, Mexico and USA, and three studies analysing both efficacy and community effectiveness--Honduras, Laos and USA), probably due to community participation, environmental and/or biological factors. Judging by the quality of existing studies, there is a lack of good study design, data quality and appropriate statistics. CONCLUSION: There is limited evidence for the use of cyclopoid copepods as a single intervention. There are very few studies, and more are needed in other communities and environments. Clear best practice guidelines for the methodology of entomological studies should be developed.

First record of the freshwater copepod Eucyclops titicacae Kiefer, 1957, new rank (Copepoda, Cyclopoida) in Colombia

The freshwater cyclopoid copepod Eucyclops titicacae Kiefer, 1957, new rank, was previously known as a subspecies of E. neumani (Pesta, 1927). Hitherto, it was recorded only from Lake Titicaca in Peru and Lake Valencia in Venezuela. This species is here recorded from Laguna Navío Quebrado, La Guajira, northern Colombia. This is the first record of E. titicacae in Colombia and the third locality in which this species has been reported from. We provide comparative data on the morphology of this copepod. The Colombian specimens have the combination of diagnostic features of E. neumani titicacae as reported in both the original description and subsequent taxonomical accounts, including: 1) spinules on caudal rami not reaching halfway the outer margin; 2) caudal rami length/width ratio= 6.0; 3) length/width ratio of third endopodal segment of fourth leg=1.66; 4) inner spine of fifth leg being shorter than the two adjacent setae. The consistent morphologic differences and the isolation of E. neumani titicacae with respect to E. neumani neumani, each related to a different biogeographic subregion in South America, support the notion that these are two separate species, E. neumani and E. titicacae. Considering this interesting addition, the number of species of Eucyclops known from Colombia increases to 8; a key for the identification of these species is also provided.

El copépodo ciclopoide de agua dulce Eucyclops titicacae Kiefer, 1957, nuevo rango, se conocía previamente como una subespecie de E. neumani (Pesta, 1927). Se había registrado solamente en los lagos Titicaca en Perú y Valencia en Venezuela. Esta especie se registra ahora en la Laguna Navío Quebrado, La Guajira, norte de Colombia. Este es el primer reporte de E. titicacae en Colombia y la tercera localidad en cual esta especie ha sido reportada. Se ofrece información comparativa sobre la morfología de este copépodo. Los especímenes de Colombia tiene la combinación de caracteres diagnósticos de E. neumani titicacae como se presentaron en la descripción original y en trabajos taxonómicos subsecuentes, incluyendo: 1) las espínulas de la rama caudal no alcanzan la mitad del margen externo, 2) la relación largo/ancho de la rama caudal = 6.0, 3) la relación longitud/ancho del tercer segmento endopodal de la cuarta pata = 1.66, 4) la espina interna de la quinta pata es más corta que las dos setas adyacentes. Las consistentes diferencias morfológicas y el aislamiento de E. neumani titicacae con respecto a E. neumani neumani, que se distribuyen en subregiones biogeográficas distintas en América del Sur, apoyan la idea de que se tratan de dos especies separadas, E. neumani y E. titicacae. Considerando esta interesante adición, el número de especies de Eucyclops conocidas para Colombia se incrementa a 8; se proporciona una clave para la identificación de estas especies.

Evaluación de la primera alimentación en larvas de capaz Pimelodus grosskopfii bajo condiciones de laboratorio / Evaluation of first feeding of capaz larvae Pimelodus grosskopfii under laboratory conditions

Objetivo. Evaluar el desempeño y sobrevivencia de larvas de capaz Pimelodus grosskopfii suministrando alimento vivo (Cladóceros, Copépodos y Artemia salina). Materiales y métodos. Larvas de capaz fueron ubicadas en recipientes plásticos con un volumen útil de 3 L, a una densidad de 10 larvas L-1, fueron alimentadas cuatro veces al día, durante 15 días con nauplios de Artemia recién eclosionadas, Cladóceros de los géneros Moina y Ceriodaphnia y Copépodos calanoides. Las larvas de capaz se pesaron y se midieron al inicio y al final del experimento para estimar ganancia en peso (GP), ganancia en longitud (GL), tasa de crecimiento específico (TCE), Factor de crecimiento relativo (FCR) y sobrevivencia (S) Resultados. El tratamiento que presentó los mejores resultados en GP, GL y S fue el de larvas alimentadas con nauplios de Artemia (3.8 ± 0.2 mg, 8 ± 0.7 mm y 48.3% respectivamente) seguido de los tratamientos donde adicionó cladóceros y copépodos Conclusiones. Los nauplios de Artemia fue el tratamiento que presentó los mejores resultados en las variables productivas evaluadas en larvas de P. grosskopfii al inicio de su alimentación exógena.

Objective. Evaluate the performance and survival of capaz larvae Pimelodus grosskopfii after supplying live food (Cladocera, Copepod and Artemia Salina). Materials and methods. Capaz larva were placed in plastic containers with an useful volume of 3 L , and a larvae density of 10 L-1, they were fed four times a day during 15 days with newly hatched Artemia nauplii, Cladocerans of the genders Moina and Ceriodaphnia and Copepods calanoides. Capaz larva were weighed and measured at the beginning and the end of the experiment in order to evaluate their weight gain (WG), length gain (LG), specific growth rate (SGR), relative growth factor (RGF), and survival rate(S). Results. The treatment that showed the best results in WG, LG and S was the lot fed with Artemia nauplii (3.8±0.2 mg, 8±0.7 mm and 48.3% respectively), followed by sample supplied with Cladocera and Copepods. Conclusions. The Artemia nauplii treatment revealed the best results on the productive variables evaluated in P. grosskopfii larvae at the beginning of their exogenous feeding.

Variación espacio-temporal de la meiofauna submareal en una playa arenosa nororiental de Venezuela / Spatio-temporal variation of subtidal meiofauna in a sandy beach from Northeastern Venezuela

Meiofauna organisms that play an important role in the trophic ecology of soft bottom benthos, have short life cycles and they respond quickly to disturbance and pollution. The present study shows the spatio-temporal variation of subtidal meiofauna (metazoans passing a 500μm sieve but retained on meshes of 40-63μm) in four shallow subtidal stations. Samples were taken in the sandy beach of San Luis, in the Northeastern coast of Venezuela, from October 2005 until September 2006. For this, three replicate sediment core samples (4.91cm²), were collected monthly to a depth of 10cm into the sediment, and preserved in 6% formalin stained with rose Bengal. Specimens of 14 meiofaunal groups (Foraminifera excluded) were collected, being the nematodes, ostracods and harpacticoid copepods the most abundant. Monthly density was comprised between 64 and 503ind./10cm², and mean density of stations between 173 and 449ind./10cm². There is a trend of low densities from October to February (end of the rainy season until the middle of the dry season). The San Luis beach control of the meiofaunal community is shared by climatic conditions and by the biology of the species found. The meiofauna mean density in San Luis beach (263ind./10cm²) was low when compared to other studies in tropical areas.

La meiofauna incluye metazoos y foraminíferos bénticos que pasan a través de un tamiz de 500mm y son retenidos en malla de 40-63μm. Se estudió la variación espacial y temporal de la meiofauna en cuatro estaciones submareales a 1m de profundidad, de una playa arenosa situada en la costa nororiental de Venezuela. Mensualmente, durante un año, en cada estación, con un nucleador de 2.5cm de diámetro interno, se tomaron tres réplicas de sedimento hasta 10cm de profundidad y se pasaron a través de un tamiz de 0.063mm de abertura de malla. Se identificaron 14 grupos meiofaunales, excluidos los foraminíferos, siendo los nemátodos, ostrácodos y copépodos harpacticoides los más abundantes. La densidad mensual estuvo comprendida entre 64 y 503ind./10cm², y la densidad media en las estaciones entre 173 y 449ind./10cm². La densidad de la meiofauna en la playa San Luis es baja en comparación con otros estudios realizados en zonas tropicales. En esta playa el control de las comunidades meiofaunísticas es compartido por las condiciones climáticas y la biología de las especies.

Diel horizontal distribution of microcrustaceans and predators throughout a year in a shallow neotropical lake / Distribuição horizontal de microcrustáceos e predadores ao longo do ano em um lago neotropical

The focus of this study is to investigate if microcrustaceans undergo diel horizontal migration (DHM) in a tropical shallow lake on a yearly basis and analyse the adaptive value regarding predation. Abundance of invertebrate predators, chaoborid larvae and water mites, and microcrustaceans (cladocerans and copepods) were evaluated on a monthly basis in three stations located on a transect during the day and at night. Both invertebrate predators were predominantly pelagic. Cladocerans did not undergo significant DHM, distributing indistinctly onshore and offshore or being mostly pelagic. Nauplii, copepodites of two copepod species and adults of Tropocyclops prasinus meridionalis Kiefer were mostly distributed offshore, and did not perform DHM. The limnological features (temperature, dissolved oxygen, pH, and conductivity) were suitable for the organisms in both zones of the lake. Algal food concentration was a little lower in the littoral than in the limnetic zone during the day, but it seems to be suitable for the organisms. However, as the algae quality was not evaluated, it is not possible to be conclusive concerning its influence. The results indicated that DHM was not performed by the microcrustaceans and is not, therefore, a strategy for decreasing predation by both invertebrates, Chaoborus brasiliensis Theobald and Krendowskia sp., on a yearly basis in this shallow lake.

O foco deste estudo é verificar se microcrustáceos apresentam migração horizontal diária (MHD) em um lago raso tropical, durante um ano, e o valor adaptativo com relação à predação. A abundância de predadores invertebrados, larvas de caoborídeos e ácaros aquáticos, e de cladóceros e copépodos foi avaliada mensalmente em três estações de coleta localizadas em um transecto, de dia e à noite. Ambos os predadores invertebrados foram predominantemente pelágicos. Os cladóceros não realizaram MHD, distribuindo-se indistintamente nas zonas litorânea e pelágica, ou foram mais abundantes na zona limnética. Os náuplios e copepoditos de duas espécies de copépodos e os adultos de Tropocyclops prasinus meridionalis Kiefer ocuparam principalmente a zona limnética, não migrando horizontalmente. As características limnológicas (temperatura, oxigênio dissolvido, pH e condutividade) foram adequadas nas duas zonas do lago. A concentração de alga foi um pouco menor no litoral do que na zona limnética durante o dia e parece ser adequada para os organismos; contudo, como a qualidade das algas não foi avaliada, não é possível ser conclusivo sobre sua influência. Os resultados indicaram que os microcrustáceos não realizaram MHD, a qual não constitui, portanto, uma estratégia para diminuir a predação dos dois invertebrados, Chaoborus brasiliensis Theobald e Krendowskia sp., em uma base anual, neste lago raso.

A new Lepeophtheirus (Copepoda: Siphonostomatoida: Caligidae) from Isla del Coco National Park, Costa Rica, Eastern Tropical Pacific / Un nuevo Lepeophtheirus (Copepoda: Siphonostomatoida: Caligidae) del Parque Nacional Isla del Coco, Costa Rica, Pacífico Tropical Oriental

Among the several groups of copepods that are teleost parasites, the siphonostomatoid family Caligidae is by far the most widespread and diverse. With more than 108 nominal species, the caligid genus Lepeophtheirus von Nordmann is one of the most speciose. There are no reports of this genus in Costa Rican waters. A new species of Lepeophtheirus is herein described based on female specimens collected from plankton samples in waters off Bahía Wafer, isla del Coco, an oceanic island in the Eastern Tropical Pacific. The new species, L. alvaroi sp. nov., has some affinities with other congeners bearing a relatively short abdomen, a wider than long genital complex and a 3-segmented exopod of leg 4. it differs from most of these species by the presence of an unbranched maxillular process and by the relative lengths of the terminal claws of leg 4, with two equally long elements. it is most closely related to two other Eastern Pacific species: L. dissimulatus Wilson, 1905 and L. clarionensis Shiino, 1959. it differs from these species by the proportions and shape of the genital complex, the shape of the sternal furca, the relative length of the maxillar segments, the absence of a pectiniform process on the distal maxillar segment, the length of leg 4 and the armature of leg 5. The new species represents the first Lepeophtheirus described from Costa Rican waters of the Pacific. The low diversity of this genus in this tropi- cal region is explained by its tendency to prefer hosts from temperate latitudes. Until further evidence is found, the host of this Lepeophtheirus species remains unknown.

Entre los varios grupos de copépodos que son parásitos de teleósteos, la familia sifonostomatoide Caligidae incluye los más dispersos y diversos. Con más de 108 especies nominales, el género de calígidos Lepeophtheirus von Nordmann es uno de los más diversos. No existen registros previos de este género en aguas de Costa Rica. Se describe una nueva especie de copépodo calígido del género Lepeophtheirus con base en especímenes femeninos recolectados a partir de muestras de plancton en aguas de Bahía Wafer, isla del Coco, una isla oceánica del Pacífico Tropical Oriental. La nueva especie, L. alvaroi sp. nov., tiene algunas afinidades con congéneres que poseen un abdomen relativamente corto, un complejo genital más ancho que largo y un exópodo de la pata 4 con 3 segmentos. Esta especie difiere de la mayoría de estas especies por la presencia de un proceso maxilular no ramificado y por el tamaño relativo de las garras terminales de la pata 4, con dos elementos igualmente largos. Está más cercanamente relacionada con otras dos especies del Pacífico Oriental: L. dissimulatus Wilson, 1905 y L. clarionensis Shiino, 1959. Difiere de estas especies por las proporciones y forma del complejo genital, la forma de la furca esternal, la longitud relativa de los segmentos maxilares, la ausencia de un proceso pectiniforme en el segmento maxilar distal, la longitud de la pata 4 y la armadura de la pata 5. La nueva especie representa el primer Lepeophtheirus descrito en aguas del Pacífico de Costa Rica. La baja diversidad del género en esta región tropical se explica por su tendencia a preferir hospederos de latitudes templadas. Hasta encontrar más evidencia, el hospedero de esta especie de Lepeophtheirus permanece desconocida.

Experimental culture of Cyclopina sp with differents microalgae’s species / Cultivo experimental de Cyclopina sp con diferentes especies de microalgas / Cultura experimental de Cyclopina sp com diferentes espécies de microalgas

Copepods are the main natural prey for most marine fish and other marine crustaceans and their nauplius, thus playing a fundamental role in aquatic food webs. There is a need to investigate the potential of copepods species found in Colombian coasts for the development of marine aquaculture. Objective: evaluate the performance of the marine copepod Cyclopina sp fed with different microalgae species. Methods: experimental cultures were conducted in 10 L aquariums with an initial density of 2 copepods/ mL, constant aeration and 24 h light. Treatments consisted of feeding the copepods with a combination of two microalgae species in a 70:30 ratio, at concentrations of 4x10(5) cells/mL, as follows: T1 = Tetraselmis suecica + Isochrysis galbana, T2 = I. galbana. + Nannochloropsis oculata, T3 = N. oculata. + T. suecica, T4 = Yeast (Saccharomyces cerevisiae). Temperature (ºC), salinity (%), dissolved oxygen (mg/L), pH, were registered daily, and the growth and population dynamics were evaluated every 48 hours for 15 days. Results: the greater density of total copepods (10± 3 copepods/ml) and number of nauplii (6 ± 2 nauplii/ mL), were registered on day 15 in T1, being significantly different (p<0.05) from any other treatments. Conclusions: the best growth and reproduction were attained in copepod populations fed with the combination of microalgae T. suecica + I. galbana (T1).

Los copépodos son la principal presa natural para la mayoría de larvas de peces y crustáceos marinos y sus nauplios como alimento vivo representan un papel fundamental en la sobrevivencia de las larvas. Objetivo: establecer el potencial de especies de copépodos presentes en las costas colombianas para el desarrollo de la piscicultura marina, siendo objetivo de esta investigación, evaluar el desempeño del copépodo marino Cyclopina sp alimentado con diferentes especies de microalgas. Métodos: cultivos experimentales se realizaron en acuarios con volumen útil de 10 litros, a densidad inicial de 2 copépodos/ ml, con aireación y luz constante. Combinaciones de microalgas (proporción 70:30) en concentración 4x10(5) cel/ml. Se usaron como tratamientos: T1 = Tetraselmis suecica + Isochrysis galbana, T2 = I. galbana + Nannochloropsis oculata, T3 = N. oculata + T. suecica, T4 = Levadura (Saccharomyces cerevisiae). Diariamente se registró la temperatura (ºC), salinidad (‰), oxígeno disuelto (mg/L), pH y se evaluaron cada 2 días el crecimiento y la composición poblacional durante el tiempo de cultivo. Resultados: la mayor densidad de copépodos totales (10 ± 3 copépodos/ml) y el mayor número de nauplios (6 ± 2 nauplios/ ml), se registraron el día 15 en T1, mostrando diferencias significativas (p<0.05) respecto a los demás tratamientos. Conclusión: los mejores crecimiento y composición poblacional, se registraron en las poblaciones alimentadas con la combinación de las microalgas T. suecica e I. galbana (T1).

Os copépodos são a principal presa natural para a maioria de larvas de peixes e crustáceos marinhos e seus náuplios como alimento vivo desempenhan um papel fundamental na sobrevivência das larvas. Objetivo: estabelecer o potencial de espécies de copépodos presentes nas costas colombianas para o desenvolvimento da piscicultura marinha, sendo o objetivo desta pesquisa avaliar o desempenho do copépodo marinho Cyclopina sp alimentado com diferentes espécies de microalgas. Métodos: culturas experimentais foram realizadas em aquarios com volume útil de 10 litros, densidade inicial de 2 copépodos/ ml, com aeração e luz constante. Combinações de microalgas (proporção 70:30) em concentração 4x10(5) cel/ml, foram usadas como tratamentos: T1 = Tetraselmis suecica + Isochrysis galbana, T2 = I. galbana + Nannochloropsis oculata, T3 = N. oculata + T. suecica, T4 = Levadura (Saccharomyces cerevisiae). Foi registrada diariamente a temperatura (°C), salinidade (‰), oxigênio dissolvido (mg/L) e pH. A cada dois días foram avaliados o crescimento e composição populacional durante o tempo de cultivo. Resultados: a maior densidade de copépodos totais (10 ± 3 copépodos/ml) e o maior número de náuplios (6 ± 2 náuplios/ ml), foram registrados no día 15 do T1, apresentando diferença estatística significativa (p<0.05) em comparação com os outros tratamentos. Conclusõe: o maior crescimento e composição populacional foi registrado na população alimentada com a combinação de microalgas T. suecica e I. galbana (T1).

Distribution of some Calanoida (Crustacea: Copepoda) from the Yucatán Peninsula, Belize and Guatemala

Southern Mexico and Central America have many water bodies of different morphology and water chemistry with an interesting zooplankton fauna, originating from North or South America. A set of 63 samples, taken in 2005 and 2008, from water bodies of the Yucatan Peninsula karst, Belize and Guatemala, were studied for the content of calanoid copepods. Old and recent literature was used to determine animals to species level. Drawings were prepared with a microscope and a camera lucida. A total of 32 samples with totally six species contained calanoid copepods: one estuarine pseudodiaptomid and five freshwater diaptomids. Pseudodiaptomus marshi was found at different salinities. It is confirmed that the commonest diaptomids in the Yucatan Peninsula are Arctodiaptomus dorsalis and Mastigodiaptomus nesus. The former was also recorded from Lake Amatitlan. Mastigodiaptomus nesus is as widespread as A. dorsalis but it is absent from the Lake Peten area in Guatemala. Mastigodiaptomus reidae was found in two shallow habitats, these specimens differ from those from the type locality by having a set of peculiar large spine-like processes on the last thoracic and the urosome segments of the females. Leptodiaptomus siciloides was found only in Lake Ayarza with high salinity. Prionodiaptomus colombiensis occurred in the highlands of Guatemala in Lago de Güija and in the Peten area in Laguna Sacpuy. We contributed with our occurrence records to a better knowledge of the geographic distribution of some calanoid copepods. Morphological findings in some species are of value for taxonomic differentiation between species.

El sur de México y América Central tienen varios cuerpos de agua con diferente morfología, composición química y una interesante fauna de zooplancton procedente de América del Norte o del Sur. Un grupo de 63 muestras, fueron tomadas en 2005 y 2008 para conocer la cantidad de copépodos calanoides en los cuerpos de agua del karst Península de Yucatán, Belice y Guatemala. Se utilizó literatura antigua y reciente para la identificación de los especímenes a nivel de especie y se preparon dibujos con un microscopio y una cámara lúcida. En un total de 32 muestras se obtuvieron seis especies de copépodos calanoides: un pseudodiaptomidos estuarino y cinco diaptomidos de agua dulce. Pseudodiaptomus marshi fue encontrado a diferentes salinidades. Además, se confirmó que los diaptomidos más comunes en la Península de Yucatán fueron: Arctodiaptomus dorsalis y Mastigodiaptomus nesus. El primero se registró también en el lago de Amatitlán. Mastigodiaptomus nesus está ampliamente distribuido al igual que A. dorsalis, pero se encuentra ausente en el área del Lago Petén en Guatemala. Mastigodiaptomus reidae fue localizado en dos hábitats poco profundos, éstos especímenes difieren de los tipos de la localidad, por tener un grupo de espinas de gran tamaño en la última parte de la caja toráxica y los segmentos del urosoma de las hembras. Leptodiaptomus siciloides se encontró sólo en el Lago Ayarza, el cual contiene alta salinidad. Prionodiaptomus colombiensis se localizó en las tierras altas de Guatemala en el Lago de Güija y en la zona del Petén en Laguna Sacpuy. Se contribuye con registros de presencia de especies para un mejor conocimiento de la distribución geográfica de algunos copépodos calanoides. De la misma forma, los hallazgos morfológicos en algunas especies son de gran valor taxonómico para la diferenciación de especies.

Influencia de las macrófitas sobre la estructura poblacional de rotíferos y microscrustáceos en un plano de inundación tropical

The influence of macrophytes on rotifer and microcrustacean assemblage in a tropical floodplain. Most studies on zooplankton ecology have been conducted in open waters. However, it has been considered of great importance to extend such studies to other habitats, such as those generated of macrophytes. We studied the spatial and temporal variation of the microcrustacean and rotifer assemblage structures associated with macrophytes, and compare them with the variation exhibited in open waters. Integrated samples were collected for zooplankton and phytoplankton biomass using a Schindler bottle, in four open water sites and four other sites covered by macrophytes in the floodplain complex of Ayapel (Córdoba, Colombia) during different limnimetric levels. The significant differences in the structure were evaluated using Kruskal & Wallis and discriminant analyses, and the similarity among sampling sites was evaluated using Bray & Curtis analysis. Zooplanktonic richness was favored by macrophytes. However, we did not find a constant spatial pattern for density, and only particular trends apparently conditionated by flood pulses. The presence of Eichhornia azurea (Pontederiaceae) contributed in a significant way with an increase in the diversity and density of benthic taxa. The density of some zooplanktonic groups was related with environmental conditions and phytoplanktonic biomass. Rev. Biol. Trop. 59 (2): 853-870. Epub 2011 June 01.

La mayoría de estudios ecológicos del zooplancton se han realizado en aguas abiertas. No obstante, es importante ampliar la exploración hacia hábitats como el de las macrófitas. En este estudio se evaluó la variación espacio-temporal de la estructura del ensamble de rotíferos y microcrustáceos asociados a macrófitas y se comparó con la variación de su estructura en aguas abiertas, para lo cual se tomaron muestras integradas de zooplancton y biomasa de fitoplancton usando una botella Schindler de 5L en cuatro sitios de aguas abiertas y en cuatro sitios cubiertos por macrófitas durante diferentes niveles limnimétricos en el complejo cenagoso de Ayapel (Córdoba, Colombia). Las diferencias significativas de la estructura se evaluaron mediante Kruskal & Wallis y discriminantes; y la similitud entre sitios de muestreo mediante Bray & Curtis. Las macrófitas favorecieron la riqueza zooplanctónica; sin embargo, no hubo un patrón espacial constante en la densidad, pero sí tendencias particulares condicionadas por el pulso de inundación. La presencia de Eichhornia azurea (Pontederiaceae) contribuyó significativamente a la mayor diversidad y densidad de taxones bentónicos y sólo la densidad de algunos taxones y grupos del zooplancton se relacionó con las condiciones ambientales y la biomasa de fitoplancton.

Microcrustacean assemblages composition and environmental variables in lakes and ponds of the Andean region - South of Chile (37-39° S) / Composição de comunidades de microcustáceos e variáveis ambientais em lagos e lagoas da região andina - sul do Chile (37-39° S)

The zooplankton assemblages in Chilean Patagonian lakes are characterised mainly by their low biodiversity and high predominance of calanoids copepods, a pattern that has been studied for large and deep lakes between 38-51° S, and shallow ponds at 51° S. The aim of the present study was analyse the zooplankton assemblages in different water bodies located in coastal zones, middle valleys and mountain zones between 37-39° S. For this purpose, the following variables were considered: maximum depth, latitude, altitude, chlorophyll-a and species number, and to these variables, a Principal Component Analysis (PCA) was applied. A co-occurrence null model analysis was also applied for determining the existence of a random process in crustacean species associations. The results denoted low species richness, and different species associations for studied sites, and the null model analysis revealed the absence of a random process as regulator of species associations. Furthermore, a low species/genera ratio was identified, which denotes low productivity of the studied sites. These results were supported by a PCA analysis which denoted that the main determinant factors are chlorophyll concentration and species number that are directly associated. The obtained results are in agreement with descriptions in the literature for species diversity for lakes of Chilean Patagonia that describes oligotrophy as the main regulator of zooplankton assemblages. Other ecological and limnological topics are discussed in the present study.

As comunidades zooplantônicas em lagos chilenos são caracterizadas, principalmente, por sua baixa biodiversidade e alta predominância de copépodos calanoides, um padrão que tem sido estudado em lagos grandes e profundos entre 38-51° S, e lagoas rasas em 51° S. O objetivo do presente estudo foi analisar as comunidades zooplantônicas em diferentes corpos de água localizados em zonas costeiras, vales intermediários e regiões de montanhas entre 37-39° S. Para este propósito, as seguintes variáveis foram consideradas: profundidade máxima, latitude, altitude, clorofila "a" e número de espécies, e a estas variáveis, foi aplicada a Análise de Componentes Principais (PCA). Um modelo nulo de coocorrência também foi aplicado para determinar a existência de um processo aleatório na associação de espécies de crustáceos. Os resultados denotam baixa diversidade de espécies e diferentes associações de espécies nos diferentes locais estudados, e o modelo nulo de análises revelou a ausência de um processo aleatório como regulador de associação de espécies. Além disso, a baixa relação espécie/gênero foi identificada, o que denota baixa produtividade dos locais estudados. Estes resultados foram apoiados pelas análises de PCA que mostraram que os fatores determinantes principais como a concentração de clorofila e número de espécies estão diretamente associados. Os resultados obtidos concordam com as descrições na literatura sobre a diversidade de espécies para lagos da Patagônia Chilena, que descreve a oligotrofia como principal regulador de comunidades zooplanctônicas. Outros tópicos ecológicos e limnológicos foram discutidos no presente estudo.

Illustrated record of the freshwater copepod Leptodiaptomus dodsoni (Calanoida, Diaptomidae) from central Mexico with comments on the distribution of the genus / Registro ilustrado del copépodo dulceacuícola Leptodiaptomus dodsoni (Calanoida, Diaptomidae) del centro de México con comentarios acerca de la distribución del género

The freshwater planktonic calanoid copepod Leptodiaptomus dodsoni Elías-Gutiérrez, Suárez-Morales & Romano, 1999, a rare species known only from western Mexico, is here recorded from the State of Aguascalientes, central Mexico. This species has a uniquely large, sinuous spine on segment 13 of the right male antennule, reaching the distal margin of segment 15. There are subtle differences between these two known populations; the morphological range of the species is complemented with data from the new specimens. This is the first record of L. dodsoni after its original description; it is probably restricted to a latitudinal fringe in central Mexico. Of the 22 nominal species of Leptodiaptomus currently recognized, up to 7 are known from the Neotropical region and some appear to be true endemics. Apparently, this primarily Nearctic genus radiated in North America and some species reached the Neotropical region where they diversified. A key for the identification of the species of the genus known from the Neotropical region is also provided.

El copépodo calanoide planctónico de aguas continentales Leptodiaptomus dodsoni Elías-Gutiérrez, Suárez-Morales & Romano, 1999, una rara especie conocida sólo en la zona occidental de México, se registra aquí para el estado de Aguascalientes, en el centro de México. Esta especie tiene una espina sinuosa distintivamente larga en el segmento 13 de la anténula derecha del macho, la espina alcanza el margen distal del segmento 15. Existen differencias sutiles entre estas dos poblaciones; se complementa el espectro morfológico de la epecie con datos de los nuevos especímenes. Este es el primer registro de L. dodsoni después de su descripción original; probablemente está restringida a una franja latitudinal del centro de Mexico. De las 22 especies nominales de Leptodiaptomus reconocidas, 7 se conocen en la zona Neotropical y algunas parecen ser verdaderos endémicos. Aparentemente, este género primariamente Neártico radió en América del Norte y estas especies alcanzaron la región Neotropical donde se diversificaron. Se presenta una clave para la identificación de las especies del género conocidas en la región Neotropical.

Native Argentinean cyclopoids (Crustacea: Copepoda) as predators of Aedes aegypti and Culex pipiens (Diptera: Culicidae) mosquitoes

Copepods from La Plata, Argentina were investigated to characterize the local community of larvivorous copepods inhabiting mosquito breeding sites and to identify new predator species of the mosquitoes which occur in artificial containers, Aedes aegypti and Culex pipiens. Diversity of larvivorous cyclopoids was highest in permanent pools. Predation by sex and age, selectivity on mosquito species, and daily predation rate during five days were studied for Acanthocyclops robustus, Diacyclops uruguayensis, Macrocyclops albidus and Mesocyclops longisetus. Female copepods presented the highest predatory capacity. No predatory preference for mosquito species was found. According to overall predation potential, copepods were ranked as follows: D. uruguayensis < A. robustus < M. albidus < M. longisetus. Copepod tolerance to desiccation and capacity to survive in water from artificial containers were also evaluated. D. uruguayensis and A. robustus survived under dry conditions, but D. uruguayensis showed lower survival in water from cemetery flower vases. M. albidus did not survive under dry conditions and did not tolerate water extracted from artificial containers. M. longisetus survival was not severely reduced after desiccation or breeding in water from flower vases. The Neotropical cyclopoids D. uruguayensis and A. robustus can be considered good candidates and merit further research as biological control agents for mosquitoes. Rev. Biol. Trop. 57 (4): 1059-1068. Epub 2009 December 01.

Se hizo una prospección de copépodos en La Plata, Argentina, con los objetivos de caracterizar la comunidad local de copépodos larvívoros en sitios de cría de mosquitos, e identificar nuevas especies depredadoras de los mosquitos de contenedores artificiales Aedes aegypti y Culex pipiens. La diversidad de ciclopoides larvívoros fue máxima en charcos permanentes. Se examinó la depredación por sexos y edad, la selectividad por especies de mosquito, y la tasa de depredación diaria durante cinco días en Acanthocyclops robustus, Diacyclops uruguayensis, Macrocyclops albidus y Mesocyclops longisetus. Los copépodos hembra presentaron la capacidad depredadora más alta. No se encontró preferencia por alguna especie de mosquito. De acuerdo al potencial de depredación en general, los copépodos se ordenan así: D. uruguayensis < A. robustus < M. albidus < M. longisetus. También se evaluó la tolerancia a la desecación del hábitat y la capacidad de resistir en agua de contenedores artificiales. D. uruguayensis y A. robustus sobrevivieron en condiciones de sequía, pero D. uruguayensis presentó menor supervivencia en agua de floreros de cementerio. M. albidus no sobrevivió condiciones de sequía y no toleró el agua extraída de contenedores artificiales. Los ciclopoides neotropicales D. uruguayensis and A. robustus son buenos candidatos y merecen investigación ulterior como agentes de control biológico de mosquitos.

Composition and abundance of zooplankton groups from a coral reef lagoon in Puerto Morelos, Quintana Roo, Mexico, during an annual cycle

Zooplankton sampling was carried out monthly from January to December 1990 at station A near the coastline, and station B near the reef barrier, in a tropical coral reef lagoon in the Mexican Caribbean Sea. Samplings were made at midnight, near surface, with a conical net (mouth 0.40 m, mesh 330 µm) for 10 min. Salinity varied from 35.1 to 36.3 psu and temperature from 26.3 to 30.2 ºC. The Bray-Curtis test applied to these results has defined two seasons: the dry season from November to May, and the wet season from June to October. A total of 37 zooplankton groups were found. Copepods were the most abundant contributing 49.0% of the total capture with Acartia espinata, Calanopia americana and Farranula gracilis as the most numerous. In the total zooplankton, however, cirripeds captured in only 15 samples of 24 were second in abundance (20.9%). Decapods, present all year-round and more abundant during the wet season, were third and contributed 19.2%. The rest of the groups were scarce and only amphipods (2.4%) and larvaceans (2.0%) were relatively abundant. The abundance of captured organisms correlated with the abiotic factors measured, thus, in the dry season, abundance was lower (mean 7.3 orgs/m3), while in the wet season the mean catch was 36.8 orgs/m3. Rev. Biol. Trop. 57 (3): 647-658. Epub 2009 September 30.

Se efectuaron muestreos mensuales de zooplancton en el Caribe de México de enero a diciembre de 1990 en dos estaciones en la laguna arrecifal de Puerto Morelos en el estado de Quintana Roo, una situada cerca de la línea de costa (A), y la otra próxima a la barrera de coral (B). Los arrastres se realizaron en condiciones de oscuridad (a medianoche), cerca de la superficie durante 10 min con una red cónica de boca de 0.40 m y malla de 330 micras. La salinidad varió de 35.1 a 36.3 ups y la temperatura de 26.3 a 30.2 oC. La prueba de Bray-Curtis definió dos épocas en el año, la de secas de noviembre a mayo, y la de lluvias de junio a octubre. Se capturaron un total de 37 grupos de zooplancton. Los copépodos, capturados en todas las muestras, contribuyeron con 49% del total en donde las especies Acartia espinata, Calanopia americana y Farranula gracilis fueron las más abundantes. Los cirripedios aún capturados únicamente en 15 ocasiones de 24, contribuyeron con 20.9% y fueron mayormente abundantes en la estación cerca de la barrera de arrecife. Los decápodos, presentes en todos los muestreos, contribuyeron con 19.2%. Otros grupos menos importantes fueron: anfípodos (2.4%) y larváceos (2.0%). La abundancia general del zooplancton coincide en general con las épocas del año, teniendo mayor abundancia durante la temporada de lluvias (36.8 org./ m3 en promedio) y menores capturas durante las secas con 7.3 org/m³ en promedio.

Seasonal variation in the copepod community structure from a tropical Amazon estuary, Northern Brazil

The main purpose of this study was to investigate the seasonal variation of copepod community structure during the months of July, September and November 2003 (dry season) and January, March and May 2004 (rainy season) in the Curuçá estuary, northern Brazil. Samples were collected during neap tides via gentle 200µm mesh net tows from a small powerboat. Measurements of surface water conductivity were accomplished in situ using an electronic conductivimeter and salinity was later obtained through the transformation of the conductivity values. Salinity varied seasonally from 7.2 ± 0.1 to 39.2 ± 1.8 (mean ± standard deviation) and was influenced mainly by differences in the amount of rainfall between the studied sampling seasons. In total, 30 Copepoda taxa were identified and Acartia tonsa comprised the most representative species throughout the entire studied period followed by Acartia lilljeborgii, Subeucalanus pileatus and Paracalanus quasimodo. In the present study, the density values, ecological indexes and copepod species dominance presented a clear seasonal pattern, showing that the studied area may be considered seasonally heterogeneous in relation to the investigated parameters.

O presente estudo teve como objetivo principal avaliar a variação sazonal na estrutura da comunidade dos copépodos durante os meses de julho, setembro e novembro de 2003 (período seco) e janeiro, março e maio de 2004 (período chuvoso) no estuário do Curuçá, Norte do Brasil. As amostras foram coletadas nas marés de quadratura com auxílio de uma rede deplâncton com 200µm de abertura de malha, rebocada por meio de uma pequena embarcação a motor. As medidas de condutividade da água foram realizadas in situ utilizando-se um condutivímetro eletrônico e a salinidade foi posteriormente obtida através da transformação dos valores de condutividade. Os valores de salinidade variaram sazonalmente de 7, 2 ± 0, 1a 39, 2 ± 1, 8 (média ± desvio padrão), tendo sido principalmente influenciados pelas diferenças nas taxas de precipitação entre os períodos de amostragem estudados. Foram identificados no total 30 táxons, com Acartia tonsa constituindo a espécie mais representativa durante todo o período de estudo,seguida por Acartia lilljeborgii, Subeucalanus pileatus e Paracalanus quasimodo. Durante este trabalho, os valores de densidade, índices ecológicos e dominância das espécies de copépodos apresentaram um padrão sazonal claro, mostrando que a área estudada pode ser considerada sazonalmente heterogênea em relação a estes parâmetros investigados.

Actividad depredadora de Mesocyclops aspericornis (Daday, 1906) sobre larvas de Culex quinquefasciatus (Say, 1823) / Depredatory action of Mesocyclops aspericomis (Daday,1906) on Culex quinquefasciatus larvae (Say, 1823)

Objectivo: evaluar si la depredación del copépodo Mesocyclops aspericornis depende de su densidad o la de sus presas, en este caso, larvas de Culex quinquefasciatus. Métodos: se realizaron 2 experimentos de depredación del copépodo Mesocyclops aspericornis, sobre larvas de primer estadio de Culex quinquefasciatus al cabo de 24 h. En el primero se valoró la depredación de diferentes cantidades del copépodo (5, 10, 15, 20 y 25 en 1 L de agua declorada) ante 120 larvas, con 10 réplicas. El segundo evaluó la influencia de la densidad de las larvas sobre la eficiencia del depredador, para ello se varió la cantidad de larvas (40, 60, 80, 100 y 150 en 1 L de agua), con igual número de réplicas ante 10 copépodos. En el procesamiento de los datos se empleó el paquete estadístico STATGRAPHIG versión 5.0. Resultados: la media de las larvas depredadas mostró una fuerte dependencia de la densidad del depredador, se obtuvo diferencias significativas en todos los casos, así para 25 copépodos se alcanzó 87 por ciento de mortalidad larvaria mientras que con 5 copépodos la mortalidad fue de 22,16 por ciento. En el siguiente experimento, la media de larvas depredadas en los 2 primeros tratamientos (40 y 60 larvas) difiere significativamente entre sí y con el resto de los tratamientos, pero a partir de 80 larvas no se encontraron diferencias significativas. Conclusiones: Mesocyclops aspericornis, incrementó la eficiencia depredatoria con su densidad en valores menores e igual que 25 copépodos/L, y que la eficiencia de depredación aumenta hasta una relación de 1 copépodo/8 larvas, que evidencia una respuesta funcional del tipo 2.

Objective: to evaluate whether the predation efficiency of copepods Mesocyclops aspericomis depends on their density or on that of their preys that are Culex quinquefasciatus in this case. Methods: Two experiments about the preying of copepod Mesocyclops aspericomis upon first stage Culex quinquefasciatus larvae were made in a 24h-interval. The first experiment assessed the preying capacity of different numbers of copepods (5, 10, 15, 20 and 25 in one liter of unchlorinated water) upon 120 larvae, with 10 replications. The second one evaluated the influence of larval density over the predation efficiency; to this end, the quantity of larvae changed (40, 60, 80,100 and 150 in one liter of water) exposed to 10 copepods, with 10 replications too. Statistical package STATGRAPHIC 5.0 allowed data processing. Results: Killed larva mean showed strong dependence on the density of predators, there were significant differences in all the cases since 25 copepods achieved 87 percent larval mortality whereas for 5 copepods, mortality rate was 22.16 percent. During the second experiment, the killed larva mean after the 2 first treatments (40 and 60 larvae) significantly differed between them and from the rest of treatment, but from 80 larvae on, no significant differences were found. Conclusions: Mesocyclops aspericornis increased their predatory efficiency depending on their density in numbers lower or equal to 25 copepods/L, and the predation efficiency rises to 1 copepod/8 larvae ratio, which evinced a type-2 functional response.

Attachment of the peritrich epibiont Zoothamnium intermedium Precht, 1935 (Ciliophora, Peritrichia) to artificial substrates in a natural environment / Colonização de substratos artificiais pelo peritríquio epibionte Zoothamnium intermedium Precht, 1935 (Ciliophora, Peritrichia), em um ambiente natural

Peritrich ciliates are commonly found as epibionts, colonizing living organisms, or attached to non-living substrates in freshwater, estuarine and marine environments. Several species of peritrich epibionts are obligate, which means that they are able to only colonize other organisms, while others are facultative attaching to living or non-living substrates. The peritrich Zoothamnium intermedium is commonly found as epibiont on the copepod species Acartia tonsa and Eurytemora affinis in Chesapeake Bay, USA. Previous studies demonstrated that Z. intermedium is not able to attach to non-living substrates in the laboratory; with free-swimming stages (telotrochs) dying when living substrates are not available for colonization. The present study investigated the ability of Z. intermdium to colonize artificial substrates in the field. Observations were carried out while the peritrich ciliate was colonizing copepods in Rhode River, a tributary of Chesapeake Bay. Results demonstrated that four species of Zoothamnium were recovered from artificial substrates, but none of them was Z. intermedium. At the same time, Z. intermedium was colonizing adults and copepodites of E. affinis and A. tonsa during the whole study period. These results, in addition to laboratory observations, suggest that Z. intermedium is an obligate epibiont.

Ciliados peritríquios são normalmente encontrados como epibiontes, colonizando substratos vivos, ou em substratos inanimados em ambientes de água doce, estuarinos e marinhos. Muitas espécies de peritríquios epibiontes podem ser consideradas obrigatórias quando estão aptas a colonizar apenas substratos vivos, ou facultativos quando conseguem colonizar substratos vivos ou inanimados. A espécie de ciliado peritríquio Zoothamnium intermedium é encontrada colonizando os copépodos Acartia tonsa e Eurytemora affinis na Chesapeake Bay, EUA. Estudos preliminares demonstraram que Z. intermedium não consegue colonizar substratos inanimados em laboratório e que os estágios livre-natantes (telotróquios) morrem quando não estão expostos a algum substrato vivo. No presente estudo, foi investigada a habilidade de Z. intermedium colonizar substratos artificiais no campo. As observações foram realizadas no Rhode River, um afluente da Chesapeake Bay, enquanto Z. intermedium era encontrado colonizando copépodos. Os resultados demonstraram que quatro espécies de Zoothamnium colonizaram os substratos artificiais, mas nenhuma delas era Z. intermedium. No mesmo período, Z. intermedium foi encontrado colonizando copepoditos e adultos de A. tonsa e E. affinis. Estes resultados, juntamente com as observações de laboratório, sugerem que Z. intermedium é um epibionte obrigatório.