Biology

Isla del Coco is an oceanic island 500km off the Pacific coast of Costa Rica. It is a National Park and its marine fauna has been relatively well protected. The island is famous for its elasmobranch (sharks, rays and skates) sightings in shallow waters. Here we present a catalogue of the deepwater elasmobranchs observed with the DeepSee submersible. Five species of sharks, six species of skates and one ray have been observed between 45 and 330m depth. Triaenodon obesus, the white tip reef shark, was commonly observed between 80 and 301m, but only in the afternoons. Sphyrna lewini, the scalloped hammerhead shark, was observed as deep a 303m, but commonly between 45 and 90m, and close to the island. Odontaspis ferox, the smalltooth sand tiger shark, was observed between 82 and 316m. Echinorhinus cookei, the prickly shark, was observed between 91 and 320m. Rhincodon typus, the whale shark, was observed only close to the island, between 77 and 80m. Taeniura meyeni, the marbled ray, was observed only close to the island, between 45 and 90m. A Dasyatis sp., similar to the the diamond stingray, was observed only once close to the island at 60m; this is the first report of this genus at Isla del Coco National Park. Manta birostris, the giant manta, was only observed close to the island at 90m. Mobula tarapacana, the sicklefin devil ray, was observed between 60 and 326m, extending its maximum depth almost 10 times what has been reported. Aetobatus narinari, the spotted eagle ray, was observed only close to the island between 60 and 82m. Torpedo peruana, the Peruvian torpedo ray, was observed only once at 313m, and is the first record of this species from Isla del Coco National Park.

The coral reefs, seagrasses and mangroves from the Costa Rican Caribbean coast have been monitored since 1999 using the CARICOMP protocol. Live coral cover at Meager Shoal reef bank (7 to 10m depth) at the Parque Nacional Cahuita (National Park), increased from 13.3% in 1999, to 28.2% in 2003, but decreased during the next 5 years to around 17.5%. Algal cover increased significantly since 2003 from 36.6% to 61.3% in 2008. The density of Diadema antillarum oscillated between 2 and 7ind/m 2 , while Echinometra viridis decreased significantly from 20 to 0.6ind/m 2 . Compared to other CARICOMP sites, live coral cover, fish diversity and density, and sea urchin density were low, and algal cover was intermediate. The seagrass site, also in the Parque Nacional Cahuita, is dominated by Thalassia testudinum and showed an intermediate productivity (2.7±1.15 g/m 2 /d) and biomass (822.8±391.84 g/m 2 ) compared to other CARICOMP sites. Coral reefs and seagrasses at the Parque Nacional Cahuita continue to be impacted by high sediment loads from terrestrial origin. The mangrove forest at Gandoca, within the Refugio Nacional de Vida Silvestre Gandoca-Manzanillo (National Wildlife Refuge), surrounds a lagoon and it is dominated by the red mangrove, Rhizophora mangle. Productivity and flower production peak was in July. Biomass (14kg/m 2 ) and density (9.0±0.58 trees/100m 2 ) in Gandoca were relatively low compared to other CARICOMP sites, while productivity in July in Costa Rica (4g/m 2 /d) was intermediate, similar to most CARICOMP sites. This mangrove is expanding and has low human impact thus far. Management actions should be taken to protect and preserve these important coastal ecosystems. Rev. Biol. Trop. 58 (Suppl. 3): 1-22. Epub 2010 October 01.

En este trabajo se estudian las propiedades estructurales y funcionales de hilados elaborados por dos sistemas de hilatura neumática (hilatura de zunchado neumático por torsión fugaz e hilatura por torsión real de zunchado) y se comparan con las de un hilado elaborado por hilatura convencional de anillos. Dichas propiedades se establecen mediante la determinación de los siguientes parámetros: diámetro aparente y deformación filar, regularidad másica, pilosidad, neps, torsión media aparente, tenacidad y elongación, vivacidad torsional, alargamiento por destorsiónretorsión Palabras clave: hilo, algodón, poliéster, hilatura neumática, hilatura convencional, estructura sacacorchos

A survey of the published records of marine organisms of Bahía Culebra, an enclosed embayment on the north Pacific coast of Costa Rica, is analyzed resulting in a list of 577 species representing 22 phyla. The most diverse groups documented were crustaceans, cnidarians and mollusks in order of species number. The first published record of any marine organism from the area, a polychaete, occurred in 1922, with a peak of published records of species between 1940 and 1949 and, more recently, from 2000 to the present. Several additional taxa are known from the region but there are no published records of their occurrence. This is especially evident for such groups as the free living flatworms and black corals. Additionally, several habitats, including soft bottom sediments, have not been sampled. Because of the paucity of knowledge on the biodiversity of Bahia Culebra, much more research is needed in order to evaluate and understand the effect of climate change and increasing anthropogenic activities.

Climate and subsurface sea temperature in Bahía Culebra, Costa Rica. Bahía Culebra, Golfo de Papagayo, Costa Rica is a seasonal upwelling area. To determine the relationship of climate and the subsurface temperature variability at Bahía Culebra, we analyzed nine records of sea subsurface temperature from the Bay, continuously recorded from 1998 to 2010. The analysis characterized the annual cycle and explored the influence of different climate variability sources on the subsurface sea temperature and air temperature recorded in Bahía Culebra. Data from an automatic meteorological station in the bay were studied, obtaining the annual and daily cycle for air surface temperature and wind speed. Sea surface temperature (SST) trend from 1854 to 2011 was calculated from reanalysis for the region that coverts 9-11°N, 85-87°W. Because of the positive SST trend identified in this region, results showed that annual and daily cycles in Bahía Culebra should be studied under a warming scenario since 1854, that is coherent with the global warming results and its climate variability is influenced by El Niño-Southern Oscillation (ENSO) in the Equatorial Pacific and by atmospheric forcing triggered by climate variability with Atlantic Ocean origin, because warm (cold) events in Bahía Culebra tend to occur in concordance with positive & negative (negative & positive) anomalies in Niño 3.4 (NAO) index. Rev.

The isolated Isla del Coco experiences periodic, extreme disturbances which devastate coral reefs surrounding the island. Scleractinian corals build the physical structure of the reef therefore ecosystem recovery relies on coral species recovery. Coral recruits can be of sexual or asexual origin, and the relative success of the two recruit types influences the speed and spread of recovery processes. Here we focus on the massive coral, Porites lobata , because it is the main reef-builder around Isla del Coco to describe the relative contribution of asexual and sexual recruits to population maintenance. P. lobata samples were collected using a spatially explicit random sampling design in three plots at Isla del Coco: Punta Ulloa (n=17), Bahia Weston (n=20) and Punta Maria (n=20) and samples were genotyped with 11 microsatellite markers. Additional sampling was conducted at three “coastal” sites near the Costa Rican mainland (Isla del Cano Biological Reserve): Cano1 (n=8), Cano2 (n=10)...

Bahía Culebra, Golfo de Papagayo, Costa Rica es una región de afloramiento estacional. Para determinar la relación entre el clima y la variabilidad de la temperatura sub-superficial, se analizaron los registros de la temperatura sub-superficial del mar de nueve estaciones localizadas en la Bahía. El análisis permitió caracterizar su ciclo anual y explorar su relación con fuentes de variabilidad climática que influencian el clima regional para el periodo 1998-2010. Los resultados se contextualizaron usando además los datos de una estación meteorológica automática que funcionó en la bahía junto con el registro de la temperatura superficial del mar para una rejilla que cubre la región de 9-11°N, 85-87°W, para el periodo 1854-2011. Debido a la tendencia positiva encontrada en la región para la temperatura superficial del mar, se concluye que los resultados mostrados asociados a los ciclos anuales y diarios en Bahía Culebra deben ser interpretados bajo un escenario de cambio climático, a...

Bahía Culebra, Golfo de Papagayo, Costa Rica es una región de afloramiento estacional. Para determinar la relación entre el clima y la variabilidad de la temperatura sub-superficial, se analizaron los registros de la temperatura sub-superficial del mar de nueve estaciones localizadas en la Bahía. El análisis permitió caracterizar su ciclo anual y explorar su relación con fuentes de variabilidad climática que influencian el clima regional para el periodo 1998-2010. Los resultados se contextualizaron usando además los datos de una estación meteorológica automática que funcionó en la bahía junto con el registro de la temperatura superficial del mar para una rejilla que cubre la región de 9-11°N, 85-87°W, para el periodo 1854-2011. Debido a la tendencia positiva encontrada en la región para la temperatura superficial del mar, se concluye que los resultados mostrados asociados a los ciclos anuales y diarios en Bahía Culebra deben ser interpretados bajo un escenario de cambio climático, a...

6.1.4.2 Relación de la profundidad con los factores físicos y biológicos del microhábitat…………………………………………………………………………………………..56 6.1.4.3 Relación entre la disponibilidad de sustrato, ubicación del juvenil, inclinación y las características de los sedimentos......………………………..………….……………..………….57 6.1.5 Clasificación de las especies según su ubicación en diferentes microhábitat para toda la comunidad de juveniles…………………………………………………………………………..58

In some spiders features of the webs of early instars may represent features of the ancestor's web. Some second instar spiderlings (first instar outside of the egg sac) of Tengella radiata (Kulczynski 1909) construct a small sheet web without any type of retreat. In subsequent instars, spiderlings construct webs that consist of a sheet with a small retreat that opens near its center. Webs gradually change as spiderlings growth and webs of 7 th instar spiders are indistinguishable from those of adult females. Spiders only begin to include cribellate threads in their webs during the 7 th instar. The growth of T. radiata is slow during the first three instars, but spiders' sizes increase steadily in the subsequent stages. Legs I of adult males are longer than in females, indicating an allometric growth that occurred mainly during the last molt of males.

In this paper, we describe the construction and function of the double sheet and tangle web of Tidarren sisyphoides (Walckenaer 1842). Web construction includes several stages: construction of the scaffolding that serves to support the rest of the web; filling in the dome-shaped and horizontal sheets; and construction of the upper tangle. During construction of the scaffolding, the spider descends by a pre-existing thread to the substrate, moves a few centimeters and attaches the dragline, then she ascends by the new thread, doubling the line or attaching it to another thread. The spider fills in the sheet while walking in an irregular pattern under the sheet, and attaching her dragline using either one or both legs IV simultaneously to hold pre-existing sheet lines against her spinnerets. During scaffolding construction and filling in the dome-shaped sheet, the spider returns frequently to the retreat, apparently using the same threads near the retreat each time. Threads of both the dome-shaped sheet and the horizontal sheet have small drops of viscid material. The domeshaped sheet and upper tangle comprise the functional trap of the web, while the horizontal sheet apparently plays only a little role in prey capture.

Gene flow in birds can be affected by urbanization depending on natural history traits and adaptability to habitat change. Contrasting results can be expected when comparing species with opposite resilience to urbanization. In this study, we assessed genetic diversity and structure for two bird species, the urban avoider white-eared ground-sparrow, Melozone leucotis, and the urban dweller house wren Troglodytes aedon. We used seven microsatellite loci and sampled five locations with differing levels of urbanization in Costa Rica. We found considerably higher genetic structure in whiteeared ground-sparrows than in house wrens. Circuit theory analyses proved a higher isolation from urban resistance for the white-eared ground-sparrow than for house wrens. These results support that urbanization is a significant barrier for gene flow in urban avoiders, in contrast to urban dweller species that showed little to no impact. Differences could be attributed to a higher plasticity in habitat and nesting site preferences in the house wren, and significant dispersal limitation for the white-eared ground-sparrow. These results emphasize the need for conservation strategies towards white-eared ground-sparrows and other urban avoider species whose habitat and connectivity have been reduced by the recent urban expansion.

In general, spiders that build long-lasting webs invest a larger amount of silk and consequently a larger amount of energy in their construction than those species that build ephemeral webs. It is expected that spiders that build longlasting webs choose rigid substrates for web construction to help preserve their investment. 1 experimentally tested this prediction by confining Cyrtophora citricola (Forsskal 1775) (Coddington 1989) spiders (n = 32) in containers provided with firm and unstable substrates for the spiders to construct their webs. This experiment confirms that C. citricola strongly prefers firm substrates to which to attach its web when it must choose between a firm and an unstable substrate.

Large part of the morphological diversity observed across taxa is attributed to the effect of sexual selection; and the static allometry of these structures vary largely from highly positive to negative, depending on their function, and position on the animal's body. In arthropods, information of how sexually selected contact and reaching male structures use during courtship scale on body size is scarce. We tested two complementary hypotheses: the reaching structure hypothesis and the contact‐function hypothesis, in the spider Kukulcania hibernalis. We used the length of the proximal segments of the male pedipalp to test the reaching structure hypothesis, and claw features to test the contact‐function hypothesis. Our results support both hypotheses. Small males have disproportionally longer pedipalps (highly negative allometry) than large males, increasing the probability of small‐bodied males to inseminate even large females. We also found that both distal contact and noncontac...

Gene flow in birds can be affected by urbanization depending on natural history traits and adaptability to habitat change. Contrasting results can be expected when comparing species with opposite resilience to urbanization. In this study, we assessed genetic diversity and structure for two bird species, the urban avoider white-eared ground-sparrow, Melozone leucotis, and the urban dweller house wren Troglodytes aedon. We used seven microsatellite loci and sampled five locations with differing levels of urbanization in Costa Rica. We found considerably higher genetic structure in white-eared ground-sparrows than in house wrens. Circuit theory analyses proved a higher isolation from urban resistance for the white-eared ground-sparrow than for house wrens. These results support that urbanization is a significant barrier for gene flow in urban avoiders, in contrast to urban dweller species that showed little to no impact. Differences could be attributed to a higher plasticity in habitat...

Gene flow connects populations and is necessary to sustain effective population sizes, and genetic diversity. In the Lower Central American (LCA) region, the complex topographic and climatic history have produced a wide variety of habitats resulting in high biodiversity. Phylogeographic studies of plants from this area are scarce, and to date none have been conducted on palms. We used SSR and chloroplast DNA (cpDNA) markers to study the genetic diversity and structure of populations of the understory palm Chamaedorea tepejilote in Costa Rica. We found that populations of C. tepejilote have moderate to high nuclear simple sequence repeat (SSR) genetic diversity, likely due to large population sizes and its outcrossing mating system. Habitat loss and fragmentation may have contributed to increased genetic structure within slopes. High-elevation mountain ranges appeared to be a significant barrier for gene flow among populations in the Caribbean and Pacific slopes; however, ranges are ...