Biología

URI permanente para esta colección

https://hdl.handle.net/10669/273

Examinar

Mostrando 1 - 11 de 11

Behavioural responses of reptiles to visitors of protected areas in Costa Rica
(2016) Barquero Arroyo, Marco David; Chávez Zapata, Jensy; Cerdas, Andreína
Tourists can have a strong impact on the behaviour of wild animals, modifying foraging strategies, diet and habitat use, increasing stress, and altering communication and escaping behaviour. Such behavioural changes have been documented for several taxa, although less commonly studied in reptiles.
Búsqueda y caracterización de proteínas biopesticidas novedosas a partir de cepas de Bacillus thuringiensis
(1999) Arrieta Castro, Glen; Rodríguez Sánchez, César; Víquez, A.; Murillo, L.; Mora Castro, Rebeca; Jiménez Ulate, Franklin; Espinoza Esquivel, Ana Mercedes
En la actualidad se desarrollan y se cultivan comercialmente plantas transgénicas que expresan endotoxinas de Bacillus thuringiensis (Bt) como biopesticida para el control específico de insectos. Sin embargo, se teme que el uso extensivo de plantas transgénicas puede conllevar al surgimiento de biotipos de insectos resistentes a las endotoxina de Bt. De ahí la necesidad de explorar nuevas fuentes de genes bacterianos de efecto tóxico en insectos. Una opción es la búsqueda de toxinas muy activas a bajas concentraciones, secretadas durante las fase vegetativa de crecimiento (VIPS), que tienen efecto sobre especies no susceptibles a las delta endotoxinas. Otra alternativa es la búsqueda de endotoxinas con diferente especificidad en cepas de Bt aisladas en ambientes tropicales. Actualmente se realiza la prospección de cepas de Bt en diferentes zonas geográficas de Costa Rica. Se realizaron aislamientos en diversos microambientes de los ecosistemas más representativos del país, con el fin de establecer un perfil de abundancia relativa de los diferentes tipos de proteínas biopesticidas según zonas geográficas. Se está caracterizando las nuevas cepas de Bt mediante ultraestructura, pruebas bioquímicas, composición proteica de los cristales y PCR. En una segunda fase se evaluará la actividad biológica de las toxinas utilizando especies de insectos y nematodos que son plagas importantes en hortalizas y granos. Actualmente se realiza el análisis molecular de 200 aislamientos de Bt provenientes de diversas zonas productoras de hortalizas de la Cordillera Volcánica Central, aisladas a partir de crucíferas cultivadas y silvestres, además de contar con alrededor de 500 muestras de suelo, hojarasca y follaje colectadas a partir de bosques seco, lluvioso, nuboso, así como de bosques transicionales, que están en proceso de aislamiento y caracterización.
Composition and species richness of the herpetofauna of a Costa Rican University campus
(2019) Barquero Arroyo, Marco David; Chaves Sánchez, Alexander; Soto Ugalde, Yordy; Salas Naranjo, Juan Carlos
The campus of the University of Costa Rica in Limón port city, Costa Rica, known as Sede del Caribe (SC), includes a secondary forest of ca. 40 years old. This forest holds a great potential for environmental education, research, and recreation, although no reliable information on the species present is available. The forest is rarely visited and neither students or staff of SC know the biodiversity of the area.
Effect of temperature on the visual displays of the Jacky dragon
(2019) Barquero Arroyo, Marco David; Peters, Richard; Whiting, Martin J.
In ectotherms such as lizards, temperature is a key determinant of their behavior and their ability to signal to conspecifics. We asked whether changes in the thermal environment along the distribution of an agamid lizard, the Jacky dragon (Amphibolurus muricatus), modifies visual signal properties (frequency and duration). We first collected temperature data from 12 weather stations to understand variation in temperature across the species’ range. We then collected field body temperatures (Tb) for three populations before measuring preferred body temperatures (Tpref) in the lab. Finally, we examined the role of temperature on the frequency and duration of display behavior at low (28 °C) and high (35 °C) temperatures consistent with what individuals experience in the wild. We found differences of 5.6-9.4 °C in mean air temperature across sites of the species’ range. Field body temperatures, but not preferred body temperatures (overall average = 32.4 °C), differed among populations, with individuals from one population attaining higher temperatures than the other two. We also found a positive relationship between air temperature and the number of displays used during intraspecific communication, as well as differences in the number of displays during high- and low-temperature treatments (more displays during the high-temperature treatment). We suggest that social signaling is plastic and able to respond to local conditions such that variation of body temperatures mirrors that of the thermal environment and in turn, influences the frequency and duration of Jacky dragon visual signals. Display behavior is therefore dependent on environmental temperature and future changes to the thermal environment could have an impact on communication through its effect on display duration and frequency
Estado actual del conocimiento sobre el perfil genético de la población de Costa Rica
(2003-10) Morera Brenes, Bernal
The population of Costa Rica has been considered historically as the product of the amalgamation of three ethnic groups: Europeans, Africans and Amerindians. In addition, it has been said that this population is highly inbred, mainly in the central regions of the country. In order to analyze these aspects of historical origin and the constitution of Costa Rica population, we have been conducting a series of studies that aim to unravel the genetic structure of that population. The results show that the Costa Rican population is certainly trihybrid, similar to those of other countries in Latin America, but differing from them in the proportions of gene flow from the ancestral populations. We found that while some specific regions inside the Central Valley maintain a high average inbreeding coefficient, the general trend towards a temporary decline over time. The percentage of inbreeding (alpha) remains high, but in general is not correlated positively with the alpha value. That suggest the existence of moderate emigrations and more unions between couples with the same geographical origin, but not consanguineous unions.
Mycorhizal diversity of epiphytic orchids in a hyperdiverse tropical forest: insights on temporal and life stage changes
(2018) Fernández Campos, Melania; Taylor, Donald Lee; Taylor, Andrew D.; Sharma, Jyotsna
Few studies have examined the diversity of fungal communities of epiphytic orchids from hyperdiverse tropical forests and its temporal dynamics. This study aims to describe the fungal diversity associated with three tropical, epiphytic orchid species from a Costa Rican hyperdiverse forest across a three year-period at the juvenile and adult stages, by applying standard Sanger sequencing methods.
Near-neighbor tropical epiphytic orchids keep distinct mycorrhizal communities across their distribution in Costa Rica
(2022) Fernández Campos, Melania; Cedeño Fonseca, Marco Vinicio; Sharma, Jyotsna
Environmental and biotic axes act in combination to define the ecological niches of plant species. Two species with shared physical space are expected to compete for access to water and nutrients. In hyper-diverse areas like tropical forests, competition is expected to be extreme, and theory predicts that coexistence is only possible through specialization. In this study, two congeneric, epiphytic orchid species that colonize the same habitats and frequently live in close proximity (< 10 cm) across their distribution were chosen to test whether competition is reduced through orchid mycorrhizal fungi (OMF) specialization. The study was conducted in Costa Rica at 5 disparate locations where the two orchids, Masdevallia nidifica and M. chontalensis, co-occur to 1) assess niche partitioning through differences in OMF composition between the two species, and 2) analyze the OMF community composition of each species across elevation and forest types. We identified that the study species hosted significantly distinct communities of OMF when occurring alone and when in close proximity. Differences were partly driven by unique Serendipitaceae and Ceratobasidiaceae OTUs colonizing each orchid host. We also show that, with few exceptions, the two orchids maintain their non-overlapping and species-specific mycorrhizal associations across an elevation gradient and across forest types.
Proceedings of the ICSEM10 Costa Rica
(2020-02-28) Rojas Alvarado, Carlos Alonso
Este documento corresponde con la memoria completa del X Congreso Internacional sobre Sistemática y Ecología de Mixomicetes (ICSEM10) celebrado en la Sede del Atlántico de la Universidad de Costa Rica entre el 25 y el 28 de febrero de 2020. El documento responde al proyecto 570-B9-7B4 de la Finca Experimental Interdisciplinaria de Modelos Agroecológicos con sede en Turrialba.
Reproductive biology of Phragmipedium longifolium and floral anatomy associated with pollinator attraction in the genus
(2019-09) Díaz Morales, Melissa; Fernández Campos, Melania; Pupulin, Franco; Blanco Coto, Mario Alberto; Sandoval Zapotitla, Estela; Benavides Acevedo, Miguel Francisco
Phragmipedium is a genus with 21 species restricted to the tropics and subtropics from Central and South America. As it is a genus capable of producing seeds from both self- and cross-pollinated flowers, it is an ideal group to investigate the components of its reproductive success. In this research some of those components are described in P. longifolium as well as anatomical floral structures possibly related to the attraction of pollinators. To study the reproductive system in P. longifolium, manual self- and cross-pollinations were carried out, and seed viability was measured by tetrazolium staining. No significant differences in fruit production between self- and cross-pollinated flowers were found. Higher seed viability was found in the self-pollinated flowers, which indicates that this species is frequently self-pollinated. Sections of the petals of P. humboldtii, P. longifolium, and P. warzewiczianum were stained with toluidine blue in order to identify and characterize anatomical structures possibly involved in the attraction of pollinators. Three kinds of glandular trichomes were observed on the petals of all three species, which are possibly involved in the secretion of fragrances to attract pollinators.
Sexual size dimorphism and ecomorphology of the Berthold’s bush anole (Polychrus gutturosus) in Costa Rica: Preliminary data
(2019) Arguedas Porras, Viviana; Barquero Arroyo, Marco David; Arguedas Porras, Randall; Ovares Campos, Lizbeth; Vargas Leitón, Rodolfo
Sexual size dimorphism (SSD) is the result of sexual or natural selection operating differently on the body sizes of females and males. Males of most lizard species are larger than females, suggesting intrasexual selection on male’s body size to be more aggressive or territorial. However, some species exhibit female-biased SSD, suggesting that selection operates on female fecundity.
Signal repertoire and contest outcome in the Jacky dragon
(2016) Barquero Arroyo, Marco David; Whiting, ‪Martin J.
Establishing dominance is an important mechanism for determining access to resources such as mates or territories. However, levels of aggression and dominance may vary among populations based on history and variation in individual traits. Here, we use an agamid lizard from Australia, the Jacky dragon (Amphibolurus muricatus), to quantify variation in traits predicting contest outcome among males of different populations.

Examinar

Examinando Biología por Tipo "contribución de congreso"

Resultados por página

Opciones de ordenación