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Life Science - Ecology |
Cintrón Berdecía, Sol Taína; Tremblay, Raymond. Ciencias Naturales Departamento de Biología, UPR Humacao.
Phenothypic selection on morphological charactheristics through female and male fitness in seven population in an epiphytic orchid.
Twelve floral characters are used to evaluate the strengh of phenotypic selection in an epiphytic orchid. Selection on floral chracters may be expressed through male (pollinaria removal) or female fitness (fruit set). We monitored seven populations of the orchid Lepanthes rupestris Stimson along river basins in the Caribbean National Forest “El Yunque” for 19 months. We measured the floral characters of one flower per plant with a dissecting microscope with an integrated micrometer. We estimated the fitness as the total number of fruits produced and number of pollinia removed. Simple linear and quadratic regression were used to evaluate the strenght of directional, uniform and stabilizing selections. These techniques estimated the total strength of the selection acting on a character through univariate analysis. The results are inconsintent among character and population and few of the characters appear to be under selection. This may suggest that different conditions and the relative success of the individuals depend on the population in which it resides.
Colón Carrión, Duamed; Fuentes Rivera, Francisco A.; Montero, Lesbia L.; Parrilla Hernández, Deborah. Departamento de Biología, UPR-Humacao.
Análisis preliminar del efecto inhibidor de la mucosa secretada en los nidos por la tortuga marina Eretmochelys imbricata
El saqueo ilegal de nidos de la tortuga marina Eretmochelys imbricata (carey de concha) en las playas de Humacao, ha obligado a utilizar la relocalización de nidos como una medida de conservación y manejo para la especie. Se ha encontrado, que los nidos relocalizados bajo las mismas condiciones del lugar donde la tortuga deshovó originalmente, son afectados por un sobrecrecimiento de raíces en la cámara de huevos del nido. Por otro lado, los nidos que no son relocalizados no son afectados por el sobrecrecimiento de las raíces. Proponemos que lo que impide el crecimiento de las raíces es la acción de algún factor químico, el cual se pierde al transportar y relocalizar los huevos. Al momento del desove los huevos están cubiertos por una mucosa espesa la cual hemos recolectado y analizado. Se han hecho pruebas preliminares de solubilidad de la sustancia y cultivos de la bacteria E. coli, los cuales demuestran un efecto inhibitorio de crecimiento por parte de la mucosa. Se realizarán análisis de los componentes químicos de la mucosa, con el propósito de determinar si existe alguna relación entre éstos y la inhibición del crecimiento de raíces en los nidos.
Cortes Baez, Carla M. Department of Biology, University of Puerto Rico - Sustache, Jose, Department of Natural Resources and Environment, Fish and Wildlife Office - Melendez, Elvia. Institute for Tropical Ecosystem Studies, University of Puerto Rico, Rio Piedras - Aragón, Susan; Morales, Mariely. Department of Biology, University of Puerto Rico, Rio Piedras - Fernández, Denny S. Department of Biology, University of Puerto Rico, Humacao.
Characterization of the plant diet of introduced goats in Mona Island Reserve
Feral goats, are one of the most common and impending threats to the biodiversity of island biotas around the world and are listed among the 100 most damaging introduced species in the world. Introduction of these animals to Mona Island, a dry forest Reserve located between the islands of Puerto Rico and Hispaniola occurred 500 years ago by Spanish settlers. While some data suggests that these animals may regulate some plant communities in the island (Cintrón, 1991), a detailed characterization of the diet of these animals is lacking. Current management of populations of these animals include a four month hunting season coordinated by the Department of Natural Resources and the Environment (DNRE) of the Commonwealth of Puerto Rico. We used this management strategy as an opportunity to directly characterize the plant species that make up the diet of these animals. This information can help to identify those species that might be most susceptible to herbivory by these animals. A preliminary study was conducted to determine the diet of these animals. A total of 87 stomach contents was collected and analized. Of the 431 species identified in Mona Island a total of 92 species of plants were found to be eaten by the feral goats. Most of the species found were woody and there was a higher frequency of herbaceus and vines. Among the highest species found in the diets we identified the endemic orquid of Mona (Pshychilis monensis) and the endengared specie Harrisia portoricensis. Galactia dubia, Centrocema virginianum, Capparis flexuosa and Capparis cynophallophora were also very common in the diets. No relationship was found between the sex and stage of maturity of animals and the composition of the diet in the animals. We did find an association between the plant composition and the type of plants (tree, shrub, vine, herb) in the stomachs of goats and the month the stomach was collected suggesting temporal changes in the diet of these animals.
Cubero, Miguel; Gonzalez, Jose A; Arocho, Alberto; Cabreras, Marilyn; Cortes, Omayra; Jimenez, Liza. Natural Sciences Department, UPR-Aguadilla.
Evaluación de la resistencia al insecticida órgano fosforado “Malathion” en poblaciones naturales del mosquito Aedes aegypti
El mosquito Aedes aegypti, vector del virus del dengue, se originó en África distribuyéndose y adaptándose a las regiones tropicales y sub-tropicales del mundo. Desde el 1960 en Puerto Rico se ha utilizado el insecticida órgano fosforado “Malathion” con el propósito de controlar la población de A. aegypti. Esta continua exposición puede reducir la susceptibilidad del mosquito hacia el insecticida. La resistencia de las larvas y pupas del A. aegypti a los insecticidas “Malathion” y “Sevin” fue evaluada en el presente estudio. Estas fueron colectadas en diferentes pueblos de la zona centro y oeste de Puerto Rico. Luego de ser colectadas, las larvas y pupas se expusieron a diferentes concentraciones de los insecticidas, y sus niveles de esterasas y acetilcolinesterasa fueron determinados.
Disla Boné, Geysa; Bruck, David L.; Mojica, José M. Biologia, Universidad de Puerto Rico Recinto de Río Piedras.
El largo del periodo de copulación para la población Santa Cruz y la de Tortola del complejo dunni
Hace algunos años este laboratorio está trabajando con la población del subgrupo dunni, que incluye la subespecie Drosophila dunni dunni de Puerto Rico (PR), la cual tiene el periodo más largo de copulación del género entero de Drosophila. Hemos concentrado los estudios de este proyecto en las poblaciones del subgrupo las cuales habitan Santa Cruz (SC), y Tortola (TO), donde las dos producen híbridos normales con Drosophila dunni dunni en el laboratorio. Como parte de nuestra investigación, comparamos el largo del periodo de copulación de las poblaciones de SC y TO con las de PR, St. Thomas, y Vieques. Hemos hechos varias pruebas estadísticas, las cuales indicaron ninguna diferencia significativa entre los largos de copulación de SC y TO, pero si encontramos diferencias entre ellas y algunas otras poblaciones del subgrupo, y discutimos el significado de lo que se encontró.
Figueroa-Rodríguez, Edwin; Asencio, Carmen. General Sciences, PUCPR.
Reproductive biology of Zamia pumila
Zamia pumila L. is one of the five species of cycads in Puerto Rico. It grows in the southern karst area. There is a population of 250 plants growing in an open calcareous hill, 435m over sea level, threatened by many quarries in the zone. The plants were monitored for two years to determine the phenology of the leaves production and of the male and female cones. The leaves are produced during January to March. Cones production starts on November. Male cones last almost five months and female cones 1.6 years at least. It is important to know the reproduction cycle of Zamia pumila in order to implement conservation procedures in the area.
Hernández García, Pablo J.; Ackerman, James D. Department of Biology, University of Puerto Rico. Rio Piedras.
A naturalized tropical orchid in Puerto Rico behaves as a nativ
Arundina graminifolia, an orchid native to tropical Asia, has been introduced to many parts of the tropics and has become naturalized and even weedy in some regions. In Puerto Rico it occupies disturbed habitats, its tall, bamboo-like shoots rising above the tall grasses. Short inflorescences arise from the apices of the stems and produce large, colorful flowers over long periods. Populations generally have flowers throughout the year. We studied a montane population over a 24-month period and asked whether or not 1) pollination was pollinator-dependent, 2) plant height was related to fruit production, and 3) flowering phenology was synchronized with pollinator activity. We found that Arundina graminifolia was self-compatible; experimental cross- and self-pollinations produced similar fruit and seed set. Unlike many invasive species, A. graminifolia is dependent on pollinators for sexual reproduction. Unvisited flowers failed to produce fruit. Pollinators were Centris haemorrhoidalis (Apidae) but visitations were rare as expected given the rewardless flowers. Plant height was highly variable, ranging from 0.8 to 3 m. Similar to other pollination systems were height has been important, we detect a relationship between height and either male or female reproductive success. Peak flowering was from August to December, and peak pollinator activity, as measured by pollinarium removals and fruits set, occurred at the same time. Thus, the breeding system of A. graminifolia and its phenological relationships with pollinators in Puerto Rico are similar to what we expect of native species.
Longo, Ana; Burrowes, Patricia; Joglar, Rafael. Biology, UPR-RP.
Study of the effect of drought on the dispersion pattern of rainforest Eleutherodactylus (Amphibia, Anura)
Populations of amphibians are declining around the world, particularly at high elevations. Puerto Rico is no exception to this rule. Of the many suspected causes of amphibian declines around the world, we have focused on climate change and disease. We found chytrid fungi (a pathogen associated to amphibian declines world-wide) in three species at El Yunque as early as 1976, and in present populations. Analysis of weather data suggest a significant warming trend and an association between years with extended periods of drought and the decline of amphibians in Puerto Rico (Burrowes, et al., accepted). We suspect a synergistic interaction between drought and the pathological effect of the chytrid fungus. The purpose of this investigation is to test the hypothesis that rainforest Eleutherodactylus (coquí frogs) that become stressed because of lack of rain, will tend to change their dispersion pattern from random to clumped. To test this hypothesize we designed a controlled experiment with six terraria in which refugia, food, light and temperature remain constant. The only variable is the amount of water received. We hypothesize that at times of drought frogs will clump in humid patches where the fungus is more likely to occur. As a consequence, there is a situation of frogs that are immunologically deprived in an area where the fungus is potentially abundant, thus, generating an epidemic that may result in declines. Results of this work are crucial to our understanding of the ecological interactions among the coquíes and the pathogen that can kill them.
Miranda, Emmanuel. Informatics Department, Inter American University, Bayamón Campus - Canales, Rafael. Natural Sciences and Mathematics Department, Inter American University, Bayamón Campus.
Computer code to simulate bat movements and its role in the formation of roosting assemblages
Mechanisms that underlie the coexistence of species are a subject of great interest in ecology. By reducing the chance of immigration from source habitats, islands such as those in the archipelago of the West Indies can provide better models than continents for examining community structuring and species coexistence. Eighty percent of the bat fauna of Puerto Rico (over 40% for the entire archipelago) consists of cave-dwelling species. Many of these cave-dwelling species roost in hot-caves, where they form non-random assemblages and may function as physical ecosystem engineers. It has been proposed that the size of the opening of caves with multi-species assemblages influences the composition and density of these assemblages. It is the objective of this project to test that hypothesis. The question of coexistence in caves will be approached through the development of a flow model of the activity of five species of bats that form non-random multispecies assemblages. The code was created using “VisualBasic.Net” and, based on a species size and speed, calculates the amount of time needed to exit caves as a function of the size of the entrance. Based on these analyses it will be possible to assess the role of the dimensions of the cave opening in limiting the number of bats. The results may offer an insight into the mechanisms underlying community structuring of Antillean bats. This final objective is achieved by simulating a grid that causes a reduction in the number of bats that can exit the cave per unit time.
Morales, Liliana; Rodríguez, Carlos Andrés; Burrowes, Patricia A. Biology, UPR-RP.
The seamless biology classroom: an integration of lab and lecture in Zoology instruction.
Teaching science by inquiry, hands-on activities and experimentation has proven to be an effective tool to promote learning with the excitement of discovery. This research’s goal is to improve learning of biology concepts and process skills through the integration of laboratory and lecture in the Zoology course at the UPR-RP. By designing and implementing new instructional materials for the integration of lab and lecture in Zoology we expect to help students understand the correlation between theory and research, enhance conceptual understanding, develop laboratory skills, and increase their motivation towards learning biology. The effect of the reformed course on improving (1) academic achievement (2) conceptual understanding, (3) laboratory process skills, (4) scientific writing, and (5) attitude towards biology will be assessed by different means. To measure changes in attitude towards biology we translated, adapted and validated the vastly recognized “Assessing attitude towards Biology test” (Sundberg, 1997). A concept-based test was developed, to measure improvement in conceptual understanding. To determine changes through-out the semester in student performance on laboratory experiments, report-writing, adequate use of equipment and exams, we will conduct time series analyses of the grades obtained. Although we do not have conclusive results at this point, students in the pilot section appear highly motivated and have improved their academic performance with respect to traditional instruction.
Olmedo-Álvarez, Carlos R.; Vélez-Villamil, Sylvia M. Biología, UPR-Humacao.
Estudio de la reproducción y sus estructuras en Galaxaura rugosa (Nemaliales, Rhodophyta)
Galaxaura rugosa (J. Ellis & Solander) J.V. Lamouroux es un alga roja perteneciente al orden de las Nemaliales, Rhodophyta, que habita en aguas tropicales y puede ser encontrada adherida a rocas y corales. Esta alga tiene ramas cilíndricas con ramificación dicótoma irregular y deposita carbonato de calcio. La identificación de fases en la historia de vida de un alga puede ayudar a contestar interrogantes con respecto a su taxonomía y de G. rugosa, al igual que de otras especies de su género se desconoce su historia de vida. Se colectaron especímenes de G. rugosa y se colocaron segmentos del talo en cultivo, en condiciones de luz máximas de 135 µ mol photons m-2s-1 en largo de día de 12:12 a una temperatura de 23-25 C. En 24 horas liberaron esporas que se desarrollaron en filamentos uniseriados, mayormente postrados. En 11 semanas se comenzaron a observar estructuras multicelulares erectas similares a los gametofitos de G. rugosa. Ni en los filamentos uniseriados ni de las estructuras multicelulares se ha podido identificar estructuras reproductoras. De las algas colectadas se realizaron estudios anatómicos lográndose identificar estructuras reproductoras tanto femenina como masculina.
Ortiz, Marcos; Deynes Roldán, Loida; Rivera Mercado, Enid; Gonzalez Cortes, Giseily; Lee Borges, Jesus. Natural Science Department, UPR Aguadilla.
Comparacion en la concentracion de clorofila-a en los rios que desembocan en la Bahia de Mayagüez (Añasco, Yagüez y Guanajibo)
El fitoplancton es un organismo unicelular fotosintatico encontrado en todo cuerpo de agua. Este es importante por ser la base de la red tráfica y jugar un papel importante en el ciclo de carbono. Esta investigación tuvo como propósito medir y comparar concentraciones de clorofila-a (chl-a) en los ríos Yagüez, Añasco y Guanajibo. Parámetros como nitrato, amonia y pH entre otros, fueron tomados mediante el uso del LaMotte Walter Monitoring Kit, mientras que la salinidad y chl-a fueron tomados con equipos como YSI y flourometro respectivamente. Se observo una reducción en la salinidad en todas las muestras obtenidas, debido a la alta precipitación y descarga de los ríos en esta temporada de lluvia. Por otra parte los valores mas altos de chl-a fueron encontrados en el río Añasco son s muestran una aparente relación entre nutriementos, luz y capacidad adaptativa del fitoplancton.
Perez, Ileana; De Jesus, Wilnelia; Porras, Andrea; Bayman, Paul. Biology, UPR Rio Piedras.
Growth and survival of Dendrobium sp. (Orchidaceae) with different mycorhizal fungi
Mycorrhizae are a symbiotic relationship between plant roots and fungi. They probably enhance the fitness of most plants species. Orchids present special cases with these mycorrhizal associations, in which the seeds will not germinate in nature without the fungus. The orchid mycorrhizal fungi are highly evolved organisms capable of extensive extraction of elemental nutrients from organic substrates. These mycorrhizal associations in orchids are restricted to fungi of the Rhizoctonia genera. The study of orchid mycorrhizae could have important applications in horticulture and conservation. Using these symbiotic techniques has helped in the propagation of many species, some of which are endangered. In this study, we explored the effect that these symbiotic relationships have on a hybrid orchid (Dendrobium sp.). Sterile plants previously grown in vitro were inoculated with four different Rhizoctonia strains: Tulasnella, Thanatephorus and two strains of Ceratobasidium. The growth of the orchids was evaluated four weeks after the inoculation. Three of the fungi showed a significant negative effect on plant survival, compared to controls. Only one of the fungi studied did not cause visible harm to the plant. Because it will be necessary to continue further studies to confirm these results, this study can be regarded as preliminary.
Rentas-Soto, Yolanda. General Sciences, P.U.C.P.R - Vázquez-Rivera, Lilliana. Biology, P.U.C.P.R.
Butterflies of the Southern Karst, Juana Díaz, Puerto Rico
During the months of September and October 2003, and January 2004 a census of lepidopters was made in the Sothern Karst region in Juana Díaz, P.R. to determine which butterfly dominated the area. These insects were captured, mounted and classified. Four hundred and thirty seven specimens of different families were identified. The results of the investigation showed that the genus Eurema (Fam. Pieridae) is the most abundant butterfly in the area. The Southern Karst in Juana Díaz, P.R. is the habitat of a great diversity of plants and animals in which the butterfly population is enormous and diverse. This area is impacted by three big quarries. If the quarries expand, this butterfly fauna is going to be in peril.
Rivera Diaz, Luis G.; Sosa Roman, Verenesse. Departamento de Biologia, UPR Mayagüez Campus.
El efecto de Beauveria bassiana en larvas de mosquitos y en Bromelina guzmania
Los hongos entomopatógenos son microorganismos utilizados como agentes de control biológico en la propagación de la población de insectos que pueden ser considerados plagas como las hormigas y los mosquitos. El hongo Beauveria bassiana limitó el crecimiento de larvas de mosquitos. Existe una gran diversidad de reservorios naturales de agua, entre ellos la planta de bromelia (Bromelina guzmania) que posee una taza central que comúnmente sirve para depósito de huevos de mosquitos. La misma fue utilizada con el fin de conocer el efecto del hongo en la morfología de la planta, dado el interés de esta investigación es el biocontrol de larvas sin afectar este reservorio natural. Se realizaron cuatro replicas de un tratamiento de 40ml de suspensión de esporas, el cual se aplicó a grupos de 20, 40 y 60 denominados Beauveria respectivamente. Estos grupos se inocularon con una suspensión de esporas de Beauveria bassiana a una concentración de 106 esporas por ml. Además se inoculó una planta de bromelia con un tratamiento de 10 ml de dicha suspensión, la cual fue aplicada en la taza central y en las raíces de la planta con una pipeta Pasteur. En las observaciones de la planta por 14 días, cambios morfológicos como cambios de color y la caída de algunas hojas no fueron cambios significativos debido a que tanto en la planta control como en la experimental surgieron los mismos cambios. En conclusión que no sólo agentes químicos pueden ser utilizados como larvicidas, si no que en la naturaleza contamos con agentes microbianos que nos pueden ayudar en el control de las diferentes plagas de insectos. B. bassiana es uno de estos agentes que son comúnmente utilizado con este fin y este experimento demuestra que puede ser muy efectivo contra las larvas de insectos.
Rodriguez, Eillen; Ricart, Carlos. Biology Department, University of Puerto Rico at Cayey.
Sugar concentration in the petioles of two populations of Heliconia caribaea in the Central Mountains of Puerto Rico.
Heliconia caribaea is a native plant species of Puerto Rico. There are aproximately 250 species within the genus Heliconia in the Neotropics. Heliconia are an important food resource for animals that also act as their pollinators (i.g, keystone species concept). In addition, Heliconias are also very important ornamental plants and thereby represent a lucrative industry for some people. Thus, populations of Heliconia caribaea were studied in two different sites in the highlands of Puerto Rico (a water basin near Aguas Buenas and a high elevation site in the Carite Forest). We measure and compare the sucrose concentration present in the leave petiole tissue of H. caribaea between the two sites. Stems of some plants are green and photosynthetic. The stems of Heliconia plants serve as carbohydrate storage when the plant is not producing flowers. Prior to flower production the plant seems to allocate sugars in the phloem tissue. The mean sucrose concentration in the petioles was measure for two populations (ƒÝAguas Buenas = 1.89; ƒÝCarite= 2.07). The results show more variation in sucrose concentration within the Heliconia clones in the Carite Forest population. However there is no significant difference in the mean sucrose concentration present in Heliconia petioles between the two sites (tvalue=-1.262,d.f. = 38, pvalue = 0.215, ƒÑ = 0.05, n1=20, n2=20). Nevertheless, the sucrose concentration detected in the Aguas Buenas population is higher than the Carite population. Probably Heliconia plants at the Carite site receive higher levels of solar radiation since they are highly exposed in the forest edge.
Rodriguez, Saul; Mangual, Vyrmar; Blanco, Juan F. Departamento de Biologia, UPR RP - Ramirez, Alonso. Instituto para Ecosistemas Tropicales, UPR RP.
Jerarquías competitivas y emigración en caracoles de río (Neritina virginea) en Puerto Rico
Durante la época de lluvias, en algunos ríos de Puerto Rico ocurren migraciones masivas de juveniles de caracoles Neritina virginea (Neritidae) que se cree son causadas por la disminución de alimento (algas bénticas) durante las crecientes, y por monopolio de los parchos remanentes por parte de los adultos. En este estudio planteamos las siguientes preguntas: 1) se distribuyen los adultos en mejores parchos que los juveniles?, 2) existen diferencias de tamaño de área de actividad entre juveniles y adultos?, 3) qué comportamientos presentan los individuos cuando interactúan con otros? 4) es la emigración una respuesta a la presencia de adultos y a la abundancia del alimento? Observaciones de campo realizadas en la parte baja del río Mameyes, cerca de la carretera PR-3 entre septiembre y noviembre de 2003, mostraron que no existen diferencias en la microdistribución espacial entre adultos y juveniles, pero que los adultos tienen una mayor área de actividad que la de los juveniles. También encontramos que “chocarse y alejarse” es el comportamiento más común (46 %) independiente del tamaño de los caracoles. El segundo comportamiento más común (28%) en los adultos es “empujar” a los juveniles, mientras que en los juveniles es “seguir” a otros individuos (25%). En un experimento de laboratorio de libre elección de parchos con o sin algas, se encontró que los juveniles tienen una tasa de emigración de 30% en presencia de competidores adultos, aun con niveles altos de algas. En ausencia de algas la tasa de emigración de juveniles aumenta (40%).
Simpson Hernandez, Jason J.; Maldonado Ramirez, Sandra L. Biology Department, UPR Mayagüez.
Nueva evidencia sobre la presencia de hongos endofitos en Thalassia testudinum
Thalassia testudinum es una planta marina que crece abundantemente en zonas del litoral costero. En el ecosistema marino, esta planta provee alimento y refugio a diversos organismos. Mediante la realización de cortes de tejido, pudimos recuperar hongos endofitos de hojas y raíces de T. testudinum. Especies de los géneros Aspergillus, Acremonium (Cephalosporium ) y Penicillium fueron recuperadas consistentemente en los 6 muestreos realizados. La data obtenida parece indicar que la presencia de hongos endofitos no depende del estado fisiológico de la hoja.
Soto, Manuel; Rodríguez, Armando. Natural Sciences Department, Inter American University, Bayamón Campus.
Relative density and diversity of bats in urban and suburban areas
In this study we examined four sites within the urban/suburban area of the San Juan Metropolitan Region, Puerto Rico, the West Indies. At each one of these sites we established a monitoring station using ANABAT, and the area was surveyed from sunset through midnight during the months of June and July. Each site was sampled a total of eight nights. We identified six of the 13 species of bats present on the island in all five families. The synanthropic species Molossus molossus accounted for most of the records. Built-up areas in the outskirts of the city do not show higher activity than inner city. Vegetation cover and, possibly, proximity of roosting areas may be more important in determining diversity.
Torres-Sánchez, David; Castrodad, Felix - Departamento de Biología, UPR-Humacao.
Aspectos ecológicos de tres especies de caracoles terrestres (Caracolus caracola Linnaeus, Caracolus marginella Gmelin, Polydontes lima Ferussac) en un bosque secundario urbano
Existen varias especies de caracoles terrestres con una distribución amplia en todo Puerto Rico. En el sureste de la isla, las especies de caracoles terrestres Caracolus caracola, Caracolus marginella y Polydontes lima se pueden encontrar habitando los bosques secundarios cercanos a lugares urbanos. Se estudió la abundancia, distribución espacial y mortalidad en las tres especies para determinar detalles de su biología en este hábitat. Otros factores como tamaño, comportamiento y preferencias de establecimiento fueron estudiados para conocer hábitos comunes de estos gastrópodos. La información obtenida de estas poblaciones de caracoles se comparó con las poblaciones encontradas en bosques primarios para determinar si las condiciones particulares de los bosques secundarios influyen en su ecología.