bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fitness Consequences of Herbivory: Impacts on Asexual Reproduction of Tropical Rain Forest Understory Plants
Authors: Dyer Lee A. , Gentry Grant , Tobler Mark A. 
Published: March 2006

ABSTRACTAlthough herbivory can affect plant fitness, few studies have investigated the effects of herbivory on the fitness of plants that reproduce vegetatively via fragmentation. Plants that reproduce in this manner are common in tropical wet forest understories, where they are subject to damage from falling branches and other debris. For these species, the ability to reproduce via fragmentation may be affected by the extent of herbivory. In this study, we determined the effects of natural and artificial herbivory on plant fragments. The leaves of four tropical understory plant species were either damaged artificially or chosen based on the extent of existing damage. Effects of real and artificial herbivory ranged from strong to no effects depending on the plant species and biotic conditions. Insect‐damaged fragments showed stronger effects than artificially damaged fragments. Herbivory may be an important predictor of mortality in reproductive fragments of understory plants.RESUMENAunque la herviboria puede afectar el vigor de las plantas, pocos estudios han investigado sus efectos en plantas que se reproducen vegetativamente por fragmentación. En el sotobosque de la selva tropical, donde las plantas están expuestas a ramas y otras partes de los árboles que les caen encima, es comün encontrar especies que se reproducen de esta manera. En estas especies, la herviboria puede afectar la habilidad de reproducirse por fragmentación. En este estudio, se determinaron los efectos de herviboria tanto natural como artificial en fragmentos de plantas. Las hojas de cuatro especies de plantas del sotobosque tropical fueron dañadas artificialmente o escogidas según su nivel de herviboria. Los efectos, tanto en hojas con daños naturales como artificiales, variaron desde grandes efectos a inexistentes, dependiendo de la especie de planta y las condiciones bióticas. Los fragmentos que fueron dañados por insectos presentaron efectos mayores que los segmentos que fueron dañados artificialmente. La herviboria puede ser un factor importante para predecir la mortalidad de fragmentos de plantas características del sotobosque.
Seed Predation on Brazil Nuts (Bertholletia excelsa) by Macaws (Psittacidae) in Madre de Dios, Peru
Authors: Trivedi Mandar R. , Cornejo Fernando H. , Watkinson Andrew R. 
Published: March 2006

ABSTRACTWe investigated the impact of seed predation by large macaws (Ara spp.) on Brazil nut, the seed of Bertholletia excelsa (Lecythidaceae). Counts of macaw‐damaged fruit below 50 focal trees in a Peruvian Brazil nut harvesting concession indicated that macaws destroyed about 10 percent of the concession's crop. We compared this impact to other sources of variation in profits from harvesting and suggest methods to compensate harvesters while encouraging them to conserve macaws in their concessions.RESUMENSe investigó el impacto causado por guacamayos (Ara spp.) en la depredación de semillas de castaña (Bertholletia excelsa: Lecythidaceae) en un rodal castañero en el Perú. En una muestra de 50 árboles se contó el número de frutos afectados por guacamayos encontrados en el suelo, y los resultados indican que alrededor del 10 porciento de la producción total del área de aprovechamiento ha sido eliminada por acción de guacamayos. Se comparó este impacto con otras causas de variabilidad en la rentabilidad de la cosecha, presentándose recomendaciones para compensar a los castañeros por la pérdida de producción, proporcionando incentivos para la conservación de guacamayos en sus áreas de aprovechamiento.
Sex in Space: Pollination among Spatially Isolated Plants
Authors: Ghazoul Jaboury , Shaanker R. Uma 
Published: March 2006

ABSTRACTPlant distributions are changing at unprecedented rates, primarily due to habitat clearance and the spread of alien invasive species. Landscape pattern and local density can affect plant sexual processes, particularly those mediated by biotic vectors, by acting on the composition and behavior of pollinators and seed dispersers. Ecologists are now grappling with the likely effects of these altered processes on future forest composition as existing plant reproductive mutualisms break down or adjust to new spatial circumstances. Here, we introduce five papers that address pollinator responses and pollination outcomes in a variety of human‐dominated landscapes and emphasize the need to better understand the dynamic nature of plant–pollinator interactions.
Does Neighborhood Floral Display Matter? Fruit Set in Carpenter Bee‐pollinated Heterophragma quadriloculare and Beetle‐pollinated Lasiosiphon eriocephalus
Authors: Somanathan Hema , Borges Renee M. , Chakravarthy V. Srinivasa 
Published: March 2006

ABSTRACTFruit set is pollen‐limited in the self‐incompatible tree Heterophragma quadriloculare (Bignoniaceae), pollinated by long‐distance flying carpenter bees, and in the self‐compatible shrub Lasiosiphon eriocephalus (Thymdeaceae), pollinated by weak‐flying, sedentary beetles. We studied a single H. quadriloculare population over high and low flowering years and found no difference in bee visitation rates between these years. For H. quadriloculare, neighborhood floral display did not make a significant contribution to reproductive success. We investigated dense and sparse L. eriocephalus populations in the same year. In the low density L. eriocephalus population, individual floral displays were higher than in the dense population, yet reproductive success was low, indicating that plant isolation was a major factor influencing fruit set. This result was due to the extremely low number of beetles per plant and per flower in this population. In the dense L. eriocephalus population, although the displays of individual neighbors were smaller and plants were closer, neighborhood floral display did not contribute significantly to reproductive success, whereas the effect of individual floral display was ambiguous. Species with self‐incompatible rather than self‐compatible breeding systems are expected to experience neighborhood effects on reproductive success; however, at the spatial scale and floral display levels of plants in this study, only individual floral display affected fruit set in H. quadriloculare, whereas neither individual nor neighborhood display influenced fruit set in L. eriocephalus. Therefore, pollinator type, pollinator behavior, and plant and population isolation, rather than breeding system alone, will determine if neighborhood floral display affects fruit set.
Effects of Animal Pollination on Pollen Dispersal, Selfing, and Effective Population Size of Tropical Trees: A Simulation Study
Authors: Degen Bernd , Roubik David W. 
Published: March 2006

ABSTRACTAnimals, especially insects, are principal pollen vectors of tropical trees and have behavior patterns that affect gene dispersal. Here, we explore complex pollination systems using a new simulation model Eco‐Gene and considering, among other factors, flowering synchrony, spatial distribution of trees, degree of selfing, population densities, pollinator flight distances, pollen deposition, and pollinator response to floral display size. Sensitivity analyses using two contrasting tree data sets (Jacaranda copaia and Dipteryx odorata) determined the importance of each parameter on three response variables: the proportion of seeds from self‐pollination, effective population size, and pollen dispersal. Spatial considerations and attractiveness of floral displays were prominent features determining the population genetic result of pollinators, and some biological implications of the results are discussed.RESUMENAnimales, insectos en particular, son los vectores principals del polen de los arboles tropicales y como consecuencia su comportamiento afecta dispersión genética. Aquí se examina sistemas de la polinización en su totalidad, aplicando un nuevo programa de simulacro Eco‐Gene, que se toma en cuenta, entre otros factores, sincronicidad de floración, distribución de arboles, grado de auto‐fecundación, densidad poblacional, distancia de vuelo, polen deposición, respuesta comportamiental de polenizadores al tamaño del anuncio floral. Sensitivity análisis con datos contrastantes de dos arboles (Jacaranda copaia y Dipteryx odorata) evaluó la importancia de cada parametro y su resultado respeto a: la proporcion de semillas producidas por autofecundación, tamano poblacional efectivo, y distancia de dispersión del polen. Las cualidades espaciales de poblaciones, y la atractividad del anuncio floral determinaban fuertemente las consecuencias de polinizacion, y se considera implicaciones biológicas y genéticas de los resultados.
Co‐Extinctions of Tropical Butterflies and their Hostplants
Authors: Koh Lian Pin , Sodhi Navjot S. , Brook Barry W. 
Published: March 2006

ABSTRACTThe co‐extinction of interdependent species in relation to massive, long–term habitat disturbance has not been thoroughly investigated. Using logistic regression analyses, we examined the relationship between the loss of butterflies and their specific hostplants from the tropical island of Singapore and report the probable occurrence of their co–extinctions at the community level. Our simulation shows that the number of extinct butterfly species is expected to increase exponentially with that of extinct hostplants. The close association between butterflies and their hostplants suggests that the preservation of whole habitats is urgently needed if we are to avoid the possible cascading effects of species (co‐)extinctions.
Herbivory by Leaf‐cutting Ants: Nutrient Balance between Harvested and Refuse Material
Authors: Bucher Enrique H. , Marchesini Victoria , Abril Adriana 
Published: March 2006

ABSTRACTFrom an ecological standpoint, the symbiosis between leaf‐cutting ants and their fungus can be described as an herbivore feeding on plant material harvested by the ants, metabolized by the fungus, and finally removed by the ants as refuse. Here, we report on a nutrient balance (soluble and insoluble carbon and nitrogen compounds) between harvested and refuse material collected from sixAcromyrmex lundinests from a semiarid woodland in Córdoba, Argentina. The nutrient balance was calculated using cellulose as an indicator. Harvested material had low protein (10%) and high fiber content (57%). Refuse material was rich in fiber (53%), total nitrogen (2%), and ash content (28%). Balance was negative for soluble carbon and phenols. Soluble fibers, lignin, and true protein remained unchanged. Surprisingly, crude protein and all soluble nitrogen fractions had a positive balance, suggesting additional nitrogen sources besides plant material. Phenol utilization by the leaf‐cutting ant fungus suggests that phenols are not harmful to the fungus. Inability to metabolize insoluble carbon compounds and a net nitrogen gain in the refuse material were peculiar and interesting features of the ant‐fungus system.RESUMENDesde un punto de vista ecológico, la simbiosis entre las hormigas cortadoras y su hongo se comporta como un herbivoro que se alimenta de material vegetal el cual es colectado por las hormigas, metabolizado por el hongo, y finalmente eliminado por las hormigas como desecho. En este trabajo se evalúa el balance de nutrientes (compuestos de carbono y nitrógeno solubles e insolubles) entre el material colectado y el desechado en seis nidos de.Acromyrmex Lundien un bosque semiárido en Córdoba, Argentina. El balance de nutrientes fue calculado usando celulosa como indicador. El material colectado presentó bajo contenido de proteina (10%) y alto contenido de fibras (57%). El material desechado era rico en fibras (53%), nitrógeno total (2%), y cenizas (28%). El balance fue negativo para el carbono soluble y los fenoles y neutro para fibra soluble, lignina, y proteina verdadera. Sorprendentemente, la proteina cruda y todas las fracciones solubles de nitrógeno tuvieron un balance positivo, sugiriendo una fuente adicional de nitrógeno aparte del material vegetal. La utilizatión de fenoles por el hongo de la simbiosis sugiereque los fenoles no serian perjudiciales para el metabolismo del hongo. La incapacidad para metabolizar compuestos de carbono insoluble y la ganancia neta de nitrógeno en el material desechado son caracteristicas particulares e interesantes del sistema hormiga–hongo.
Does Mangrove Leaf Chemistry Help Explain Crab Herbivory Patterns?
Authors: Erickson Amy A. , Bell Susan S. , Dawes Clinton J. 
Published: March 2006

ABSTRACTWe examined feeding by the mangrove tree crabAratus pisoniiin Tampa Bay, Florida, in relation to the percent dry weight of carbohydrate, protein, phenolics, condensed tannins, ash, carbon, nitrogen, carbonmitrogen ratio, water content, and sclerophylly for leaves of the red mangroveRhizophora mangle.Comparisons of leaf chemistry were made among leaves that experienced variable levels of crab damage. BecauseR. mangleis the crab's preferred food source based on damage patterns in the field, comparisons ofR. mangleleaf chemistry were made in relation to that of the black mangroveAvicennia germinansand the white mangroveLaguncularia racemosa.We observed a negative relationship between level of leaf damage and percent dry weight of nitrogen, carbohydrates, condensed tannins, and sclerophylly. In contrast, a positive relationship was found between leaf damage and the carbon:nitrogen ratio. The chemical constituents that provided the best explanation for differences in damage among the three mangrove species include condensed tannins, nitrogen, carbon:nitrogen ratio, carbohydrates, phenolics, water content, and ash. The results from this study suggest that chemistry only partially explains food preference byA. pisonii.It appears thatA. pisoniifeeding behavior and preference may be influenced by a more complex series of factors and interactions, which may include reproduction by, predation on, and interspecific competition withA. pisonii.
Differential Wing Strength in Pierella Butterflies (Nymphalidae, Satyrinae) Supports the Deflection Hypothesis
Authors: Hill Ryan I. , Vaca Jarol F. 
Published: March 2006

ABSTRACTThe “deflection hypothesis” asserts that conspicuous marginal patches on insect wings function to deflect predator attacks toward such patches and away from more vital body parts. As a result of selection from predator attacks, these marks are predicted to increase the probability of escape by tearing relatively easily. To test if a conspicuous marginal patch is weak relative to a homologous wing area without such a patch, hindwing tear weight was compared among three Pierella species (Satyrinae) differing in the presence of a conspicuous patch in the hindwing tornus. The species with a conspicuous white hindwing patch (P. astyoche) had significantly lower tear weights than the two species lacking the patch (P. lamia and P. lena). Forewing length did not explain variation in wing‐tear weight, but wing‐tear weight was positively related to insect age in a manner consistent with the deflection hypothesis. Older individuals of P. lamia and P. lena had higher tear weight, whereas this relationship was absent in P. astyoche. These results represent the first direct evidence that deflection marks on butterfly wings are relatively weak and should have an increased tendency to tear when handled by a predator.RESUMENLa “hipótesis de desvio” propone que las conspicuas manchas marginales en alas de insectos funcionan para desviar los ataques de depredadores hacia tales manchas y lejos de partes del cuerpo más vitales. Como resultado de selección por ataques de depredadores, se predice que estas manchas deberian rompese fácilmente para aumentar la probabilidad de escape. Para probar si un mancha marginal conspicua es débil comparada con un área homóloga de alas sin tales manchas, se comparó el peso de rotura del ala posterior entre tres especies de Pierella (Satyrinae) que difieren en la presencia de un mancha visible en el tornus del ala posterior. Las alas posteriores de la especie con una mancha blanca visible (P astyoche) se rasgaron con pesos significativamente más bajos comparadas con las alas posteriores de las dos especie sin mancha (P. lamia y P. lena). La longitud del ala anterior no explicó la variación en el peso de rotura, pero el peso de rotura estuvo relacionado positivamente con la edad del insecto de una manera consistente con la hipotesis de desvio. Los individuos más viejos de P. lamia y P. lena tuvieron los pesos de rotura más altos, mientras que esta relación no se encontró en P. astyoche. Estos resultados representan la primera evidencia directa de que las manchas de desvio en alas de mariposas son relativamente débiles y deben tener una tendencia aumentada a romperse cuando son manipuladas por un depredador.
Introduced Honeybees (Apis mellifera) Reduce Pollination Success without Affecting the Floral Resource Taken by Native Pollinators
Authors: do Carmo Roselaini Mendes , Franceschinelli Edivani Villaron , da Silveira Fernando Amaral 
Published: March 2006

ABSTRACTDetrimental effects of introduced honeybees (Apis mellifera L.) on native plant pollination have been predicted based on their observed deterrence or expulsion of native pollinators or their depletion of floral resources. Here, a case is reported in which floral visitation by the introduced honeybee affects male fitness and probably fruit and seed production of a tropical tree without affecting the resource sought by the native pollinator. Clusia arrudae is a dioecious species and is pollinated by individuals of Eufriesea nigrohirta that visit its flowers to collect resin. Male flowers, however, are also visited by individuals of A. mellifera, which remove ca 99 percent of their pollen grains. When E. nigrohirta leaves flowers previously visited by A. mellifera, they carry on their bodies less than 0.1 percent of the pollen grains carried by bees leaving flowers not visited by the honeybee. This may explain why the frequency of A. mellifera at male flowers is negatively correlated with the number of seeds produced by female flowers. This novel situation may affect other plants offering alternative rewards for pollinators, such as resins, oils, and aromatic compounds.RESUMOA polinização de espécies nativas de plantas pode ser prejudicada em decorrȩncia das visitas da abelha introduzida Apis mellifera. Isto tern sido previsto com base em registros de situaç&#x006f;̧es em que esta abelha impede o acesso de polinizadores nativos ou os expulsa das flores e também pelo fato dela exaurir os recursos florais. Clusia arrudaeé polinizada por Eufriesea nigrohirta que busca resina em suas flores. Apis mellifera visita as flores masculinas de Clusia arrudae e remove cerca de 99 percento dos grãos do pólen da flor visitada. Quando E. nigrohirta visita flores já visitadas por A. mellifera, ela carrega em seu corpo menos de 0.1 percent dos grãos de pólen carregados por abelhas que visitam flores ainda não visitadas por A. mellifera. Isto pode explicar porque a freqüȩncia de A. mellifera em flores masculinas é negativa‐mente correlacionada com a quantidade de sememes produzidas por flores femininas. Esta é uma situação que ainda não havia sido registrada e que pode afetar outras plantas que oferecem recursos alternatives para o polinizador, como resinas, óleos, e compostos aromáticos.
Flower Mites of Calyptrogyne ghiesbreghtiana (Arecaceae): Evidence for Dispersal Using Pollinating Bats1
Authors: Tschapka Marco , Cunningham Saul A. 
Published: March 2006

ABSTRACTWe describe the association between a new species of flower mite (tribe Melicharini) and Neotropical flower‐visiting bats. Analogous to the well‐known hummingbird‐mite interactions, these mites appear to use bat visitors of the lowland tropical palm Calyptrogyne ghiesbreghtiana as a means of traveling to new inflorescences. Phenology data show tight coupling between the occurrence of mites on bats and flowering phenology of C. ghiesbreghtiana, suggesting that the palm is the most important host for the mites.RESUMENDescribimos la asociación entre una nueva especie de ácaro de las flores (tribu Melicharini) y murciélagos Neotropicales que visitan flores. Similar a la interacción bien conocida entre colibries y ácaros, aparentemente estos ácaros utilizan a los murciélagos que visitan las inflorescencias de la palma Calyptrogyne ghiesbreghtiana como medio de transporte hacia nuevas inflorescencias. Datos de fenologia indican una fuerte asociacion entre los registros de los ácaros en los murciélagos y la fenologia floral de C. ghiesbreghtiana, sugierendo que la palma es el hospedero más importante para los ácaros.
Population Dynamics of a Resident Colony ofLeptonycteris curasoae(Chiroptera: Phyllostomidae) in Central México
Authors: Galindo G. Cristobal , Sánchez Q. Adalinda , Quijano Ramón H. , Herrera M. L. Gerardo 
Published: March 2006

ABSTRACTWe studied the population dynamics of the lesser long–nosed batLeptonycteris curasoaein a cave in central Mexico for a two‐year time. The population had substantial seasonal changes in size and composition during this time. Colony size was largest from February to July (22,000–27,000 adults) and contained equal numbers of males and females. In June and July, males had enlarged testes and presumably mated with females. In August, the population size began to decline and was mostly composed of pregnant females. Between September and December, the colony was composed exclusively of pregnant and lactating females and their young, and population size decreased to about one–third of the observed maximum size. In January, adult males returned to the roost and the population size increased. We also observed an increase in body mass and fat accumulation in both sexes, apparently related to reproductive activity. This is the first report of the continuous presence of a substantial female population ofL. curasoaethroughout the year in a single roost in Mexican tropics, indicating that some populations ofL curasoaein central Mexico complete their life cycle without having to migrate.RESUMENSe estudió la dinámica poblacional del murciélago nectarivoroLeptonycteris curasoaeen una cueva localizada en el centro de México durante dos años. La población presentó cambios sustanciales en su tamaño y composición durante este periodo. El tamaño más grande de la población se registró entre febrero y julio (22,000–27,000 individuos) con una proporción similar de hembras y machos. En junio y Julio los testfculos de los machos crecieron y aparentemente se aparearon con las hembras. En agosto, la población empezó a disminuir y se encontraron casi exclusivamente hembras preñadaz. Entre septiembre y diciembre, la colonia estuvo compuesta exclusãvamente de hembras preñadaz o lactantes y de sus cri'as. La población disminuyó en este periodo hasta equivaler a una tercera pane del tamaño máximo registrado en el año. En enero, la población empezo a crecer de nuevo con la incorporación de machos adultos. Durante el ano, en ambos sexos se observaron también cambios en la masa corporal y en la acumulación de grasa aparentemente relacionados con la actividad reproductiva. Este es el primer estudio que reporta la presencia continua de hembras en una colonia deL. curasoaeen la misma cueva durante todo el ano para el centro de México. Nuestros resultados indican que esta población no es migratoria a diferencia de otras poblaciones de esta especie.
Predation‐mediated Mortality of Early Life Stages: A Field Experiment with Nymphs of an Herbivorous Stick Insect (Metriophasma diocles)
Authors: Berger Jürgen R. , Wirth Rainer 
Published: March 2006

ABSTRACTWe quantified predation pressure on first instar nymphs of a stick insect in predator‐exclusion experiments in the forest of Barro Colorado Island, Panamá. After considering intrinsic mortality (19%) and potential emigration (negligible), we estimated that 54 percent of the nymphs died due to predation in a two‐week period. Predation on nymphs was highest at night and may explain the low abundance of Metriophasma diodes in the understory.