bluuebunny/crossref_metadata_2025 huggingface dataset:
Temporal and Spatial Diversity and Distribution of Arboreal Carabidae (Coleoptera) in a Western Amazonian Rain Forest1
Authors: Lucky Andrea , Erwin Terry L. , Witman Jon D.
Published: March 2006

Diversity of arboreal carabid beetles was sampled by fumigation in 100 3 × 3 m stations within a 100 × 1000 m terra firme forest plot in Ecuadorian Amazonia. Nine sampling dates from January 1994 to October 1996 yielded 2329 individuals belonging to 318 species of which more than 50 percent were undescribed species. A high percentage of the species sampled were rare; the proportion that occurred once per sampling date (singletons) ranged from 50.0 to 62.5 percent. Estimates of species richness were from 82 to 282 species of arboreal carabids in the study plot on a given sampling date. Most richness values were greater than 173 species. Species accumulation curves attained asymptotes for all but one sampling date, indicating that an adequate level of sampling effort was used to characterize the diversity of carabid fauna. Total accumulation curves based on pooled data failed to reach asymptotes. There was a high turnover in species composition between sampling dates; less than 50 percent of the species between the majority of sampling dates were shared, suggesting that the total species pool may be extremely large. Although species composition changed seasonally, species richness varied little. Spatial autocorrelation analysis revealed that the structure of this species assemblage was significantly patterned at distances below 280 m. Taken together, the large percentage of undescribed species, die failure of the overall species accumulation curves to level off, and the high turnover in species composition indicate that the species diversity of carabid beetles is far higher than previously thought.
Flower Visitation by Bats in Cloud Forests of Western Ecuador1
Authors: Muchhala Nathan , Jarrin ‐V. Pablo
Published: March 2006

The importance of bat pollination has been demonstrated for many plant species. Yet this mutualism has rarely been studied on a community–wide level. In this paper we present results of a yearlong study of a bat–flower community in cloud forests on the western slopes of the Ecuadoran Andes. Of eight plant–visiting bat species caught, only Anoura caudifera and A. geoffroyi were carrying pollen. These species of Anoura supplement their diets with insects. Unlike glossophagines in other environments, however, which switch completely to a frugivorous or insectivorous diet during certain seasons, they are nectarivorous year–round and were never found with seeds or fruit pulp in their feces. Of the 13 morphotypes of pollen carried by the bats, 11 were identified to genus and 7 to species. Floral characteristics of all of these plants fit the traditional chiropterophilous syndrome well. Our study represents the first direct evidence of bat pollination for those plants identified to species, including four species of Burmeistera (Campanulaceae), as well as the first record of bat pollination for a plant of the genus Meriania (Melastomataceae). While overlap in the diets of the two Anoura was high, significant differences in visitation frequencies to particular plant species were detected. The larger bat species (A. geoffroyi) preferred large flowers, whereas the smaller species (A. caudifera) preferred small flowers.
Host Specialization among Wood‐Decay Polypore Fungi in a Caribbean Mangrove Forest1
Authors: Gilbert Gregory S. , Sousa Wayne P.
Published: March 2006

Host specialization in highly diverse tropical forests may be limited by the low local abundance of suitable hosts. To address whether or not fungi in a low‐diversity tropical forest were released from this restriction, fruiting bodies of polypore basidiomycete fungi were collected from three species of mangroves (Avicennia germinans, Laguncularia racemosa, and Rhizophora mangle) in a Caribbean mangrove forest in Panama. Unlike other tropical forests, the polypore assemblage in this mangrove forest was strongly dominated by a few host‐specialized species. Three fungal species, each with strong preference for a different mangrove host species, comprised 88 percent of all fungi collected.
Abundance and Diversity of Euglossine Bees in the Fragmented Landscape of the Brazilian Atlantic Forest1
Authors: Tonhasca Athayde , Blackmer Jacquelyn L. , Albuquerque Gilberto S.
Published: March 2006

Male euglossine bees were sampled with chemical baits every two months from September 1997 to July 1999 at nine sites in the Desengano mountain range, Rio de Janeiro State, Brazil. Four sites were located in Atlantic Forest mature second growth, two sites in disturbed forest, and three sites in forest fragments of 200, 156, and 14 ha, respectively. We collected 3653 male euglossine bees from at least 21 species. Analyses of variance indicated no differences among the three habitat types for total number of bees, and 5 of the 6 dominant species. Bootstrapping indicated significant variation in species richness and diversity for some sites, but there was no clear indication of differences among habitats. Similarity as measured with the Morisita–Horn index was inversely related to distance between sites, but relatively high for most site combinations. These results suggest that the euglossine bee community in the three habitats was essentially the same. Although some species were associated with each habitat type, most appeared to respond to temporal local conditions. Our results do not support the hypothesis that forest fragmentation or habitat alteration reduces abundance and diversity of euglossine bees.
Insect Pollination in the Cycad Genus Bowenia Hook, ex Hook. f. (Stangeriaceae)1
Authors: Wilson Gary W.
Published: March 2006

All confirmed records of entomophilic pollination in cycads are for species in the Zamiaceae. This paper presents details of entomophily in both species of Bowenia in the Stangeriaceae. Seed set in female cones from which wind and water‐borne pollen, but not insects, was excluded, indicates that pollination is obligately entomophilous. The pollination vectors are Miltotranes weevils and the relationships are species‐specific and possibly coevolutionary.
Mutualistic Association between a Tiny Amazonian Stingless Bee and a Wax‐Producing Scale Insect1
Authors: Camargo Joao M. F. , Pedro Silvia R. M.
Published: March 2006

The Amazonian stingless bee Schwarzula sp. houses and attends, in its nest, soft scale insects, Cryptostigma sp. (Coc‐cidae), from which obtains sweet secretions (honeydew) for their feeding and additional wax to build their nests. The bees nests in tunnels burrowed by moth larvae in branches of Campsiandra angustifolia, Caesalpiniaceae.
Low Density of Ant Lion Larva (Myrmeleon crudelis) in Ant‐Acacia Clearings: High Predation Risk or Inadequate Substrate?1
Authors: Gatti Maria Genoveva , Farji‐Brener Alejandro G.
Published: March 2006

We experimentally determined whether the low density of antlion larvae found in ant‐acacia clearings is due to high levels of ant predation or an inadequate substrate for pit‐trap construction. Pit establishment was more affected by soil improvement than by the exclusion of ants, suggesting that soil condition is the main factor that affect antlions’density. The low density of this ant‐predator in ant‐acacia clearings may be considered as an indirect advantage of the ant's pruning behavior.
Massive Seed Predation of Pseudobombax grandiflorum (Bombacaceae) by Parakeets Brotogeris versicolurus (Psittacidae) in a Forest Fragment in Brazil1
Authors: Francisco Mercival Roberto , de Oliveira Lunardi Vltor , Galetti Mauro
Published: March 2006

Here we report massive seed predation of Pseudobombax grandiflorum (Bombacaceae) by Botogeris versicolurus (Psittacidae) in a forest fragment in Brazil. The intensity of seed predation was very high when compared to other studies in continuous forest, perhaps resulting from a scarcity of resources in such areas. This scarcity may limit the range of parrot's diet to a few plant species. It suggests that studies of Psittacidae seed predation may be important for conservation of some plants in fragments.
Labile Phosphorus in Soils of Forest Fallows and Primary Forest in the Bragantina Region, Brazil
Authors: Frizano Jacqueline , Vann David R. , Johnson Arthur H. , Johnson Christine M. , Vieira Ima C. G. , Zarin Daniel J.
Published: March 2006

We used the Hedley sequential extraction procedure to measure nine different organic inorganic soil phosphorus fractions in forest soil of the Bragantina region of Para, Brazil. We compared the labile fractions (resin‐extractable P + HCO3‐extractable inorganic and organic P) in Oxisols from three secondary forests (10, 20, and 40 years old) and a primary forest. These stands were located in an area that has supported shifting agriculture for approximately a century. After agricultural use, total P and labile P in soils of young secondary forests are diminished compared to the amounts presents in the primary forest soil. Within each stand, organic carbon content was a good predictor of labile organic and inorganic P, consistent with the large body of research indicating that mineralization of organic matter is important to plant nutrition in tropical ecosystems. During the reorganization of P pools during forest development, the pool of labile organic P (HCO3‐extractable) diminishes more than the other labile fractions, suggesting that it is directly or indirectly an important source of P for the regrowing forest vegetation. Across the four age classes of forest, the soil reservoir of labile P was equal to or greater than the total amount of P in the vegetation. If labile P measured by this method adequately represents P available to plants in the short term (as suggested by the current consensus), we would conclude that plant‐available P is reasonable abundant, and that the effects of agriculture on available P pools are detectable but not sufficient to compromise forest regrowth in this area.
Galling Insects (Diptera: Cecidomyiidae) Survive Inundation during Host Plant Flooding in Central Amazonia
Authors: Guerra Betsabé R. , Zuanon Jansen , Venticinque Eduardo M.
Published: March 2006

The effect of host plant inundation on survivorship of Symmeria paniculatas galling herbivores was investigated in Central Amazonian floodplain forest. The majority of submerged galls were alive (62% of morphospecies 1 and 70% of morphospecies 2). Survivorship was similar between submerged leaves and new leaves that were never submerged. Some submerged galls were eaten by fish. To the best of our knowledge, this is the first report of galling insect survivorship under severe flooding.

O efeito da inundação da planta hospedeira na sobrevivȩncia dos herbívoros galhadores de Symmeria paniculata foi investigado numa floresta inundável da Amazo̧nia Central. A maioria dos insetos galhadores submersos estava viva (62% para morfoespécie 1 e 70% para morfoespécie 2). A sobrevivéncia foi semelhante entre folhas submersas e folhas que nunca foram submersas. Algumas galhas submersas foram predadas por peixe. Este e o primeiro estudo que relata sobrevivȩncia de insetos galhadores à rigorosa inundação.
Tropical Bees (Trigona hockingsi) Show No Preference for Nectar with Amino Acids
Authors: Gardener Mark C. , Rowe Richard J. , Gillman Michael P.
Published: March 2006

We offered Australian tropical stingless bees (Trigona hockingsi) artificial nectar (30% sucrose w/v) either with or without added amino acids (3.30 mM). Bees showed no preference for nectar type, suggesting that sugars, rather than amino acids, play a greater role in nectar choice by this species.
Benthic Community Structure and Invertebrate Drift in a Pacific Island Stream, Kosrae, Micronesia1
Authors: March James G. , Benstead Jonathan P. , Pringle Catherine M. , Luckymis Marston
Published: March 2006

Tropical Pacific island streams have poorly understood communities that deserve scientific attention. We examined benthic macroinvertebrates and fishes of the Inem River on Kosrae, Federated States of Micronesia. Larval chironomids, lepidopterans, odonates, and freshwater shrimps dominated the benthos and drift. Diel periodicity in drift was not evident. Nine fishes, two shrimps, and one snail species were identified. Kosrae's stream fauna appears even more depauperate than other Pacific high islands, possible due to its extreme isolation.
Size and Structure of Fine Root Systems in Old‐growth and Secondary Tropical Montane Forests (Costa Rica)
Authors: Hertel Dietrich , Leuschner Christoph , Hölscher Dirk
Published: March 2006

The fine root systems of three tropical montane forests differing in age and history were investigated in the Cordillera Talamanca, Costa Rica. We analyzed abundance, vertical distribution, and morphology of fine roots in an early successional forest (10–15 years old, ESF), a mid‐successional forest (40 years old, MSP), and a nearby undisturbed old‐growth forest (OGF), and related the root data to soil morphological and chemical parameters. The OGF stand contained a 19 cm deep organic layer on the forest floor (i.e., 530 mol C/m2), which was two and five times thicker than that of the MSF (10 cm) and ESF stands (4 cm), respectively. There was a corresponding decrease in fine root biomass in this horizon from 1128 g dry matter/m2 in the old‐growth forest to 337 (MSF) and 31 g/m2 (ESF) in the secondary forests, although the stands had similar leaf areas. The organic layer was a preferred substrate for fine root growth in the old‐growth forest as indicated by more than four times higher fine root densities (root mass per soil volume) than in the mineral topsoil (0–10 cm); in the two secondary forests, root densities in the organic layer were equal to or lower than in the mineral soil. Specific fine root surface areas and specific root tip abundance (tips per unit root dry mass) were significantly greater in the roots of the ESF than the MSF and OGF stands. Most roots of the ESF trees (8 abundant species) were infected by VA mycorrhizal fungi; ectomycorrhizal species (Quercus copeyemis and Q. costaricensis) were dominant in the MSF and OGF stands. Replacement of tropical montane oak forest by secondary forest in Costa Rica has resulted in (1) a large reduction of tree fine root biomass; (2) a substantial decrease in depth of the organic layer (and thus in preferred rooting space); and (3) a great loss of soil carbon and nutrients. Whether old–growth Quercus forests maintain a very high fine root biomass because their ectomycorrhizal rootlets are less effective in nutrient absorption than those of VA mycorrhizal secondary forests, or if their nutrient demand is much higher than that of secondary forests (despite a similar leaf area and leaf mass production), remains unclear.
Ant Protection against Herbivory in Three Species of Tococa (Melastomataceae) Occupying Different Environments1
Authors: Michelangeli Fabian A.
Published: March 2006

The genus Tococa is comprised of 47 species of small trees and shrubs distributed from southern Mexico to Bolivia. About 30 of the species have ant domatia that develop at the base of the leaf blade or at the apex of the petiole. Ant exclusion experiments on three different species of Tococa occupying different environments were carried out to assess their effect in protecting the plant against herbivores. Additionally, ant behavior was monitored in control plants to study how they might be conferring protection against herbivory. Herbivory was significantly lower on control plants (ants maintained) than on experimental plants (ants removed), demonstrating the role of the ants as defenses against herbivores. Herbivory rates in open and disturbed areas were higher than in the forest understory. Ant exclusion experiments showed that both timid and aggressive ants protect their host plants against potential herbivores by killing or warding off scouts of leaf‐cutter ants (Atta sp.) and removing the eggs of Lepidoptera and Coleoptera from the surface of the plants.

El género Tococa esta compuesto por 47 especies de arbustos y árboles pequeños distribuidos desde el sur de México hasta Bolivia. Cerca de 30 especies poseen domacios que se desarrollan en la base de la lámina de la hoja o en el ápice del pecíolo. Se llevaron a cabo experimentos de exclusión de hormigas en tres especies de Tococa en distintos hábitat con el fin de evaluar su rol potencial de protectión contra la herbivoría. Adicionalmente, se observó el comportamiento de las hormigas en las plantas del grupo control con el fin de estudiar su papel como defensa contra los herbívoros. Las diferencias en las tasas de herbivoría entre plantas con y sin hormigas fue siempre significativa, demostrando así el rol de las hormigas como defensa contra los herbívoros. Además, en las zonas abiertas y secundarias, la cantidad de herbivoría fue siempre mayor que en el dosel del bosque. Estos experimentos también demuestran que tanto las hormigas tímidas como las agresivas protegen a las plantas que habitan, ya sea matando o ahuyentando los exploradores de las hormigas cortadoras de hoja (Atta sp.) o removiendo los huevos de Lepidoptera y Coleoptera de la superficie de las plantas.
Macroecology of Aquatic Insects: A Quantitative Analysis of Taxonomic Richness and Composition in the Andes Mountains of Northern Ecuador
Authors: Sites Robert W. , Willig Michael R. , Linit Marc J.
Published: March 2006

To determine the spatial dynamics of Neotropical lotic insect species, specimens were collected from 41 streams on the eastern and western flanks of the Andes Mountains in Ecuador. We examined the manner in which taxonomic richness and composition differed with elevation, latitude, and versant. Statistical analyses were limited to 5 families (Ephemeroptera: Baetidae, Leptohyphidae, Oligoneuriidae; Heteroptera: Naucoridae; Coleoptera: Elmidae), comprising 32 genera and 85 species, for which identifications or morphospecies assignments were reliable. Assessment of taxonomic diversity was based on the richness of genera and species at each site. In addition, each site was characterized by species richness within each of 4 families with more than 10 species. The effects of versant and transect on composition and structure were family‐specific. Mean site differences between versants in elmid richness at generic and specific levels depended on transect. Only baetid richness was affected by versant and transect in a consistent manner. Variation among sites in composition based on all genera and species was captured using multidimensional scaling (MDS). Subsequent MANOVAs based on scores from MDS axes revealed that differences between versants were much stronger in the southern transect, although transects differed from each other at specific and generic levels. A Jaccard's similarity matrix was computed for each family to reflect the spatial organization of taxonomic composition. Mesogeographic patterns of species composition for each of the four families were correlated (Mantel analysis) at both the regional level and at the level of the entire study area. At the regional level, the only pair of families to exhibit correlated patterns of species composition was elmids and naucorids in the southwestern region. The pattern of species composition for each family was correlated with the patterns for one or more other families at the level of the entire study area. Thus, spatial dynamics of species composition was similar for the families examined, suggesting that the Andes exert a consistent influence on species distributions within families, regardless of ordinal affiliation. At a local scale, however, the way in which taxonomic composition changed with latitude and versant was family‐specific. Mayflies, the most vagile of the taxa studied, had the highest percentage of species overlap between versants. Of three genera of Naucoridae collected, species of Ambrysus, of probable Mexican origin, were found only on the eastern versant, corroborating other evidence that the genus is recent in South America. Moreover, dispersion by Ambrysus across the Andes Mountains may not have occurred, as it has for Cryphocricos and Limnocoris, which are of probable South American origin.
Florivory by the Crab Armases angustipes (Grapsidae) Influences Hummingbird Visits to Aechmea pectinata (Bromeliaceae)1
Authors: Canela Maria Bernadete F. , Sazima Marlies
Published: March 2006

Armases angustipes (Grapsidae) crabs were recorded on 31.5 percent of Aechmea pectinata inflorescences, a common ornithofilous bromeliad in rain forests of southeastern Brazil. Crabs foraged mainly in the morning and used newly opened flowers, usually damaging the corolla, consuming the stamens and stigma, and interfering with hummingbird visits. This florivory may reduce the reproductive success of A. pectinata, both directly through consumption of flowers and indirectly by reducing pollinator visits.
Effects of Land Crabs on Leaf Litter Distributions and Accumulations in a Mainland Tropical Rain Forest1
Authors: Sherman Peter M.
Published: March 2006

The effect of the fossorial land crabGecarcinus quadratus(Gecarcinidae) on patterns of accumulation and distribution of leaf litter was studied for two years in the coastal primary forests of Costa Rica's Corcovado National Park. Within this mainland forest,G, quadratusachieve densities up to 6 crabs/m2in populations extending along the Park's Pacific coastline and inland forca600 m. Crabs selectively forage for fallen leaf litter and relocate what they collect to burrow chambers that extend from 15 to 150 cm deep (N= 44), averaging (±SE) 48.9 ± 3.0 cm. Preference trials suggested that leaf choice by crabs may be species‐specific. Excavated crab burrows revealed maximum leaf collections of 11.75 g dry mass– 2.5 times more leaf litter than collected by square‐meter leaf fall traps over several seven‐day sampling periods. Additionally, experimental crab exclosures (25 m2) were established using a repeated measures randomized block design to test for changes in leaf litter as a function of reduced crab density. Exclosures accumulated significantly more (5.6 ± 3.9 times) leaf litter than did control treatments during the wet, but not the dry, seasons over this two‐year study. Such extensive litter relocation by land crabs may affect profiles of soil organic carbon, rooting, and seedling distributions.
A Method to Determine the Minimum Number of Litter Traps in Litterfall Studies1
Authors: Finotti Ricardo , Freitas Simone Rodrigues , Cerqueira Rui , Vieira Marcus Vinícius
Published: March 2006

Litterfall was collected in a 0.64 ha area for three months, using 25 litter traps. Resampling methods were used to calculate the total litterfall mass grand mean and coefficient ofvariation (CV) for each month using different numbers of litter traps (2–25). Based on the variation of those two statistics, it was possible to determine the minimum number of litter traps necessary to achieve accuracy (variation in grand mean) and precision (magnitude of CV)
Impact of Cotyledon and Leaf Removal on Seedling Survival in Three Tree Species with Contrasting Cotyledon Functions1
Authors: Kitajima Kaoru
Published: March 2006

The relative importance of cotyledons and leaves for seedling survival was evaluated using a factorial field experiment on three neotropical tree species with contrasting cotyledon functional morphologies (photosynthetic, epigeal reserve vs. hypogeal reserve). In all species, cotyledon and leaf removal shortly after leaf expansion had additive negative effects on seedling survival over 7 weeks. Carbon supplies from cotyledons and other carbohydrate reserves apparently enhanced ability of seedlings to cope with herbivory and disease.
Pleistocene Plant Fossils in and near La Selva Biological Station, Costa Rica1
Authors: Horn Sally P. , Sanford Robert L. , Dilcher David , Lott Terry A. , Renne Paul R. , Wiemann Michael C. , Cozadd Duane , Vargas Orlando
Published: March 2006

Radiocarbon dating and 40Ar/39Ar analysis of overlying tephra indicate that plant fossil assemblages exposed by stream erosion and well construction in and near La Selva Biological Station in eastern lowland Costa Rica are Pleistocene in age. We identified plant taxa based on wood, leaves, fruits, seeds, pollen, and spores examined from three sites at ca 30 m elevation. Extrapolating from modern ranges and surface temperature lapse rates suggests paleotemperatures 2.5–3.1°C cooler than at present
Impact of Atta colombica Colonies on Understory Vegetation and Light Availability in a Neotropical Forest1
Authors: Hull‐Sanders Helen M. , Howard Jerome J.
Published: March 2006

We quantified patterns of vegetation removal and light availability above Atta colombica nests on Barro Colorado Island, Panama. Ants cleared vegetation less than 1 cm in diameter from an area of 77 m2, and up to 3 m above ground level. Overall light availability 1.5 m above ground level was 49 percent greater at ant nest sites than at sites in undisturbed understory. These higher light levels fell within the range known to enhance growth of both shade tolerant and pioneer species.
Changes in Forest Structure and Species Composition during Secondary Forest Succession in the Bolivian Amazon1
Authors: Peña‐Claros Marielos
Published: March 2006

Changes in forest structure and species diversity throughout secondary succession were studied using a chronosequence at two sites in the Bolivian Amazon. Secondary forests ranging in age from 2 to 40 years as well as mature forests were included, making a total of 14 stands. Fifty plants per forest layer (understory, subcanopy, and canopy) were sampled using the transect of variable area technique. Mean and maximum height, total stem density, basal area, and species number were calculated at the stand level. Species diversity was calculated for each stand and for each combination of forest layer and stand. A correspondence analysis was performed, and the relationship between relative abundance of the species and stand age was modeled using a set of hierarchical models. Canopy height and basal area increased with stand age, indicating that secondary forests rapidly attain a forest structure similar in many respects to mature forests. A total of 250 species were recorded of which ca 50 percent made up 87 percent of the sampled individuals. Species diversity increased with stand age and varied among the forest layers, with the lowest diversity in the canopy. The results of the correspondence analysis indicated that species composition varies with stand age, forest layer, and site. The species composition of mature forests recovered at different rates in the different forest layers, being the slowest in the canopy layer. Species showed different patterns of abundance in relation to stand age, supporting the current model of succession.
Consequences of Habitat Fragmentation on Age Structure and Life History in a Tortoise Population1
Authors: Aponte César , Barreto Guillermo R. , Terborgh John
Published: March 2006

We studied changes in a population of red‐footed Amazonian tortoises, Geochelone carbonaria, consequent to isolation in an insular forest fragment. Altered age structure, population density, and body growth rate are shown here for the first time to be associated responses. Age structure was strongly biased toward juveniles and growth rates were reduced compared to the mainland. Our data suggest that density‐dependent processes induced by habitat fragmentation changed demography and life history parameters in a scant 16 years.
Gregarious Oviposition and Clutch Size Adjustment by a Heliconius Butterfly1
Authors: Reed Robert D.
Published: March 2006

Female Heliconius hewitsoni butterflies were found to aggregate during oviposition, producing multi‐parent egg clutches. This behavior occurred when host plants were locally plentiful, indicating that females chose to oviposit gregariously. Collective clutch size correlated with host growth rate and with the number of females contributing to a clutch. Eggs did not positively bias host plant growth. Collective clutch size adjustment may represent a mechanism for facilitating larval aggregation while reducing intraspecific competition.
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

Although 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.

Aunque 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

We 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.

Se 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

Plant 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

Fruit 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

Animals, 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.

Animales, 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

The 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

From 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.

Desde 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

We 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

The “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.

La “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

Detrimental 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.

A 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 situaço̧es 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.