bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

ABSTRACTMale 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

ABSTRACTAll 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

ABSTRACTThe 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

ABSTRACTWe 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

ABSTRACTHere 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

ABSTRACTWe 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

ABSTRACTThe 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.RESUMOO efeito da inundação da planta hospedeira na sobrevivȩncia dos herbívoros galhadores de Symmeria paniculata foi investigado numa floresta inundável da Amaz&#x006f;̧nia 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

ABSTRACTWe 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

ABSTRACTTropical 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

ABSTRACTThe 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

ABSTRACTThe 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.RESUMENEl 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

ABSTRACTTo 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

ABSTRACT 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

ABSTRACTThe 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

ABSTRACTLitterfall 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

ABSTRACTThe 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

ABSTRACTRadiocarbon 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

ABSTRACTWe 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

ABSTRACTChanges 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

ABSTRACTWe 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

ABSTRACTFemale 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.