Desmopsisterriflora, an extraordinary new species of Annonaceae with flagelliflory

Flagelliflory refers to the production of inflorescences exclusively on long, whip-like branches which emerge from the main trunk and extend along the ground or below it. It is the rarest type of cauliflory and only a few cases have been reported in the world. Here, a new species of Annonaceae with flagelliflory is described and illustrated. The phylogenetic relationships of the new species were inferred using a hybrid-capture phylogenomic approach and we present some notes on its reproductive ecology and pollen characteristics. The new species, namely Desmopsisterriflorasp. nov., is part of a clade composed of Mexican species of Stenanona with long, awned petals. Desmopsisterriflora is distinguished by its flageliflorous inflorescences, basely fused sepals, thick red petals, reduced number of ovules per carpel, pollen grains with a weakly rugulate to fossulate exine ornamentation, and its globose, apiculate fruits with a woody testa. The morphological characteristics of the flagella suggest that these are specialized branches rather than inflorescences, and the absence of ramiflory implies an exclusively reproductive function. The flowers are infrequently visited by insects, their potential pollinators being flies and ants.

Host plant richness and environment in tropical forest transformation systems shape arbuscular mycorrhizal fungal richness

Transformation of tropical lowland rain forests into rubber tree and oil palm plantations is the cause of massive loss of vegetation diversity. The consequences for associated mycorrhizal fungi are not fully understood. We hypothesized that generalist arbuscular mycorrhizal fungi are resistant to removal of host species richness and that forest conversion to oil palm and rubber leads to loss of arbuscular mycorrhizal fungal (AMF) species with host preferences. Plant identities and AMF species were determined by molecular barcoding of 112 roots collected in three land-use systems (rain forest, rubber tree and oil palm plantation) in two landscapes on Sumatra (Indonesia), a world hotspot of forest transformation. The collected roots were from 43 forest plant species, in addition to rubber trees and oil palms. We detected 28 AMF species of which about 75% were present in forest trees and 25% shared among the land use systems. Only one AMF species present in plantation roots was not detected in the analyzed forest roots. Host specificity of arbuscular mycorrhizal fungi was not detected. Oil palm and rubber tree roots exhibited a strong reduction in AMF richness compared with roots from rainforests and were differentiated by soil resources. On basis of an individual root, oil palm had a lower AMF species richness than forest or rubber tree roots. Our results demonstrate that tropical AMF communities are shaped by two mechanisms: (i) root habitat diversity as the result of plant diversity and (ii) habitat properties as the result of plant traits or environmental conditions and management. Collectively, deterioration of habitat diversity and properties exacerbates impoverishment of AMF assemblages.

DNA Barcoding Reveals Generalization and Host Overlap in Hummingbird Flower Mites: Implications for the Mating Rendezvous Hypothesis

AbstractHummingbird flower mites are assumed to monopolize single host plant species owing to sexual selection for unique mating rendezvous sites. We tested the main assumption of the mating rendezvous hypothesis-extreme host specialization-by reconstructing interactions among tropical hummingbird flower mites and their host plants using DNA barcoding and taxonomic identifications. We collected 10,654 mites from 489 flowers. We extracted DNA from 1,928 mite specimens and amplified the cytochrome c oxidase I (CO1) DNA barcode. We analyzed the network structure to assess the degree of generalization or specialization of mites to their host plants. We recorded 18 species of hummingbird flower mites from three genera (Proctolaelaps, Rhinoseius, and Tropicoseius) interacting with 14 species of plants. We found that generalist mites are common, and congeneric mite species often share host plants. Our results challenge the assumption of strict specialization that supports this system as an example of mating rendezvous evolution.

Revison of Metaplagia Coquillett (Diptera: Tachinidae) with description of five new species from Area de Conservación Guanacaste in northwestern Costa Rica

Background

We revise the genus Metaplagia Coquillett, 1895 and describe five new species from Area de Conservación Guanacaste (ACG) in northwestern Costa Rica. All new species were reared from an ongoing inventory of wild-caught caterpillars spanning a variety of species within the family Sphingidae (Lepidoptera: Sphingidae). Our study provides a concise description of each new species using morphology, life history, molecular data and photographic documentation. In addition to the new species, the authors provide a re-description of the genus and a revised key to the species of Metaplagia.

New information

The following five new species of Metaplagia are described: Metaplagialeahdennisae Fleming & Wood sp. n., Metaplagialindarobinsonae Fleming & Wood sp. n., Metaplagiapaulinesaribasae Fleming & Wood sp. n., Metaplagiarobinsherwoodae Fleming & Wood sp. n. and Metaplagiasvetlanakozikae Fleming & Wood sp. n.

The following is proposed by Fleming & Wood as new combination of Plagiomima Brauer & Bergenstamm, 1891: Plagiomimalatifrons (Reinhard, 1956) comb. n.

Land snails and slugs of Bau limestone hills, Sarawak (Malaysia, Borneo), with the descriptions of 13 new species

This study presents a list of land snails and slugs found on limestone hills in the District of Bau, the state of Sarawak in Malaysian Borneo. Systematic and random sampling for land snails was conducted at eight limestone outcrops, namely, Gunung Stulang, Padang Pan, Gunung Kapor, Gunung Lobang Angin, Gunung Doya, Gunung Batu, Bukit Sekunyit and Gunung Sebayat. A total of 122 land snail species was documented with photographs of each species. Of the 122 species collected, 13 are new to science, namely, Acmellabauensissp. nov., Japoniabauensissp. nov., Plectostomamargaretchanaesp. nov., Microcystinaarabiisp. nov., Microcystinaatonisp. nov., Microcystinapariparisp. nov., Microcystinaliratasp. nov., Microcystinaoswaldbrakenisp. nov., Microcystinakilatsp. nov., Philalankajambusanensissp. nov., Everettiamicrorhytidasp. nov., Everettiaminutasp. nov., and Paralaomasarawakensissp. nov.

Biodiversity and Spatiotemporal Variation of Longhorn Beetles (Coleoptera: Cerambycidae) in Tropical Forest of Thailand

Simple Summary

Longhorn beetles are a large family of beetles and have a wide-geographic distribution. Some of them are pests of many economic plants and invasive species. They also play roles in decomposition and nutrient cycling in forest ecosystems. They feed on living, dying, or dead woody plants in the larval stage. So far, 308 species of longhorn beetles have been reported from northern Thailand. However, the biodiversity and distribution of longhorn beetles in different elevation gradients and seasons, associated with environmental factors across six regions in the country, has not yet been investigated. In this study, longhorn beetle specimens were collected by malaise trap from 41 localities in 24 national parks across six regions in Thailand. A total of 199 morphospecies were identified from 1376 specimens. Seasonal species richness and abundance of longhorn beetles peaked during the hot and early rainy season in five regions, except for the southern region, which peaked in the rainy season. Our finding revealed that most species’ distribution was correlated with the region and forest type (at middle and low elevations). Quantitative data from this study can be useful to manage agricultural and forest plantations.

Abstract

Longhorn beetles are highly diversified and important for agriculture and health of the environment. However, the fauna and ecology of these beetles are not well known in Thailand. This study is the first to report the biodiversity, elevation, and seasonal distribution of longhorn beetles. Specimens were collected by malaise traps from 41 localities in 24 national parks throughout the country during 2006–2009. The traps were operated at each site for 12 consecutive months with a monthly service. A total of 199 morphotaxa in 36 tribes of 6 subfamilies were identified from 1376 specimens. Of these, 40.7% and 14.5% of total taxa were singletons and doubletons, respectively. The Shannon diversity index and observed species richness at Panernthung, Loei Forest Unit and Mae Fang Hotspring were high at 0.96 (30), 0.88 (50), and 0.86 (34), respectively. Local richness ranged between 3 and 50 species, while the species richness estimator showed between 6 and 1275 species. The most relatively abundant species, Nupserha lenita, Pterolophia sp.1, Oberea sp.3, Acalolepta pseudospeciosa, and Ac. rustricatrix represented 4.80%, 4.80%, 4.80%, 4.5%, and 4.43% of the species, respectively. The species with the widest distribution range of percentage of species occurrence (% SO) was Pt. sp.1 (63.4%), followed by Ac. rustricatrix (39%) and Moechotypa suffusa (39%). In a significantly negative relationship between species richness and elevation (p > 0.05, R² = 0.04), the species richness pattern showed a hump-shaped curve that peaked at the middle elevation (501–1000 m asl). Regarding seasonal variation, most of the species occurred during the hot season (March–April) and peaked in early rainy season (May), while a low number of species were found during the mid-rainy (June–October) and cold season (November–February). Ordination analysis indicated that the distribution of most species was associated with regions and forest type, and most of the species correlated with forest located at middle and low elevation. The results of this study indicated the very high biodiversity of longhorn beetles in Thailand, which suggests that an understanding of their seasonal and elevational distribution will be of value to agriculture management and conservation. They also indicated that malaise traps are appropriate for the evaluation of biodiversity.

Mosquitoes (Diptera: Culicidae) From the Southwestern Brazilian Amazon: Liberdade and Gregório Rivers

The mosquito community from remote locations toward the southern border of the Brazilian State of Amazonas, in four localities along the Liberdade and Gregório Rivers, was sampled using CDC and Malaise traps, complemented with net sweeping and immature collections. During May 2011, 190 collections yielded 13,012 mosquitoes, from 15 genera and 112 different species, together with 10 morphospecies, which may represent new undescribed taxa. Among the species collected, there are two new geographical distribution records for the State of Amazonas. Culex, the most abundant genus, also had the highest number of species. Both Aedes and Uranotaenia had the second highest number of species, although they were the second and seventh most abundant, respectively. The most abundant species were Aedes (Ochlerotatus) fulvus (Wiedemann), Aedes (Ochlerotatus) nubilus (Theobald), Culex (Culex) mollis Dyar & Knab, Nyssorhynchus (Nyssorhynchus) oswaldoi sensu lato, Culex (Melanoconion) pedroi Sirivanakarn & Belkin, and Culex (Melanoconion) gnomatos Sallum, Hutchings & Ferreira. The epidemiological implications of mosquito species are discussed and compared with other mosquito inventories from the Amazon region. These results represent the first standardized mosquito inventories of the Liberdade and Gregório Rivers, with the identification of 112 species and 10 morphospecies, within the municipalities of Ipixuna and Eirunepé, from which we have only few records in the published literature.

Modifications of the rain forest frugivore community are associated with reduced seed removal at the community level

Tropical rain forests worldwide are under increasing pressure from human activities, which are altering key ecosystem processes such as plant-animal interactions. However, while the direct impact of anthropogenic disturbance on animal communities has been well studied, the consequences of such defaunation for mutualistic interactions such as seed dispersal remains chiefly understood at the plant species level. We asked whether communities of endozoochorous tree species had altered seed removal in forests affected by hunting and logging and if this could be related to modifications of the frugivore community. At two contrasting forest sites in French Guiana, Nouragues (protected) and Montagne de Kaw (hunted and partly logged), we focused on four families of animal-dispersed trees (Sapotaceae, Myristicaceae, Burseraceae, and Fabaceae), which represent 88% of all endozoochorous trees that were fruiting at the time and location of the study. We assessed the abundance of the seed dispersers and predators of these four focal families by conducting diurnal distance sampling along line transects. Densities of several key seed dispersers such as large-bodied primates were greatly reduced at Montagne de Kaw, where the specialist frugivore Ateles paniscus is probably extinct. In parallel, we estimated seed removal rates from fruit and seed counts conducted in 1-m² quadrats placed on the ground beneath fruiting trees. Seed removal rates dropped from 77% at Nouragues to 47 % at Montagne de Kaw, confirming that the loss of frugivores associated with human disturbance impacts seed removal at the community level. In contrast to Sapotaceae, whose seeds are dispersed by mammals only, weaker declines in seed removal for Burseraceae and Myristicaceae suggest that some compensation may occur for these bird- and mammal-dispersed families, possibly because of the high abundance of Toucans at the disturbed site. The defaunation process currently occurring across many tropical forests could dramatically reduce the diversity of entire communities of animal-dispersed trees through seed removal limitation.

Revision of Telothyria van der Wulp (Diptera: Tachinidae) and twenty-five new species from Area de Conservación Guanacaste in northwestern Costa Rica with a key to Mesoamerican species

Background

We describe 25 new species in the genus Telothyria van der Wulp, 1890 from Area de Conservación Guanacaste (ACG) in northwestern Costa Rica. All species herein described were reared from an ongoing inventory of wild-caught caterpillars spanning two families (Lepidoptera: Crambidae, and Tortricidae). Our study provides a concise description of each new species using morphology, life history, molecular data, and photographic documentation; a redescription of the genus, and its type species as well as a revised key to species of Telothyria occurring in the Mesoamerican region. We also suggest seven new synonymies resulting in 11 new combinations.

New information

The following 25 new species of Telothyria are described: T.aidanisp. n., T.alexanderisp. n., T.auranticrussp. n., T.auriolussp. n., T.bicuspidatasp. n., T.carolinacanoaesp. n., T.clavatasp. n., T.cristatasp. n., T.diniamartinezaesp. n., T.duniagarciaesp. n., T.duvalierbricenoisp. n., T.eldaarayaesp. n., T.erythropygasp. n., T.fimbriatasp. n., T.fulgidasp. n., T.gloriashihezaraesp. n., T.griseasp. n., T.harryramirezisp. n., T.incisasp. n., T.manuelpereiraisp. n., T.obscurasp. n., T.omissasp. n., T.osvaldoespinozaisp. n., T.peltatasp. n., and T.ricardocaleroisp. n.

The following are proposed by Fleming & Wood as new generic synonyms of Telothyria: Comatacta Coquillett Syn. n., Floradalia Thompson Syn. n., Ptilomyia Curran Syn. n., Ptilomyiopsis Townsend Syn. n., Ptilomyoides Curran Syn. n., EuptilomyiaSyn. n., Eutelothyria Townsend Syn. n.

The following new combinations are proposed as a result of the new synonymies: Telothyriabequaerti (Curran, 1925) Comb. n., Telothyriacruenta (Giglio-Tos, 1893) Comb. n., Telothyriafrontalis (Townsend, 1939) Comb. n., Telothyriainsularis (Curran, 1927) Comb. n., Telothyriaitaquaquecetubae (Townsend, 1931) Comb. n., Telothyriamajor (Thompson, 1963) Comb. n., Telothyriamicropalpus (Curran, 1925) Comb. n., Telothyriaminor (Thompson, 1963) Comb. n., Telothyrianautlana (Townsend, 1908) Comb. n., Telothyriaplumata (Curran, 1925) Comb. n., Telothyriatrinitatis (Thompson, 1963) Comb. n., Telothyriavariegata (Fabricius, 1805) Comb. n.Muscatricincta Fabricius is synonymized under Telothyriavariegata Fabricius, Syn. n.

Telothyriaschineri Fleming & Wood nom. n. is proposed as a replacement name for Miltogrammabrevipennis Schiner.

Additionally we provide redescriptions of two previously named species: the type species Telothyriacupreiventris (van der Wulp) due to its being the type species, and Telothyriarelicta (van der Wulp) due to its having been reared as an outcome of the inventory.

A preliminary study of resource overlap between howling monkeys (Alouatta palliata) and other arboreal mammals in the tropical rain forest of Los Tuxtlas, Mexico

Potential resource overlap between howling monkeys and other arboreal mammals was studied in the rain forest of Los Tuxtlas, Veracruz, Mexico. Eight species of mammals belonging to the orders Primates, Carnivora, Rodentia, and Marsupialia were found to share the canopy and to overlap trophically with howling monkeys. These mammals made up 77% and Alouatta 23% of the arboreal mammalian biomass under consideration. The arboreal porcupine and spider monkey were the only mammals that also fed on leaves. However, in this feeding niche, Alouatta is the only important mammalian folivore in Los Tuxtlas, and resource depression derived from leaf-eating insects is more important. The eight arboreal mammals may exert more pressure upon fruit resources, for they consumed 75% of the estimated total dry weight of fruit/ha/yr consumed by arboreal mammals.

A new species of Trismegistomya Reinhard (Diptera: Tachinidae) from Area de Conservación Guanacaste in northwestern Costa Rica

Background

The New World genus Trismegistomya Reinhard, 1967b (Diptera: Tachinidae) previously included only the type species Trismegistomyapumilis (Reinhard, 1967a) from Arizona, U.S.A.

New information

We describe a new species of Trismegistomya, Trismegistomyajimoharai Fleming & Wood sp. n., from Area de Conservación Guanacaste (ACG) in northwestern Costa Rica, reared from wild-caught caterpillars of Melipotisjanuaris (Guenée, 1852) (Lepidoptera: Erebidae). Our study provides a concise description of the new species using morphology, life history, molecular data and photographic documentation. In addition to the new species description, we provide a redescription of the genus, as well as of its type species Trismegistomyapumilis.

Mapping the Evolution of Mercury (Hg) Research in the Amazon (1991⁻2017): A Scientometric Analysis

Because the Amazon rain forest is ecologically relevant on a global scale, we applied scientometric techniques to integrate studies dealing with mercury research in this unique ecosystem between 1991 and 2017. Using a combination of co-authorship and co-citation analyses, keyword mapping and overlay visualization of topics in the field, this article identified three major areas in the 26-year period of mercury research: (1) human exposure to mercury (artisanal small-scale gold mining-ASGM) and methylmercury through fish consumption, and their respective risks for human health; (2) mercury accumulation in the environment and its relation to ASGM and atmospheric concentration; and (3) mercury geochemistry and its presence in soils, sediments, and water. The paper also identified the leading institutions related to the published research and respective influential scholars in the context of this study. Overall, the analyses revealed patterns of convergence and divergence between authors, specialization, and interdisciplinary engagement in mercury investigation, thus highlighting strengths and weaknesses of research topics in the field. This scientometric approach could be a useful tool to monitor/assess the implementation of the Minamata Convention.

Soil fertility and flood regime are correlated with phylogenetic structure of Amazonian palm communities

BACKGROUND AND AIMS

Identifying the processes that generate and maintain biodiversity requires understanding of how evolutionary processes interact with abiotic conditions to structure communities. Edaphic gradients are strongly associated with floristic patterns but, compared with climatic gradients, have received relatively little attention. We asked (1) How does the phylogenetic composition of palm communities vary along edaphic gradients within major habitat types? and (2) To what extent are phylogenetic patterns determined by (a) habitat specialists, (b) small versus large palms, and (c) hyperdiverse genera?

METHODS

We paired data on palm community composition from 501 transects of 0.25 ha located in two main habitat types (non-inundated uplands and seasonally inundated floodplains) in western Amazonian rain forests with information on soil chemistry, climate, phylogeny and metrics of plant size. We focused on exchangeable base concentration (cmol+ kg-1) as a metric of soil fertility and a floristic index of inundation intensity. We used a null model approach to quantify the standard effect size of mean phylogenetic distance for each transect (a metric of phylogenetic community composition) and related this value to edaphic variables using generalized linear mixed models, including a term for spatial autocorrelation.

KEY RESULTS

Overall, we recorded 112 008 individuals belonging to 110 species. Palm communities in non-inundated upland transects (but not floodplain transects) were more phylogenetically clustered in areas of low soil fertility, measured as exchangeable base concentration. In contrast, floodplain transects with more severe flood regimes (as inferred from floristic structure) tended to be phylogenetically clustered. Nearly half of the species recorded (44 %) were upland specialists while 18 % were floodplain specialists. In both habitat types, phylogenetic clustering was largely due to the co-occurrence of small-sized habitat specialists belonging to two hyperdiverse genera (Bactris and Geonoma).

CONCLUSIONS

Edaphic conditions are associated with the phylogenetic community structure of palms across western Amazonia, and different factors (specifically, soil fertility and inundation intensity) appear to underlie diversity patterns in non-inundated upland versus floodplain habitats. By linking edaphic gradients with palm community phylogenetic structure, our study reinforces the need to integrate edaphic conditions in eco-evolutionary studies in order to better understand the processes that generate and maintain tropical forest diversity. Our results suggest a role for edaphic niche conservatism in the evolution and distribution of Amazonian palms, a finding with potential relevance for other clades.

Soil Type Has a Stronger Role than Dipterocarp Host Species in Shaping the Ectomycorrhizal Fungal Community in a Bornean Lowland Tropical Rain Forest

The role that mycorrhizal fungal associations play in the assembly of long-lived tree communities is poorly understood, especially in tropical forests, which have the highest tree diversity of any ecosystem. The lowland tropical rain forests of Southeast Asia are characterized by high levels of species richness within the family Dipterocarpaceae, the entirety of which has been shown to form obligate ectomycorrhizal (ECM) fungal associations. Differences in ECM assembly between co-occurring species of dipterocarp have been suggested, but never tested in adult trees, as a mechanism for maintaining the coexistence of closely related tree species in this family. Testing this hypothesis has proven difficult because the assembly of both dipterocarps and their ECM associates co-varies with the same edaphic variables. In this study, we used high-throughput DNA sequencing of soils and Sanger sequencing of root tips to evaluate how ECM fungi were structured within and across a clay-sand soil nutrient ecotone in a mixed-dipterocarp rain forest in Malaysian Borneo. We compared assembly patterns of ECM fungi in bulk soil to ECM root tips collected from three ecologically distinct species of dipterocarp. This design allowed us to test whether ECM fungi are more strongly structured by soil type or host specificity. As with previous studies of ECM fungi on this plot, we observed that clay vs. sand soil type strongly structured both the bulk soil and root tip ECM fungal communities. However, we also observed significantly different ECM communities associated with two of the three dipterocarp species evaluated on this plot. These results suggest that ECM fungal assembly on these species is shaped by a combination of biotic and abiotic factors, and that the soil edaphic niche occupied by different dipterocarp species may be mediated by distinct ECM fungal assemblages.

Five new species of Vibrissina Rondani (Diptera: Tachinidae) from Area de Conservación Guanacaste in Northwestern Costa Rica

Background

We describe five new species in the genus Vibrissina Rondani from Area de Conservación Guanacaste (ACG). All species were reared from wild-caught sawfly larvae (Hymenoptera: Symphyta: Argidae and Tenthredinidae). We provide a morphological description of each species together with information on life history, molecular data, and photographic documentation.

New information

Five new species of Vibrissina Rondani: Vibrissinarandycurtisisp. n., V.randyjonesisp. n., V.robertwellsisp. n., V.danmartinisp. n., V.hallwachsorumsp. n.

DIRECT AND INDIRECT ESTIMATES OF NEIGHBORHOOD AND EFFECTIVE POPULATION SIZE IN A TROPICAL PALM, ASTROCARYUM MEXICANUM

To estimate the relative importance of genetic drift, the effective population size ∗∗∗(N_e ) can be used. Here we present estimates of the effective population size and related measures in Astrocaryum mexicanum, a tropical palm from Los Tuxtlas rain forest, Veracruz, Mexico. Seed and pollen dispersal were measured. Seeds are primarily dispersed by gravity and secondarily dispersed by small mammals. Mean primary and secondary dispersal distances for seeds were found to be small (0.78 m and 2.35 m, respectively). A. mexicanum is beetle pollinated and pollen movements were measured by different methods: a) using fluorescent dyes, b) as the minimum distance between active female and male inflorescences, and c) using rare allozyme alleles as genetic markers. All three estimates of pollen dispersal were similar, with a mean of approximately 20 m. Using the seed and pollen dispersal data, the genetic neighborhood area (A) was estimated to be 2,551 m² . To obtain the effective population size, three different overlapping generation methods were used to estimate an effective density with demographic data from six permanent plots. The effective density ranged from 0.040 to 0.351 individuals per m² . The product of effective density and neighborhood area yields a direct estimate of the neighborhood effective population size (N_b ). N_b ranged from 102 to 895 individuals. Indirect estimates of population size and migration rate (Nm) were obtained using F_st for five different allozymic loci for both adults and seeds. We obtained a range of Nm from 1.2 to 19.7 in adults and a range of Nm from 4.0 to 82.6 for seeds. We discuss possible causes of the smaller indirect estimates of Nm relative to the direct and compare our estimates with values from other plant populations. Gene dispersal distances, neighborhood size, and effective population size in A. mexicanum are relatively high, suggesting that natural selection, rather than genetic drift, may play a dominant role in patterning the genetic variation in this tropical palm.

DEMOGRAPHIC GENETICS OF A PIONEER TROPICAL TREE SPECIES: PATCH DYNAMICS, SEED DISPERSAL, AND SEED BANKS

We consider whether changes in population-genetic structure through the life cycle of Cecropia obtusifolia, a tropical pioneer tree, reflect its gap-dependent demography and the role of evolutionary processes that are important for this species. We asked whether the spatial scale at which population-genetic subdivision occurs corresponds to the scale of habitat patchiness created by gap dynamics; whether patterns of seed dispersal and storage in the soil affect spatial genetic patterns; and whether spatial genetic patterns change through the species life cycle. We estimated Wright's F-statistics for six successive life-history stages for individuals grouped into subpopulations according to occurrence in natural gaps, physical proximity, or occurrence within large quadrats. For each life stage, F_ST -statistics were significantly higher when individuals were grouped by gaps, although concordant patterns across life stages for the three grouping methods were obtained. This supports the hypothesis that patchy recruitment in gaps or among-gap heterogeneity influences the species' genetic structure. F-statistics of seeds collected from females before dispersal (tree seeds), seed-rain seeds, soil seeds, seedlings, juveniles, and adults grouped by gaps, were, respectively: F_IT = 0.004, 0.160, 0.121, 0.091, -0.0002, -0.081; F_IS = -0.032, 0.124, 0.118, 0.029, -0.016, -0.083; and F_ST = 0.035, 0.041, 0.003, 0.063, 0.015, 0.002. Spatial genetic differentiation in rain seeds was not significantly lower than that of tree seeds. The loss of genetic structure in the soil seed bank, relative to that found in the seed rain may be due to sampling artifacts, but alternative explanations, such as microsite selection or temporal Wahlund effect are also discussed. If structure among soil seeds is unbiased, the peak in seedling F_ST may be due to microsite selection. F_IS of seeds in the rain and soil were significantly greater than zero. A Wahlund effect is the most likely cause of these positive F_IS values. Such fine-scale substructuring could be caused by correlated seed deposition by frugivores. The decrease in F_IS from seedlings to adults could result from loss of fine-scale genetic structure during stand thinning or from selection.

Nine new species of Uramya Robineau-Desvoidy (Diptera: Tachinidae) from Area de Conservación Guanacaste in northwestern Costa Rica, with a key to their identification

Background

We describe nine new species in the genus Uramya Robineau-Desvoidy, 1830 from Area de Conservación Guanacaste (ACG) in northwestern Costa Rica. All species were reared from an ongoing inventory of wild-caught caterpillars spanning a variety of families (Lepidoptera: Erebidae; Limacodidae; Megalopygidae; Lasiocampidae and Dalceridae). Our study provides a concise description of each new species using morphology, life history, molecular data, and photographic documentation. In addition to the new species the authors provide a redescription the previously described Uramyasibinivora Guimarães, which was also collected within ACG during this study. We also provide a redescription of the genus, and a revised key to species of Uramya occurring in Central and South America.

New information

The following nine new species of Uramya, all authored by Fleming & Wood, are described: Uramyaalbosetulosa Fleming & Wood sp. nov., Uramyaconstricta Fleming & Wood sp. nov., Uramyacontraria Fleming & Wood sp. nov., Uramyainfracta Fleming & Wood sp. nov., Uramyalativittata Fleming & Wood sp. nov., Uramyalunula Fleming & Wood sp. nov., Uramyanitida Fleming & Wood sp. nov., Uramyapannosa Fleming & Wood sp. nov., and Uramyapenicillata Fleming & Wood sp. nov.

The following are proposed by Wood as new synonyms of Uramya: Olinda Townsend, syn. nov. and Procleonice Townsend, syn. nov. The following new combination is proposed as a result of the new synonymies: Uramyabrasiliensis Macquart, comb. nov.Procleoniceprolixa Townsend is synonymized under Uramyabrevicauda Curran, syn. nov.

Mosquitoes (Diptera: Culicidae) From the Northwestern Brazilian Amazon: Padauari River

The mosquito fauna (Culicidae) from remote northern areas of the State of Amazonas were sampled using Centers for Disease Control and Prevention, Shannon, Malaise, and Suspended traps, together with net sweeping and immature collections. One hundred and seven collections were performed in five localities along the Padauari River, State of Amazonas, Brazil, during June 2010. The 20,557 mosquitoes collected are distributed in 17 genera, representing 117 different species, of which four are new distributional records for the State of Amazonas. Furthermore, there are 10 morphospecies that may represent undescribed new taxa, eight of which are also new records for the State of Amazonas. The genus Culex had the highest number of species and the largest number of individuals. Aedes and Psorophora both represented 10% of the total sample and had the second highest number of species and individuals. The most abundant species was Culex (Melanoconion) gnomatos Sallum, Hutchings & Ferreira, followed by Aedes (Ochlerotatus) fulvus (Wiedemann), Culex (Melanoconion) vaxus Dyar, Culex (Melanoconion) portesi Senevet & Abonnenc, Psorophora (Janthinosoma) amazonica Cerqueira, Culex (Culex) mollis Dyar & Knab, Psorophora (Janthinosoma) albigenu (Peryassú), and Culex (Melanoconion) theobaldi Lutz. The epidemiological and ecological implications of mosquito species found are discussed and are compared with other mosquito inventories from the Amazon region. The results represent the most diverse standardized inventory of mosquitoes along the Padauari River, with the identification of 127 species-level taxa distributed in five localities, within two municipalities (Barcelos and Santa Isabel do Rio Negro).

Branch Width and Height Influence the Incorporation of Branches into Foraging Trails and Travel Speed in Leafcutter Ants Atta cephalotes (L.) (Hymenoptera: Formicidae)

Fallen branches are often incorporated into Atta cephalotes (L.) foraging trails to optimize leaf tissue transport rates and economize trail maintenance. Recent studies in lowlands show laden A. cephalotes travel faster across fallen branches than on ground, but more slowly ascending or descending a branch. The latter is likely because (1) it is difficult to travel up or downhill and (2) bottlenecks occur when branches are narrower than preceding trail. Hence, both branch height and width should determine whether branches decrease net travel times, but no study has evaluated it yet. Laden A. cephalotes were timed in relation to branch width and height across segments preceding, accessing, across, and departing a fallen branch in the highlands of Costa Rica. Ants traveled faster on branches than on cleared segments of trunk-trail, but accelerated when ascending or descending the branch-likely because of the absence of bottlenecks during the day in the highlands. Branch size did not affect ant speed in observed branches; the majority of which (22/24) varied from 11 to 120 mm in both height and width (average 66 mm in both cases). To determine whether ants exclude branches outside this range, ants were offered the choice between branches within this range and branches that were taller/wider than 120 mm. Ants strongly preferred the former. Our results indicate that A. cephalotes can adjust their speed to compensate for the difficulty of traveling on branch slopes. More generally, branch size should be considered when studying ant foraging efficiency.

A new species of Phosocephala Townsend, 1908 (Diptera: Tachinidae) from Area de Conservación Guanacaste in northwestern Costa Rica

Background

We describe a new species of Phosocephala Townsend, and provide a new collection record, and description of the previously unknown male, of Phosocephalametallica Townsend, from Area de Conservación Guanacaste (ACG), northwestern Costa Rica. All ACG specimens were reared from wild-caught Lepidoptera larvae (Lepidoptera: Erebidae, Nolidae). We provide a concise description of both species using morphology, life history, molecular data, and photographic documentation. The new species is authored and described by Fleming and Wood.

New information

Phosocephalaalexanderisp. n.

Two new species of Erythromelana Townsend, 1919 (Diptera: Tachinidae) from Area de Conservación Guanacaste in northwestern Costa Rica

Background

We describe two new species in the genus Erythromelana Townsend, 1919 from Area de Conservación Guanacaste (ACG) in northwestern Costa Rica. Both species were reared from wild-caughtcaterpillars of Eois spp. (Lepidoptera: Geometridae). We provide a concise description of each species using morphology, life history, molecular data, and photographic documentation.

New information

Erythromelanajimmychevezi Fleming & Wood sp. nov.

Erythromelanaglenriverai Fleming & Wood sp. nov.

Vegetation and floristics of a lowland tropical rainforest in northeast Australia

Background

Full floristic data, tree demography, and biomass estimates incorporating non-tree lifeforms are seldom collected and reported for forest plots in the tropics. Established research stations serve as important repositories of such biodiversity and ecological data. With a canopy crane setup within a tropical lowland rainforest estate, the 42-ha Daintree Rainforest Observatory (DRO) in Cape Tribulation, northern Australia is a research facility of international significance. We obtained an estimate of the vascular plant species richness for the site, by surveying all vascular plant species from various mature-phase, remnant and open vegetation patches within the site. We also integrate and report the demography and basal areas of trees ≥ 10 cm diameter at breast height (dbh) in a new 1-ha core plot, an extension to the pre-existing forest 1-ha plot under the canopy crane. In addition, we report for the canopy crane plot new demography and basal areas for smaller-size shrubs and treelets subsampled from nine 20 m² quadrats, and liana basal area and abundance from the whole plot. The DRO site has an estimated total vascular plant species richness of 441 species, of which 172 species (39%) are endemic to Australia, and 4 species are endemics to the Daintree region. The 2 x 1-ha plots contains a total of 262 vascular plant species of which 116 (1531 individuals) are tree species ≥ 10 cm dbh. We estimate a stem basal area of 34.9 m² ha^-1, of which small stems (tree saplings and shrubs <10cm dbh) and lianas collectively contribute c.4.2%. Comparing the stem density-diversity patterns of the DRO forest with other tropical rainforests globally, our meta-analysis shows that DRO forests has a comparatively high stem density and moderate species diversity, due to the influence of cyclones. These data will provide an important foundation for ecological and conservation studies in lowland tropical forest.

New information

We present a floristic checklist, a lifeform breakdown, and demography data from two 1-ha rainforest plots from a lowland tropical rainforest study site. We also present a meta-analysis of stem densities and species diversity from comparable-sized plots across the tropics.

Nine new species of Itaplectops (Diptera: Tachinidae) reared from caterpillars in Area de Conservación Guanacaste, northwestern Costa Rica, with a key to Itaplectops species

Nine new species of Itaplectops Townsend (Diptera: Tachinidae) are described from Area de Conservación Guanacaste (ACG), northwestern Costa Rica. All specimens have been reared from ­various species of ACG caterpillars in the families Limacodidae and Dalceridae. By combining morphological, photographic, and genetic barcode data we provide clear yet concise descriptions. The following nine new species are described in the genus Itaplectops: Itaplectopsakselpalolai, Itaplectopsanikenpalolae, Itaplectopsargentifrons, Itaplectopsaurifrons, Itaplectopsericpalolai, Itaplectopsgriseobasis, Itaplectopsomissus, Itaplectopsshellymcsweeneyae, Itaplectopstristanpalolai. We move Itaplectops to the tribe Uramyini from its original placement within the Blondeliini, and we discuss its systematic placement. We also provide a key differentiating the, genera of the tribe Uramyini as well as the known species of Itaplectops.

Threshold Responses to Soil Moisture Deficit by Trees and Soil in Tropical Rain Forests: Insights from Field Experiments

Many tropical rain forest regions are at risk of increased future drought. The net effects of drought on forest ecosystem functioning will be substantial if important ecological thresholds are passed. However, understanding and predicting these effects is challenging using observational studies alone. Field-based rainfall exclusion (canopy throughfall exclusion; TFE) experiments can offer mechanistic insight into the response to extended or severe drought and can be used to help improve model-based simulations, which are currently inadequate. Only eight TFE experiments have been reported for tropical rain forests. We examine them, synthesizing key results and focusing on two processes that have shown threshold behavior in response to drought: (1) tree mortality and (2) the efflux of carbon dioxdie from soil, soil respiration. We show that: (a) where tested using large-scale field experiments, tropical rain forest tree mortality is resistant to long-term soil moisture deficit up to a threshold of 50% of the water that is extractable by vegetation from the soil, but high mortality occurs beyond this value, with evidence from one site of increased autotrophic respiration, and (b) soil respiration reaches its peak value in response to soil moisture at significantly higher soil moisture content for clay-rich soils than for clay-poor soils. This first synthesis of tropical TFE experiments offers the hypothesis that low soil moisture–related thresholds for key stress responses in soil and vegetation may prove to be widely applicable across tropical rain forests despite the diversity of these forests.

Three new species of Trigonospila Pokorny (Diptera: Tachinidae), from Area de Conservación Guanacaste, northwestern Costa Rica, with a key for their identification

We describe three new species of Trigonospila Pokorny (Tachinidae: Blondeliini) from Area de Conservación Guanacaste (ACG), northwestern Costa Rica. All were reared from ­various species of ACG caterpillars during an ongoing inventory of caterpillars, their food plants and their parasitoids in dry forest, rain forest and cloud forest. By coupling morphology, photographic documentation, life history and molecular data, we provide a clear and concise description of each species. All species published as new, are known to be previously undescribed as a result of careful study of the genus by DMW. This study builds on the current knowledge of the genus by adding three new species to the current 7 described in the New World. Trigonospilaedwinbermudezisp. n., Trigonospilauniformissp. n., and Trigonospilajosemariamoragaisp. n. are all authored and described as new by Fleming and Wood, with a key to their identification. The authors also offer a new record and description of the previously unknown male of Trigonospilapanamensis (Townsend), reared from ACG caterpillars.

Three new species of Ametadoria Townsend (Diptera: Tachinidae) from Area de Conservación Guanacaste, Costa Rica

We describe three new species in the genus Ametadoria Townsend from Area de Conservación Guanacaste (ACG), Costa Rica. All three were reared from wild-caught Zygaenidae and Lacturidae caterpillars. We provide a concise description of each species using morphology, life history and molecular data, with photographic documentation. The new species are authored and described by Fleming and Wood: Ametadoriakarolramosaesp. nov., Ametadorialeticiamartinezaesp. nov., and Ametadoriamauriciogurdianisp. nov. The following are proposed by Wood as new synonyms of Ametadoria Townsend: Adidyma Townsend syn. nov., and Abolodoria Townsend syn. nov. The following new combinations occur as a result of these new synonymies: Ametadoriaabdominalis (Townsend) comb. nov., Ametadoriaaustrina (Coquillett) comb. nov., Ametadoriahumilis (Wulp) comb. nov., Ametadoriamisella (Wulp) comb. nov.Ametadoriaadversa (Townsend) is proposed as a junior synonym of ​Ametadoriaunispinosa Townsend, syn. nov​.

Human seroprevalence indicating hantavirus infections in tropical rainforests of Côte d'Ivoire and Democratic Republic of Congo

Hantaviruses are members of the Bunyaviridae family carried by small mammals and causing human hemorrhagic fevers worldwide. In Western Africa, where a variety of hemorrhagic fever viruses occurs, indigenous hantaviruses have been molecularly found in animal reservoirs such as rodents, shrews, and bats since 2006. To investigate the human contact to hantaviruses carried by these hosts and to assess the public health relevance of hantaviruses for humans living in the tropical rainforest regions of Western and Central Africa, we performed a cross-sectional seroprevalence study in the region of Taï National Park in Côte d’Ivoire and the Bandundu region near the Salonga National Park in the Democratic Republic (DR) of Congo. Serum samples were initially screened with enzyme-linked immunosorbent assays using nucleoproteins of several hantaviruses as diagnostic antigens. Positive results were confirmed by Western blotting and immunofluorescence testing. Seroprevalence rates of 3.9% (27/687) and 2.4% (7/295), respectively, were found in the investigated regions in Côte d’Ivoire and the DR Congo. In Côte d’Ivoire, this value was significantly higher than the seroprevalence rates previously reported from the neighboring country Guinea as well as from South Africa. Our study indicates an exposure of humans to hantaviruses in West and Central African tropical rainforest areas. In order to pinpoint the possible existence and frequency of clinical disease caused by hantaviruses in this region of the world, systematic investigations of patients with fever and renal or respiratory symptoms are required.

Seven new species of Spathidexia Townsend (Diptera: Tachinidae) reared from caterpillars in Area de Conservación Guanacaste, Costa Rica

We describe seven new species of Spathidexia (Diptera: Tachinidae) reared from Area de Conservación Guanacaste (ACG), northwestern Costa Rica. All were reared from ­various species of ACG caterpillars during an ongoing inventory of caterpillars, their food plants and their parasitoids. By coupling morphology, photographic documentation, life history and molecular data, we provide a clear and concise description of each species. All are known to be previously undescribed as a result of a comprehensive study of the genus by DMW. Spathidexiaatripalpussp. n., Spathidexiajuanvialesisp. n., Spathidexiamarioburgosisp. n., Spathidexialuisrobertogallegosisp. n., Spathidexialuteolasp. n., Spathidexiahernanrodriguezisp. n. and Spathidexiaaurantiacasp. n. are all authored and described by Fleming and Wood. Minthodexiopsis Townsend is proposed by Wood as a new synonym of Spathidexia. A new combination proposed by Wood as a result of the new synonymy is S.flavicornis (Brauer & Bergenstamm) comb. n.

A new species of Cordyligaster Macquart, reared from caterpillars in Area de Conservacion Guanacaste, northwestern Costa Rica

We describe a new species of Cordyligaster Macquart (Diptera: Tachinidae) from Area de Conservacion Guanacaste (ACG) in northwestern Costa Rica. Cordyligastercapelliisp. n., is described and photographed. All specimens of C.capellii were reared from Syngamiaflorella (Stoll, 1781) (Lepidoptera, Crambidae, Spilomelinae), a leaf-rolling caterpillar collected in ACG rain forest. By coupling morphology, photographic documentation, life history and molecular data, we provide a clear and concise description of this new species. In addition the authors provide new distribution and host records for C.fuscipennis (Macquart) reared in ACG.

Forest carbon in lowland Papua New Guinea: Local variation and the importance of small trees

Efforts to incentivize the reduction of carbon emissions from deforestation and forest degradation require accurate carbon accounting. The extensive tropical forest of Papua New Guinea (PNG) is a target for such efforts and yet local carbon estimates are few. Previous estimates, based on models of neotropical vegetation applied to PNG forest plots, did not consider such factors as the unique species composition of New Guinea vegetation, local variation in forest biomass, or the contribution of small trees. We analysed all trees >1 cm in diameter at breast height (DBH) in Melanesia's largest forest plot (Wanang) to assess local spatial variation and the role of small trees in carbon storage. Above-ground living biomass (AGLB) of trees averaged 210.72 Mg  ha⁻¹ at Wanang. Carbon storage at Wanang was somewhat lower than in other lowland tropical forests, whereas local variation among 1-ha subplots and the contribution of small trees to total AGLB were substantially higher. We speculate that these differences may be attributed to the dynamics of Wanang forest where erosion of a recently uplifted and unstable terrain appears to be a major source of natural disturbance. These findings emphasize the need for locally calibrated forest carbon estimates if accurate landscape level valuation and monetization of carbon is to be achieved. Such estimates aim to situate PNG forests in the global carbon context and provide baseline information needed to improve the accuracy of PNG carbon monitoring schemes.

Richness and Abundance of Ichneumonidae in a Fragmented Tropical Rain Forest

Because of the magnitude of land use currently occurring in tropical regions, the local loss of animal species due to habitat fragmentation has been widely studied, particularly in the case of vertebrates. Many invertebrate groups and the ichneumonid wasps in particular, however, have been poorly studied in this context, despite the fact that they are one of the most species-rich groups and play an important role as regulators of other insect populations. Here, we recorded the taxonomic composition of ichneumonid parasitoids and assessed their species richness, abundance, similarity, and dominance in the Los Tuxtlas tropical rain forest, Mexico. We compared two forest types: a continuous forest (640 ha) and a forest fragment (19 ha). We sampled ichneumonids using four malaise traps in both forest types during the dry (September-October) and rainy (March-April) seasons. A total of 104 individuals of Ichneumonidae belonging to 11 subfamilies, 18 genera, and 42 species were collected in the continuous forest and 11 subfamilies, 15 genera, and 24 species were collected in the forest fragment. Species richness, abundance, and diversity of ichneumonids were greater in the continuous forest than in the forest fragment. We did not detect differences between seasons. Species rank/abundance curves showed that the ichneumonid community between the forest types was different. Species similarity between forest types was low. The most dominant species in continuous forest was Neotheronia sp., whereas in the forest fragment, it was Orthocentrus sp. Changes in the ichneumonid wasp community may compromise important tropical ecosystem processes.

Altitudinal changes in temperature responses of net photosynthesis and dark respiration in tropical bryophytes

BACKGROUND AND AIMS

There is a conspicuous increase of poikilohydric organisms (mosses, liverworts and macrolichens) with altitude in the tropics. This study addresses the hypothesis that the lack of bryophytes in the lowlands is due to high-temperature effects on the carbon balance. In particular, it is tested experimentally whether temperature responses of CO(2)-exchange rates would lead to higher respiratory carbon losses at night, relative to potential daily gains, in lowland compared with lower montane forests.

METHODS

Gas-exchange measurements were used to determine water-, light-, CO(2)- and temperature-response curves of net photosynthesis and dark respiration of 18 tropical bryophyte species from three altitudes (sea level, 500 m and 1200 m) in Panama.

KEY RESULTS

Optimum temperatures of net photosynthesis were closely related to mean temperatures in the habitats in which the species grew at the different altitudes. The ratio of dark respiration to net photosynthesis at mean ambient night and day temperatures did not, as expected, decrease with altitude. Water-, light- and CO(2)-responses varied between species but not systematically with altitude.

CONCLUSIONS

Drivers other than temperature-dependent metabolic rates must be more important in explaining the altitudinal gradient in bryophyte abundance. This does not discard near-zero carbon balances as a major problem for lowland species, but the main effect of temperature probably lies in increasing evaporation rates, thus restricting the time available for photosynthetic carbon gain, rather than in increasing nightly respiration rates. Since optimum temperatures for photosynthesis were so fine tuned to habitat temperatures we analysed published temperature responses of bryophyte species worldwide and found the same pattern on the large scale as we found along the tropical mountain slope we studied.

The relationships of wood-, gas- and water fractions of tree stems to performance and life history variation in tropical trees

BACKGROUND AND AIMS

The volume of tree stems is made up of three components: solid wood, gas and water. These components have important consequences for the construction costs, strength and stability of trees. Here, the importance of stem components for sapling growth and survival in the field was investigated, and then these stem components were related to two important life history axes of variation: the light requirements for regeneration and the adult stature of the species.

METHODS

Stem fractions of wood, gas and water were determined for saplings and adults of respectively 30 and 58 Bolivian tropical moist-forest species. Sapling height growth and survival were monitored for 2 years in the field as indicators of sapling performance.

KEY RESULTS

Sapling stems consisted of 26 % wood (range 7-36 % for species), 59 % water (range 49-88 %), and 15 % gas (range 0-38 %) per unit volume. The wood fraction was the only determinant of sapling performance and was correlated with increased survival and decreased growth rate across species. The wood fraction decreased with light requirements of the species, probably because a high wood fraction protects shade-tolerant species against pathogens and falling debris. The gas fraction increased with the light requirements and adult stature of the species; probably as an aid in realizing a rapid height growth and accessing the canopy in the case of light-demanding species, and for rapidly attaining stability and a large reproductive size in the case of tall species. The water fraction was not correlated with the life history variation of tree species, probably because it leads to increased stem loading and decreased stability.

CONCLUSIONS

The wood fraction might partially explain the growth-survival trade-off that has been found across tropical tree species. The wood and gas fractions are closely related to the regeneration light requirements of the species. Tall species have a high gas fraction, probably not only because gas is a cheap filler, but also because it might lead to an increased stability of these tall trees.

In tropical lowland rain forests monocots have tougher leaves than dicots, and include a new kind of tough leaf

BACKGROUND AND AIMS

There has been little previous work on the toughness of the laminae of monocots in tropical lowland rain forest (TLRF) despite the potential importance of greater toughness in inhibiting herbivory by invertebrates. Of 15 monocot families with >100 species in TLRF, eight have notably high densities of fibres in the lamina so that high values for toughness are expected.

METHODS

In north-eastern Australia punch strength was determined with a penetrometer for both immature leaves (approx. 30 % final area on average) and fully expanded, fully toughened leaves. In Singapore and Panama, fracture toughness was determined with an automated scissors apparatus using fully toughened leaves only.

KEY RESULTS

In Australia punch strength was, on average, 7x greater in shade-tolerant monocots than in neighbouring dicots at the immature stage, and 3x greater at the mature stage. In Singapore, shade-tolerant monocots had, on average, 1.3x higher values for fracture toughness than neighbouring dicots. In Panama, both shade-tolerant and gap-demanding monocots were tested; they did not differ in fracture toughness. The monocots had markedly higher values than the dicots whether shade-tolerant or gap-demanding species were considered.

CONCLUSIONS

It is predicted that monocots will be found to experience lower rates of herbivory by invertebrates than dicots. The tough monocot leaves include both stiff leaves containing relatively little water at saturation (e.g. palms), and leaves which lack stiffness, are rich in water at saturation and roll readily during dry weather or even in bright sun around midday (e.g. gingers, heliconias and marants). Monocot leaves also show that it is possible for leaves to be notably tough throughout the expansion phase of development, something never recorded for dicots. The need to broaden the botanist's mental picture of a 'tough leaf' is emphasized.

Monocot leaves are eaten less than dicot leaves in tropical lowland rain forests: correlations with toughness and leaf presentation

BACKGROUND AND AIMS

In tropical lowland rain forest (TLRF) the leaves of most monocots differ from those of most dicots in two ways that may reduce attack by herbivores. Firstly, they are tougher. Secondly, the immature leaves are tightly folded or rolled until 50-100 % of their final length. It was hypothesized that (a) losses of leaf area to herbivorous invertebrates are generally greatest during leaf expansion and smaller for monocots than for dicots, and (b) where losses after expansion are appreciable any difference between monocots and dicots then is smaller than that found during expansion.

METHODS

At six sites on four continents, estimates were made of lamina area loss from the four most recently mature leaves of focal monocots and of the nearest dicot shoot. Measurements of leaf mass per unit area, and the concentrations of water and nitrogen were made for many of the species. In Panama, the losses from monocots (palms) and dicots were also measured after placing fully expanded palm leaflets and whole dicot leaves on trails of leaf-cutter ants.

KEY RESULTS

At five of six sites monocots experienced significantly smaller leaf area loss than dicots. The results were not explicable in terms of leaf mass per unit area, or concentrations of water or nitrogen. At only one site was the increase in loss from first to fourth mature leaf significant (also large and the same in monocots and dicots), but the losses sustained during expansion were much smaller in the monocots. In the leaf-cutter ant experiment, losses were much smaller for palms than for dicots.

CONCLUSIONS

The relationship between toughness and herbivory is complex; despite the negative findings of some recent authors for dicots we hypothesize that either greater toughness or late folding can protect monocot leaves against herbivorous insects in tropical lowland rain forest, and that the relative importance varies widely with species. The difficulties of establishing unequivocally the roles of leaf toughness and leaf folding or rolling in a given case are discussed.

Fruit Characteristics of Species Dispersed by the Black Lemur (Eulemur macaco) in the Lokobe Forest, Madagascar

ABSTRACT

I describe the fruit characteristics of species closely associated with black lemur seed dispersal (i.e., species that are often dispersed by die black lemur and only dispersed by the black lemur in die Lokobe Forest). A black lemur group was habituated and observed during the day and night for all months of die year (total 1272 h). When fruits were eaten, die plant species was identified, die maturity of the fruit and treatment of the seeds noted, and the fruit described in terms of ripe fruit color, husk thickness, fruit length, and seed length and width. Black lemur feces were searched for seeds; these were identified and signs of damage noted. Other potential dispersers feeding on the fruits of species eaten by the black lemur were also noted. The black lemurs were seen eating die fruits of 70 species. Of these, 51 species were defined as closely associated with black lemur dispersal and 16 species had seeds that were either often preyed upon or wasted by the black lemur, or were seen being eaten by other potential seed dispersers. Fruits of species in the former group were often dull colored (94% of species); rarely less than 1 cm long (6%); rarely had seeds less than 0.1 cm long or less than 0.1 cm wide (2 and 4%, respectively); never had seeds more than 4 cm long or greater than 2 cm wide; and quite often had either thick husks (49%) or thin husks (51%). In contrast, the fruits of the latter group were often brightly colored (75% of species) and nearly always had a thin husk (94%). Also, this latter group included more small and very large fruits and seeds than the former group. Fruit characteristics significantly associated with the former group were: dull color, thick husk, fruit length greater than 2 cm, seed length 1–4 cm, and seed width 1–2 cm. The extent to which these traits are the result of coevolution between plants and the guild of lemur dispersers that includes the black lemur is not clear, but a coevolved lemur–fruit syndrome remains a possibility.

RESUMES

Cette étude porte sur la description des caracteristiques des fruits appartenant aux espèces dont la dissemination des graines est étroitement liée au Eulemur macaco. Ces espèces sont definies comme étant souvent disséminees par E. macaco et uniquement disséminées par E. macaco dans la for○t de Lokobe. Dans le but d'identifier ces espéces, un groupe de E. macaco a été habituéà la présence humaine et observé jour et nuit pendant tous les mois de 1'année (en total 1272 h). Une fois le fruit consommé, I'espèce était identifyée, la maturityé du fruit ainsi que le traitement de la graine notés et le fruit était dàcrit en termé de couleur á maturityé, d'épaisseur de I'enveloppe, de longueur de fruit et de longueur et de largeur de graine. Par la suite, les féces sont recherchés afin d'identifier les graines qu'ils contiennent et routes signes d'endommagement de celles‐ci sont notés. Les autres agents de dissémination potentiels, consomma‐teurs des fruits appartenant aux espèces consommées par E. macaco, ont étéégalement notés. Les E. macaco ont été vu consommer les fruits de 70 espèces. De ces dernières, 51 espèces étaient définies comm.éaetant étroitement liées à la dissémination par E. macaco et les graines de 16 espèces sont soit consommées, soit gaspillées par E. macaco, soit ont été vu consommées par d'autres agents de dissémination potentiels. Les fruits des espèces appartenant au groupe précédent sont souvent d'une couleur sombre (94% des espèces), d'une longueur rarement < 1 cm (6%), avaient rarement des fruits < 0.1 cm de long ou < 0.1 cm de large (2 et 4% respectivement) et n'ont jamais des graines > 4 cm de long ou > 2 cm de large, et presque souvent avaient une enveloppe épaisse (49%) et presque souvent une enveloppe mince (51%). Par contre, les fruits du dernier groupe sont souvent d'une couleur claire (75% des espèces) 'et presque toujours ont une enveloppe mince (94%). De plus, ce groupe inclut plus de petits et de très larges fruits et graines que le premier groupe. Les classes des caractéristiques des fruits significativement associées au premier groupe sont: couleur sombre, enveloppe épaisse, longueur de fruit >2 cm, longueur de graine 1‐4 cm, et largeur de graine 1‐2 cm. Cependant, 1'importance du ro̧le joué par la coévolution entre les plantes et le groupe des lémuriens disséminateurs, comprennant Eulemur m., dans le développement des caractéristiques de ces fruits n'est pas connue.

The effect of water on the ground nesting habits of the giant tropical ant, Paraponera clavata

The large predatory ant, Paraponera clavata, exerts measurable top-down effects in wet and moist Neotropical forests, and therefore its distribution has potential ecological implications. To determine how water affects the presence of this important predator, the ground nesting ecology of P. clavata was examined with respect to various habitat characteristics. Four hectares of disturbed Costa Rican lowland rain forest were surveyed for ant colonies to determine nest distribution patterns in wet and dry habitat; significantly more colonies were found in dry habitat. Seventeen of 19 nests built on slopes of > 5 degrees inclination were positioned on the downward side of the tree, possibly using the trunk as a shield against runoff during rain showers. Moisture and pH inside nests were significantly different from adjacent soil. These results suggest that water influences the ground nesting habits of P. clavata, thus ecological differences between comparatively wet and dry portions of tropical forests may arise from the relative abundance of this ant species.

The ants of North and Central America: the genus Mycocepurus (Hymenoptera: Formicidae)

We provide a review of the North American ants (north of Colombia) of the ant genus Mycocepurus, including keys to the workers and females, illustrations and distribution maps. The distribution of M. tardus is extended to Nicaragua and Costa Rica. The female of M. curvispinosus is described.

Nutrients obtained from leaf litter can improve the growth of dipterocarp seedlings

• In tropical rain forests the rate of litterfall is high, and is the most important nutrient cycling pathway in these ecosystems. We tested two hypotheses using seedlings of dipterocarp species: (1) addition of leaf litter improves growth; (2) and litter addition affects both ectomycorrhizal (ECM) colonization and community structure. • Three dipterocarp species with contrasting ecologies (Parashorea tomentella, Hopea nervosa and Dryobalanops lanceolata) were grown in a nursery in forest soil with or without the addition of litter. • Litter addition improved the growth of all three species. There was no effect of litter addition on total percentage ECM colonization but ECM diversity and percentage colonization by Cenococcum geophilum were lower with litter addition. Foliar δ¹⁵ N was lower in two of the three species grown in the presence of litter, reflecting the lower δ¹⁵ N of the litter compared with the soil. There was a negative correlation between δ¹⁵ N and percentage ECM, suggesting a role for ECMs in accessing litter-derived N sources. • This study shows that litter addition improved the growth of dipterocarp seedlings and that the ECM associations of dipterocarps facilitated access to this organic nutrient source. This has implications for the successful regeneration of seedlings in the rain forest understorey.

Exploring the Phylogenetic Structure of Ecological Communities: An Example for Rain Forest Trees

Because of the correlation expected between the phylogenetic relatedness of two taxa and their net ecological similarity, a measure of the overall phylogenetic relatedness of a community of interacting organisms can be used to investigate the contemporary ecological processes that structure community composition. I describe two indices that use the number of nodes that separate taxa on a phylogeny as a measure of their phylogenetic relatedness. As an example of the use of these indices in community analysis, I compared the mean observed net relatedness of trees (≥10 cm diameter at breast height) in each of 28 plots (each 0.16 ha) in a Bornean rain forest with the net relatedness expected if species were drawn randomly from the species pool (of the 324 species in the 28 plots), using a supertree that I assembled from published sources. I found that the species in plots were more phylogenetically related than expected by chance, a result that was insensitive to various modifications to the basic methodology. I tentatively infer that variation in habitat among plots causes ecologically more similar species to co-occur within plots. Finally, I suggest a range of applications for phylogenetic relatedness measures in community analysis.

Exploring the Phylogenetic Structure of Ecological Communities: An Example for Rain Forest Trees

Because of the correlation expected between the phylogenetic relatedness of two taxa and their net ecological similarity, a measure of the overall phylogenetic relatedness of a community of interacting organisms can be used to investigate the contemporary ecological processes that structure community composition. I describe two indices that use the number of nodes that separate taxa on a phylogeny as a measure of their phylogenetic relatedness. As an example of the use of these indices in community analysis, I compared the mean observed net relatedness of trees (≥10 cm diameter at breast height) in each of 28 plots (each 0.16 ha) in a Bornean rain forest with the net relatedness expected if species were drawn randomly from the species pool (of the 324 species in the 28 plots), using a supertree that I assembled from published sources. I found that the species in plots were more phylogenetically related than expected by chance, a result that was insensitive to various modifications to the basic methodology. I tentatively infer that variation in habitat among plots causes ecologically more similar species to co-occur within plots. Finally, I suggest a range of applications for phylogenetic relatedness measures in community analysis.

Annual carbon balance and nitrogen-use efficiency in tropical C3 and CAM epiphytes

Over the course of 12 months, diel (24 h) measurements of gas exchange were performed on leaves of three epiphytic species growing in the crown of a kapok tree on Barro Colorado Island, Panama: a drought-deciduous orchid with the C₂ , pathway (Catasetum viridiflavum Hook.), an evergreen C₂ fern (Polypodium crassifolium L.), and an evergreen epiphyte with an intermediate C₃ -C₃ -CAM pathway of photosynthesis (Clusia uvitana Pitt.), The gas exchange characteristics of all three species; were strongly affected during the four-month dry season. Compared with the rainy season, mean daily carbon gain of Clusia uvitana was reduced by almost 40° paralleled bY a strong decrease in daytime CO₂ uptake and an increase in CO₂ uptake at night. The orchid, growing new leaves in the second half of the dry season, showed markedly decreased stomatal conductances and greatly reduced carbon gain. In the fern, daily carbon balance became negative during the dry season and chronic photoinhibition was indicated by reduced F_V /F_M ratios and a decreased photon-use efficiency of photosynthetic O₂ evolution. Annual carbon gain was similar far the three species (about 1000₂ CO₂ m^-2 yr_-1 ) as was long-term nitrogen-use efficiency (annual carbon gain/mean leaf nitrogen content, about 1·1 g CO₂ mg N^-1 yr_-1 ). In the C₃ CAM epiphyte, the long-term water use efficiency of net CO₂ uptake was more than twice as high as in the two C₃ epiphytes.

Some observations on the present distribution and conservation of Alouatta and Ateles in Southern Mexico

Some information on the past and present distribution of Alouatta and Ateles in southern Mexico and on the impact of habitat destruction on their future existence is presented. Three surveys of primate populations and forest habitats were carried out between 1981 and 1983 in southeastern Mexico. Rapid destruction of the forest is reducing the number of forested areas where Alouatta and Ateles can exist and co-occur. Illegal hunting of the two primates also contributes to their rapid decline. Alouatta and Ateles live a precarious existence in a few large and small islands of forest, and efforts are needed to set aside some of these areas as reserves so that their future survival is ensured.